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TABLE OF CONTENTS
ITEM 8. CONSOLIDATED FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA
ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K10‑K

For the Fiscal Year Ended December 31, 2017

or

For the transition period from           to          .

Commission File Number: 0-208590‑20859

GERON CORPORATION

(Exact name of registrant as specified in its charter)

Registrant'sRegistrant’s telephone number, including area code:(650) 473-7700473‑7700

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:None

Indicate by check mark if the registrant is a well-knownwell‑known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  o☐    No  ý☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  o☐    No  ý☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ý☒    No  o☐

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-TS‑T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).  Yes  ý☒    No  o☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-KS‑K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant'sregistrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K10‑K or any amendment to this Form 10-K.10‑K.  ý☒

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-acceleratednon‑accelerated filer, or a smaller reporting company, or emerging growth company. See the definitions of "large“large accelerated filer", "accelerated filer"filer,” “accelerated filer,” “smaller reporting company,” and "smaller reporting company"“emerging growth company” in Rule 12b-212b‑2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-212b‑2 of the Act).  Yes    o☐  No  ý☒

The aggregate market value of voting and non-votingnon‑voting common equity held by non-affiliatesnon‑affiliates of the registrant was approximately $501,005,000$438,713,000 based upon the closing price of the registrant'sregistrant’s common stock on June 30, 20142017 on the Nasdaq Global Select Market. The calculation of the aggregate market value of voting and non-votingnon‑voting common equity held by non-affiliatesnon‑affiliates of the registrant excludes shares of common stock held by each officer, director and stockholder that the registrant concluded were affiliates on that date. This determination of affiliate status is not necessarily a conclusive determination for other purposes.

As of March 6, 2015,7, 2018, there were 157,700,375160,654,027 shares of common stock outstanding.

DOCUMENTS INCORPORATED BY REFERENCE:

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In this report, unless otherwise indicated or the context otherwise requires, "Geron," "the“Geron,” “the registrant," "we," "us,"” “we,” “us,” and "our"“our” refer to Geron Corporation, a Delaware corporation.

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Forward-LookingForward‑Looking Statements

This annual report on Form 10-K,10‑K, including "Business"“Business” in Part I, Item 1 and "Management's“Management’s Discussion and Analysis of Financial Condition and Results of Operations"Operations” in Part II, Item 7, contains forward-lookingforward‑looking statements that involve risks and uncertainties, as well as assumptions that, if they never materialize or prove incorrect, could cause the results of Geron Corporation, or Geron or the Company, to differ materially from those expressed or implied by such forward-lookingforward‑looking statements. All statements other than statements of historical fact are statements that could be deemed forward-lookingforward‑looking statements. In some cases, forward-lookingforward‑looking statements can be identified by the use of terminology such as "may," "expects," "plans," "intends," "will," "should," "projects," "believes," "predicts," "anticipates," "estimates," "potential,"“may,” “expects,” “plans,” “intends,” “will,” “should,” “projects,” “believes,” “predicts,” “anticipates,” “estimates,” “potential,” or "continue"“continue” or the negative thereof or other comparable terminology. The risks and uncertainties referred to above include, without limitation, risks related to our research and development efforts, our dependence on Janssen Biotech, Inc., or Janssen, for the development, regulatory approval, manufacture and commercialization of our sole product candidate, imetelstat, need for future capital, uncertainty of clinical trial results or regulatory approvals or clearances, the future development of imetelstat, including any future efficacy or safety results that cause the benefit-riskbenefit‑risk profile of imetelstat to become unacceptable, our ability to identify and acquire and/or in‑license other oncology products, product candidates, programs or companies to grow and diversify our business, our need for additional capital to support the development and commercialization of imetelstat in collaboration with Janssen and to otherwise grow our business, enforcement of our patent and proprietary rights, reliance upon investigators, potential competition and other risks that are described herein and that are otherwise described from time to time in our Securities and Exchange Commission reports including, but not limited to, the factors described in Part I, Item 1A, "Risk“Risk Factors,"” of this annual report on Form 10-K.10‑K. Geron assumes no obligation for and except as required by law, disclaims any obligation to update these forward-lookingforward‑looking statements to reflect future information, events or circumstances.

Calculation of Aggregate Market Value of Non-AffiliateNon‑Affiliate Shares

For purposes of calculating the aggregate market value of shares of our common stock held by non-affiliatesnon‑affiliates as set forth on the cover page of this annual report on Form 10-K,10‑K, we have assumed that all outstanding shares are held by non-affiliates,non‑affiliates, except for shares held by each of our executive officers, directors and 5% or greater stockholders. In the case of 5% or greater stockholders, we have not deemed such stockholders to be affiliates unless there are facts and circumstances which would indicate that such stockholders exercise any control over our company.Company. These assumptions should not be deemed to constitute an admission that all executive officers, directors and 5% or greater stockholders are, in fact, affiliates of our company,Company, or that there are no other persons who may be deemed to be affiliates of our company.Company. Further information concerning shareholdings of our executive officers, directors and principal stockholders is incorporated by reference in Part III, Item 12 of this annual report on Form 10-K.10‑K.

PART I

ITEM 1.  BUSINESS

Company Overview

We are a clinical stage biopharmaceutical company focused onthat currently supports the clinical stage development of a telomerase inhibitor, imetelstat, in hematologic myeloid malignancies. The discovery and early development of imetelstat, our sole product candidate, was based on our core expertise in telomerase and telomere biology. Telomerase is an enzyme that enables cancer cells, including malignant progenitor cells, to maintain telomere length, which provides them with the capacity for limitless, uncontrolled proliferation. Using our proprietary nucleic acid chemistry, we designed imetelstat to be an oligonucleotide that targets and binds with high affinity to the active site of telomerase, thereby directly inhibiting telomerase activity and impeding malignant cell proliferation. Molecular responsesmalignancies, by Janssen Biotech, Inc., or Janssen. Early clinical data in essential thrombocythemia, or ET, and remission responses, including reversal of bone marrow fibrosis,

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in myelofibrosis, or MF, and myelodysplastic syndromes, or MDS, suggest imetelstat has disease-modifyingmay have disease‑modifying activity by inhibiting the progenitor cells of the malignant cloneclones for the underlying disease in a relatively selective manner.diseases.

On November 13, 2014, we entered into an exclusivea collaboration and license agreement, or the Collaboration Agreement, withpursuant to which we granted Janssen Biotech, Inc., or Janssen,the exclusive rights to develop and commercialize imetelstat worldwide for all indications in oncology, including hematologic myeloid malignancies, and all other human therapeutic uses. The Collaboration Agreement became effective on December 15, 2014, and we received $35 million from Janssen as an upfront payment. Additional consideration under the Collaboration Agreement includes potential payments of up to a potentialan aggregate maximum total of $900 million for the achievement of development, regulatory and commercial milestones, as well as royalties on worldwide net sales.sales of imetelstat. The Collaboration Agreement also provides for a joint governance structure that includes a Joint Steering Committee, or JSC, with equal membership from both companies. See “Licensing—Collaboration and License Agreement with Janssen” below, for more information about the Collaboration Agreement, including economic terms and termination provisions of the Collaboration Agreement. The

information provided should be reviewed in the context of the sections entitled “Risks Related to Our Collaboration with Janssen” and “Risks Related to Clinical Development, Regulatory Approval and Commercialization of Imetelstat” under Item 1A, “Risk Factors”.

Under the Collaboration Agreement, Janssen is wholly responsible for the development,developing, manufacturing, and commercialization of, and seeking regulatory approval for, and commercialization of, imetelstat worldwide. DevelopmentJanssen is currently conducting two clinical trials of imetelstat: IMbark, a Phase 2 trial in MF, in which the first patient was dosed in September 2015 and the last patient was enrolled in October 2016; and IMerge, a Phase 2/3 trial in MDS, in which the first patient was dosed in January 2016. We contribute 50% of the development costs for these trials, which Janssen is solely conducting.

For IMbark, Janssen completed internal data reviews in September 2016, April 2017 and March 2018. In these data reviews, activity within multiple outcome measures was observed with imetelstat treatment that suggest potential clinical benefit in patients with MF who are relapsed after or refractory to prior treatment with a janus kinase, or JAK, inhibitor. However, new patient enrollment in IMbark was suspended in October 2016 because an insufficient number of patients met the protocol defined interim efficacy criteria to continue enrollment. In March 2018, Janssen will officially close the trial to new patient enrollment. The JSC expects that the over 100 patients enrolled in IMbark to date will be adequate to assess overall survival. Patients who remain in the treatment phase of IMbark may continue to receive imetelstat, and until the protocol-specified primary analysis, all safety and efficacy assessments are being conducted as planned in the protocol, including following patients, to the extent possible, until death, to enable an assessment of overall survival. In March 2018, based on the rate of deaths occurring in the trial, the JSC determined that the protocol-specified primary analysis of IMbark, which includes an assessment of overall survival, will begin by the end of the second quarter of 2018. Upon the protocol-specified primary analysis, the main trial will be completed. The IMbark protocol is being amended to establish an extension phase of the trial to enable patients remaining in the treatment phase to continue to receive imetelstat treatment, per investigator discretion. Following completion of the primary analysis, Janssen must notify us of its decision, or the Continuation Decision, whether to: (i) maintain the license rights granted under the Collaboration Agreement and continue the development of imetelstat will proceed under a mutually agreed clinicalor (ii) discontinue the development plan, which includes two Phase 2 studies to be pursued initially, one in myelofibrosis, referred to asof imetelstat and terminate the Initial Phase 2 MF Study, and one in myelodysplastic syndrome, referred to as the Initial Phase 2 MDS Study.Collaboration Agreement. We expect Janssen to initiate the Initial Phase 2 MF Study in mid-2015, followedinform us of its decision by the Initial Phase 2 MDS Study to be initiated at the end of 2015.the third quarter of 2018.

For IMerge, Janssen completed internal data reviews in September 2016 and April 2017. In addition, preliminary data from Part 1 of IMerge were presented at the clinicalAmerican Society of Hematology Annual Meeting, or ASH, in December 2017. These data showed that among the 32 red blood cell transfusion-dependent MDS patients enrolled in Part 1of the trial, a subset of 13 patients who had not received prior treatment with either a hypomethylating agent or lenalidomide and did not have a deletion 5q chromosomal abnormality, or non-del(5q), exhibited an increased rate and durability of transfusion independence compared to the overall trial population. Based on the preliminary data from this 13-patient subset, Janssen has expanded new patient enrollment in Part 1 of IMerge to enroll approximately 20 additional patients to increase the experience and confirm the benefit-risk profile of imetelstat in this refined target patient population. In November 2017, the first patient was dosed in the expanded Part 1 and enrollment was completed in February 2018. Using the preliminary data from Part 1, Janssen sponsored an application to the United States Food and Drug Administration, or the FDA, for Fast Track designation for the potential treatment of adult patients with transfusion-dependent anemia due to Low or Intermediate-1 risk MDS who are non-del(5q) and who are refractory or resistant to treatment with an erythropoiesis stimulating agent. The FDA granted Fast Track designation to imetelstat in October 2017.

We had approximately $109.2 million in cash and investments as of December 31, 2017. To grow and diversify our business, we plan to continue our business development planefforts to identify, and seek to acquire and/or in‑license other oncology product candidates, programs or companies. Acquisition or in‑licensing opportunities that we may also include additional, possible registration studies in MFpursue could materially affect our liquidity and myelodysplastic syndrome, or MDS,capital resources and possible exploratory Phase 2 and potential follow-on Phase 3 studies in acute myelogenous leukemia, or AML.

        We believe our current operational and financial resources, including the upfront payment received from Janssen under the Collaboration Agreement, may enablerequire us to acquire oneincur indebtedness or more oncology products, programsseek equity capital, or companies to diversify our business.both.

Telomerase: Scientific Rationale

Telomeres and Telomerase in Normal Development

In the human body, normal growth and maintenance of tissues occurs by cell division. However, most cells are only able to divide a limited number of times, and this number of divisions is regulated by telomere length. Telomeres are repetitions of a deoxyribonucleic acid, or DNA, sequence located at the ends of chromosomes. They act as protective caps to maintain stability and integrity of the chromosomes, which contain the cell'scell’s genetic material.

Normally, every time a cell divides, the telomeres shorten. Eventually, they shrink to a critically short length, and as a result, the cell either dies by apoptosis or stops dividing and senesces.

Telomerase is a naturally occurring enzyme that maintains telomeres and prevents them from shortening during cell division in cells, such as stem cells that must remain immortalized to support normal health. Telomerase consists of at least two essential components: a ribonucleic acid, or RNA, template (hTR), which binds to the telomere, and a catalytic subunit (hTERT) with reverse transcriptase activity, which adds a specific DNA sequence to the chromosome ends. The 2009 Nobel Prize for Physiology andor Medicine was awarded to Drs. Elizabeth H. Blackburn, and Carol W. Greider together with Dr.and Jack Szostak, who were former Geron collaborators, for the discovery of how chromosomes are protected by both telomeres and the enzyme telomerase.

Telomerase is active during embryonic development, enabling the rapid cell division that supports normal growth. During the latter stages of human fetal development and in adulthood, telomerase is repressed in most cells, and telomere length gradually decreases during a lifetime. In tissues that have a high turnover throughout life, such as blood and gut, telomerase can be transiently upregulated in progenitor cells to enable controlled, self-limitedself‑limited proliferation to replace cells lost through natural cell aging processes. In proliferating progenitor cells, relatively long telomeres are maintained by upregulated telomerase. As the progeny of progenitor cells mature, telomerase is downregulated and telomeres shorten with cell division, preventing uncontrolled proliferation.

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Telomeres and Telomerase in Cancer

Telomerase is upregulated in many tumor progenitor cells, which enablesenabling the continued and uncontrolled proliferation of the malignant cells that drive tumor growth and progression. Telomerase expression has been found to be present in approximately 90% of biopsies taken from a broad range of human cancers. Our nonclinical studies, in which the telomerase gene was artificially introduced and expressed in normal cells grown in culture, have suggested that telomerase does not itself cause a normal cell to become malignant. However,Instead, the sustained upregulation of telomerase enables tumor cells to maintain telomere length, providing them with the capacity for limitless proliferation. We believe that the sustained upregulation of telomerase is critical for tumor progression as it enables malignant progenitor cells to acquire cellular immortality and avoid apoptosis, or cell death.

Telomerase Inhibition: Inducing Cancer Cell Death

We believe that inhibiting telomerase may be an attractive approach to treating cancer because it may limit the proliferative capacity of malignant cells. We and others have observed in various in vitro and rodent tumor models that inhibiting telomerase results in telomere shortening and arrests uncontrolled malignant cell proliferation and tumor growth. In vitro studies have suggested that tumor cells with short telomeres may be especially sensitive to the anti-proliferativeanti‑proliferative effects of inhibiting telomerase. Our nonclinical data also suggest that inhibiting telomerase is particularly effective at limiting the proliferation of malignant progenitor cells, which have high levels of telomerase and are believed to be important drivers of tumor growth and progression.

        Many hematologic malignancies, such as ET, MF, and polycythemia vera, or PV, are known to arise from malignant progenitor cells in the bone marrow that express higher telomerase activity and have shorter telomeres when compared to normal healthy cells. Recent nonclinical data reported in the journalCell Stem Cell in December 2014 by Steven Lane, M.D., Ph.D., Queensland Institute of Medical Research, one of our nonclinical collaborators, provided proof-of-concept of the role of telomerase in disease initiation and progression in AML. Leukemic stem cells, or LSCs, are functionally described as cells within AML that are capable of initiating and maintaining the disease. Through their high expression of telomerase, LSCs are believed to be responsible for chemotherapy resistance and relapse in AML which make them an important therapeutic target as a durable treatment for AML. Data from the nonclinical study conducted by Dr. Lane suggest that imetelstat has the potential for disease-modifying activity in AML by targeting LSCs.

Imetelstat: The First Telomerase Inhibitor to Advance to Clinical Development

Imetelstat is a lipid conjugated 13-mer13‑mer oligonucleotide that iswe designed to be complementary to and bind with high affinity to the RNA template of telomerase, thereby directly inhibiting telomerase activity. Imetelstat does not elicit its effect through an antisense inhibition of protein translation. The compound has a proprietary thio-phosphoramidatethio‑phosphoramidate backbone, which is designed to provide resistance to the effect of cellular nucleases, thus conferring improved stability in plasma and tissues, as well as improved binding affinity to its target. To improve the ability of imetelstat to permeate throughpenetrate cellular membranes, we conjugated the oligonucleotide to a lipid group. Imetelstat'sImetelstat’s IC50, or half maximal inhibitory concentration, is 0.5-100.5 ‑ 10 nM in cell free assays. The tissue half-life ofSingle‑dose kinetics in patients has shown dose‑dependent increases in exposure to imetelstat, orwith a plasma half‑life, which is the time it takes for the concentration or amount of imetelstat to be reduced by half, in bone marrow, spleen, liver and tumor has been estimated to be 41 hours in humans, based on dataranging from 4 ‑ 5 hours. Data from animal studies and clinical trial data. The tissue half-life indicates howtrials have suggested that the residence time of imetelstat in bone marrow is long, with 0.19 ‑ 0.51 µM observed at 41 ‑ 45 hours after a drug will remain present7.5 mg/kg dose in the tissues, and a longer tissue half-life may enable a drug to remain at effective doses for a longer period of time.

patients. Imetelstat also has been shown in nonclinical studies to exhibit relatively preferential inhibition of the clonal proliferation of malignant progenitor cells compared to normal progenitors. For this reason,these reasons, imetelstat has been studied as a potential treatment for malignant diseases.

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Imetelstat is the first telomerase inhibitor to advance to clinical development. The Phase 1 trials that we completed evaluated the safety, tolerability, pharmacokinetics and pharmacodynamic effects of imetelstat. DosesWe established doses and dosing schedules were established that were tolerable and achieved target exposures in patients that were consistent with those required for efficacy in animal models. We believe adverse events were generally manageable and reversible. The dose-limiting toxicities were thrombocytopenia, or reduced platelet count, and neutropenia, or reduced neutrophil count. Following intravenous administration of imetelstat using tolerable dosing regimens, clinically relevant and significant inhibition of telomerase activity was observed in various types of tissue in which telomerase activity is measurable, including normal bone marrow hematopoietic cells, malignant plasma cells, hair follicle cells and peripheral blood mononuclear cells.

Developing Imetelstat to Treat Hematologic Myeloid Malignancies Dose‑limiting toxicities included thrombocytopenia, or reduced platelet count, and neutropenia, or reduced neutrophil count.

Proof-of-Concept in Essential ThrombocythemiaDisease Characteristics of Hematologic Malignancies

        Myeloproliferative neoplasms,Hematologic malignancies, or MPNs,blood cancers, are classified according to the predominant location of the malignancy. A hematologic myeloid malignanciesmalignancy is a cancer that arise from malignant hematopoietic myeloid progenitor cellsoccurs in the bone marrow, such as the precursor cells ofto red blood cells, platelets and granulocytes. Proliferation of malignant progenitor cells leads to an overproduction of any combination of myeloid white cells, red blood cells and/or platelets, depending onsuch as granulocytes. Examples include acute myelogenous leukemia, chronic myelogenous leukemia, MDS and the disease. These overproduced cells may also be abnormal, leading to additional clinical complications. MPN diseases include PV,myeloproliferative neoplasms, such as ET, polycythemia vera and MF. ET is an MPN characterized by a high platelet count, often accompanied by a highThese are different from lymphocytic malignancies which typically occur in the lymphoid lineage that includes white cell count,blood cells, such as T lymphocytes and an increased riskB lymphocytes. Examples of thrombosis, or bleeding, in higher risk patients.lymphoid malignancies include acute lymphoblastic leukemia, chronic lymphocytic leukemia, lymphomas and multiple myeloma.

        In January 2011, we initiated a Phase 2 clinical trial of imetelstat in patients with ET. The Phase 2 ET trial was a multi-center, single arm, and open label trial that we designed to provide proof-of-concept for the potential use of imetelstat as a treatment forMany hematologic myeloid malignancies, such as ET, MF, MDS or AML. The trial leveraged clinical observations from Phase 1 trials suggesting that imetelstat reduces platelet counts, as well as nonclinical observations that imetelstat distributes well to bone marrow in rodent models and selectively inhibits the proliferation of malignant progenitors ex vivo from patients with ET. Hematologic responses were measured by reductions in platelet counts, and molecular responses were measured by reductions in the JAK2 V617F mutant allele burden in circulating granulocytes as assessed by a reduction in the proportion of the abnormal Janus kinase 2, or JAK2, gene compared to the normal, or wild type JAK2 gene. We believe a decrease in the proportion of the JAK2 V617F mutant relative to the wild type JAK2 is consistent with selective inhibition of the malignant progenitor cells responsible for the disease.

        Data from the primary efficacy analysis of the Phase 2 ET trial in October 2013 showed that imetelstat induced platelet count reductions in all 18 patients in the trial (a 100% hematologic response rate) and normalizations in 16 out of 18 patients (an 89% complete response rate). The median time on therapy was 17.1 months (range 6.9 months to 2.7 years). The JAK2 V617F gene mutation was detected in eight patients at baseline. Seven out of the eight (88%) patients achieved 72% to 96% reductions in JAK2 V617F allele burden that qualified as partial molecular responses with a median duration of 15.5 months. These data suggest that imetelstat inhibits the progenitor cells of the malignant clone believed to be responsible for the underlying disease in a relatively selective manner.

        Adverse events reported in the Phase 2 ET trialMDS, have been similarshown to the adverse events reported in other imetelstat clinical trials, with fatigue, gastrointestinal symptoms (specifically nausea, diarrhea, constipation, and vomiting) and cytopenias being the most frequently observed adverse events. One patient experienced Grade 3 hepatic cirrhosis and encephalopathy which was assessed by the investigator to be possibly attributable to imetelstat, and later died of bleeding esophageal varices. Two patients experienced reversible Grade 3 alanine transaminase, which was assessed by the investigator to be possibly attributable to imetelstat. At least one abnormal liver function test, or LFT, was observed in

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laboratory findings in all patients in the trial, with some patients experiencing persistent low-grade LFT abnormalities with longer dosing. With longer dosing, Grade 1 increases in alkaline phosphatase were observed, associated with mostly Grade 1 to some Grade 2 unconjugated hyperbilirubinemia. The clinical significance and long-term consequences of such persistent low-grade LFT abnormalities is currently undetermined.

        In March 2014, we received written noticearise from the United States Food and Drug Administration, or FDA, that our Investigational New Drug application, or IND, for imetelstat had been placed on full clinical hold following the FDA's review of safety data in our then ongoing clinical studies. A full clinical hold is an order that the FDA issues to a trial sponsor to suspend all ongoing clinical trials and delay all proposed trials under a given IND. With this clinical hold, any patients in an ongoing Geron-sponsored clinical trial could not receive any further treatment with imetelstat. Therefore, we stopped imetelstat treatment in our Phase 2 Geron-sponsored clinical trials in ET and multiple myeloma, or MM. In our Phase 2 ET trial, imetelstat treatment was stopped in eight patients and in our Phase 2 MM trial, imetelstat treatment was stopped in two patients. See below for discussion of removal of the full clinical hold.

        In their notice to us, the FDA cited the following safety issues as the basis for the clinical hold: lack of evidence of reversibility of hepatotoxicity, risk for chronic liver injury and lack of adequate follow-up in patients who experienced hepatotoxicity. To address the clinical hold, we were required to provide clinical follow-up information on patients who experienced LFT abnormalities until LFT abnormalities resolved to normal or baseline and to provide information regarding the reversibility of the liver toxicity after chronic imetelstat administration in animals.

        We submitted a complete response to the FDA to seek release of the full clinical hold. In the complete response, we provided clinical follow-up information from patients in the previously ongoing Geron-sponsored Phase 2 trials in ET and MM. Our analysis of these data concluded that in the Phase 2 ET trial, LFT abnormalities resolved to normal or baseline in 14 of 18 follow-up patients. For the remaining four ET patients, at the time of the data cut-off, three showed improvement in LFT abnormalities and one had unresolved LFT abnormalities. In the Phase 2 MM trial, LFT abnormalities resolved to normal or baseline in all nine follow-up patients. In addition, no emergent hepatic adverse events were reported during follow-up for either study. In the complete response, we also provided data from our previously conducted nonclinical toxicology studies, which included a six-month study in mice and a nine-month study in cynomolgus monkeys. In those studies, no clinical pathology changes indicative of hepatocellular injury were observed, and no clear signal of LFT abnormalities were identified.

        On October 31, 2014, the FDA removed the full clinical hold on our IND for imetelstat. In addition, the FDA stated that our proposed clinical development plan for imetelstat that is focused on high-risk myeloid malignancies, such as MF, is acceptable. The FDA acknowledged that we do not intend to conduct further studies in, or develop imetelstat for, the treatment of ET or PV, which is consistent with our plans as originally disclosed in April 2013.

        Prior to initiation of the Initial Phase 2 MF Study, we plan to transfer our IND for imetelstat to Janssen as required by our Collaboration Agreement with them. For further discussion of the collaboration with Janssen, see the sub-section entitled, "Future Development of Imetelstat in Collaboration with Janssen".

Clinical Development in Myelofibrosis

        MF is a myeloproliferative neoplasm among related diseases, such as ET, and is characterized by clonal proliferation of malignant hematopoietic progenitor cells in the bone marrow that causes bone marrow fibrosis, elevationexpress higher telomerase activity and have shorter telomeres when compared to normal healthy cells.

Unmet Medical Need in bone density, known as osteosclerosis, andMyelofibrosis

MF, a type of myeloproliferative neoplasm, is a chronic blood cancer in which abnormal rapid proliferation of blood vessels, known as pathological angiogenesis. MF patients may exhibit abnormally low red blood

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cells/hemoglobin, known as progressive anemia, abnormally low white blood cells, known as leukopenia, abnormally high white blood cells, known as leukocytosis, abnormally low platelets, known as thrombocytopenia, abnormally high platelets, known as thrombocytosis, immature blood cells, known as peripheral blood leukoerythroblastosis, and abnormally highor malignant precursor cells in the blood, known as excess circulating blasts. In addition, impairedbone marrow proliferate rapidly, causing scar tissue, or fibrosis, to form. As a result, normal blood production fromin the bone marrow causes blood production tois impaired and may shift to other organs such as the spleen and liver, known as extramedullary hematopoiesis, which leadscan cause them to an enlarged spleen, known as splenomegaly,enlarge substantially. People with MF may have abnormally low or an enlarged liver, known as hepatomegaly.high numbers of circulating red blood cells, white blood cells or platelets, and abnormally high numbers of immature cells in the blood or bone marrow. MF patients can also suffer from debilitating constitutional symptoms, such as drenching night sweats, fatigue, severe itching, known asor pruritus, abdominal pain, fever and bone pain. The estimated prevalence of MF in the United States, or U.S., is approximately 13,000 patients, with an annual incidence of approximately 3,000 patients. Up to 20% of patients with MF develop acute myeloid leukemia, or AML.

Approximately 70% of MF patients have two to threeare classified as having intermediate‑2 or high risk factors (intermediate-2) or four or more risk factors (high risk),disease, as defined by the Dynamic International Prognostic Scoring System Plus, or DIPSS Plus, described in a 2011Journal of Clinical Oncology article. TheseThere is currently only one targeted drug therapy, ruxolitinib, approved by the FDA and other health authorities for treating these MF patients. Currently, no drug therapy is approved for those patients have awho fail or no longer respond to that treatment, and median survival offor such MF patients is only approximately oneseven to three years,16 months, representing a significant unmet medical need.

        Allogeneic hematopoietic cell transplantation, or allo-HCT,Unmet Medical Need in Myelodysplastic Syndromes

MDS is the only current treatment approach for MF that can lead to complete remissiona group of the disease with normalization of peripheral blood counts, regression of bone marrow fibrosis, disappearance of cytogenetic abnormalities, normalization of spleen size and resolution of constitutional symptoms. However, use of allo-HCT is limited to a very small number of eligible patients due to the lack of suitable donors, older age and/or comorbid conditions. In addition, graft vs. host disease and life-threatening infections are other limitations of allo-HCT treatment.

        Recent data presenteddisorders in December 2014 at the American Society of Hematology, or ASH, Annual Meeting by Dr. Ron Hoffman of the Mount Sinai School of Medicine from in vitro translational studies have demonstrated that imetelstat inhibits malignant hematopoiesis and malignant megakaryopoiesis. In one study, hematopoietic stem cells were obtained from spleens of MF patients and normal cord blood. Imetelstat treatment on both in vitro cultures of stem cells showed selective inhibition of the proliferation of hematopoietic stem cells and myeloid progenitor cells and preferential depletion of malignant hematopoietic progenitor cells. In another study, peripheral blood mononuclear cells, or PBMCs, were taken from MF patients and normal patients. Imetelstat treatment on both in vitro cultures of cells showed selective inhibition ofwhich the proliferation of malignant megakaryocytic progenitor cells from myelofibrosis PBMCs; a reductioncell clones in the bone marrow results in disordered and ineffective production of the myeloid lineage, which includes red blood cells, white blood cells and platelets. In MDS, bone marrow and peripheral blood cells may have abnormal, or dysplastic, cell morphology. MDS is frequently characterized clinically by severe anemia, or low red cell counts, and low hemoglobin. In addition, other peripheral cytopenias, or low numbers of white blood cells and platelets, may cause life‑threatening infections and bleeding. Transformation to AML occurs in up to 30% of MDS cases and results in poorer overall survival.

MDS is the most common of the myeloid malignancies. There are approximately 60,000 people in the United States living with the disease and approximately 16,000 reported new cases of MDS in the United States every year. MDS is primarily a disease of the elderly, with median age at diagnosis around 70 years. The majority of patients, approximately 70%, fall into what are considered to be the lower risk groups at diagnosis, according to the International Prognostic Scoring System, or IPSS, that takes into account the presence of a number of malignant megakaryocytes from myelofibrosis PBMCs;disease factors, such as cytopenias and inhibitioncytogenetics, to assign relative risk of late-stage megakaryocytic maturation derived from both myelofibrosisprogression to AML and overall survival.

Chronic anemia is the predominant clinical problem in patients who have lower risk MDS. Many of these patients become dependent on red blood cell transfusions, which can lead to elevated levels of iron, which the body has no normal PBMCs. These in vitro data support the clinical remission responses observedway to dateeliminate, in the investigator-initiatedblood and other tissues. Iron overload is a potentially dangerous condition. Studies in patients with MDS have shown that iron overload resulting from regular red blood cell transfusions is associated with a poorer overall survival and a higher risk of developing AML.

Developing Imetelstat to Treat Hematologic Myeloid Malignancies

Proof‑of‑Concept of Imetelstat’s Disease‑Modifying Potential

We believe that imetelstat may have the potential to suppress the proliferation of malignant progenitor cell clones to allow recovery of normal hematopoiesis in patients with hematologic myeloid malignancies. Early clinical data from a Phase 2 trial of myelofibrosis beingimetelstat in patients with ET, or the ET Trial, and a pilot study of imetelstat in patients with MF conducted at Mayo Clinic, or the MF Pilot Study, suggest imetelstat may exhibit such disease‑modifying activity. These data were published in two separate articles in a September 2015 issue of The New England Journal of Medicine.

Reported adverse events, or AEs, and laboratory investigations associated with imetelstat in the ET Trial and the disease-modifying activity suggested by the MF Pilot Study results.included cytopenias, gastrointestinal symptoms, constitutional symptoms, and hepatic biochemistry abnormalities. Dose‑limiting toxicities, such as profound and prolonged thrombocytopenia and neutropenia, and other safety issues, including death, were observed in the ET Trial and the Pilot Study. In those trials, such myelosuppression was managed by dose holds and modification rules.

Pilot Study in Myelofibrosis (MF Pilot Study)Imetelstat Clinical Trials Under the Collaboration with Janssen

        Based onUnder the data from theCollaboration Agreement (as described below), Janssen is conducting two clinical trials of imetelstat: IMbark and IMerge.

IMbark

Trial Design

IMbark was designed as a Phase 2 ETclinical trial in November 2012, Dr. Ayalew Tefferi, or the investigator, initiated the MF Pilot Study to assess the effectevaluate two starting dose levels of imetelstat (either 4.7 mg/kg or 9.4 mg/kg administered by intravenous infusion every three weeks) in approximately 200 patients with MF. The MF Pilot Study is an open label trial in patients with primary MF, post-ET MF,Intermediate-2 or post-PVHigh risk MF who have tworelapsed after or are refractory to three risk factors (intermediate-2) or four or more risk factors (high risk) as defined by DIPSS Plus. Inprior treatment with a JAK inhibitor.

The co-primary efficacy endpoints for the MF Pilot Study, imetelstat is administered as a single agent over a two hour intravenous infusion to patients in multiple patient cohorts. In the first cohort, Cohort A, imetelstat is given once every three weeks. In the second cohort, Cohort B, imetelstat is given weekly for four weeks, followed by one dose every three weeks. Under the protocol, patients in Cohorts A and B may receive an intensified dosing regimen, up to once per week, after the initial six cycles of treatment. The starting dose of imetelstat in Cohorts A and B is 9.4 mg/kg, with dose reductions and dose holds allowed for toxicity. The primary endpoint in the MF Pilot Study is overalltrial are spleen response rate, which is defined byas the

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proportion of patients who achieve a ≥35% reduction in spleen volume assessed by imaging, and symptom response rate, defined as the proportion of patients who achieve a ≥50% reduction in Total Symptom Score, at 24 weeks. Key secondary endpoints are classified as responders, which means that they have achieved either asafety and overall survival. Other secondary efficacy endpoints include the number of patients achieving complete remission, or CR, or partial remission, or PR, clinical improvement, or CI, partial remission, or PR, or complete remission, or CR,and anemia, spleen and symptom responses. Exploratory endpoints include cytogenetic and molecular responses, as well as leukemia‑free survival.

The first patient in IMbark was dosed in September 2015 and the last patient was enrolled in October 2016. The trial is being conducted at multiple medical centers across North America, Europe and Asia. Trial design information for IMbark, including patient eligibility criteria, and locations of clinical sites, is posted on clinicaltrials.gov.

Preliminary Observations and Actions

Since IMbark was initiated, Janssen has conducted internal data reviews in September 2016 and April 2017. Based on these reviews, the JSC made the following observations and implemented the following actions:

In October 2017, Janssen submitted to the FDA data from the aforementioned internal reviews, as well as additional efficacy and safety data, including information about deaths and tolerability.overall survival in IMbark, in response to an FDA information request regarding the benefit-risk profile of imetelstat in relapsed or refractory MF and justification for continued treatment of patients enrolled in the trial. Since that submission, the FDA has not requested any additional information regarding IMbark, nor has the FDA requested any changes to the trial.

Current Status of IMbark

In March 2018, Janssen completed a third internal data review of IMbark, based on a January 2014, Mayo Clinic2018 data cut, to enable a protocol amendment to allow the long-term treatment and follow up of patients, including for survival, and the JSC made the following observations and implemented the following actions:

Continuation Decision Timing

        Prior to initiationFollowing completion of the Initial Phase 2 MF Study, we plan to transfer the IND for the MF Pilot Study, as well as responsibility for the conduct of the MF Pilot Study as the trial sponsor, to Janssen, and they do not intend to enroll additional patients in the MF Pilot Study. The remaining patients in the MF Pilot Study will continue to receive imetelstat treatment and Janssen will continue to collect data and information from the MF Pilot Study. For further discussion of the collaboration with Janssen under the Collaboration Agreement, see the sub-section entitled, "Future Development of Imetelstat in Collaboration with Janssen".

Updated Preliminary Data from MF Pilot Study

        In December 2014, the investigator presented updated preliminary efficacy and safety data (as of September 10, 2014) from Cohorts A and B of the MF Pilot Study (n=33) at the 2014 ASH Annual Meeting. The data presented in December 2014 updated the investigator's previous analysis from the preliminary data he had presented at ASH in December 2013. We believe that the updated preliminary data from the MF Pilot Study continue to suggest that imetelstat has disease-modifying activity in MF, with remissions that have been durable (median 11.1 months; range 6.9 months - 16.2 months as of September 10, 2014). The investigator reported that no new safety signals had been observed and myelosuppression continued to be the principal dose-limiting toxicity.

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Patient Demographics and Status

        Below is a table setting forth the demographics of the first 33 patients enrolled in the MF Pilot Study, including certain disease characteristics and exposure to any prior treatments:

        As of September 10, 2014, the median duration of treatment was 11 cycles (range two cycles - 21 cycles). Median time on treatment was 14.3 months (range 6.5 months - 18.9 months) for patients with a CR, PR or CI response. All other patients had a median time on treatment of 6.9 months (range 1.4 months - 16.4 months).

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        Of these 33 patients, a total of nine patients remained on imetelstat treatment as of September 10, 2014. The following table describes patient status and reason for treatment discontinuation for each of the 33 patients, as reported by the investigator.

Updated Efficacy Data

        The following table presents Geron's analysis of updated efficacy data as of September 10, 2014 for the first 33 eligible patients enrolled in the MF Pilot Study, using the IWG-MRT criteria:

        Median onset of remission occurred at five cycles (range one cycle - nine cycles). As of September 10, 2014, six of seven CR/PR patients remained in remission with median duration of 11.1 months (range 6.9 months - 16.2 months). All four CR patients achieved reversal of bone marrow fibrosis including three with complete molecular response. Three CR/PR patients who were transfusion dependent at baseline became transfusion independent. Three CR/PR patients with splenomegaly at baseline achieved splenic response.

        Additional efficacy results reported by the investigator included spleen response, transfusion independence and resolution of circulating blasts, leukoerythroblastosis, marked leukocytosis and thrombocytosis:

•

Eight of 23 (34.8%) patients with splenomegaly achieved spleen responses by palpation, which is defined as either greater than or equal to 50% decrease if the baseline is greater than or equal to 10 centimeters or becoming non palpable if baseline is five to less than 10 centimeters. The median spleen size at baseline was 15 centimeters below the left costal margin (range five centimeters - 33 centimeters).

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•

Four of 13 patients (30.8%) who were transfusion dependent at baseline became transfusion independent which is defined as absence of any packed red blood cells transfusions during any consecutive 12-week interval with a hemoglobin level of³8.5 grams per deciliter.



•

17 of 21 (81.0%) patients with circulating blasts, or immature cells, at baseline achieved complete (n=14, 66.7%) or partial (n=3, 14.3%) resolution.



•

22 of 27 (81.5%) patients with leukoerythroblastosis, a condition characterized by circulating immature granulocytes and nucleated red blood cells, achieved complete (n=13, 48.1%) or partial (n=9, 33.3%) resolution.



•

Eight of 10 (80.0%) patients with marked leukocytosis, a condition characterized by very elevated white blood cell counts, achieved complete (n=3, 30.0%) or partial (n=5, 50.0%) resolution.



•

11 of 11 (100.0%) patients with thrombocytosis, a condition characterized by high platelet counts in blood, achieved complete (n=10, 90.9%) or partial (n=1, 9.1%) resolution.

Updated Safety Data

        The following table sets forth the non-hematologic adverse events as of September 10, 2014, which were generally mild to moderate and not dose-limiting, for the first 33 eligible patients enrolled in the MF Pilot Study:

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        The following table sets forth all hematologic adverse events greater than or equal to Grade 3 as of September 10, 2014 for the first 33 patients enrolled in the MF Pilot Study.

        The following table sets forth hematologic adverse events related to imetelstat as reported by the investigator lasting greater than or equal to four weeks as of September 10, 2014. These events mainly were observed in a small number of patients who received weekly dosing initially.

        To mitigate the risk of severe, persistent cytopenias, the protocol for the MF Pilot Study was amended to raise the hematologic threshold for retreatment and include more stringent monitoring and dose adjustment criteria. Since then, no further episodes of significant bleeding events associated with thrombocytopenia, or infections associated with neutropenia, or additional episodes of febrile neutropenia have been reported to us by the investigator. As a result, we believe that the myelosuppressive effect of the drug may be manageable through dose hold rules and dose modifications.

        Since the MF Pilot Study is ongoing, additional data from the remaining patients enrolled in the MF Pilot Study continues to be generated and is not reflected in the data discussed above. In this regard, additional and updated safety and efficacy data generated from the MF Pilot Study may be materially different from the data discussed above. Additional or updated data from the MF Pilot Study are also subject to any review or verification procedures that Janssen may conduct as the trial sponsor for the MF Pilot Study after it assumes responsibility for the conduct of the MF Pilot Study, and since this could result in material differences from the data reported by the investigator or us, additional or updated data that may be reported from the MF Pilot Study should be considered carefully and with caution. Analyses performed by Janssen after it becomes the sponsor of the MF Pilot Study may result in conclusions that are materially different from the investigator's analyses or ours, and therefore preliminary data should be considered carefully and with caution. As such, final data from the MF Pilot Study may be materially different from the data discussed above. Accordingly, the data discussed above should be considered carefully and with caution. Please refer to the risk factor

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entitled "Risks Related to Clinical and Commercialization Activities—Success in early clinical trials may not be indicative of results in subsequent clinical trials. Likewise, preliminary data reported by investigators from time-to-time are subject to review and verification procedures that could result in material differences to final data and may change as more patient data become available" under Part I, Item 1A, "Risk Factors," of this annual report on Form 10-K.

Future Development of Imetelstat in Collaboration with Janssen

        On November 13, 2014, we entered into the Collaboration Agreement with Janssen to develop and commercialize imetelstat worldwide for all indications in oncology, including hematologic myeloid malignancies, and all other human therapeutic uses. The Collaboration Agreement became effective on December 15, 2014, and we received $35 million from Janssen as an upfront payment.

        Under the Collaboration Agreement, we granted to Janssen exclusive worldwide rights to develop and commercialize imetelstat for all indications, and Janssen is responsible for the development, manufacturing and commercialization of, and seeking regulatory approval for, imetelstat worldwide. Development of imetelstat will proceed under a mutually agreed clinical development plan, which includes the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study. We expect Janssen to initiate the Initial Phase 2 MF Study in mid-2015, followed later by the Initial Phase 2 MDS Study to be initiated at the end of 2015. In addition, the clinical development plan may also include possible registration studies in MF and MDS, and possible exploratory Phase 2 and potential follow-on Phase 3 studies in AML. Development costs for the planned Initial Phase 2 MF Study and the planned Initial Phase 2 MDS Study will be shared between the parties on a 50/50 basis.

        Following theIMbark protocol-specified primary analysis, of the Initial Phase 2 MF Study, which results are referred to in this annual report on Form 10-K as the Initial Phase 2 MF Results, or a certain time period after the initiation of the first Phase 3 MF study, Janssen must notify us of their decision, or aits Continuation Decision. We expect the protocol-specified primary analysis for IMbark to begin by the end of the second quarter of 2018. As such, we expect the Continuation Decision as to whether they elect to maintainoccur by the license rights granted to them underend of the third quarter of 2018. Janssen could discontinue the imetelstat program and terminate the Collaboration Agreement at any time, such as before the start of the IMbark primary analysis, and continuefor any reason, irrespective of whether there is data from IMbark suggesting an adequate improvement in survival in relapsed or refractory MF or whether there is data from IMerge to advancesupport the developmentbenefit-risk profile of imetelstat in lower risk MDS. In this regard, we believe that without an adequate improvement in survival in relapsed or refractory MF, with the determination of adequacy to be assessed by Janssen in its sole discretion, Janssen would decide to discontinue the imetelstat program and terminate the Collaboration Agreement.

IMerge

Trial Design

IMerge is a two-part clinical trial evaluating imetelstat in transfusion dependent patients with Low or Intermediate-1 risk, also referred to as lower risk, MDS, who have relapsed after or are refractory to prior treatment with an erythropoiesis stimulating agent, or ESA. To be eligible for IMerge, patients must be transfusion‑dependent, defined as requiring at least four units of packed red blood cells, or RBCs, over eight weeks before entry into the trial. Part 1 of the trial was designed as a Phase 2, open-label, single-arm trial to assess the efficacy and safety of imetelstat administered as an intravenous infusion at a starting dose of 7.5 mg/kg every four weeks in approximately 30 patients. Part 2 of the trial is planned as a Phase 3 double-blind, randomized, placebo controlled trial in approximately 170 patients.

The primary efficacy endpoint is the rate of RBC transfusion-independence, or RBC TI, lasting at least 8 weeks, defined as the proportion of patients without any indication.RBC transfusion during any consecutive 8 weeks since entry to the trial. Key secondary endpoints include the rate of RBC TI lasting at least 24 weeks and the rate of hematologic improvement-erythroid, or HI-E, defined as a rise in hemoglobin of at least 1.5 g/dL above the pretreatment level for at least 8 weeks or a reduction of at least 4 units of RBC transfusions over 8 weeks compared with the prior RBC transfusion burden. Other secondary efficacy endpoints include the time to and duration of RBC TI; the proportion of patients achieving CR or PR according to the 2006 International Working Group, or IWG, criteria for MDS; the proportion of patients requiring RBC transfusions and the transfusion burden; the proportion of patients requiring the use of myeloid growth factors and the dose; assessments of the change in the patients’ quality of life using several validated instruments; as well as an assessment of overall survival and time to progression to AML.

The first patient in IMerge was dosed in January 2016. The trial is being conducted at multiple medical centers across North and South America, Europe and Asia. Trial design information for IMerge, including patient eligibility criteria and locations of clinical sites, is posted on clinicaltrials.gov.

Preliminary Data from Part 1 of IMerge

Data, as of October 2017, from 32 patients enrolled in Part 1 of IMerge with a median follow-up of over a year were presented at the American Society for Hematology, or ASH, Annual Meeting and Exposition held in December 2017.

The Part 1 patients were heavily transfusion dependent, with a median baseline RBC transfusion burden of six units over 8 weeks, ranging from four to 14 units. In the event that the Initial Phase 2 MF Study has been terminated early or suspended, Janssen must instead notify usoverall trial population of their Continuation Decision by the date that is the later of 24 months32 patients, approximately one-third achieved ≥8-week RBC TI after the initiationtreatment with imetelstat. Approximately 15% of the planned Initial Phase 2 MDS Study or 24 months afterpatients achieved ≥24-week RBC TI, with the terminationmedian duration of transfusion independence exceeding one year and sustained rises in hemoglobin by at least 1.5g/dL from pretreatment levels for these patients. Nearly two-thirds of the Initial Phase 2 MF Studypatients achieved HI-E. Almost all patients experienced some reduction in transfusion burden, with the average relative transfusion burden being reduced by approximately two-thirds compared to baseline levels. These data suggest clinical benefit of imetelstat among transfusion-dependent patients with lower risk MDS.

In the overall trial population, the rate of ≥8-week RBC TI did not differ based on the presence of ringed sideroblasts, indicating activity of imetelstat across different subtypes of MDS. In addition, the rate of ≥8-week RBC TI appeared to be independent of serum erythropoietin, or commencementsEPO, levels at baseline.

Among the 32 patients enrolled in Part 1 of IMerge, a subset of 13 patients had not received prior treatment with either a hypomethylating agent, or HMA, or lenalidomide, and did not have a deletion 5q chromosomal abnormality, or non-del(5q). This 13-patient subset showed an increased durability and rate of transfusion independence compared to the overall trial population. Approximately half of the suspension period, as applicable.13-patient subset population achieved ≥8-week RBC TI after treatment with imetelstat, and almost one-third of the subset population achieved ≥24-week RBC TI.

The safety profile in Part 1 was consistent with prior clinical trials of imetelstat in hematologic malignancies, and no new safety signals were identified. The most frequently reported adverse events were cytopenias, which were predictable, manageable and reversible, in most cases, including Grade 3 and 4, or severe, neutropenia and thrombocytopenia. In addition, reported adverse events did not differ significantly between the event thatoverall trial population and the 13-patient subset.

In October 2017, the FDA granted Fast Track designation to imetelstat for the treatment of adult patients with transfusion-dependent anemia due to Low or Intermediate-1 risk MDS who are non-del(5q) and who are refractory or resistant to treatment with an ESA. Janssen notifies ussponsored the application for Fast Track designation, supported by preliminary data from Part 1 of IMerge.

Current Status of IMerge

Based on preliminary data from the 13-patient subset, Janssen has expanded Part 1 of IMerge to enroll approximately 20 additional patients who are non-del(5q) and naïve to HMA and lenalidomide treatment to increase the experience and confirm the benefit-risk profile of imetelstat in a total of approximately 30 patients in this refined target population in Part 1. The first patient in the expanded Part 1 was dosed in November 2017, and enrollment was completed in February 2018. As such, in the first quarter of 2018, no data from the expanded Part 1 of IMerge were available to be reviewed.

Janssen has not committed to begin Part 2 of IMerge. We believe Janssen will initiate Part 2 only following an affirmative Continuation Decision, we will then have an option to share further U.S. developmentif any. Janssen could discontinue the imetelstat program and promotion costs, orterminate the U.S. Opt-In Rights, in exchange for higher tiered royalty rates and higher future potential milestone payments if imetelstat is successfully developed and approved. If we exerciseCollaboration Agreement at any time, such as, before the U.S. Opt-In Rights, then we and Janssen will share U.S. development and promotion costs on a 20/80 basis (Geron 20%, Janssen 80%), we will receive a $65 million milestone payment at the timestart of the Continuation Decision,IMbark primary analysis, and will be eligiblefor any reason, irrespective of whether there is data from IMbark suggesting an adequate improvement in survival in relapsed or refractory MF or whether there is data from IMerge to receive additional potential payments of up to $470 million in development and regulatory milestones, up to $350 million in sales milestones, and tiered royalties ranging from a mid-teens up to a low twenties percentage rate on worldwide net salessupport the benefit-risk profile of imetelstat in any countries where regulatory exclusivity existslower risk MDS. In this regard, we believe that without an adequate improvement in survival in relapsed or there are valid claims underrefractory MF, with the patent rights exclusively licensed to Janssen. In addition, if we exercise the U.S. Opt-In Rights, we will also have a separate co-promotion option, or the U.S. Co-Promotion Option, to provide 20%determination of the U.S. selling effort with sales force personnel, in lieu of funding 20% of U.S. promotion costs, upon regulatory approval and commercial launch of imetelstat in the United States. Such co-promotion would be conducted under a Janssen prepared promotion plan, and in accordance with a co-promotion agreementadequacy to be agreed by us and Janssen at the time of our exercise of the U.S. Co-Promotion Option. We would be responsible for all costs associated with establishing and maintaining our sales force in any conduct of such co-promotion. All product sales would be booked by Janssen. If we do not exercise the U.S. Opt-In Rights upon an affirmative Continuation Decisionassessed by Janssen then all further developmentin its sole discretion, Janssen would decide to discontinue the imetelstat program and promotion costs

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beyond the Initial Phase 2 MF Study or Initial Phase 2 MDS Study will be borne by Janssen, we will receive a $65 million milestone payment at the time of the Continuation Decision plus a $70 million payment for Janssen's retention of full U.S. rights, and will be eligible to receive additional potential payments of up to $415 million in development and regulatory milestones, up to $350 million in sales milestones, and tiered royalties ranging from a double-digit up to a mid-teens percentage rate on worldwide net sales in any countries where regulatory exclusivity exists or there are valid claims under the patent rights exclusively licensed to Janssen.

        Under the terms ofterminate the Collaboration Agreement, we and Janssen have created a joint governance structure, including joint development and steering committees and working groups, to oversee and manage worldwide regulatory, development and manufacturing work under the joint clinical development plan and promotional activities (assuming we exercise the U.S. Opt-In Rights) for imetelstat, with Janssen responsible for the operational implementation of those activities. In addition, both we and Janssen may propose to the joint development committee imetelstat development for any new indications not then provided for in the joint clinical development plan and if we and Janssen agree such development should be conducted outside of the joint clinical development plan, both we and Janssen would be entitled to independently undertake such development at the developing party's own cost, subject to the other party's obligation to provide reimbursement for its specified portion of the development costs plus a premium following marketing approval of imetelstat in such newly proposed indication as a result of such independent development. In the event that we do not exercise the U.S. Opt-In Rights following Janssen's Continuation Decision, the joint governance structure under the Collaboration Agreement would be dissolved, a joint oversight committee would monitor the progress of the collaboration, and we would have no further rights to conduct any independent imetelstat development.Agreement.

Research and Development

        Since our inception, we have devoted a significant amount of resources to develop our current and former product candidates. For information regarding research and development expenses incurred during 2014, 2013 and 2012, see Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations—Research and Development Expenses".

        In light of projected reduced operational demands as a result of the Collaboration Agreement with Janssen, on March 3, 2015, we announced an organizational resizing to reduce our workforce from 39 to 21 positions, representing a reduction of approximately 46% of our workforce. As a result of this action, we expect personnel related research and development expenses to decrease in the future. For a further discussion, see Note 15 on Subsequent Event in Notes to Consolidated Financial Statements of this annual report on Form 10-K.

Intellectual Property

Intellectual property, including patent protection, is very important to our business. We file patent applications in the United States and other jurisdictions, and we also rely on trade secret protection and contractual arrangements to protect aspects of our business. An enforceable patent with appropriate claim coverage can provide an advantage over competitors who may seek to employ similar approaches to develop therapeutics, and so the future commercial success of imetelstat in collaboration with Janssen, and therefore our future commercial success, will be in part dependent on our intellectual property strategy. The information provided in this section should be reviewed in the context of the section entitled "Risks“Risks Related to Protecting Our Intellectual Property"Property” under Item 1A, "Risk Factors"“Risk Factors”.

The development of biotechnology products, including ours,imetelstat, typically includes the early development of a technology, followed by rounds of increasingly focused innovation around a product opportunity, including identification and definition of a specific product candidate and uses thereof,

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manufacturing processes, product formulation and administration methods. The result of this process is that biotechnology products are often protected by several families of patent filings that are filed at different times during product development and cover different aspects of the product. Consequently, earlier filed, broad technology patents will usually expire ahead of patents covering later developments such as product formulations, so that patent expirations on a product may span several years. Patent coverage may also vary from country to country based on the scope of available patent protection. There are also opportunities to obtain an extension of patent coverage for a product in certain countries, which addadds further complexity to the determination of patent life.

We endeavor to monitor worldwide patent filings by third parties that are relevant to our business. Based on this monitoring, we may determine that an action is appropriate to protect our business interests. Such actions may include negotiating patent licenses where appropriate, filing oppositions or reexaminationsagainst a patent, filing a request for post grant review against a patent or filing a request for the declaration of an interference with a United States patent application or issued patent.

Imetelstat

        The following table showsImetelstat

We own issued patents in the estimated latest expiration dates for the composition of matter patents for our sole product candidate,United States, Europe and other countries related to imetelstat. Composition of matter patents generally provide the most material coverage, and therefore may convey competitive advantages. Because imetelstat is still under development, subsequent innovation and associated patent filings may provide additional patent coverage with later expiration dates. Examination of overseas patent applications typically lags behind U.S. examination particularly where cases are filed first in the United States. The stated U.S. expiration date includes aIt may be possible to obtain patent term adjustmentextensions of some patents in some countries for delays in prosecution byclaims covering imetelstat which could further extend the U.S. Patent and Trademark Office, but does not account for a potential patent term extension that may be available to compensate us for delays in FDA regulatory review of a new drug application.term.

Our patent rights relating to imetelstat which have been exclusively licensed to Janssen for all disorders or medical conditions include those covering the nucleic acid sequence of hTR, the RNA component of telomerase, against which the oligonucleotide component of imetelstat is targeted; composition claims to the drug molecule and related nucleic acid telomerase inhibiting molecules; the amidate nucleic acid chemistry used in the oligonucleotide;molecules, as well as reagents useful in manufacturing processes for the drug, and method of treatment and kit claims, certain of which are co-owned by us.co‑owned with other entities. Our proprietary nucleic acid chemistrypatent rights for imetelstat and related products whose mechanism of action is covered by patent families that we acquired in 2002 from Lynx Therapeutics, Inc.,telomerase inhibition have been exclusively licensed (even as well as in patents that we filedto us) to Janssen for further developments of this chemistry. Certainall human disorders or medical conditions. In addition, certain of our patent rights for measuring the expression of telomerase activity or the length of telomeres in cells have been non-exclusivelynon‑exclusively licensed to Janssen.

        As noted previously, we granted to Janssen exclusive worldwide rights to develop and commercialize imetelstat for all disorders or disease conditions. Under the terms of the Collaboration Agreement with Janssen, we remain responsible for prosecuting, at Janssen'sJanssen’s direction, the patents exclusively licensed to Janssen, with costs shared between us and Janssen on a 50/50 basis. For intellectual property developed under the Collaboration Agreement, the party having sole ownership interest in such intellectual property will be responsible for prosecuting any such patents, with Janssen bearing all of the patent costs for such intellectual property solely owned by Janssen and with patent costs for such intellectual property either jointly owned or solely owned by us such patent costs to be shared between the parties on a 50/50 basis.

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Telomerase

Our U.S. patent rights relating to telomerase that cover technologies such as variants of the cloned genes that encode the catalytic protein component (hTERT) of human telomerase, or hTERT, and cellsantibodies or antigen binding fragments that are immortalized by expression of recombinantspecifically bind to hTERT, are co-ownedco‑owned with and in-licensedin‑licensed exclusively from the University of Colorado. Certain patentsWe expect the last of these U.S. patent rights to expire in 2019. A U.S. patent for identifying telomerase modulators or diagnosing cancer by measuring the expressioninhibitors of telomerase activity are co-owned and in-licensedis in‑licensed from the University of Texas Southwestern Medical Center and the University of California.California and will expire in 2019. See Item 1A, “Risk Factors” for additional information regarding our patent rights relating to telomerase.

Licensing

Collaboration and License Agreement with Janssen

On November 13, 2014, we entered into the Collaboration Agreement, pursuant to which we granted to Janssen the exclusive rights to develop and commercialize imetelstat worldwide for all indications in oncology, including hematologic myeloid malignancies, and all other human therapeutic uses. The Collaboration Agreement became effective on December 15, 2014, and we received $35 million from Janssen as an upfront payment. Additional consideration under the Collaboration Agreement includes potential payments of up to an aggregate maximum total of $900 million for the achievement of development, regulatory and commercial milestones, as well as royalties on worldwide net sales.

Under the Collaboration Agreement, Janssen is wholly responsible for developing, manufacturing, seeking regulatory approval for, and commercialization of, imetelstat worldwide. To that end, Janssen is currently conducting

two clinical trials, IMbark and IMerge. We are contributing 50% of the development costs for these clinical trials, which Janssen is solely conducting.

Following the protocol‑specified primary analysis of IMbark by Janssen, if completed, or a certain time period after the initiation of the first Phase 3 MF study, if any, Janssen must notify us of their Continuation Decision as to whether they elect to maintain the license rights granted to them under the Collaboration Agreement and continue to advance the development of imetelstat in any indication. We expect the protocol-specified primary analysis for IMbark to begin by the end of the second quarter of 2018. As such, we expect the Continuation Decision to occur by the end of the third quarter of 2018. In the event that IMbark is terminated early, or placed on clinical hold or suspended by a regulatory authority for an extended period of time, then Janssen must instead notify us of their Continuation Decision by the date that is approximately 24 months after the initiation of IMerge.

In the event that Janssen notifies us of an affirmative Continuation Decision, we then would have an option, or the U.S. Opt‑In Rights, to share further U.S. development and promotion costs, including our share of development costs incurred to date by Janssen beyond IMbark or IMerge, in exchange for higher tiered royalty rates and higher future development and regulatory milestone payments if imetelstat is successfully developed and approved. If we exercise the U.S. Opt‑In Rights, then we and Janssen would share U.S. development and promotion costs beyond IMbark and IMerge on a 20/80 basis (Geron 20%, Janssen 80%), we would receive a $65 million milestone payment, or the Continuation Fee, at the time of an affirmative Continuation Decision, and would be eligible to receive additional potential payments of up to $470 million for the achievement of certain development and regulatory milestones, up to $350 million for the achievement of certain sales milestones, and tiered royalties ranging from a mid‑teens up to a low twenties percentage rate on worldwide net sales of imetelstat in any countries where regulatory exclusivity exists or there are valid claims under the patent rights exclusively licensed to Janssen. In addition, if we exercise the U.S. Opt‑In Rights, we then would also have a separate co‑promotion option, or the U.S. Co‑Promotion Option, to provide 20% of the U.S. selling effort with our sales force personnel, in lieu of funding 20% of U.S. promotion costs, upon regulatory approval and commercial launch of imetelstat in the United States. Such co‑promotion would be conducted under a Janssen prepared promotion plan, and in accordance with a co‑promotion agreement to be agreed by us and Janssen at the time of our exercise of the U.S. Co‑Promotion Option. We would be responsible for all costs associated with establishing and maintaining our sales force in any conduct of such co‑promotion. All product sales would be booked by Janssen. If we do not exercise the U.S. Opt‑In Rights, then all further development and promotion costs beyond IMbark or IMerge would be borne by Janssen, we would receive the $65 million Continuation Fee at the time of an affirmative Continuation Decision plus a $70 million payment for Janssen’s retention of full U.S. rights to imetelstat, and would be eligible to receive additional potential payments of up to $415 million for the achievement of certain development and regulatory milestones, up to $350 million for the achievement of certain sales milestones, and tiered royalties ranging from a double‑digit up to a mid‑teens percentage rate on worldwide net sales of imetelstat in any countries where regulatory exclusivity exists or there are valid claims under the patent rights exclusively licensed to Janssen.

Under the terms of the Collaboration Agreement, we and Janssen have created a joint governance structure, including joint development and steering committees and working groups, to oversee and manage worldwide regulatory, development and manufacturing work under the joint clinical development plan and promotional activities (assuming we exercise the U.S. Opt‑In Rights) for imetelstat, with Janssen responsible for the operational execution of those activities. In addition, both we and Janssen may propose to the joint development committee imetelstat development for any new indications not then provided for in the joint clinical development plan and if we and Janssen agree such development should be conducted outside of the joint clinical development plan, both we and Janssen would be entitled to independently undertake such development at the developing party’s own cost, subject to the other party’s obligation to provide reimbursement for its specified portion of the development costs plus a premium following marketing approval of imetelstat in such newly proposed indication as a result of such independent development. In the event that we do not exercise the U.S. Opt‑In Rights following Janssen’s affirmative Continuation Decision, the joint governance structure under the Collaboration Agreement would be dissolved, a joint oversight committee would monitor the progress of the collaboration, and we would have no further rights to conduct any independent imetelstat development.

After an affirmative Continuation Decision by Janssen, the Collaboration Agreement would remain in effect until the expiration of the last‑to‑expire patent or the royalty obligations on sales of imetelstat cease, unless terminated earlier. If Janssen does not effect an affirmative Continuation Decision, then the Collaboration Agreement would

terminate and all rights to the imetelstat program would revert to us. Janssen may terminate the Collaboration Agreement at any time for convenience or due to a safety‑related concern. If a notice of termination from Janssen occurs, we would be entitled to certain continued operational support from Janssen and cost‑sharing under various circumstances and all rights to the imetelstat program would revert to us. The information provided in this section should be reviewed in the context of the sections entitled “Risks Related to Our Collaboration with Janssen” and “Risks Related to Clinical Development, Regulatory Approval and Commercialization of Imetelstat” under Item 1A, “Risk Factors”.

Other License Agreements

In addition to the Collaboration Agreement with Janssen (see the section entitled "Future Development of Imetelstat in Collaboration with Janssen" above for further discussion of the Collaboration Agreement with Janssen),agreements, we have also granted licenses to a number of other organizations in the ordinary course of our business to utilize aspects of our technologies to develop and commercialize products outside of ourthe imetelstat program. These include:

•

a license to Janssen Pharmaceuticals, Inc., or Janssen Pharmaceuticals, an affiliate of Janssen, for the research, development and commercialization of products based on specialized oligonucleotide backbone chemistry and novel amidates for disorders, excluding cancers originating from the blood or bone marrow. In connection with this license, we also granted to Janssen Pharmaceuticals a non‑exclusive worldwide license under our patent rights covering the synthesis of monomers, which are the building blocks of oligonucleotides. These non‑exclusively licensed patent rights are licensed exclusively to Janssen under the Collaboration Agreement for the imetelstat program, and our license with Janssen Pharmaceuticals expressly excludes products whose predominant or primary mechanism of action is telomerase inhibition and is subject to the rights and licenses granted to Janssen under the Collaboration Agreement;

licenses to several biotechnology and pharmaceutical companies to use or commercialize telomerase immortalized cells in drug discovery research;



•

licenses to several companies to commercialize telomerase immortalized cells for drug discovery applications;



•

licenses to several companies to sell antibodies specific to telomerase for research purposes;



•

licenses to several companies to develop and commercialize reagent kits, or to provide services, for the measurement of telomere length or telomerase activity for research purposes;



•

a license to a company to develop and commercialize a particular telomerase telomerase‑based technology for cancer detection; and



•

a license to a company for the development of cancer immunotherapies for veterinary applications.

See Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Revenues” for a further discussion of revenues from our license agreements. We expect revenues under our license agreements related to our telomerase technology to decline significantly in the coming years, and to be eliminated by the end of 2019, due to upcoming patent expirations on such technology.

Concentration of Revenues

Our revenues were $1.1 million, $6.2 million and $36.4 million for the years ended December 31, 2017, 2016 and 2015, respectively. We operate in one operating segment and have operations solely in the United States. All of our long‑lived assets are maintained in the United States. See Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Revenues” for additional detail regarding the composition of our revenues.

Research and Development

Our research and development costs were $11.0 million, $18.0 million and $17.8 million for the years ended December 31, 2017, 2016 and 2015, respectively. See Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Research and Development Expenses” for additional detail regarding our research and development activities.

CompetitionManufacturing

A typical sequence of steps in the manufacture of imetelstat drug product includes the following key components:

In accordance with the Collaboration Agreement, Janssen is now responsible for the manufacture and management of the supply of imetelstat on a global basis for clinical trials and, after any regulatory approval, all commercial activities. Consequently, we are, and expect to remain, dependent on Janssen to appropriately supply imetelstat and other clinical trial materials. Currently, third‑party contractors perform certain process development and other technical and scientific work with respect to imetelstat, as well as supply starting materials and manufacturing drug substance and drug product. Janssen does not have direct control over third‑party personnel or operations. These third‑party contractors, and/or any other contractors that Janssen may rely upon for the manufacture and/or supply of imetelstat, typically complete their services on a proposal by proposal basis under master supply agreements and may need to make substantial investments to enable sufficient capacity increases and cost reductions, and to implement those regulatory and compliance standards necessary for successful Phase 3 clinical trials and commercial production. These third‑party contractors, and/or any other contractors that Janssen may rely upon for the manufacture and/or supply of imetelstat, may not be able to achieve such capacity increases, cost reductions, or regulatory and compliance standards, and even if they do, such achievements may not be at a commercially reasonable cost. Janssen is responsible for establishing any long‑term commitments or commercial supply agreements with any of the third‑party contractors for imetelstat. The information provided in this section should be reviewed in the context of the section entitled “Risks Related to Manufacturing” under Item 1A, “Risk Factors”.

Consultants

We have consulting agreements with drug development professionals, clinicians and regulatory experts with experience in numerous fields, including oncology and drug regulations. We retain each consultant according to the terms of a consulting agreement. Under such agreements, we pay them a consulting fee and reimburse them for out‑of‑pocket expenses incurred in performing their services for us. In addition, some consultants hold options to purchase our common stock, subject to the vesting requirements contained in the consulting agreements. Our consultants may be employed by other entities and therefore may have commitments to their employer, or may have other consulting or advisory agreements that may limit their availability to us.

Competition

The pharmaceutical and biotechnology industries are intensely competitive. Other pharmaceutical and biotechnology companies and research organizations currently engage in or have in the past engaged in efforts related to the biological mechanisms related to imetelstat, including the study of telomeres, telomerase, andor our proprietary oligonucleotide chemistry, and the research and development of therapies for the treatment of hematologic myeloid malignancies. In addition, other products and therapies that could directly compete directly with imetelstat currently exist or are being developed by pharmaceutical and biopharmaceutical companies and by academic institutions, government agencies and other public and private research organizations.

        Our sole product candidate, imetelstat, We expect Janssen’s decisions regarding continued development and/or commercialization, if approved for marketing, will face significant competition from approved drugs, drugs currently under development and any other drugs that may be subsequently approved. Imetelstat would have to compete successfully based on efficacy, safety, convenience, price, cost-effectiveness and other relevant factors. In addition, imetelstat would have to compete against other drugs with a variety of decision makers, including physicians, patients, government and private third-party payors, technology assessment groups and patient advocacy organizations. We cannot guarantee that we, in collaboration with Janssen, will be able to compete successfully on any, of these factors. If we imetelstat, including completing IMerge and/or Janssen cannot compete successfully on anyIMbark, its Continuation Decision or the termination of the factors described previously, Janssen may terminate the Collaboration Agreement, and our business may fail.

Development; Senior Vice President, Therapeutic Development, Oncology; and Senior Vice President, Strategic Portfolio Management. From 1990 to 1998, Ms. Behrs worked at Genetics Institute, Inc., a biotechnology research and development company, serving initially as Assistant Treasurer and then as Associate Director of Preclinical Operations where she was responsible for all business development, regulatory, and project management activities for the Preclinical Development function. Ms. Behrs received a B.S. from Boston College and an M.B.A. from Babson College.

Andrew J. Grethlein, Ph.D., has served as our Executive Vice President, Development and Technical Operations, since July 2014. Prior to that he servedHe joined Geron in September 2012 as our Executive Vice President, Technical Operations, since September 2012.Operations. Prior to joining Geron, Dr. Grethlein was Executive Vice President and Chief Operating Officer for Inspiration Biopharmaceuticals, a biopharmaceutical company, from January 2010 to September 2012. From October 2008 until January 2010, Dr. Grethlein was Senior Vice President of Biotechnology and Portfolio Management Team Leader for Hematology at Ipsen S.A., a global specialty pharmaceutical company. His responsibilities at Ipsen

included planning and execution of worldwide strategy for product and portfolio development in the hematologic therapeutic area. From 2003 to 2008, Dr. Grethlein served as Senior Vice President of Pharmaceutical Operations at Tercica, Inc., an endocrinology-orientedendocrinology‑oriented biopharmaceutical company. In this role,company, where he was a member of the senior executive team that governed corporate strategy, business planning and company operations, and had responsibility for all manufacturing and quality functions. Before joining Tercica, Dr. Grethlein served in various positions at Elan Corporation, a biotechnology company, from 1997 to 2003, including as Senior Director, South San Francisco Pharmaceutical Operations, where he had responsibility as site head for commercial manufacturing operations.Operations. From 1995 to 1997, Dr. Grethlein served as Manager, Biologics Development and Manufacturing, for Athena Neurosciences, Inc., a pharmaceutical company. Prior to this, he served in various engineering positions for the Michigan Biotechnology Institute, a nonprofit technology research and business development corporation. Dr. Grethlein received his A.A. degree in liberal arts from Simon'sSimon’s Rock Early College, his B.S. in biology from Bates College, and his M.S. and Ph.D. in chemical engineering from Michigan State University.

Stephen N. Rosenfield, J.D., has served as our Executive Vice President, General Counsel and Corporate Secretary since February 2012, General Counsel and Secretary since January 2012 and Secretary since October 2011. From July 2009 to February 2012, Mr. Rosenfield has beenserved as a consultant to private companies. From October 2008June 2004 until June 2009, Mr. Rosenfield was theheld several positions at Tercica, Inc., an endocrinology‑oriented biopharmaceutical company, and through its acquisition by Ipsen, S.A. in October 2008, including General Counsel and Secretary of Tercica, Inc., a U.S. subsidiary of Ipsen, S.A., a global specialty pharmaceutical company. From June 2004 until October 2008, Mr. Rosenfield was the General Counsel and Secretary of Tercica, Inc., an endocrinology-oriented biopharmaceutical company, from January 2006 until October 2008, he was also the Executive Vice President of Legal Affairs, and from June 2004 until January 2006, Mr. Rosenfield was the Senior Vice President of Legal Affairs.Secretary. Prior to joining Tercica, Mr. Rosenfield served as the Executive Vice President of Legal Affairs, General Counsel and Secretary of InterMune, Inc., a biotechnology company that focused inon pulmonology and fibrotic diseases. Prior to joining InterMune, Mr. Rosenfield was an attorney at Cooley LLP, an international law firm, where he served as outside counsel for biotechnology and technology clients. Mr. Rosenfield received a B.S. from Hofstra University and a J.D. from Northeastern University School of Law.

Employees

As of December 31, 2014,2017, we had 4215 full‑time and three part‑time employees. Two of our employees of whom 7 hold Ph.D. degrees and 13seven hold other advanced degrees. Of this current total workforce, 22two employees were engaged in, or directly supported, our research and development activities, and 2016 employees were engaged in business development, legal, finance and administration. None of our employees are covered by a collective bargaining agreement; nor have we experienced work stoppages. We consider relations with our employees to be good.

        On March 3, 2015, we announced an organizational resizing to reduce our workforce from 39 to 21 positions, representing a reduction of approximately 46% of our workforce. For a further discussion, see Note 15 on Subsequent Event in Notes to Consolidated Financial Statements of this annual report on Form 10-K.

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Corporate Information

Geron Corporation was incorporated in the State of Delaware on November 28, 1990.

Available Information

Our internet address is www.geron.com. Information included on our website is not part of this annual report on Form 10-K.10‑K. We make available free of charge on our website our annual reports on Form 10-K,10‑K, quarterly reports on Form 10-Q,10‑Q, current reports on Form 8-K,8‑K, and all amendments to those reports as soon as reasonably practicable after such material is electronically filed with or furnished to the United States Securities and Exchange Commission, or the SEC. In addition, copies of our annual reports are available free of charge upon written request. The SEC also maintains an Internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC. The address of that site is www.sec.gov.

ITEM 1A.    RISK FACTORS

Our business is subject to various risks and uncertainties that may have a material adverse effect on our business, financial condition or results of operations. You should carefully consider the risks and uncertainties described below, together with all of the other information included in this annual report on Form 10-K.10‑K. Our business faces significant risks and uncertainties, and those described below may not be the only risks and uncertainties we face. Additional risks and uncertainties not presently known to us or that we currently believe are immaterial may also significantly impair our business, financial condition or results of operations. If any of these risks or uncertainties occur, our business, financial condition or results of operations or financial condition could suffer, the market price of our common stock could decline and you could lose all or part of your investment in our common stock.

RISKS RELATED TO OUR BUSINESS
COLLABORATION WITH JANSSEN

We are dependent upon our collaborative relationship with Janssen to further develop, manufacture and commercialize imetelstat,have outlicensed our sole product candidate.candidate, imetelstat, to Janssen. If Janssen fails to perform as expected,discontinues the potential for us to generate future revenues from milestone paymentsimetelstat program and/or terminates the Collaboration Agreement, our business and royalties from imetelstatbusiness prospects would be significantly reduced,severely harmed, and we might cease operations, the development and/or commercialization of imetelstat maywould be terminated or substantially delayed, and the market price of our common stock would be adversely affected.

Janssen may terminate the Collaboration Agreement at any time at its sole discretion. If imetelstat fails to meet criteria determined by Janssen to support an affirmative Continuation Decision, or for any other reason, Janssen may discontinue the imetelstat program and terminate the Collaboration Agreement. In this regard, we believe that without an adequate improvement in survival in relapsed or refractory MF in IMbark, with the determination of adequacy to be assessed by Janssen in its sole discretion, Janssen would decide to discontinue the imetelstat program and terminate the Collaboration Agreement.

In addition, Janssen could discontinue the imetelstat program and terminate the Collaboration Agreement at any time and for any reason, irrespective of whether there is data from IMbark suggesting an adequate improvement in survival in relapsed or refractory MF or whether there is data from IMerge to support the benefit-risk profile of imetelstat in lower risk MDS. Any discontinuation of the imetelstat program or termination of the Collaboration Agreement by Janssen at any time would severely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations, and the market price of our common stock would be adversely affected.

If Janssen terminates the Collaboration Agreement:

If Janssen does not provide an affirmative Continuation Decision in a timely manner, or at all, our business and business prospects would be severely harmed.harmed, and we might cease operations.

Under the terms of the Collaboration Agreement, Janssen is not obligated to make any additional payments to us until it makes an affirmative Continuation Decision following the protocol-specified primary analysis of IMbark, or, if IMbark is terminated early, or placed on clinical hold or suspended by a regulatory authority for an extended period of time, within approximately 24 months after the initiation of IMerge. In March 2018, the JSC agreed that the protocol-specified primary analysis for IMbark will begin by the end of the second quarter of 2018. As such, we expect the Continuation Decision to occur by the end of the third quarter of 2018. If Janssen terminates IMbark early based on preliminary or ongoing data assessments, safety concerns or for any other reason, or the trial is placed on clinical hold or suspended by a regulatory authority, the protocol-specified primary analysis for IMbark may not take place at all, which would further delay the timing of any Continuation Decision or result in a negative Continuation Decision. Delays in the timing of the Continuation Decision or a negative Continuation Decision from Janssen could increase our development costs and would impair our ability to earn revenues from milestone payments or royalties under the Collaboration Agreement, any of which would severely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations.

If there are further delays in IMerge or IMbark, Janssen may decide to cease the development of imetelstat and terminate the Collaboration Agreement, and our business and business prospects would be severely harmed.

The expansion of enrollment in Part 1 of IMerge has prolonged the development of imetelstat in lower risk MDS, and Janssen have createdcould decide not to proceed with Part 2 of IMerge. Janssen has made no commitment to commence Part 2 of IMerge. Even if Janssen obtains additional data from the refined target patient population, such data may not support the development of imetelstat in the refined target patient population for Part 2. In any event, we believe Janssen will initiate Part 2 only following an affirmative Continuation Decision, if any. Janssen could discontinue the imetelstat program and terminate the Collaboration Agreement at any time, such as, before the start of the IMbark primary analysis, and for any reason, irrespective of whether there is data from IMbark suggesting an adequate improvement in survival in relapsed or refractory MF or whether there is data from IMerge to support the benefit-risk profile of imetelstat in lower risk MDS. In this regard, we believe that without an adequate improvement in survival in relapsed or refractory MF, with the determination of adequacy to be assessed by Janssen in its sole discretion, Janssen would decide to discontinue the imetelstat program and terminate the Collaboration Agreement. In addition, delays, including in the commencement of Part 2 of IMerge, could cause Janssen to discontinue the imetelstat development program and terminate the Collaboration Agreement.

For IMbark, although we expect the protocol-specified primary analysis to begin by the end of the second quarter of 2018, the primary analysis may not occur on the timing that we expect, or at all, if any of the following occurs:

Even if Janssen obtains longer-term efficacy and safety data for IMbark, Janssen or the FDA or any other regulatory authorities may determine that such data do not show an adequate improvement in survival to support further development and steering committeespotential regulatory approval for imetelstat in relapsed or refractory MF patients, which we expect would result in a decision by Janssen to discontinue IMbark and working groups,the imetelstat program and terminate the Collaboration Agreement. In addition, the time needed to overseeobtain longer-term efficacy and managesafety data for IMbark, including sufficient data to assess overall survival, could significantly further delay the development of imetelstat in MF and in lower risk MDS, and the timing of a Continuation Decision, if any.

If our collaboration with Janssen is not successful, our business and business prospects would be severely harmed.

Our collaboration with Janssen may be unsuccessful due to many factors, including the following:

If our collaboration with Janssen is unsuccessful as a result of any of the above factors, or any other factors, then Janssen may terminate the Collaboration Agreement or cease its efforts to develop, manufacture or commercialize imetelstat, and we would not be eligible for any further payments from Janssen under the Collaboration Agreement, which would adversely impact our financial results, business and business prospects, and the future of imetelstat, and could cause us to cease operations.

If Janssen does not perform in the manner we expect or fulfill its responsibilities under the Collaboration Agreement in a timely manner, or at all, the clinical development, manufacturing, andregulatory approval and/or commercialization activities for imetelstat; however, Janssen is solely responsible for the operational implementation of those activities. Accordingly, theimetelstat could be further delayed or terminated.

The timely and successful completion by Janssen of thosethe development, manufacturing, regulatory and commercialization activities for imetelstat will significantly affect the timing and amount of any revenues from milestone payments and royalties we may receive under the Collaboration Agreement, and these activities will be influenced by, among other things, the efforts and allocation of resources by Janssen, none of which we control. If Janssen does not perform in the manner we expect or fulfill its responsibilities in a timely manner, or at all, the clinical development, manufacturing, regulatory approval and/or commercialization efforts related to imetelstat could be delayed or terminated, and it could become necessary for us to assume the responsibilities for the clinical development, manufacturing, regulatory approval and/or commercialization of imetelstat at our own expense. Accordingly, there can be no assurance that any of the development, regulatory or sales milestones under the Collaboration Agreement will be achieved or that we will receive any future milestone or royalty payments under the Collaboration Agreement.

In addition, because Janssen is solely responsible for the operational implementationexecution of worldwide regulatory, development, manufacturing and commercialization activities related to imetelstat, we are solely dependent on

Janssen to provide us with timely and accurate information concerning these

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activities. activities as well as information about the costs incurred under the Collaboration Agreement. If we do not receive accurate information from Janssen in a timely manner, or at all, regarding these activities, including, for example, plans for, and enrollment of, and efficacy and safety results from, clinical trials of imetelstat, and commercialization assumptions or criteria set by Janssen for the continued development and commercialization of imetelstat, then the timeliness and accuracy of our public disclosures, as well as our governance-related decision-making regarding these activities, may be adversely affected.

        Our collaboration with Janssen may be unsuccessful due to other factors, including the following:

•

Janssen may choose to terminate the Collaboration Agreement for convenience;



•

Janssen may provide a negative Continuation Decision and halt itsAny development of imetelstat;



•

the results of the Initial Phase 2 MF Study and/or the Initial Phase 2 MDS Study may be negative or inconclusive, or Janssen may observe safety issues in either of these studies, which may result in a negative Continuation Decision by Janssen, in which case we would receive no further payments from Janssen under the Collaboration Agreement;



•

Janssen may choose not to develop and commercialize imetelstat in certain markets or for one or more indications, if at all;



•

Janssen may take considerably more time advancing imetelstat through the clinical and regulatory process than we currently anticipate, which could materially delay the achievement of milestones and, consequently the receipt of milestone payments from Janssen, and ultimately, any royalties on worldwide net sales;



•

in the event of a dispute between us and Janssen regarding Janssen's performance under the Collaboration Agreement, it may be difficult for us to prove that Janssen breached its obligation to use "commercially reasonable efforts" with regard to the development, regulatory approval, manufacture and commercialization of imetelstat under the Collaboration Agreement;



•

Janssen may not dedicate the resources necessary to carry imetelstat through clinical development or may not obtain the necessary regulatory approvals, and this would delay the achievement of development, regulatory or sales milestones;



•

Janssen's ability to achieve development and manufacturing objectives or milestones may be delayed or substantially impacted if we fail to transfer technology and information related to imetelstat to Janssen in a timely manner or at all;



•

subject to our election of the U.S. Co-Promotion Option, Janssen will be responsible for all aspects of the commercialization of imetelstat worldwide, including pricing decisions which would affect the royalties on worldwide net sales we could receive;



•

Janssen may change the focus of its commercialization efforts or prioritize other programs more highly and, accordingly, reduce the efforts and resources allocated to imetelstat, which would have the direct effect of reducing our royalties or share of potential co-promotion activities since the extent of our U.S. Co-Promotion Option is limited to a percentage of overall promotion activities under the Collaboration Agreement;



•

after assuming manufacturing responsibilities for imetelstat, Janssen may fail to manufacture or supply sufficient quantities of imetelstat for use in planned clinical trials, which could delay, suspend or stop any imetelstat clinical activities;



•

Janssen may fail to develop a commercially viable formulation or manufacturing process for imetelstat, and may fail to manufacture or supply sufficient quantities of imetelstat for commercial use, if approved, which would result in lost sales revenue and reduced royalties for us;

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•

Janssen may not comply with all applicable regulatory requirements or may fail to report safety data in accordance with all applicable regulatory requirements, which could delay, suspend or stop clinical activities being performed by Janssen or by us; and



•

if Janssen is acquired during the term of our collaboration, the acquirer may have different strategic priorities that could cause it to terminate the Collaboration Agreement or reduce its commitment to our collaboration.

If our collaboration with Janssen is unsuccessful as a result of any of the above factors, or any other factor, then Janssen may terminate the Collaboration Agreement, and we would not be eligible for any further payments from Janssen under the Collaboration Agreement, which would severely and adversely affect our business and business prospects.

Delays in the initiation of, or the inability to initiate, subsequent clinical trials of imetelstat, such as the Initial Phase 2 MF Study or the Initial Phase 2 MDS Study planned to be conducted under the Collaboration Agreement, could result in increased development costs and would delay our ability to earn revenues from milestone payments or royalties from the Collaboration Agreement with Janssen.

        To date, we have not initiated any clinical trials evaluating imetelstat in any hematologic myeloid malignancies (other than essential thrombocythemia), including myelofibrosis, or MF. Advancing clinical development of imetelstat will be influenced by results from existing clinical trials, such as the MF Pilot Study, and potential future clinical trials of imetelstat in hematologic myeloid malignancies, such as the Initial Phase 2 MF Study or the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement. The commencement of potential future clinical trials of imetelstat could be delayed or abandoned for a variety of reasons, including as a result of failures or delays by Janssen in:

•

obtaining regulatory clearance to commence subsequent clinical trials of imetelstat in a timely manner, or at all, in the United States or other countries;



•

properly designing, commencing, enrolling, conducting or completing potential future clinical trials, including the Initial Phase 2 MF Study or the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, and promptly or adequately reporting data from such trials;



•

demonstrating sufficient safety and efficacy in future Phase 2 clinical trials, including the Initial Phase 2 MF Study or the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, to obtain regulatory clearance to commence subsequent clinical trials in a timely manner, or at all, in the United States or other countries;



•

properly conducting and/or completing the MF Pilot Study;



•

manufacturing sufficient quantities of imetelstat and in a manner that meets the quality standards of the FDA and other regulatory agencies;



•

ensuring the ability to manufacture imetelstat at acceptable costs for Phase 3 clinical trials and commercialization;



•

obtaining clearance or approval of proposed trial designs or manufacturing specifications from the FDA and other regulatory authorities;



•

reaching agreement on acceptable terms and on a timely basis, if at all, with collaborators and vendors located in the United States or foreign jurisdictions, including contract research organizations, laboratory service providers and trial sites, on all aspects of clinical trials;



•

obtaining institutional review board or ethics committee approval to conduct clinical trials at prospective clinical trial sites; and

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•

identifying and successfully screening and enrolling appropriate subjects for participation in clinical trials and retaining those subjects in the clinical trials.

Failures or delays with respect to any of these events could adversely affect the ability to initiate, maintain or successfully complete any future clinical trials of imetelstat, which could increase development costs, impair our ability to earn revenues from milestone payments or royalties from the Collaboration Agreement with Janssen or cause Janssen to terminate the Collaboration Agreement, any of which could adversely impact our financial results and would have severe adverse effects on our business and business prospects.

If there are any safety or efficacy results that cause the benefit-risk profile of imetelstat to become unacceptable, the clinical development of imetelstat would be delayed or halted, and Janssen may terminate the Collaboration Agreement, which would severely and adversely affect our business prospects, and may cause us to cease operations.

        Imetelstat may prove to have undesirable or unintended side effects or other characteristics adversely affecting its safety, efficacy, cost-effectiveness or marketability that could prevent or limit its approval for marketing and successful commercial use, or that could delay or prevent the commencement and/or completion of clinical trials for imetelstat. For example, although the FDA removed the full clinical hold on our IND for imetelstat, if patients in current or future clinical trials experience similar or more severe hepatotoxicity, including elevated LFTs or severe hepatic adverse events, such IND for imetelstat may again be placed on clinical hold, and we, in collaboration with Janssen, may be precluded from further developing imetelstat. In addition, if regulatory submissions requesting approval to market imetelstat are submitted, after reviewing the data in such submissions, the FDA and regulatory agencies in other countries may conclude that the overall benefit-risk profile of imetelstat treatment, including hepatotoxicity or severe hepatic adverse events, may preclude approval of imetelstat for marketing or further development for any indications, including hematologic malignancies. Any of these events would severely harm our business and prospects, and would likely cause us to cease operations.

        Further, in our Phase 1 clinical trials of imetelstat, we observed dose-limiting toxicities, including thrombocytopenia when the drug was used as a single agent, and neutropenia when the drug was used in combination with paclitaxel, as well as a low incidence of severe infusion reactions. In our Phase 2 clinical trials of imetelstat in ET, MM, and solid tumors, we have observed hematologic toxicities as well as gastrointestinal events, infections, muscular and joint pain, fatigue and infusion reactions. In addition, in our Phase 2 clinical trials of imetelstat, we have observed LFT abnormalities, the clinical significance and long-term consequences of which are currently undetermined. In our Phase 2 trial in ET, one patient died of bleeding esophageal varices, a complication of chronic liver disease, for which imetelstat could not be excluded as a causative agent. In the MF Pilot Study, myelosuppression has been the primary dose-limiting toxicity reported to date, consistent with our observations in previous Geron-sponsored imetelstat studies. However, during the MF Pilot Study, more persistent and profound myelosuppression, particularly thrombocytopenia, was observed with imetelstat administered on a weekly basis. This included one case of febrile neutropenia after prolonged myelosuppression with intracranial hemorrhage resulting in patient death, which was assessed as possibly related to imetelstat by the investigator. Since the MF Pilot Study is an ongoing study with additional data being generated, the benefit-risk profile of imetelstat in MF will continue to be assessed, including the risk of hepatotoxicity and severe cytopenias that may be associated with life-threatening clinical outcomes.

        Clinical trials by their nature examine the effect of a potential therapy in a sample of the potential future patient population. As such, clinical trials conducted with imetelstat, to date and in the future, may not uncover all possible adverse events that patients treated with imetelstat may experience. In collaboration with Janssen, we may observe or report dose-limiting toxicities or other safety issues in potential future clinical trials of imetelstat, including the Initial Phase 2 MF Study and the Initial

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Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement. Likewise, because previously enrolled patients continue to receive imetelstat in the MF Pilot Study, additional or more severe toxicities or safety issues in the MF Pilot Study, including additional serious adverse events and clinically significant LFT abnormalities, may be observed or reported as patient treatment continues and more data become available. If such toxicities or other safety issues in any clinical trial of imetelstat result in an unacceptable benefit-risk profile, then:

•

the commencement and/or completion of any current or future clinical trials, including the MF Pilot Study and the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, would likely be delayed or prevented;



•

the MF Pilot Study or any potential future clinical trials, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, may be placed on clinical hold or halted by regulatory authorities, such as the previous clinical holds placed by the FDA on our IND for imetelstat and the IND for the MF Pilot Study; or



•

additional, unforeseen trials or preclinical studies may be required to be conducted.

The occurrence of any of these events would likely cause Janssen to abandon their development of imetelstat entirely and terminate the Collaboration Agreement. Any termination of the Collaboration Agreement by Janssen would have a material adverse effect on our results of operations, financial condition, business prospects and the future of imetelstat, any of which may cause us to cease operations.

If Janssen does not elect to continue the development of imetelstat in a timely manner, or at all, our business and business prospects would be severely harmed.

        Under the terms of the Collaboration Agreement, Janssen is not obligated to make any additional payments to us until it makes an affirmative Continuation Decision following the results of the Initial Phase 2 MF Study, or, if the Initial Phase 2 MF Study is terminated early or suspended for an extended period of time, within a certain time period thereafter as set forth in the Collaboration Agreement. The timing of Janssen's Continuation Decision also affects the timing and availability of our decision regarding U.S. Opt-In Rights, as well as our election of the U.S. Co-Promotion Option. If the Initial Phase 2 MF Study is terminated early, suspended for an extended period of time, or is otherwise unsuccessful, Janssen may provide a negative Continuation Decision, in which case, the Collaboration Agreement would terminate, we would not be eligible for any further payments from Janssen under that agreement and our business and business prospects would be severely and adversely affected.

        In addition, Janssen may terminate the Collaboration Agreement at any time for convenience. If Janssen terminates the Collaboration Agreement, then, depending on the timing of such event:

•

we would no longer have the right to receive any milestone payments or royalties under the Collaboration Agreement;



•

the development of imetelstat would likely be terminated or significantly delayed;



•

we would bear all of the risks and costs related to the further clinical development, manufacturing, regulatory approval and commercialization of imetelstat;



•

we would need to raise additional capital if we were to choose to pursue imetelstat development on our own, or we would need to establish alternative collaborations with third-party collaboration partners, which may not be possible in a timely manner or at all, or may not be possible on terms acceptable to us, in which case it would likely be necessary for us to limit the

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size or scope of the imetelstat development program or seek additional funding by other means to accommodate the increased expenditures; and

•

we would need to hire additional employees to support the development and commercialization of imetelstat, which would increase our need for additional funding.

Any termination of the Collaboration Agreement by Janssen at any time would have a material adverse effect on our results of operations, financial condition, business prospects and the future of imetelstat, any of which would have severe adverse effects on our business and business prospects, and may cause us to cease operations.

Our decision to exercise our U.S. Opt-In Rights under the Collaboration Agreement with Janssen for imetelstat must be made within a limited time after Janssen makes an affirmative Continuation Decision and, as a result, we may be required to make a substantial capital investment based on limited clinical data.

        We must elect to exercise our U.S. Opt-In Rights within a short timeframe following Janssen's Continuation Decision. Although we expect to receive information from Janssen regarding data from the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study, proposed future clinical development plans and costs, estimates in timing for commercializing imetelstat and related promotional activities, and calculation of our share of development costs incurred to date by Janssen that we will be required to reimburse if we exercise our U.S. Opt-In Rights, we will be required to rapidly decide whether to make a substantial capital investment in imetelstat prior to the conclusion of any Phase 3 registration-enabling clinical trial. Accordingly, if imetelstat were to become unsuccessful in any Phase 3 registration-enabling clinical trial or fails to receive regulatory approval, we would not receive any financial return on this substantial capital investment. Such an occurrence would negatively impact our financial condition and results of operations.

Our Collaboration Agreement with Janssen prohibits us from developing or commercializing any product that operates through the same mechanism of action as imetelstat, and our U.S. co-promotion rights may be terminated if we market or promote any such products for any oncology indication. As a result of this, or for any other reason, we may not be able to successfully acquire or in-license promising product opportunities for development, which would limit our growth and revenue potential.

        We plan to seek to diversify our sole product candidate development risk by identifying promising product opportunities for development, which we may seek to acquire or in-license. However, the Collaboration Agreement with Janssen prohibits us from commercializing, under the intellectual property we have licensed exclusively to Janssen, any substance whose identified or known mechanism of action is telomerase inhibition. Further, if we exercise our U.S. Co-Promotion Option under the Collaboration Agreement, we will be required to certify at the time of exercising our U.S. Co-Promotion Option that we are not marketing or promoting, and have no right to market or promote, any such products for any oncology indication. Our right to co-promote in the U.S. may be terminated by Janssen if we develop or commercialize a product for treating an oncology indication that acts through the same mechanism of action as imetelstat or that is substitutable for imetelstat. Accordingly, our Collaboration Agreement with Janssen could adversely affect our ability to acquire or in-license, or to research, develop or market, promising product candidates.

        In addition, we may not be able to identify promising product candidates. The competition to acquire or in-license rights to promising product candidates is fierce, and many of our competitors are large, multinational pharmaceutical and biotechnology companies with considerably more financial, development and commercialization resources and experience than we have. Thus, even if we succeed in identifying promising product candidates, we may not be able to acquire rights to them on acceptable terms, or at all. In any event, any growth through acquisition or in-licensing will depend upon our identifying and obtaining promising product candidates, our ability to develop those product

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candidates and the availability of funding to complete the development of, obtain regulatory approval for and commercialize these product candidates. If we are unable to identify and acquire promising product candidates, we will be unable to diversify our sole product candidate development risk, and our growth and revenue potential could be limited.

We may not be able to successfully retain key personnel to support our collaboration with Janssen or to manage any future growth.

        Under the terms of the Collaboration Agreement, we and Janssen have created a joint governance structure, including committees and working groups, to manage worldwide regulatory, development, manufacturing and commercialization activities for imetelstat, and we will have ongoing responsibilities to oversee and participate in the collaboration with Janssen. In addition, we will remain responsible for prosecuting, at Janssen's direction, the patents we licensed to Janssen, and have sole responsibility for those patents that were not licensed to Janssen. If we are unable to successfully retain, motivate and incentivize our personnel, our ability to support the Collaboration Agreement with Janssen could be impaired, and our business and the price of our common stock would be adversely impacted.

        In addition, our future growth and success depend to a significant extent on the skills, experience and efforts of our executive officers and key members of our clinical and scientific staff. We face intense competition for qualified individuals from numerous pharmaceutical, biopharmaceutical and biotechnology companies, as well as academic and other research institutions. The previous restructurings we implemented and the recently announced organizational resizing, as well as our collaboration with Janssen and uncertainties regarding our ability to diversify our sole product candidate development risk, could have an adverse impact on our ability to retain and recruit qualified personnel or we may incur unanticipated inefficiencies caused by our reduced personnel resources. We may be unable to retain our current personnel or attract or assimilate other highly qualified management and development personnel in the future on acceptable terms. The loss of any or all of these individuals could harm our business and could impair our ability to support our collaboration with Janssen or to support future growth.

We and certain of our officers have been named as defendants in three purported securities lawsuits, two of which are securities class action lawsuits, and certain of our officers and directors have been named as defendants in a derivative lawsuit. These, and potential similar or related lawsuits, could result in substantial damages, divert management's time and attention from our business, and have a material adverse effect on our results of operations. These lawsuits and any other lawsuits will be costly to defend or pursue and are uncertain in their outcome.

        Securities-related class action lawsuits and derivative litigation has often been brought against companies, including many biotechnology companies, which experience volatility in the market price of their securities. This risk is especially relevant for us because biotechnology and biopharmaceutical companies often experience significant stock price volatility in connection with their product development programs.

        On March 14, 2014, a purported securities class action lawsuit was commenced in the United States District Court for the Northern District of California, or the California District Court, naming as defendants us and certain of our officers. The lawsuit alleges violations of the Securities Exchange Act of 1934 in connection with allegedly false and misleading statements made by us related to our Phase 2 trial of imetelstat in patients with ET or PV. The plaintiff alleges, among other things, that we failed to disclose facts related to the occurrence of persistent low-grade LFT abnormalities observed in our Phase 2 trial of imetelstat in ET or PV patients and the potential risk of chronic liver injury following long-term exposure to imetelstat. The plaintiff seeks damages and an award of reasonable costs and expenses, including attorneys' fees.

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        On March 28, 2014, a second purported securities class action lawsuit was commenced in the California District Court, naming as defendants us and certain of our officers. This lawsuit, which is based on the same factual background as the purported securities class action lawsuit that commenced on March 14, 2014, also alleges violations of the Securities Exchange Act of 1934 and seeks damages and an award of reasonable costs and expenses, including attorneys' fees.

        On June 30, 2014, both of the foregoing lawsuits, or the Class Action Lawsuits, were consolidated for all purposes, and a lead plaintiff and lead counsel were appointed by the California District Court. On July 21, 2014, the California District Court ordered the lead plaintiff to file its consolidated amended complaint in the Class Action Lawsuits, which was filed on September 19, 2014. We filed our motion to dismiss the consolidated amended complaint on November 18, 2014. The plaintiff's opposition to our motion to dismiss was filed on January 20, 2015, and we filed our reply on February 25, 2015. The court hearing for the motion to dismiss has been scheduled for April 10, 2015.

        On June 6, 2014, a purported securities lawsuit, not styled as a class action, was commenced in the United States District Court for the Southern District of Mississippi, or the Mississippi District Court, naming as defendants us and certain of our officers. This lawsuit, which is based on the same factual background as the Class Action Lawsuits, also alleges violations of the Securities Exchange Act of 1934 and seeks damages and an award of reasonable costs and expenses, including attorneys' fees. On August 11, 2014, we filed a motion to transfer the purported securities lawsuit filed in the Mississippi District Court to the California District Court so it could be consolidated with the purported Class Action Lawsuits. On November 4, 2014, the Mississippi District Court granted our motion and transferred the case to the California District Court, and the transferred case has been consolidated by the California District Court with the purported Class Action Lawsuits filed in the California District Court.

        On April 21, 2014, a stockholder purporting to act on our behalf filed a derivative lawsuit in the Superior Court of California for the County of San Mateo against certain of our officers and directors. The lawsuit alleges breaches of fiduciary duties by the defendants and other violations of law. In general, the lawsuit alleges that the defendants caused or allowed the dissemination of allegedly false and misleading statements related to our Phase 2 trial of imetelstat in patients with ET or PV. The plaintiff is seeking unspecified monetary damages and other relief, including reforms and improvements to our corporate governance and internal procedures.

        It is possible that additional suits will be filed, or allegations received from stockholders, with respect to these same or other matters and also naming us and/or our officers and directors as defendants. These lawsuits and any other related lawsuits are subject to inherent uncertainties, and the actual defense and disposition costs will depend upon many unknown factors. The outcome of these lawsuits is necessarily uncertain. We could be forced to expend significant resources in the defense against these lawsuits and we may not prevail. In addition, we may incur substantial legal fees and costs in connection with these lawsuits. We currently are not able to estimate the possible cost to us from these matters, as these lawsuits are currently at an early stage, and we cannot be certain how long it may take to resolve these matters or the possible amount of any damages that we may be required to pay. We have not established any reserve for any potential liability relating to these lawsuits. It is possible that we could, in the future, incur judgments or enter into settlements of claims for monetary damages. A decision adverse to our interests on these actions could result in the payment of substantial damages, or possibly fines, and could have a material adverse effect on our cash flow, results of operations and financial position.

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We may also be subject to litigation arising from our proposed or completed strategic transactions or if the results of our business and collaboration activities are not successful.

        On October 1, 2013, we closed the transaction to divest our human embryonic stem cell assets and our autologous cellular immunotherapy program pursuant to the terms of the Contribution Agreement that we entered into in January 2013 with BioTime and Asterias. On November 13, 2014, we announced that we had entered into the Collaboration Agreement with Janssen to develop and commercialize imetelstat worldwide. We may face litigation arising from or related to the value received by our stockholders, if any, from our distribution of the Asterias Series A common stock and/or the BioTime Warrants distributed by Asterias under the Contribution Agreement, or our role as a named underwriter with respect to our distribution of the Asterias Series A common stock, including the delays we experienced with respect to completing our distribution of the Asterias Series A common stock, or we may face litigation based on other matters related to the Contribution Agreement and the Collaboration Agreement or the transactions contemplated thereby, including if we are unable to generate substantial value under the Collaboration Agreement with Janssen or such collaboration is not otherwise successful.

        As a result of these and other factors, we may be exposed to a number of litigation risks related to the transactions contemplated by the Contribution Agreement and the Collaboration Agreement, including declines or fluctuations in our stock price, additional advisor and legal fees, distractions to our management caused by activities undertaken in connection with resolving any disputes related to the transactions, or the loss of important contractual rights. As another example, some of our investors purchased shares of our common stock because they were interested in the opportunities presented by our human embryonic stem cell programs. Thus, certain stockholders may have attributed substantial financial value to our stem cell assets and may believe that the Asterias Series A common stock, BioTime Warrants and/or cash received in the distributions pursuant to the Contribution Agreement were inadequate consideration for such assets.

        Similarly, the announcement and/or completion of these strategic transactions could result in litigation arising out of any claims that our stockholders suffered financial losses due to the transactions, the approval of our stockholders was required under applicable law or otherwise should have been obtained prior to the completion of either or both of these transactions, or that our officers and directors breached their fiduciary duties in connection with the approval and completion of these transactions. Although we believe that stockholder approval was not required under applicable law in order to complete either or both of these transactions and therefore we neither sought nor intend to seek such stockholder approval, it is possible that persons who were stockholders at the time of the applicable transaction may claim that their approval was required, in which case litigation could follow, which could result in substantial damages to us and/or could negatively affect our rights and obligations under either of these agreements or, in the case of the Collaboration Agreement, could result in the termination of that agreement.

        Likewise, our stockholders may believe that the financial and other terms of the Collaboration Agreement are not favorable to either us or our stockholders, including any belief that the potential payments we may receive under the Collaboration Agreement are inadequate. Litigation brought by our stockholders challenging the validity of, or financial losses resulting from, these transactions could also result in claims against us by Asterias and/or Janssen, and each of the Contribution Agreement and the Collaboration Agreement provide for indemnification by us of BioTime and Janssen, respectively, against all losses and expenses relating to breaches of our representations, warranties and covenants in the applicable agreement, which could expose us to further financial obligations and damages. The occurrence of any one or more of the above could have a significant adverse impact on our business and financial condition.

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        In addition, if the results of our business and collaboration activities are not successful, including without limitation, if:

•

we or Janssen are otherwise unable to continue development of imetelstat due to actions by regulatory authorities, such as the previous full clinical hold that was placed by the FDA on our IND for imetelstat in March 2014;



•

we, Janssen or any investigators ascertain that the use of imetelstat results in significant systemic or organ toxicities, including hepatotoxicity, or other safety issues resulting in an unacceptable benefit-risk profile;



•

the conduct of previous clinical trials, such as the MF Pilot Study, and future clinical trials, such as the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, results in patient injury or death, or any failure to meet regulatory and compliance requirements;



•

the final or any preliminary results from the MF Pilot Study, or any subsequent clinical trial of imetelstat, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, are not deemed to be successful;



•

Janssen discontinues the further development of imetelstat and terminates the Collaboration Agreement; or



•

Asterias is unable to develop our stem cell assets, and we are not able to receive any royalties from the sale of any potential stem cell products by Asterias,

our stock price would likely decline, and future litigation may result. A decision adverse to our interests in any such lawsuits could result in the payment of substantial damages by us, and could have a material adverse effect on our cash flow, results of operations and financial position or could otherwise severely harm our business.

        Our business may also bring us into conflict with our licensees, licensors, or others with whom we have contractual or other business relationships, or with our competitors or others whose interests differ from ours. If we are unable to resolve those conflicts on terms that are satisfactory to all parties, we may become involved in litigation brought by or against us. For example, we are subject to the risk of possible disagreements with Janssen, including those regarding the development and/or commercialization of imetelstat, interpretation of the Collaboration Agreement and ownership of proprietary rights. In addition, in certain circumstances we may believe that we have achieved a particular milestone and Janssen may disagree with our belief. In that case, receipt of that milestone payment may be delayed or may never be received, which would adversely affect our financial condition and may require us to adjust our operating plans. While the Collaboration Agreement provides for a joint governance structure to oversee and manage worldwide regulatory, development, manufacturing and commercialization activities for imetelstat, Janssen generally will, subject to limited exceptions, have the deciding vote in the event of any disagreement. In any event, the joint governance structure contemplated by the Collaboration Agreement will be dissolved in the event that we do not exercise our U.S. Opt-In Rights, which would preclude our ability to participate in any further decision-making for imetelstat. Reliance on a joint governance structure also subjects us to the risk that changes in key management personnel that are members of the various joint committees may materially and adversely affect the functioning of these committees, which could significantly delay or preclude imetelstat development and/or commercialization. As a result of possible disagreements with Janssen, we also may become involved in litigation or arbitration, which would be time-consuming and expensive.

        Monitoring, initiating and defending against legal actions, including our currently-pending securities-related lawsuits and derivative litigation, are time-consuming for our management, likely to be expensive and may detract from our ability to fully focus our internal resources on our business

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activities. The outcome of litigation is always uncertain, and in some cases could include judgments against us that require us to pay damages, enjoin us from certain activities, or otherwise negatively affect our legal or contractual rights, which could have a significant adverse effect on our business. In addition, the inherent uncertainty of such litigation, including our currently-pending securities-related lawsuits and derivative litigation, could lead to increased volatility in our stock price and a decrease in the value of our stockholders' investment in our common stock.

RISKS RELATED TO CLINICAL AND COMMERCIALIZATION ACTIVITIES

The research and development of imetelstat is subject to numerous risks and uncertainties.

        The science and technology of telomere biology, telomerase and our proprietary oligonucleotide chemistry are relatively new. There is no precedent for the successful commercialization of a therapeutic product candidate based on these technologies. In collaboration with Janssen, we must undertake significant research and development activities to develop imetelstat, our sole product candidate, based on these technologies, which may take years to accomplish, if at all.

        Because of the significant scientific, regulatory and commercial challenges that must be overcome for the research, development and commercialization of imetelstat to be successful, the development of imetelstat in hematologic myeloid malignancies, including MF and MDS, or any other indications, may be delayed or abandoned, even after significant resources have been expended on it. Our decisions to discontinue our Phase 2 clinical trial of imetelstat in metastatic breast cancer in September 2012, and to discontinue our development of imetelstat in solid tumors with short telomeres in April 2013, are examples of this. Any further delay or abandonment of the development of imetelstat in hematologic myeloid malignancies would have a material adverse effect on our collaboration with Janssen which could result in the termination of the Collaboration Agreement. Any of these events would have severe adverse effects on our business and business prospects and likely result in the failure of our business.

Success in early clinical trials may not be indicative of results in subsequent clinical trials. Likewise, preliminary data reported by investigators from time-to-time are subject to review or verification procedures that could result in material differences to final data and may change as more patient data become available.

        A number of new drugs and biologics have shown promising results in initial clinical trials, but subsequently failed to establish sufficient safety and efficacy data to obtain necessary regulatory approvals. Data obtained from preclinical and clinical activities are subject to varying interpretations, which may delay, limit or prevent regulatory approval.

        Data from our preclinical studies and Phase 1 and Phase 2 clinical trials of imetelstat, as well as preliminary, additional or updated data from the MF Pilot Study, should not be relied upon as evidence that subsequent or larger-scale clinical trials of imetelstat will succeed. The positive efficacy results we have obtained from the Phase 2 clinical trial of imetelstat in ET may not predict the future therapeutic benefit of imetelstat, if any, in other hematologic myeloid malignancies, including MF. For example, the known LFT abnormalities and dose-limiting toxicities associated with imetelstat, such as profound thrombocytopenia and neutropenia and other safety issues, including death, that have been observed in both Geron-sponsored and investigator-sponsored trials, including the MF Pilot Study, could cause complexities in treating patients with MF and could result in the discontinuation of the MF Pilot Study and any future clinical trials of imetelstat, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement. Also, the criteria used to assess efficacy in the MF Pilot Study have not been validated for clinical use and may not be considered by the FDA or other regulatory agencies to be accurate predictors of efficacy for different endpoints that may be required by the FDA or other regulatory agencies for Phase 3 clinical trials.

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        The preliminary results of the MF Pilot Study presented by the investigator at the ASH annual meeting in December 2013 and the updated preliminary results presented at ASH in December 2014 will need to be confirmed in one or more larger Phase 2 and Phase 3 trials in MF at multiple treating centers. The results reported by us, Janssen or by the investigator in the MF Pilot Study may not be reproduced in any subsequent imetelstat trials conducted in the future, including the Initial Phase 2 MF Study or the Initial Phase 2 MDS Study planned to be conducted under the Collaboration Agreement, or by any other investigator or group of investigators, or in any trial enrolling a larger number of patients or conducted at multiple treating centers, and thus should not be relied upon as indicative of future clinical results of imetelstat in MF or any other hematologic myeloid malignancy.

        In addition, from time-to-time, we or Janssen may report or announce preliminary data from current or potential future clinical trials, such as the Initial Phase 2 MF Study and Initial Phase 2 MDS Study planned to be conducted under the Collaboration Agreement. For example, the investigator for the MF Pilot Study reported preliminary data from the trial in December 2013 and updated preliminary data in December 2014. Since those data were preliminary, the final data from the MF Pilot Study may be materially different than the data reported in December 2013 or December 2014. Since patients previously enrolled in the MF Pilot Study continue to receive imetelstat, safety and efficacy data continue to be generated, and such additional and updated data may materially change the overall conclusions from the preliminary data reported in December 2013 or December 2014. Therefore, such preliminary data should be considered carefully and with caution. Additional and updated data from the MF Pilot Study are also subject to any review or verification procedures that Janssen may conduct as the trial sponsor for the MF Pilot Study after it assumes responsibility for the conduct of the MF Pilot Study, and since this could result in material differences from the data reported by the investigator or us, additional or updated data that may be reported from the MF Pilot Study should be considered carefully and with caution. Analyses performed by Janssen may result in conclusions that are materially different from the investigator's analyses or ours, and therefore such preliminary data should be considered carefully and with caution.

        Material adverse changes in final data from the MF Pilot Study could jeopardize our Collaboration Agreement with Janssen and if Janssen were to terminate the Collaboration Agreement, our business prospects would be severely and adversely affected. Even if final safety and efficacy data from the MF Pilot Study are positive, significant additional clinical testing will be necessary for the future development of imetelstat in MF. Any such final safety and efficacy data from the MF Pilot Study may not be reproducible in future clinical trials, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement.

        Before Janssen can seek to obtain regulatory approval for the commercial sale of imetelstat, multiple clinical trials, including larger-scale Phase 3 clinical trials, will need to be conducted to demonstrate that imetelstat is safe and effective for use in a diverse population. There is typically an extremely high rate of attrition from the failure of drug candidates proceeding through clinical trials. If imetelstat cannot be developed in future clinical trials, including Phase 3 clinical trials, our Collaboration Agreement with Janssen will be negatively impacted and could be terminated altogether, which would have severe adverse effects on our business and business prospects, and likely result in the failure of our business.

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Conducting and completing potential future clinical trials of imetelstat, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, on a timely basis is subject to risks and uncertainties.

        Delays or terminations of potential future clinical trials, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, could be caused by matters such as:

•

not receiving timely regulatory clearances or approvals in any jurisdiction, whether within or outside of the United States, including, if we, Janssen or future investigators do not obtain and maintain regulatory clearance to commence studies of imetelstat in MF, MDS or any additional hematologic myeloid malignancies in a timely manner or at all, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement;



•

the inability by Janssen to maintain the INDs for imetelstat that we expect to transfer to Janssen, including the IND for the MF Pilot Study, without such INDs being placed on full or partial clinical hold by the FDA;



•

the inability to properly design, conduct and/or complete current and potential future clinical trials of imetelstat including the MF Pilot Study and the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study;



•

data showing lack of effectiveness of imetelstat during clinical trials, or results that do not demonstrate statistically significant efficacy;



•

safety issues, side effects or dose-limiting toxicities, including any additional or more severe safety issues related to imetelstat in addition to those which have been observed to date in Geron-sponsored or investigator-sponsored trials, whether or not in the same indications or therapeutic areas;



•

disruptions due to drug supply or quality issues;



•

not receiving acceptance of new manufacturing specifications or procedures or clinical trial protocol amendments by regulatory authorities;



•

failure by investigators conducting future clinical trials of imetelstat, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, to timely commence, enroll, complete or report data from such clinical trials;



•

not receiving timely institutional review board or ethics committee approval of clinical trial protocols or protocol amendments;



•

delays in patient enrollment due to size or nature of patient population, nature of protocols, proximity of patients to clinical sites, availability of effective treatments for the relevant disease and eligibility criteria for the trial;



•

inability to retain patients to complete clinical trials or to return for post-treatment follow-up;



•

difficulty in obtaining or accessing necessary clinical data, including additional and future data from the MF Pilot Study, which may result in incomplete data sets;



•

unavailability of any study-related treatment (including comparator therapy);



•

issues or disputes with key vendors of clinical services, such as contract research organizations, clinical trial sites and laboratory service providers; or

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•

governmental or regulatory delays in any jurisdiction, whether within or outside of the United States, information requests, clinical holds, such as the previous clinical holds placed by the FDA on our IND for imetelstat and the IND for the MF Pilot Study, and changes in regulatory requirements, policies and guidelines.

        Advancing clinical development of imetelstat in the United States is dependent on obtaining positive results from existing and potential future clinical trials of imetelstat in hematologic myeloid malignancies, including the MF Pilot Study and the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement. Obtaining additional and future data from the MF Pilot Study may provide additional insights into the further development of imetelstat for MF, MDS or AML, including with respect to Janssen's ability to initiate the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement. Accordingly, a delay in the timely completion of the MF Pilot Study, including any delay caused by any future clinical hold placed by the FDA on the INDs for imetelstat, including the IND for the MF Pilot Study, that we plan to transfer to Janssen prior to initiation of the Initial Phase 2 MF Study, could have a material adverse effect on advancing the development of imetelstat to subsequent clinical trials, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement. Also, adverse safety results from clinical trials of imetelstat, including those results that have been reported and those that may in the future be reported from the MF Pilot Study or the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, could delay or prevent the initiation or continuation of further clinical development of imetelstat, whether under the Collaboration Agreement or otherwise. Occurrence of any of these events would delay the timing of any Continuation Decision Janssen could provide to us or could cause Janssen to terminate the Collaboration Agreement which would severely and adversely affect the future of imetelstat and our business prospects.

        In addition, enrollment goals for potential future clinical trials of imetelstat, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, may not be met. The inability to retain or treat patients who have enrolled in a clinical trial but may be prone to withdraw due to side effects from imetelstat, lack of efficacy or personal issues, or who are lost to further follow-up, could result in clinical trial delays, the inability to complete clinical trials, or incomplete data sets. Further, any future clinical trials may be overseen by a safety monitoring committee, which may determine to significantly modify, delay or suspend one or more of these trials due to safety or futility findings based on emerging data occurring during a clinical trial. Data that we have received or that we or Janssen may in the future receive from investigators may be flawed or incomplete if the investigators fail to follow appropriate clinical or quality practices. Delays in timely initiation or completion of clinical testing of imetelstat could increase research and development costs and could prevent or would delay obtaining regulatory approval for imetelstat, either of which would delay the timing of any Continuation Decision Janssen could provide to us or could cause Janssen to terminate the Collaboration Agreement which would severely and adversely affect the future of imetelstat and our business prospects.

Obtaining regulatory clearances and approvals to develop and market imetelstat in the United States and other countries is a costly and lengthy process, and we cannot predict whether or when regulatory authorities will permit additional imetelstat development or approve imetelstat for commercial sale.

        Federal, state and local governments in the United States and governments in other countries have significant regulations in place that govern drug research and development and may prevent us, in collaboration with Janssen, from successfully conducting development efforts or from commercializing imetelstat. Imetelstat must receive all relevant regulatory approvals before it may be marketed in the United States or other countries. Obtaining regulatory approval is a lengthy, expensive and uncertain

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process. Because imetelstat involves the application of new technologies and a new therapeutic approach, it may be subject to substantial additional review by various government regulatory authorities, and, as a result, the process of obtaining regulatory approvals for imetelstat may proceed more slowly than for product candidates based upon more conventional technologies, and any approval that may be received could limit the use of imetelstat.

        Prior to initiating future clinical trials of imetelstat, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement, the clinical trial protocols must be submitted to the FDA or regulatory authorities in other countries. Questions or comments from these agencies that must be addressed would likely delay further clinical development of imetelstat and the timing of any Continuation Decision by Janssen or could cause Janssen to terminate the Collaboration Agreement, which would severely and adversely affect the future of imetelstat and our business prospects.

        Prior to submission of any regulatory application seeking approval to commence commercial sales of imetelstat, extensive preclinical and clinical testing will be required to be conducted. If the interpretation of safety and efficacy data obtained from these preclinical and clinical studies varies from interpretations by the FDA or regulatory authorities in other countries, this would likely delay, limit or prevent further development and approval of imetelstat which may cause Janssen to terminate the Collaboration Agreement. For example, the FDA and regulatory authorities in other countries may require more or different data than what has been generated from our preclinical studies and our prior Geron-sponsored Phase 2 clinical trials or the MF Pilot Study or that may be generated by potential future clinical trials, including the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement. In addition, delays or rejections of regulatory approvals, or limitations in marketing authorizations, may be encountered as a result of changes in regulatory environment or regulatory agency policy during the period of product development and/or the period of review of any application for regulatory agency approval for imetelstat. We do not expect imetelstat to be approved for commercial sale for many years, if at all.

        Delays in obtaining regulatory agency clearances and approvals or limitations in the scope of such clearances or approvals could:

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significantly harm the commercial potential of imetelstat;



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impose costly procedures upon future development activities;



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diminish any competitive advantages that may have been available; or



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adversely limit the amount of, or affect our ability to receive, any milestone payments or royalties under the Collaboration Agreement with Janssen.

        Even if the necessary time and resources are committed by us and Janssen, the required regulatory agency clearances and approvals may not be obtained for imetelstat. Even if regulatory agency clearances and approvals are obtained to commence commercial sales of imetelstat, they may entail limitations on the indicated uses or other aspects of the product label for which imetelstat can be marketed, which could limit the potential commercial use of imetelstat, or an approval might be contingent on the performance of costly additional clinical trials that would be required after approval. The occurrence of any of these events could delay any applications for regulatory approval and therefore delay the payment of potential milestone payments to us, or, if approved for commercial sale, could reduce the market demand for imetelstat and therefore result in decreased sales and reduced royalties for us under the Collaboration Agreement. Occurrence of any of these events could negatively impact our collaboration with Janssen or cause Janssen to terminate the Collaboration Agreement, which would severely and adversely affect our business and business prospects.

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Failure to achieve continued compliance with government regulation could delay or halt commercialization of imetelstat, our sole product candidate.

        Approved products and their manufacturers are subject to continual review, and discovery of previously unknown problems with a product or its manufacturer may result in restrictions on the product or manufacturer, including import restrictions, seizure and withdrawal of the product from the market. If approved for commercial sale, future sales of imetelstat will be subject to government regulation related to numerous matters, including the processes of:

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manufacturing;



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advertising and promoting;



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selling and marketing;



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labeling; and



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distribution.

If, and to the extent that, we are or Janssen is unable to comply with these regulations, our ability to earn potential milestone payments and royalties from worldwide net sales of imetelstat would be materially and adversely impacted.

        Failure to comply with regulatory requirements can result in severe civil and criminal penalties, including but not limited to:

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recall or seizure of products;



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injunctions against the import, manufacture, distribution, sales and/or marketing of products; and



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criminal prosecution.

The imposition of any of these penalties or other commercial limitations could negatively impact our collaboration with Janssen or cause Janssen to terminate the Collaboration Agreement, either of which would severely and adversely affect our business and business prospects.

Janssen's development activities conducted under a Janssen Independent Development Plan, or IDP, may create significant reimbursement obligations for us, which could result in reduced cash inflow from future milestone payments and royalties until we have fully paid our obligations.reimbursement obligations under the Collaboration Agreement.

Under the Collaboration Agreement, Janssen may conduct certain development activities for imetelstat under a Janssen IDP, if we and Janssen agree that such activities should be performed outside of the mutually agreed global clinical development plan. Although Janssen would bear all of the costs for such Janssen IDP, if we exercised our U.S. Opt-In Rights and if any data from a Janssen IDP supports approval by a regulatory agencyauthority in the United States or other countries, then we would be required to reimburse Janssen for our share of the costs of that Janssen IDP plus a premium pursuant to the terms of the Collaboration Agreement. This cost reimbursement is payable as a lump sum up to a certain threshold upon receipt of regulatory approval for the Janssen IDP. Any remaining amounts in excess of the threshold are payable in installments by offsetting milestone payments or royalties received by us over a certain period of time, at which time any remaining reimbursement amount would be payable in a lump sum. This payment mechanism could result in reduced cash inflow from future milestone payments and royalties, which would adversely affect our results of operations and financial condition.

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Under the Collaboration Agreement, with Janssen, if we develop imetelstat independently under our own IDP, the success of that IDP may dependdepends on providingour ability to provide adequate financial and technical resources. Failure to successfully conduct or fund our own IDP activities may adversely affect our business.

Under the Collaboration Agreement, with Janssen, we may conduct certain development activities for imetelstat under a Geron IDP if we and Janssen agree that such activities should be performed outside of the mutually agreed global clinical development plan. In the event we conduct any clinical activities under a Geron IDP, we will be responsible for paying all of the development costs for the Geron IDP. Because the outcome of any clinical activities and/or regulatory approval process is highly uncertain, we cannot reasonably estimate whether any Geron IDP activities we may undertake will succeed. Since we are only eligible for reimbursement from Janssen for their share of the Geron IDP costs plus a premium if any data from a Geron IDP supports approval by a regulatory agencyauthority in the United States or other countries, we may not recoup our investment in any Geron IDP, which could adversely affect our financial condition. In addition, we may need additional capital to support any Geron IDP activities and we cannot assure you that our existing capital resources, future interest income, potential milestone payments and royalties under the Collaboration Agreement and potential future sales of our common stock will be sufficient to fund these future activities. If sufficient capital is not available, we may be unable to pursue activities under a Geron IDP, which could adversely affect our business.

To execute activities under a Geron IDP, we likely would be required to collaborate with contract research organizations, investigators, academic institutions, vendors, clinical trial sites, scientific consultants and others. We would be dependent upon the ability of these parties to perform their responsibilities reliably. In addition, we would have limited control over the activities of these organizations, investigators, scientific consultants and vendors. Except as otherwise required by our agreements with them, we could expect only limited amounts of their time to be dedicated to our activities. If any of these third parties were unable or refuserefused to contribute to projects on which we needed their help, our ability to conduct activities under a Geron IDP could be significantly harmed. Also, if the performance of these services is not of the highest quality, does not achieve necessary regulatory compliance standards, or if such organization or vendor stops or delays its performance for any reason, it would impair and delay our ability to report data from clinical activities under a Geron IDP which would, in turn, hinder our ability to make the necessary representations or provide the necessary information to regulatory authorities, if at all. As a result, we may not obtain regulatory approval and receive any reimbursement from Janssen for their share of the costs for the Geron IDP, which could adversely affect our business and financial condition.

WeIf Janssen makes an affirmative Continuation Decision under the Collaboration Agreement, our decision to exercise our U.S. Opt-In Rights must thereafter be made within a short timeframe and, as a result, we may be required to invest substantial capital based on limited clinical data and information.

If Janssen makes an affirmative Continuation Decision under the Collaboration Agreement, we must decide whether to elect to exercise our U.S. Opt-In Rights within a short timeframe following such a decision, and although we expect to receive information from Janssen regarding data from IMbark and IMerge, proposed future clinical development plans and costs for imetelstat, estimates in timing for commercializing imetelstat and related promotional activities, and a calculation of our share of development costs incurred to date by Janssen that we will be dependentrequired to reimburse if we exercise our U.S. Opt-In Rights, we will be required to rapidly decide whether to make a substantial capital investment in imetelstat prior to the conclusion of any Phase 3 registration-enabling clinical trial. Accordingly, if we exercise our U.S. Opt-In Rights and imetelstat were to become unsuccessful in any Phase 3 registration-enabling clinical trial or were to fail to receive regulatory approval, we would not receive any financial return on this substantial capital investment. Such an occurrence would negatively impact our financial condition and results of operations, and might cause us to cease operations.

RISKS RELATED TO CLINICAL DEVELOPMENT, REGULATORY APPROVAL AND COMMERCIALIZATION OF IMETELSTAT

The research and development of imetelstat is subject to numerous risks and uncertainties.

The science and technology of telomere biology, telomerase and our proprietary oligonucleotide chemistry are relatively new. There is no precedent for the successful commercialization of a therapeutic product candidate based on these technologies. Significant research and development activities will be necessary to further develop imetelstat, which is our sole product candidate that we have exclusively outlicensed to Janssen, which may take years to accomplish, if at all.

Because of the significant scientific, regulatory and commercial challenges that must be overcome to successfully research, develop and commercialize imetelstat, the development of imetelstat in hematologic myeloid malignancies, including MF and MDS, or any other indications, may be further delayed or abandoned, even after significant resources have been expended on it. Examples of such decisions include:

Any further delay, suspension or abandonment of the development of imetelstat in hematologic myeloid malignancies, including delays resulting from potential future protocol amendments for IMerge, IMbark or potential future clinical trials of imetelstat, would have a material adverse effect on our collaboration with Janssen, which could result in the termination of the Collaboration Agreement. Any of these events would have severe adverse effects on the future of imetelstat and our business prospects and likely result in the failure of our business.

Imetelstat may cause, or have attributed to it, undesirable or unintended side effects or other adverse events that delay or prevent the commencement and/or completion of clinical trials for imetelstat, delay or prevent its regulatory approval, or limit its commercial potential.

Imetelstat may cause, or have attributed to it, undesirable or unintended side effects or other adverse events affecting its safety or efficacy that could cause Janssen to interrupt, delay or halt current or potential future clinical trials of imetelstat. For example, adverse events and dose limiting toxicities observed in previous clinical trials of imetelstat include:

Such adverse events and other safety issues, including deaths, have also been observed by Janssen in IMbark and IMerge. If patients in current or potential future clinical trials of imetelstat experience similar or more severe adverse events, or new or unusual adverse events, or if the FDA or other regulatory authorities determine that efficacy and safety data in current or potential future clinical trials of imetelstat, do not support an adequate benefit-risk profile to justify continued treatment of patients, then the FDA or other regulatory authorities may again place the INDs for imetelstat on clinical hold, as occurred in March 2014.

Further, clinical trials by their nature examine the effect of a potential therapy in a sample of the potential future patient population. As such, clinical trials conducted with imetelstat, to date and in the future, may not uncover all possible adverse events that patients treated with imetelstat may experience. Because remaining patients in the treatment phase continue to receive imetelstat in the Pilot Study, IMbark and IMerge, including the expanded Part 1, additional or more severe toxicities or safety issues, including additional serious adverse events and dose limiting toxicities, may be observed as patient treatment continues and more data become available. In addition, since IMbark, IMerge and the Pilot Study are ongoing studies in which additional data are being generated, the benefit-risk profile of imetelstat will continue to be assessed, including the risk of hepatotoxicity, severe cytopenias, fatal bleeding with or without any associated thrombocytopenia, patient injury or death, and any other severe adverse effects that may be associated with life-threatening clinical outcomes. If such toxicities or other safety issues in any clinical trial of imetelstat are determined by Janssen, the FDA or any other regulatory authority to result in an unacceptable benefit-risk profile, then:

The occurrence of any of these events could cause Janssen to further delay its Continuation Decision, or abandon the development of imetelstat entirely and terminate the Collaboration Agreement. Any termination of the

Collaboration Agreement by Janssen would have a severe adverse effect on our results of operations, financial condition, business prospects and the future of imetelstat, any of which might cause us to cease operations.

Success in early clinical trials may not be predictive or indicative of results in current clinical trials or potential future clinical trials. Likewise, preliminary data from clinical trials should be considered carefully and with caution since the final data may be materially different from the preliminary data, particularly as more patient data become available.

A number of new drugs and biologics have shown promising results in preclinical studies and initial clinical trials, but subsequently have failed to establish sufficient safety and efficacy data to obtain necessary regulatory approvals to initiate commercial sale. There is typically an extremely high rate of attrition from the failure of product candidates proceeding through clinical trials. Data obtained from preclinical and clinical activities are subject to varying interpretations, which may delay, limit or prevent regulatory approval. Product candidates in later stages of clinical trials may fail to show the desired benefit-risk profile despite having progressed through preclinical studies and initial clinical trials.

Data from our preclinical studies and Phase 1 and Phase 2 clinical trials of imetelstat, including the Pilot Study, as well as the results of the past or future internal data reviews conducted by Janssen for IMbark and IMerge, should not be relied upon as predictive or indicative of future clinical results, including any final results in the Pilot Study, IMbark or IMerge or the results in potential subsequent or larger-scale clinical trials of imetelstat. The results we obtained from the ET Trial and the Pilot Study and the results that have been obtained by Janssen in the internal data reviews conducted for IMbark and IMerge, as well as any future results that may be obtained by Janssen from IMbark and IMerge, may not predict the future therapeutic effect of imetelstat, if any, in hematologic myeloid malignancies, including MF and MDS. For example, the potential disease-modifying activity observed through molecular responses in the ET trial and partial or complete remissions observed in the Pilot Study may not be seen in current or future clinical trials of imetelstat. Since remaining patients in the treatment phase for the Pilot Study, IMbark and IMerge, including the expanded Part 1, continue to receive imetelstat, efficacy and safety data continue to be generated. Such additional and updated data may materially change the overall conclusions from the preliminary data reported for the Pilot Study, IMbark or IMerge. In addition, such additional and updated efficacy and safety data may not support an adequate benefit-risk profile to justify continued treatment of patients enrolled in current clinical trials of imetelstat. Also, the criteria used to assess efficacy in the Pilot Study have not been validated for clinical use and may not be considered by the FDA or other regulatory authorities to be accurate predictors of efficacy for different endpoints that may be required by the FDA or other regulatory authorities for Phase 3 clinical trials.

From time-to-time, preliminary or interim data from current clinical trials, such as the Pilot Study, IMbark and IMerge, or potential future clinical trials, may be reported or announced by Janssen, its investigators, or us. For example, preliminary results of the Pilot Study were presented by the investigator at the American Society of Hematology, or ASH, annual meeting in December 2013, and updated by the investigator at ASH in December 2014, and preliminary data were reported by the investigator from a cohort of MDS patients in the Pilot Study in December 2015. In addition, preliminary data from Part 1 of IMerge was announced in November 2017 and presented at ASH in December 2017. Since such data are preliminary, the final data from any final analysis which may be conducted, or any future analyses of the Pilot Study, IMbark or IMerge, or potential future clinical trials of imetelstat, may be materially different. In addition, changes in study design, including changes in patient enrollment criteria and target patient population, such as the decision to expand enrollment in Part 1 of IMerge for patients in a refined target population, may cause data from later stage clinical trials to differ significantly from data obtained in earlier clinical trials. Preliminary or interim results from the Pilot Study, IMbark or IMerge reported by us, Janssen or by investigators in those trials may not be reproduced in any potential future clinical trials of imetelstat, and thus should not be relied upon as indicative of future clinical results of imetelstat in MF, MDS or in any other hematologic myeloid malignancy. Preliminary or interim data should be considered carefully and with caution.

Material adverse differences in final data, compared to preliminary or interim data, from the Pilot Study, IMbark or IMerge, or potential future clinical trials of imetelstat, could result in a decision by Janssen to discontinue the imetelstat program, further delay its Continuation Decision, or terminate the Collaboration Agreement, any of which would severely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations. Even if final safety and/or efficacy data from the Pilot Study, IMbark or IMerge or potential future clinical trials of imetelstat are positive, significant additional clinical testing will be

necessary to advance the future development of imetelstat in hematologic myeloid malignancies, including MF or MDS.

Clinical development involves a lengthy and expensive process with uncertain outcomes. Current clinical trials of imetelstat being conducted by Janssen, including IMbark, IMerge and the Pilot Study, and potential future clinical trials of imetelstat may fail to demonstrate sufficient safety and efficacy of imetelstat to warrant further development of the drug, which could prevent or further delay regulatory approval and commercialization of imetelstat.

Before regulatory approvals for the commercial sale of imetelstat can be obtained, clinical testing must be conducted to show that imetelstat is both safe and effective for use in each target indication. Such clinical testing is expensive, can take many years to complete and is inherently uncertain. Failure can occur at any time during clinical testing. Most product candidates that commence clinical trials are never approved as commercial products.

The clinical development of imetelstat will be influenced by results from current clinical trials being conducted by Janssen and third partiespotential future clinical trials of imetelstat. The advancement of current clinical trials of imetelstat and commencement of potential future clinical trials of imetelstat could be further delayed or abandoned for a variety of reasons, including as a result of failures or delays by Janssen in:

Failures or delays with respect to any of these events could adversely affect Janssen’s ability to continue or successfully complete any current clinical trials of imetelstat or to initiate potential future clinical trials of imetelstat, which could increase development costs, further delay the timing of the Continuation Decision from Janssen, impair our ability to earn revenues from milestone payments or royalties under the Collaboration Agreement or cause Janssen to terminate the Collaboration Agreement, any of which could severely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations.

If Janssen encounters difficulties enrolling or retaining patients in current or potential future clinical trials of imetelstat, including the expanded Part 1 of IMerge, clinical development and commercialization activities could be further delayed or otherwise adversely affected, which would cause our business and business prospects to be severely harmed.

The timely completion of a clinical trial in accordance with its protocol depends, among other things, on the ability to enroll a sufficient number of patients who remain in the trial until its conclusion. Janssen may experience difficulties in patient enrollment or retention in IMbark and IMerge, including the expanded Part 1, or potential future clinical trials of imetelstat, for a variety of reasons. The enrollment and retention of patients depends on many factors, including:

In addition, IMbark and IMerge compete, and potential future clinical trials of imetelstat will compete, with other clinical trials for product candidates that are in the same therapeutic areas with imetelstat, and this competition will reduce the number and type of patients available to enroll or remain in the imetelstat clinical trials. Since the number of qualified clinical investigators is limited, IMbark and IMerge are being conducted, and potential future

clinical trials of imetelstat are expected to be conducted, at the same clinical trial sites that competitors use, which will reduce the number of patients who are available for the imetelstat clinical trials at such clinical trial sites. Moreover, because imetelstat represents a departure from more commonly used methods for cancer treatment, potential patients and their doctors may be inclined to use conventional therapies, rather than enroll patients into imetelstat clinical trials.

Delays in patient enrollment or the inability to retain or treat patients could result in increased costs, lead to incomplete data sets, or adversely affect the timing or outcome of current or potential future clinical trials of imetelstat, which could prevent completion of these trials and adversely affect the clinical development and commercialization of imetelstat. For example, delays in or the inability to collect sufficient safety and efficacy data from the expanded Part 1 of IMerge will delay or potentially preclude an assessment of clinical benefit, if any, in the refined target patient population in Part 1. For IMbark, if the data necessary for the protocol-specified primary analysis are not available as a result of patient withdrawals from the trial, insufficient follow-up time, and/or inability to collect follow-up data on such patients, then Janssen will be unable to assess overall survival in IMbark. If Janssen is unable to assess overall survival in IMbark or believes there is not an adequate improvement in survival, we believe Janssen would decide to discontinue the imetelstat program and terminate the Collaboration Agreement. However, Janssen could discontinue the imetelstat program and terminate the Collaboration Agreement at any time and for any reason, irrespective of whether there is data from IMbark suggesting an adequate improvement in survival in relapsed or refractory MF or whether there is data from IMerge to support the benefit-risk profile of imetelstat in lower risk MDS. Such occurrences would severely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations.

Obtaining regulatory clearances and approvals to continue clinical development of, and in the future, to potentially market imetelstat in the United States and other countries, is a costly and lengthy process, and we cannot predict whether or when regulatory authorities will permit additional imetelstat development or approve imetelstat for commercial sale.

Federal, state and local governments in the United States and governments in other countries have significant regulations in place that govern drug research and development and may prevent us, in collaboration with Janssen, from successfully conducting development efforts or from commercializing imetelstat. Delays in obtaining regulatory clearances and approvals or limitations in the scope of such clearances or approvals could:

Prior to initiating potential future clinical trials of imetelstat, clinical trial protocols must be submitted to the FDA or regulatory authorities in other countries. Questions or comments from these agencies regarding any protocol amendments of current clinical trials of imetelstat, including IMbark or IMerge, or protocols for potential future clinical trials of imetelstat, must be addressed in a timely and adequate manner. The inability to timely or adequately address any questions, comments or requests for information from regulatory authorities could impede further clinical development of imetelstat, which could cause Janssen to further delay its Continuation Decision or discontinue the imetelstat program entirely and terminate the Collaboration Agreement, which would severely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations.

Before Janssen can seek to obtain regulatory approval for the commercial sale of imetelstat, multiple clinical trials, including larger-scale Phase 3 clinical trials, will need to be conducted to demonstrate if imetelstat is safe and effective for use in a diverse population. If imetelstat cannot be developed in potential future clinical trials, including Phase 3 clinical trials, our Collaboration Agreement with Janssen will be negatively impacted and likely be terminated

altogether, which would have severe adverse effects on our business and business prospects, and might result in the failure of our business.

If the interpretation by Janssen or us of safety and efficacy data obtained from preclinical and clinical studies varies from interpretations by the FDA or regulatory authorities in other countries, this would likely delay, limit or prevent further development and approval of imetelstat which may cause Janssen to terminate the Collaboration Agreement. For example, the FDA and regulatory authorities in other countries may require more or different data than what has been generated from our preclinical studies and previous or ongoing clinical trials, such as IMbark, IMerge or the Pilot Study. In addition, delays or rejections of regulatory approvals, or limitations in marketing authorizations, may be encountered as a result of changes in the regulatory environment or regulatory policy during the period of product development and/or the period of review of any application for regulatory approval for imetelstat.

The benefit-risk profile of imetelstat will also affect the assessment by the FDA and regulatory authorities in other countries of the drug’s cost-effectiveness and/or marketability, which assessment could prevent or limit its approval for marketing and successful commercial use. If regulatory submissions requesting approval to market imetelstat are submitted, the FDA and regulatory authorities in other countries may conclude that the overall benefit-risk profile of imetelstat treatment does not merit approval of imetelstat for marketing or further development for any indication. Any of these events could cause Janssen to terminate the Collaboration Agreement, which would severely harm our business and business prospects, and might cause us to cease operations.

Imetelstat must receive all relevant regulatory approvals before it may be marketed in the United States or other countries. Obtaining regulatory approval is a lengthy, expensive and uncertain process. For example in June 2016, the electorate in the United Kingdom voted in favor of exiting the European Union, and in March 2017, the Government of the United Kingdom initiated the formal procedure of withdrawal from the European Union. Although the impact of the withdrawal of the United Kingdom from the European Union will not be known for some time, this could lead to a period of considerable uncertainty in relation to the regulatory process in Europe, which could result in a delay in the review of regulatory submissions made in Europe by biotechnology and pharmaceutical companies, and could also lead to less efficient, more expensive, and potentially lengthier regulatory review processes for companies, including Janssen and us, who may seek to obtain regulatory approval for drug products in the European Union or the United Kingdom. Likewise, the Trump Administration has appointed and employed and will appoint and employ many new secretaries, directors and the like into positions of authority in the U.S. federal government dealing with the pharmaceutical and healthcare industries that may potentially have a negative impact on the prices and the regulatory pathways for pharmaceuticals. Such changes could adversely affect and/or delay the ability of Janssen to obtain approval of, and market and sell, imetelstat in the United States. In addition, because imetelstat involves the application of new technologies and a new therapeutic approach, it may be subject to substantial additional review by various government regulatory authorities, and, as a result, the process of obtaining regulatory approvals for imetelstat may proceed more slowly than for product candidates based upon more conventional technologies, and any approval that may be received could limit the use of imetelstat. We do not expect imetelstat to be approved for commercial sale for many years, if at all.

Even if the necessary time and resources are committed by Janssen, the required regulatory clearances and approvals may not be obtained for imetelstat. Further, if regulatory clearances and approvals are obtained to commence commercial sales of imetelstat, they may impose significant limitations on the indicated uses or other aspects of the product label for which imetelstat can be marketed. An approval might also be contingent on the performance of costly additional post-marketing clinical trials. The occurrence of any of these events could limit the potential commercial use of imetelstat, and therefore delay the payment of potential milestone payments to us, or, if approved for commercial sale, could reduce the market demand for imetelstat and therefore result in decreased sales for Janssen and reduced royalties for us under the Collaboration Agreement. Occurrence of any of these events could negatively impact our collaboration with Janssen or cause Janssen to terminate the Collaboration Agreement, which would severely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations.

Although orphan drug designation has been granted to imetelstat for the treatment of MF and MDS, these designations may not be maintained, which would eliminate the benefits associated with orphan drug designation, including the potential for market exclusivity, which would likely result in the reduction of potential imetelstat sales revenue for Janssen, if any, and would likely harm our business and business prospects.

Although the FDA granted orphan drug designation to imetelstat in June 2015 for the treatment of MF and for the treatment of MDS in December 2015, and the European Medicines Agency, or EMA, granted it in December 2015 for the treatment of MF, Janssen may not be the first to obtain marketing approval of a product candidate for the orphan-designated indication due to the uncertainties associated with developing pharmaceutical products. In addition, exclusive marketing rights in the United States or the European Union, if granted, may be limited if Janssen seeks approval for an indication broader than the orphan-designated indication or such marketing exclusivity may be lost if the FDA or the EMA later determines that the request for orphan drug designation was materially defective, or if Janssen is unable to ensure and provide sufficient quantities of imetelstat to meet the needs of patients with the rare disease or condition. Further, even if Janssen obtains orphan drug exclusivity for imetelstat, that exclusivity may not effectively protect imetelstat from competition because different drugs with different active moieties can be approved for the same condition. Even after an orphan drug product is approved, the FDA or EMA can subsequently approve a different drug with the same active moiety for the same condition if the FDA or EMA concludes that the later drug is safer, more effective, or makes a major contribution to patient care. The occurrence of any of these events could result in decreased sales for Janssen and reduced royalties for us, and may harm our business and business prospects. In addition, orphan drug designation will neither shorten the development time nor regulatory review time for imetelstat, and does not give imetelstat any advantage in the regulatory review or approval process.

A fast track designation by the FDA, such as the Fast Track designation received for imetelstat, does not guarantee approval and may not lead to a faster development, regulatory review or approval process.

In October 2017, following submission by Janssen of an application to the FDA requesting fast track designation for the imetelstat clinical development program for the treatment of adult patients with transfusion-dependent anemia due to Low or Intermediate-1 risk MDS who are non-del(5q) and who are refractory or resistant to treatment with an ESA, the FDA notified Janssen that imetelstat has been granted such fast track designation. Fast track designation provides opportunities for frequent interactions with FDA review staff, as well as eligibility for priority review, if relevant criteria are met, and rolling review. Fast track designation is intended to facilitate and expedite development and review of a New Drug Application to address unmet medical needs in the treatment of serious or life-threatening conditions. However, fast track designation does not accelerate conduct of clinical trials or mean that the regulatory requirements are less stringent, nor does it ensure that imetelstat will receive marketing approval or that approval will be granted within any particular timeframe. In addition, the FDA may withdraw fast track designation if it believes that the designation is no longer supported by data emerging from the imetelstat clinical development program.

Failure to achieve continued compliance with government regulations could delay or halt commercialization of imetelstat, which we have exclusively outlicensed to Janssen.

Approved products and their manufacturers are subject to continual review, and discovery of previously unknown problems with a product or its manufacturer may result in restrictions on the product or manufacturer, including import restrictions, seizure and withdrawal of the product from the market. If approved for commercial sale, future sales of imetelstat will be subject to government regulation related to numerous matters, including the processes of:

If, and to the extent that, we are or Janssen is unable to comply with these regulations, our ability to earn potential milestone payments and royalties from worldwide net sales of imetelstat would be materially and adversely impacted.

Failure to comply with regulatory requirements can result in severe civil and criminal penalties, including but not limited to:

The imposition of any of these penalties or other commercial limitations could negatively impact our collaboration with Janssen or cause Janssen to terminate the Collaboration Agreement, either of which would severely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations.

RISKS RELATED TO MANUFACTURING IMETELSTAT

Failure by Janssen to manufacture or provide adequate clinical and commercial quantities of imetelstat which couldon a timely basis, or at all, would result in a delay of clinical trials or regulatory approvalapprovals, or lost sales.sales, and our business and business prospects could be severely harmed.

        UnderIn accordance with the Collaboration Agreement, after a transition period, Janssen will beis responsible for the manufacture and/or manageand management of the supply of imetelstat on a global basis for all clinical trials and all commercial activities. Consequently, we will be,are, and expect to remain, dependent on Janssen to appropriately supply imetelstat. Janssen may encounter difficulties inimetelstat and other clinical trial materials. The process of manufacturing imetelstat is complex and subject to several risks, including:

As a result of these risks, Janssen may not perform as agreed or may default in its obligations to supply imetelstat or other clinical trial materials for clinical trials and/or commercial activities. Janssen also may fail to deliver the required quantities of imetelstat or other clinical trial materials on a timely basis.basis, or at required or applicable quality standards. If Janssen were to terminate the Collaboration Agreement, and we chose to pursue imetelstat development independently, we would be reliant upon Janssen for the manufacture and supply of adequate clinical quantities of imetelstat or other clinical trial materials, until such time as we could establish our own independent third-party manufacturers or suppliers, which might not be feasible for a significant period of time, and could significantly delay our ability to further develop imetelstat independently. Any such failure by Janssen to supply imetelstat or other clinical trial materials for clinical trials and/or commercial activities, including to us in the event that the Collaboration Agreement was terminated, could delay current and/or potential future clinical trials and any applications for regulatory approval and therefore delay the payment of potential milestone payments to us, or, if approved for commercial sale, could impair Janssen'sJanssen’s ability to meet the market demand for imetelstat and therefore result in decreased sales for Janssen and reduced royalties for us.us which would severely and adversely affect our financial results, business and business prospects, and might cause us to cease operations.

If third parties that manufacture imetelstat fail to perform as needed, then the clinical and commercial supply of imetelstat will be limited.

Currently, third-party contractors perform certain process development or other technical and scientific work with respect to imetelstat, as well as supply starting materials and manufacture drug

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substance and drug product. We do not have direct control over their personnel or operations. We relyJanssen, which is responsible for the manufacture and management of the supply of imetelstat on a global basis for clinical trials and, after any regulatory approval, all commercial activities, currently relies on these third-party contractors to produce and deliver sufficient quantities of imetelstat and other clinical trial materials to support clinical trials on a timely basis and to comply with applicable regulatory requirements. If requested by Janssen wedoes not have direct control over these third-party personnel or operations. Reliance on these third-party manufacturers is subject to numerous risks, including:

Each of these or other reasonsrisks could lead to delays or shortages in drug supply.supply, or the inability to manufacture drug supply necessary for preclinical and clinical activities, and commercialization. In addition, any decision by Janssen to self-manufacture imetelstat, change third-party manufacturers or make changes to manufacturing processes, product vial size or packaging, or formulations for imetelstat, could result in manufacturing delays. Manufacturing delays could adversely impact the initiation or completion of futurecurrent clinical trials, such as the Initial Phase 2 MF StudyIMbark and IMerge, or the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement,initiation of potential future clinical trials, which may cause Janssen to terminate the Collaboration Agreement or further delay the timing of any Continuation Decision that Janssen could provide to us, either of which would severely and adversely affect our financial results, business prospects.and business prospects, and the future of imetelstat, and might cause us to cease operations.

In addition, current third-party contractors and/or any other contractors utilized by Janssen may need to make substantial investments to enable sufficient capacity increases and cost reductions, and to implement those regulatory and compliance standards necessary for successful Phase 3 clinical trials and commercial production.production of imetelstat. These third-party contractors may not be able to achieve such capacity increases, cost reductions, or regulatory and compliance standards, and even if they do, such achievements may not be at commercially reasonable costs. Neither we nor Janssen currently does not have any long-term commitments or commercial supply agreements with any of the third-party contractors for imetelstat, and changing manufacturers may be prolonged and difficult due to inherent technical complexities and because the number of potential manufacturers is limited. It may be difficult or impossible for Janssen to find a replacement manufacturer on acceptable terms, or at all.

        There are other risks and uncertainties with respect to manufacturing that could adversely impact the initiation or completion of future clinical trials. For example, certain commonly used reagents and solvents may experience market shortages and, if these shortages occur, such shortages may adversely impact the ability to manufacture imetelstat. If a significant issue arises regarding manufacturing, this may cause Janssen to terminate the Collaboration Agreement or delay the timing of any Continuation Decision that Janssen could provide to us, either of which would severely and adversely affect our business prospects.

ImetelstatIt may not be ablepossible to be manufacturedmanufacture imetelstat at costs or scales necessary to conduct clinical trials or potential future commercialization activities.

Oligonucleotides are relatively large molecules produced using complex chemistry, and the cost of manufacturing an oligonucleotide like imetelstat is greater than the cost of making typical small-molecule drugs. Therefore, imetelstat for clinical use is more expensive to manufacture than most other treatments currently available today or that may be available in the future. Similarly, the cost of manufacturing imetelstat for commercial use will need to be significantly lower than our current costs in order for imetelstat to become a commercially successful product. However, Janssen may not be able to achieve sufficient scale increases or cost reductions necessary for successful commercial production of imetelstat, whichimetelstat. Failure to achieve necessary cost reductions could result in decreased sales for Janssen and reduced royalties for us.us, could negatively impact our collaboration with Janssen or could cause Janssen to terminate the Collaboration Agreement, any of which would materially and adversely affect our financial results, business and business prospects, and the future of imetelstat, and might cause us to cease operations.

Manufacturing imetelstat is subjectRISKS RELATED TO MANAGING OUR GROWTH AND OTHER BUSINESS OPERATIONS

We may not be able to processsuccessfully identify and technical challengesacquire and/or in-license other oncology products, product candidates, programs or companies to grow and regulatory risks.diversify our business, and, even if we are able to do so, we may not be able to successfully manage the risks associated with integrating any such products, product candidates, programs or companies into our business or we may otherwise fail to realize the anticipated benefits of these licenses or acquisitions.

We have facedexclusively outlicensed imetelstat, which was our sole product candidate, to Janssen. Accordingly, we are relying exclusively upon our collaborative relationship with Janssen to further develop, manufacture and Janssencommercialize imetelstat. To grow and diversify our business, we plan to continue our business development efforts to identify and seek to acquire and/or in-license other oncology products, product candidates, programs or companies. Such efforts have not yet resulted in any transaction, and may never result in a transaction. Future growth through acquisition or in-licensing will continuedepend upon the availability of suitable products, product candidates, programs or companies for acquisition or in-licensing on acceptable prices, terms and conditions. Even if appropriate opportunities are available, we may not be able to face numerousacquire rights to them on acceptable terms, or at all. The competition to acquire or in-license rights to promising products, product candidates, programs and companies is fierce, and many of our competitors are large, multinational pharmaceutical and biotechnology companies with considerably more financial, development and commercialization resources, personnel, and experience than we have. In order to compete successfully in the current business climate, we may have to pay higher prices for assets than may have been paid historically, which may make it more difficult for us to realize an adequate return on any acquisition. In addition, even if we succeed in identifying promising products, product candidates, programs or companies, we may not have the ability to develop, obtain regulatory approval for and commercialize such opportunities, or the financial resources necessary to pursue them.

Even if we are able to successfully identify and acquire or in-license new products, product candidates, programs or companies, we may not be able to successfully manage the risks associated with integrating such products, product candidates, programs or companies into our business or the risks arising from anticipated and unanticipated problems in connection with an acquisition or in-licensing, including risks related to intellectual property, research, manufacturing, regulatory approval and/or commercialization. Further, while we seek to mitigate risks and liabilities of potential acquisitions through, among other things, due diligence, there may be risks and liabilities that such due diligence efforts fail to discover, that are not disclosed to us, or that we inadequately assess. Any failure in identifying and managing these risks and uncertainties with regardeffectively would have a material adverse effect on our business. In any event, we may not be able to manufacturing imetelstat. Regulatory requirementsrealize the anticipated benefits of any acquisition or in-licensing for oligonucleotide products are less well-defined than for small-molecule drugs, and there is no guaranteea variety of reasons, including the possibility that Janssen will achieve sufficienta product quality standards required for Phase 3candidate fails to advance to clinical development, proves not to be safe or effective in clinical trials, or forfails to reach its forecasted commercial approvalpotential or that the integration of a product, product candidate, program or company gives rise to unforeseen difficulties and manufacturing ofexpenditures. Any failure in identifying and managing these risks and uncertainties would have a material adverse effect on our business.

TableIn addition, acquisitions create other uncertainties and risks, particularly when the acquisition takes the form of Contentsa merger or other business consolidation. We may encounter unexpected difficulties, or incur unexpected costs, in connection with transition activities and integration efforts, which include:

If we fail to integrate or otherwise manage an acquired business successfully and in a timely manner, resulting operating inefficiencies could increase our costs more than we planned, could negatively impact the market price of our common stock and could otherwise distract us from execution of our strategy. Failure to maintain effective financial controls and reporting systems and procedures could also impact our ability to produce timely and accurate financial statements.

In addition, the Collaboration Agreement with Janssen prohibits us from commercializing, under the intellectual property we have licensed exclusively to Janssen, any substance whose identified or known mechanism of action is telomerase inhibition. Further, if we exercise our U.S. Co-Promotion Option under the Collaboration Agreement, we will be required to certify to Janssen at the time of exercising our U.S. Co-Promotion Option that we are not marketing or promoting, and have no right to market or promote, any such products for any oncology indication. Our right to co-promote in the manufacturing processes or formulations for imetelstat thatUnited States may be made during later stagesterminated by Janssen if we develop or commercialize a product for treating an oncology indication that acts through the same mechanism of clinical development, including during Phase 3 clinical trials, may result in regulatory delays, the needaction as imetelstat or that is substitutable for further clinical trials, rejection of a marketing application, or limitation on marketing authorization by regulatory authorities, and therefore delay the payment of potential milestone payments to us, or, if approved for commercial sale,imetelstat. Accordingly, our Collaboration Agreement with Janssen could impair Janssen'sadversely affect our ability to meetacquire or in-license, or to research, develop or market, promising products, product candidates or programs.

We may be unable to successfully retain or recruit key personnel to support our collaboration with Janssen or to manage any future growth.

Our future growth and success depend to a significant extent on the market demandskills, experience and efforts of our executive officers and key members of our staff. We face intense competition for qualified individuals from numerous pharmaceutical, biopharmaceutical and biotechnology companies, as well as academic and other research institutions. The previous restructurings we implemented, as well as the fact that we exclusively outlicensed imetelstat, which was our sole product candidate, to Janssen, and the uncertainties regarding our ability to diversify our business or related to the continued development of imetelstat by Janssen, could have an adverse impact on our ability to retain and recruit qualified personnel or we may incur unanticipated inefficiencies caused by our reduced personnel resources. In addition, if we acquire or in-license new products, product candidates, programs or companies as a result of our

business development efforts, we may not be able to successfully retain or recruit any executive officers or key staff members knowledgeable about such new products, product candidates, programs or companies. Under the terms of the Collaboration Agreement, we and Janssen have created a joint governance structure, including joint committees and working groups, to manage worldwide regulatory, development, manufacturing and commercialization activities for imetelstat, and therefore resultwe have ongoing responsibilities to oversee and participate in decreased salesthe collaboration with Janssen. In addition, we remain responsible for prosecuting, at Janssen’s direction, the patents we exclusively licensed to Janssen, and reduced royaltieshave sole responsibility for us.those patents that were non-exclusively licensed to Janssen. If we are unable to successfully retain, motivate and incentivize our personnel or attract or assimilate other highly qualified management and development personnel in the future on acceptable terms, our ability to support the Collaboration Agreement with Janssen and any future growth could be impaired, and our business and the price of our common stock would be adversely impacted.

We have not yet negotiated our agreement with Janssen specifying all of the terms for our co-promotion of imetelstat should we exercise our U.S. Co-Promotion Option. In addition, we do not have a sales force and may not develop one.an effective one, if at all.

Pursuant to the Collaboration Agreement with Janssen, we have a U.S. Co-Promotion Option if we exercise our U.S. Opt-In Rights. Assuming we exercise the U.S. Co-Promotion Option, we can elect to provide 20% of the U.S. imetelstat selling effort with Geron sales force personnel, in lieu of funding 20% of U.S. promotion costs upon regulatory approval and commercial launch of imetelstat in the United States. While the Collaboration Agreement includes the material terms of our U.S. Co-Promotion Option, we and Janssen mutually agreed to negotiate a separate agreement specifying the detailed activities and responsibilities with respect to the marketing and co-promotion of imetelstat following our election to exercise our U.S. Co-Promotion Option. WeIf Janssen makes an affirmative Continuation Decision, and we subsequently exercise our U.S. Opt-In Rights and U.S. Co-Promotion Option, we will need to negotiate this separate agreement with Janssen and, as a result, Janssen may placeimpose restrictions or additional obligations on us, including financial obligations. Any restrictions or additional obligations may restrict our co-promotion activities or involve more significant financial or other obligations than we currently anticipate. In addition, we have no sales experience as a company, and there are risks involved with establishing our own sales force capabilities. Developing an internalcapabilities, including:

Accordingly, we may be unable to establish our own sales force, which could effectivelywould delay or preclude us from participating in co-promoting imetelstat in the United States. In addition, because of our current lack of expertise in sales operations, any sales force we establish may not be effective, or may be less effective than any sales force that Janssen utilizes to promote imetelstat. In such event, the commercialization of imetelstat may be adversely affected, whichsince we would be wholly reliant on Janssen’s sales efforts, and this could materially and adversely affect any sales milestone or royalties we may receive under the Collaboration Agreement.

The Collaboration Agreement limits our ability to transfer our U.S. Co-Promotion Option to a potential acquirer.

Although the Collaboration Agreement permits us to be acquired by any company, our right to transfer our U.S. Co-Promotion Option toin the case of an acquisition, merger, consolidation, share exchange, business combination, recapitalization, sale of a potential acquirermajority of assets or similar transaction is limited, and subject to Janssen'sJanssen’s sole discretion under certain circumstances. If we are acquired underoutside of such limited circumstances, then we may not be able to transfer the U.S. Co-Promotion Option to such acquirer as part of the acquisition. This limiting provision may discourage potential acquisition bids for us or lower our value, thus preventing holders of our common stock from benefiting from what they may believe are the positive aspects of an acquisition, including the potential realization of a higher rate of return on their investment from this type of transaction.

We may not be able to obtain or maintain sufficient insurance on commercially reasonable terms or with adequate coverage against potential liabilities in order to protect ourselves against product liability claims.

Our business exposes us to potential product liability risks that are inherent in the testing, manufacturing and marketing of human therapeutic and diagnostic products. We may become subject to product liability claims if the use of imetelstat is alleged to have injured patients, including any injuries alleged to arise from any hepatotoxicity or hemorrhagic event associated with the use of imetelstat. We currently have limited clinical trial liability insurance, and we may not be able to maintain this type of insurance for any clinical trials, including clinical trials that we may conduct under a Geron IDP or in collaboration with Janssen under the Collaboration Agreement. In addition, product liability insurance is becoming increasingly expensive. Being unable to obtain or maintain product liability insurance in the future on acceptable terms or with adequate coverage against potential liabilities could have a material adverse effect on our business.

We have been, and may in the future be, involved in securities-related legal actions that are expensive and time consuming. Any securities-related legal actions, if resolved adversely, could harm our business, financial condition, or results of operations.

Securities-related class action lawsuits and/or derivative lawsuits have often been brought against companies which experience volatility in the market price of their securities. This risk is especially relevant for us because biotechnology and biopharmaceutical companies often experience significant stock price volatility in connection with their product development programs.

We and certain of our officers were named as defendants in two purported class action securities lawsuits filed in the United States District Court for the Northern District of California, or the California District Court, as well as a third securities lawsuit, not styled as a class action, which was transferred to the California District Court. These three cases, or the Class Action Lawsuits, were consolidated for all purposes and settled in July 2017. In connection with the settlement, in April 2017, we paid $250,000 and our insurance providers paid $6.0 million to a settlement escrow account to be paid to members of the settlement class, less payment of attorneys’ fees and costs to plaintiff’s counsel.

It is possible that additional suits will be filed, or allegations received from stockholders naming us and/or our officers and directors as defendants with respect to these same or other matters. Monitoring, initiating and defending against legal actions is time-consuming for our management, is likely to be expensive and may detract from our ability to fully focus our internal resources on our business activities. We could be forced to expend significant resources in the settlement or defense of any additional lawsuits, and we may not prevail in such lawsuits. We have not established any reserve for any potential liability relating to any additional lawsuits. It is possible that we could, in the future, incur judgments or enter into settlements of claims for monetary damages. A decision adverse to our interests in any such lawsuit, or in similar or related litigation, could result in the payment of substantial damages, or possibly fines, and could have a material adverse effect on our business, cash flow, results of operations and financial condition.

We may be subject to litigation, including securities-related litigation, if the results of our business and collaboration activities are not successful, and such litigation would be costly to defend or pursue and uncertain in its outcome.

Our business may bring us into conflict with our licensees, licensors, or others with whom we have contractual or other business relationships, or with our competitors or others whose interests differ from ours. If we are unable to resolve those conflicts on terms that are satisfactory to all parties, we may become involved in litigation brought by or against us.

On November 13, 2014, we announced that we had entered into the Collaboration Agreement with Janssen. We may face litigation arising from or related to the Collaboration Agreement or the transactions contemplated thereby, including if we are unable to generate substantial value under the Collaboration Agreement with Janssen or such collaboration is otherwise unsuccessful. For example, as a result of possible disagreements with Janssen, we may become involved in litigation or arbitration, which would be time-consuming and expensive. Possible disagreements with Janssen could include disagreements regarding the development and/or commercialization of imetelstat, interpretation of the Collaboration Agreement and ownership of proprietary rights. In addition, in certain circumstances we may believe that a particular milestone under the Collaboration Agreement has been achieved, and

Janssen may disagree with our belief. In that case, receipt of that milestone payment may be delayed or may never be received, which would adversely affect our financial condition and may require us to adjust our operating plans. While the Collaboration Agreement provides for a joint governance structure to oversee and manage worldwide regulatory, development, manufacturing and commercialization activities for imetelstat, Janssen generally will, subject to limited exceptions, have the deciding vote in the event of any disagreement. In any event, the joint governance structure contemplated by the Collaboration Agreement will be dissolved in the event that Janssen makes an affirmative Continuation Decision and we do not exercise our U.S. Opt-In Rights, which would preclude our ability to participate in any further decision-making for imetelstat. Reliance on a joint governance structure also subjects us to the risk that changes in key Janssen management personnel that are members of the various joint committees may materially and adversely affect the functioning of these committees, which could significantly delay or preclude imetelstat development and/or commercialization.

The Collaboration Agreement could also result in litigation arising out of any claims that our stockholders suffered financial losses due to the transaction, the approval of our stockholders was required under applicable law or otherwise should have been obtained prior to the completion of the transaction, or that our officers and directors breached their fiduciary duties in connection with the approval and completion of the transaction. Although we believe that stockholder approval was not required under applicable law in order to complete our transaction with Janssen, and therefore we neither sought nor intend to seek such stockholder approval, it is possible that persons who were stockholders at the time of the transaction may claim that their approval was required, in which case litigation could follow, which could result in substantial damages to us and/or could negatively affect our rights and obligations, or result in the termination of, the Collaboration Agreement.

Likewise, our stockholders may believe that the financial and other terms of the Collaboration Agreement are not favorable to either us or our stockholders, including any belief that the potential payments we may receive under the Collaboration Agreement are inadequate. Litigation brought by our stockholders challenging the validity of, or financial losses resulting from the Collaboration Agreement could also result in claims against us by Janssen, and the Collaboration Agreement provides for indemnification by us of Janssen against all losses and expenses relating to breaches of our representations, warranties and covenants in the Collaboration Agreement, which could expose us to further financial obligations and damages. The occurrence of any one or more of the above could have a significant adverse impact on our business and financial condition.

In addition, if the results of our business and collaboration activities are not successful, including without limitation, for example, if:

our stock price would decline significantly, and future litigation may result. In addition, allegations against us may be made related to the duration and nature of follow-up of patients, or any other activities conducted by Janssen or us in current and potential future clinical trials of imetelstat, and the nature and timing of our disclosures related to efficacy or safety data observed in current and potential future clinical trials of imetelstat may be alleged to have been inadequate or incomplete.

Monitoring, initiating and defending against legal actions is time-consuming for our management, likely to be expensive and may detract from our ability to fully focus our internal resources on our business activities. In addition,

despite the availability of insurance, we may incur substantial legal fees and costs in connection with litigation. Lawsuits are subject to inherent uncertainties, and defense and disposition costs depend upon many unknown factors. Lawsuits could result in judgments against us that require us to pay damages, enjoin us from certain activities, or otherwise negatively affect our legal or contractual rights, which could have a significant adverse effect on our business. In addition, the inherent uncertainty of such litigation could lead to increased volatility in our stock price and a decrease in the value of our stockholders’ investment in our common stock.

RISKS RELATED TO PROTECTING OUR INTELLECTUAL PROPERTY

We remain responsible for prosecuting, at Janssen'sJanssen’s direction, the patents we have exclusively licensed to Janssen. The success of our collaboration with Janssen will depend on our ability to protect our technologies and imetelstat through patents and other intellectual property rights.

Protection of our proprietary technology is critically important to our business, especially with respect to our collaboration with Janssen. Our success will depend in part on our ability to obtain, maintain, enforce and extend our patents and maintain trade secrets, both in the United States and in other

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countries. If we are unsuccessful in any of these regards, the value of our technologies and imetelstat will be adversely affected, and we and/or Janssen may be unable to continue development of imetelstat. By way of example, we do not yet have issued compound patent coverage for imetelstat in Europe after 2020. Further, ourOur patents may be challenged, invalidated or circumvented, and our patent rights may not provide proprietary protection or competitive advantages to us or Janssen. In the event that we or our licensors are unsuccessful in obtaining, maintaining, and enforcing our patents and other intellectual property rights, the value of our technologies and imetelstat will be adversely affected, and we or Janssen may not be able or willing to further develop or commercialize imetelstat. Loss or impairment of our intellectual property related to imetelstat any of which couldmight delay or halt ongoing or potential future clinical trials of imetelstat and any applications for regulatory approval, and therefore delay or halt the payment of potential milestone payments to us or,under the Collaboration Agreement. Further, if imetelstat is approved for commercial sale, such events could impair Janssen'sJanssen’s ability to sell imetelstat and therefore result in decreased sales for Janssen and reduced royalties for us. Occurrence of any of these events could negatively impact our collaboration with Janssen or cause Janssen to terminate the Collaboration Agreement, which would materially and adversely affect our financial results, business and we may be unablebusiness prospects, and the future of imetelstat, and might cause us to continuecease operations.

Changes in U.S. or foreign patent law or interpretations of such patent laws could diminish the value of our operations.patents in general, thereby impairing our ability to protect our technologies and imetelstat.

The patent positions of pharmaceutical and biopharmaceutical companies, including ours, are highly uncertain and involve complex legal and technical questions. In particular, legal principles for biotechnology and pharmaceutical patents in the United States and in other countries are evolving, and the extent to which we will be able to obtain patent coverage to protect our technologies and imetelstat, or enforce or defend issued patents, is uncertain. If we or Janssen infringe the patents of others, we or Janssen may be blocked from continuing development work or be required to obtain licenses on terms that may impact the value of imetelstat or cause it to be commercially impracticable.

        A number of significant changes to U.S. patent law occurred when the Leahy-Smith America Invents Act, or the AIA, was signed into law on September 16, 2011. These include provisions that affect the way patent applications will be prosecuted and may affect patent litigation. The United States Patent and Trademark Office, or the Patent Office, has developed new and untested regulations and procedures to govern the full implementation of the AIA. Many of the substantive changes to patent law associated with the AIA, and in particular, the first to file provisions, became effective on March 16, 2013. For example, under the AIA, patent rights are awarded to the first inventor to file a patent application with respect to a particular invention. Since the publication of discoveries in scientific or patent literature tends to lag behind actual discoveries by at least several months and sometimes several years, the persons or entities that we or our licensors name as inventors in our patents and patent applications may not have been the first to invent the inventions disclosed in the patent applications or patents, or the first to file patent applications for these inventions. As a result, we may not be able to obtain patents for discoveries that we otherwise would consider patentable and that we consider to be extremely significant to the future success of imetelstat. Thus, our ability to protect our patentable intellectual property depends, in part, on our ability to be the first to file patent applications with respect to our inventions or any joint inventions that we may develop with Janssen. Delay in the filing of a patent application for any purpose, including further development or refinement of an invention, may result in the risk of loss of patent rights.

A number of significant changes to U.S. patent law occurred when the Leahy-Smith America Invents Act, or the AIA, was signed into law on September 16, 2011. These include provisions that affect the way patent applications are examined and may affect patent litigation. Many of the substantive changes to patent law associated with the AIA, and in particular, the first to file provisions, became effective on March 16, 2013. For example, the AIA limits where a patentee may file a patent infringement suit. The AIA and its implementation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents. Significant impairment

U.S. court rulings have narrowed the scope of our imetelstat patent protection available in certain circumstances and weakened the rights would have a material adverse effectof patent owners in certain situations. For example, on our business and could cause Janssen to terminateJune 13, 2013, the Collaboration Agreement which would severely and adversely affect our business prospects.

        The U.S. Supreme Court, or the Court, has also issued decisions affecting patents. On June 13, 2013,a decision inAssociation for Molecular Pathology v. Myriad Genetics, Inc. the Court held holding that claims to isolated genomic DNA were not patentable subject matter, but claims to complementary DNA, or cDNA, molecules were

patentable subject matter. The effect of the decision on patents for other isolated natural products is uncertain. On March 20, 2012, inMayo Collaborative Services, DBA Mayo Medical Laboratories, et al. v. Prometheus Laboratories, Inc., the Court held that several claims drawn to measuring drug metabolite levels from patient samples and correlating them to drug doses were not

patentable subject matter. The decision has created uncertainty aroundIn addition, court rulings in cases such as BRCA1- & BRCA2-Based Hereditary Cancer Test Patent Litig. and Promega Corp. v. Life Technologies Corp. have also narrowed the abilityscope of patent protection available in certain circumstances. In addition to patent certain biomarker-related method patents. These decisions have increased theincreasing uncertainty with regard to our ability to obtain patents in the future, as well asthis combination of events may have created uncertainty with respect to the value of currentcertain patents we have previously obtained or in-licensed.

In addition, in June 2016, the electorate of the United Kingdom voted to exit the European Union, and futurein March 2017 the Government of the United Kingdom initiated the formal procedure of withdrawal from the European Union. While the exit of the United Kingdom from the European Union is to be completed in 2019, the exact timing of the withdrawal and the resulting effect of withdrawal will not be known for some time, which could lead to a period of considerable uncertainty relating to our ability to obtain and maintain Supplementary Protection Certificates (SPCs) of our products based on our United Kingdom patents once obtained. and our ability to establish and maintain European trademarks in the United Kingdom.

Depending on decisions by the U.S. federal courts, and the Patent Office and similar authorities in foreign jurisdictions, the interpretation of laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents. Occurrence of these events could significantly impairand/or significant impairment of our imetelstat patent rights which would have a material adverse effect onseverely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and could cause Janssen to terminate the Collaboration Agreement.Agreement, which might cause us to cease operations.

Challenges to our patent rights canwould result in costly and time-consuming legal proceedings that maycould prevent or limit development of imetelstat.

Our patents may be challenged through administrative or judicial proceedings. Such proceedings, are typically lengthy and complex, and an adverse decision canwhich could result in the loss of important patent rights. For example, where more than one party seeks U.S. patent protection for the same technology, the Patent Office may declare an interference proceeding in order to ascertain the party to which the patent should be issued. Patent interferences are typically complex, highly contested legal proceedings, subject to appeal. They are usually expensive and prolonged, and can cause significant delay in the issuance of patents. Our pending patent applications, or our issued patents, may be drawn into interference proceedings or be challenged through post-grant review procedures or litigation, any of which maycould delay or prevent the issuance of patents, or result in the loss of issued patent rights.

Under the AIA, interference proceedings have been eliminated forbetween patent applications filed on or after March 16, 2013 and have been replaced with other types of proceedings, including derivation proceedings. The AIA also includes post-grant review procedures subjecting U.S. patents to post-grant review procedures similar to European oppositions.oppositions, such as inter partes review, or IPR, covered business method post-grant reviews and other post-grant reviews. This applies to all of our U.S. patents, even those issued before March 16, 2013. Because of a lower evidentiary standard necessary to invalidate a patent claim in Patent Office proceedings compared to the evidentiary standard in U.S. federal court, a third party could potentially provide evidence in a Patent Office proceeding sufficient for the Patent Office to hold a claim invalid even though the same evidence would be insufficient to invalidate the claim if first presented in a district court action. Accordingly, a third party could attempt to use the Patent Office procedures to invalidate patent claims that would not have been invalidated if first challenged by the third party as a defendant in a district court action. U.S. patents owned or licensed by us may therefore be subject to post-grant review procedures, as well as other forms of review and re-examination. A decision in such proceedings adverseIn addition, the IPR process under the AIA permits any person, whether they are accused of infringing the patent at issue or not, to challenge the validity of certain patents. As a result, entities associated with hedge funds have challenged valuable pharmaceutical patents through the IPR process. Significant impairment of our interests could result in the loss of valuableimetelstat patent rights which would have a material adverse effect onseverely and adversely affect our financial results, business and business prospects, and the future of imetelstat, and could cause Janssen to terminate the Collaboration Agreement, which would severely and adversely affect our business prospects.might cause us to cease operations.

Certain jurisdictions, such as Europe, New Zealand and Australia, permit oppositions to be filed against granted patents or patents proposed to be granted. Under the Collaboration Agreement, Janssen could commercialize imetelstat internationally if approved by regulatory authorities for commercial sale. Therefore, securing both

proprietary protection and freedom to operate outside of the United States is important to the Collaboration Agreement with Janssen and our business.

        We have been involved in both opposing the grant of patents to others through such opposition Opposition proceedings and in defending our patent applications against oppositions filed by others. These opposition proceedings requiredrequire significant time and costs, to protect our intellectual property rights. Ifand if we are unsuccessful or are unable to commit these types of resources forto protect our imetelstat patent rights, we could lose our patent rights and we and/or Janssen could be prevented or limited in the development and commercialization of imetelstat. Occurrence of any of these events could negatively impact our collaboration with Janssen or cause Janssen to terminate the Collaboration Agreement which would severely and adversely affect our business prospects.

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As more groups become engaged in scientific research and product development in the areas of telomerase biology, the risk of our patents, or patents that we have in-licensed, being challenged through patent interferences, derivation proceedings, IPRs, post-grant proceedings, oppositions, re-examinations, litigation or other means will likely increase. For example, litigation may arise as a result of our decision to enforce our patent rights against third parties. Challenges to our patents through these procedures canwould be extremely expensive and time-consuming, even if the outcome iswas favorable to us. An adverse outcome in a patent dispute could severely harm our collaboration with Janssen or cause Janssen to terminate the Collaboration Agreement, or could otherwise have a material adverse effect on our business, and might cause us to cease operations, by:

•

causing us to lose patent rights in the relevant jurisdiction(s);



•

subjecting us to litigation, or otherwise preventing Janssen or us from commercializing imetelstat in the relevant jurisdiction(s);



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requiring Janssen or us to obtain licenses to the disputed patents;



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forcing Janssen or us to cease using the disputed technology; or



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requiring Janssen or us to develop or obtain alternative technologies.

We or Janssen may be subject to infringement claims that are costly to defend, and as to which we may be obligated to indemnify Janssen or obtain unblocking licenses, and such claims may limit our or Janssen'sJanssen’s ability to use disputed technologies and prevent us or Janssen from pursuing research, and development, manufacturing or commercialization of imetelstat.

The commercial success of imetelstat will depend upon our and Janssen'sJanssen’s ability to research, develop, manufacture, market and sell imetelstat without infringing or otherwise violating the intellectual property and other proprietary rights of third parties. There is considerable intellectual property litigation in the biotechnology and pharmaceutical industries, and many pharmaceutical companies, including potential competitors, have substantial patent portfolios. In the event our technologies infringe the rights of others or require the use of discoveries and technologies controlled by third parties, we or Janssen may be prevented from pursuing research, development, manufacturing or commercialization of imetelstat, or may be required to obtain licenses to those patents or other proprietary rights or develop or obtain alternative technologies. For example, we are aware that certain third parties have or may be prosecuting patents and patent estates that may relate to imetelstat, and while we believe these patents will expire before imetelstat is commercialized and/or that these patents are invalid and/or would not be infringed by the manufacture, use or sale of imetelstat, it is possible that the owner(s) of these patents will assert claims against us and/or Janssen in the future. Under the Collaboration Agreement, we are obligated under certain circumstances to indemnify Janssen from any claim of infringement of the patent rights of third parties in Janssen'sJanssen’s development, manufacture or commercialization of imetelstat, or to obtain unblocking licenses from such third parties, at our cost.

Since we cannot be aware of all intellectual property rights potentially relating to imetelstat and its uses, we do not know with certainty that imetelstat, or the intended commercialization thereof, does not and will not infringe or otherwise violate any third party'sparty’s intellectual property. Any infringement claims against us or Janssen would likely be expensive to resolve, and the cost of any indemnification of Janssen or unblocking license that we could be required to obtain under the Collaboration Agreement is unpredictable and could be significant. If we or Janssen are unable to resolve an infringement claim successfully, we or Janssen could be subject to an injunction which would prevent us or Janssen from commercializing imetelstat, and could also require us or Janssen to pay substantial damages. In addition to infringement claims, in the future we or Janssen may also be subject to other claims relating to intellectual property, such as claims that we or Janssen have misappropriated the trade secrets of third parties. We expectProvided that as imetelstatJanssen continues to progress inthe development of imetelstat, we willexpect to see more efforts by others to obtain patents that are positioned to cover imetelstat. Our success therefore

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depends significantly on our and Janssen'sJanssen’s ability to operate without infringing patents and the proprietary rights of others.

We or Janssen may become aware of discoveries and technologies controlled by third parties that are advantageous to developing or manufacturing imetelstat. Under such circumstances, we or Janssen may initiate negotiations for licenses to other technologies as the need or opportunity arises. We or Janssen may not be able to obtain a license to a technology required for the research, development, manufacturingmanufacture or commercialization of imetelstat on commercially favorable terms, or at all, or oursuch licenses may be terminated on certain grounds, including as a result of our or Janssen’s failure to comply with ourthe obligations under such licenses. If we or Janssen do not obtain a necessary license or if such a license is terminated, we or Janssen may need to redesign oursuch technologies or obtain rights to alternatealternative technologies, which may not be possible, and even if possible, could cause delays in the development efforts for imetelstat and could increase the development and/or production costs of imetelstat. In cases where we or Janssen are unable to license necessary technologies, we and/or Janssen could be subject to litigation and prevented from researching, developing, manufacturing or commercializing imetelstat, and in certain circumstances we may be required to indemnify Janssen for infringement claims arising from Janssen'sJanssen’s research, development, manufacture or commercialization of imetelstat, which could materially and adversely impact our business. Failure by us or Janssen to obtain rights to alternative technologies or a license to any technology that may be required to research, develop, manufacture or commercialize imetelstat would delay potential future clinical trials of imetelstat and any applications for regulatory approval and therefore delay the payment of potential milestone payments to us, or, if imetelstat is approved for commercial sale, could impair Janssen'sJanssen’s ability to sell imetelstat and therefore result in decreased sales for Janssen and reduced royalties for us. Occurrence of any of these events could negatively impact our collaboration with Janssen or cause Janssen to terminate the Collaboration Agreement, which would materially and adversely affect our business, and we may be unablemight cause us to continue ourcease operations.

We may become involved in disputes with Janssen or any past or future collaborator(s) over intellectual property inventorship or ownership, and publications by ourus or Janssen, or by investigators, scientific consultants, and research collaborators or others could impair our ability to obtain patent protection or protect our proprietary information, which, in either case, could have a significant impact on our business.

Inventions discovered under research, material transfer or other such collaborative agreements, including our Collaboration Agreement with Janssen, may become jointly owned by us and the other party to such agreements in some cases and the exclusive property of either party in other cases. Under some circumstances, it may be difficult to determine who invents and owns a particular invention, or whether it is jointly owned, and disputes couldcan arise regarding inventorship and ownership of those inventions. These disputes could be costly and time consumingtime-consuming and an unfavorable outcome could have a significant adverse effect on our business if we were not able to protect or license rights to these inventions. In addition, clinical trial investigators, scientific consultants and research collaborators generally have contractual rights to publish data and other proprietary information, subject to review by us and/or Janssen. Publications by us or Janssen, or by investigators, scientific consultants, andprevious employees, research collaborators containing such information,or others, either with permission or in contravention of the terms of their agreements or otherwise, may impair the ability to obtain patent protection or protect proprietary information which would have a material adverse effect on our business and could cause Janssen to terminate the Collaboration Agreement.Agreement, which might cause us to cease operations.

Much of the information and know-how that is critical to our business is not patentable, and we may not be able to prevent others from obtaining this information and establishing competitive enterprises.

We sometimes rely on trade secrets to protect our proprietary technology, especially in circumstances in which we believe patent protection is not appropriate or available. We attempt to protect our proprietary technology in part by confidentiality agreements with our employees, consultants, collaborators and contractors. We cannot provide assurance that these agreements will not

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be breached, that we would have adequate remedies for any breach, or that our trade secrets will not otherwise become known or be independently discovered by competitors, any of which would harm our business significantly.

In May 2016, the Defend Trade Secrets Act of 2016, or the DTSA, was enacted, providing a federal cause of action for misappropriation of trade secrets. Under the DTSA, an employer may not collect enhanced damages or attorney fees from an employee or contractor in a trade secret dispute brought under the DTSA, unless certain advanced provisions are observed. We cannot provide assurance that our existing agreements with employees and contractors contain notice provisions that would enable us to seek enhanced damages or attorneys’ fees in the event of any dispute for misappropriation of trade secrets brought under the DTSA.

Significant disruptions of information technology systems, including cloud-based systems, or breaches of data security could adversely affect our business.

Our business is increasingly dependent on critical, complex and interdependent information technology systems, including cloud-based systems, to support business processes as well as internal and external communications. Our computer systems are potentially vulnerable to breakdown, malicious intrusion and computer viruses that may result in the impairment of key business processes. Such disruptions and breaches of security could have a material adverse effect on our business, financial condition and results of operations.

In addition, our data security and information technology systems are potentially vulnerable to data security breaches, whether by employees or others, that may expose sensitive data to unauthorized persons. Such data security breaches could lead to the loss of trade secrets or other intellectual property, public disclosure of sensitive clinical or commercial data, and the exposure of personally identifiable information (including sensitive personal information) of our employees, collaborators, clinical trial patients and others. A data security breach or privacy violation that leads to disclosure or modification of or prevents access to patient information, including personally identifiable information or protected health information, could result in increased costs or loss of revenue as a result of:

If we are unable to prevent such data security breaches or privacy violations or implement satisfactory remedial measures, our operations could be disrupted, and we may suffer loss of reputation, financial loss and other regulatory penalties because of lost or misappropriated information, including sensitive patient data. In addition, these breaches and other inappropriate access can be difficult to detect, and any delay in identifying them may lead to increased harm of the type described above. Moreover, the prevalent use of mobile devices that access confidential information increases the risk of data security breaches, which could lead to the loss of confidential information, trade secrets or other intellectual property. While we have implemented security measures to protect our data security and information technology systems, such measures may not prevent such events.

RISKS RELATED TO OUR FINANCIAL POSITION AND NEED FOR ADDITIONAL FINANCING

WeAlthough we reported a small profit for the year ending December 31, 2015, we have a history of losses and anticipate continued future losses, and our continued losses could impair our ability to sustain operations.

        We haveUntil 2015, we had never been profitable and we had incurred operating losses every year since our operations began in 1990. While we were profitable in 2015 due to the recognition of revenue in connection with the upfront payment from Janssen under the Collaboration Agreement, we expect to incur additional operating losses and, as clinical development activities for imetelstat continue under our Collaboration Agreement with Janssen, our operating losses may increase in size. As of December 31, 2014,2017, our accumulated deficit was approximately $928.4$985.8 million. Losses have resulted principally from costs incurred in connection with our research and development activities and from general and administrative costs associated with our operations. We expect to incur additional operating losses and, as clinical development activities continue under our Collaboration Agreement with Janssen, our operating losses may increase in size.

Substantially all of our revenues to date have been research support payments under collaborative agreements and milestones, royalties and other revenues from our licensing arrangements. Any revenues generated from our licensing arrangements or ongoing collaborative agreements, and revenues from our licensing arrangements, including the Collaboration Agreement with Janssen, may not be sufficient alone to sustain our operations. For example, we expect revenues under our license agreements related to our telomerase technology to decline significantly in the coming years, and to be eliminated by the end of 2019, due to upcoming patent expirations on such technology. In addition, there can be no assurance that we will receive any milestone payments or royalties from Janssen in the future. We may be unsuccessful in entering into any new corporate collaboration, partnership or license agreements that result in revenues, or existing collaborative agreements or license arrangements, such as the Collaboration Agreement with Janssen, may be terminated or expire.

We also expect to experience negative cash flow for the foreseeable future as we fund our operating lossesoperations and capital expenditures. This will result in decreases in our working capital, total assets and stockholders'stockholders’ equity, which may not be offset by milestone payments or royalties from Janssen or by future financings. We will need to generate significant revenues to achieve consistent future profitability. We may not be able to generate these revenues fromunder the Collaboration Agreement with Janssen through milestone payments or royalties, and we may never achieve consistent future profitability. Even if we do become profitable in the future, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to achieve consistent future profitability could negatively impact the market price of our common stock and our ability to sustain operations. Even if we do become profitable, we may not be able to sustain or increase profitability on a quarterly or annual basis.

We may require additional capital to support development and commercialization of imetelstat in collaboration with Janssen and to otherwise grow our business, and our ability to obtain the necessary funding is uncertain.

We may need additional capital resources in order to support development and commercialization of imetelstat, especially if we elect to exercise our U.S. Opt-In Rights and U.S. Co-Promotion Option under the Collaboration Agreement and potentially independently pursue imetelstat development under our own IDP, and to otherwise support the future growth of our business through the potential acquisition and/or in-licensing of other oncology products, product candidates, programs or companies. We cannot assure you that our existing capital resources, future interest income, potential milestone payments and royalties under the Collaboration Agreement with Janssen and potential future sales of our common stock, including pursuant to our At-The-Market Issuance2015 Sales Agreement or sales agreement, with MLV & Co. LLC, or MLV, will be sufficient to fund future planned activities. The timing and degree of any future capital requirements will depend on many factors, including:

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the accuracy of the assumptions underlying our estimates for our capital needs;



•

whether Janssen discontinues development of imetelstat and/or terminates the Collaboration Agreement, and we elect U.S. Opt-In Rightschoose to share future U.S.develop imetelstat ourselves;

further changes or delays in Janssen’s development and promotion costsplans for imetelstat, including changes to or further expansion of or delays in ongoing clinical trials decided upon by Janssen or required by regulatory authorities, such as clinical holds or other requirements, or any other factors;

the achievement of development, regulatory and sales milestones resulting in payments to us from Janssen under the Collaboration Agreement with Janssen;

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to the extent permitted under the Collaboration Agreement, whether we independently pursue imetelstat development under our own IDP;



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our potential reimbursement obligations to Janssen if any data from a Janssen IDP support approval by a regulatory agencyauthorities in the United States or other countries;



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the achievement of development, regulatory and commercial milestones resulting

in the paymentevent that Janssen provides an affirmative Continuation Decision to us, from Janssenwhether we then elect our U.S. Opt-In Rights to share further U.S. development and promotion costs for imetelstat beyond IMbark or IMerge under the Collaboration Agreement, and the timingincluding our share of receipt of such payments, if any;



•

changes or delays in our and Janssen's development plans for imetelstat, including changes which may result from any future clinical holds on the INDs for imetelstat, including the IND for the MF Pilot Study,costs incurred to date by Janssen that we expectwill be required to transfer to Janssen;



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Janssen'sreimburse if we exercise our U.S. Opt-In Rights;

Janssen’s ability to meaningfully reduce manufacturing costs of imetelstat;



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the progress, timing, magnitude, scope and costs of clinical development, manufacturing and commercialization forof imetelstat, including the number of indications being pursued, subject to permission fromclearances and approvals by the FDA;



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FDA and other regulatory authorities;

the time and costs involved in obtaining regulatory clearances and approvals in the United States and in other countries;



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Janssen's

Janssen’s ability to successfully market and sell imetelstat, upon regulatory approval or clearance, in the United States and other countries;



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if we exercise our U.S. Opt-In Rights, our decision to also exercise our U.S. Co-Promotion Option, including the costs and timing of building a U.S. sales force;

the sales price for imetelstat;





•

•

the availability of coverage and adequate third-party reimbursement for imetelstat;

the timing, receipt and amount of royalties under the Collaboration Agreement on worldwide net sales of imetelstat, upon regulatory approval or clearance, if any;



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the timing, receipt and amount of royalties on sales of any stem cell products by Asterias, upon development, regulatory approval or clearance, if any;



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the sales price and availability of adequate third-party reimbursement for imetelstat;



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the cost of acquiring and/or licensing any newin-licensing other oncology products, product candidates, programs or companies, if any;



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the progress, timing, magnitude, scope and costs of clinical development, manufacturing and commercialization of any acquired or in-licensed oncology products, product candidates, programs, or companies, including the number of indications being pursued, subject to clearances and approvals by the FDA and other regulatory authorities;

expenses associated with the pending and potential additional related purported securities lawsuits and derivative lawsuits, as well as any otherfuture litigation; and



•

the costs involved in preparing, filing, prosecuting, maintaining, defending and enforcing patent claims.

In addition, changes in our business may occur that would consume available capital resources sooner than we expect. If our existing capital resources, future interest income, and potential milestone payments and royalties under the Collaboration Agreement with Janssen are insufficient to meet future capital requirements, we will need to raise additional capital to fund our operations. operations, including pursuant to our 2015 Sales Agreement with MLV.

Further, if the Collaboration Agreement is terminated, including as a result of Janssen'sJanssen’s failure to provide an affirmative Continuation Decision to us, or for any other reason, we would not receive any milestone payments or royalties under the Collaboration Agreement, and then, depending on the timing of such event, we would be required to fund all clinical development, manufacturing and commercial activities for imetelstat should we elect to continue the development of imetelstat ourselves, which would require us to raise substantial additional capital or establish alternative collaborations with third-party collaboration partners, which may not be possible. If the Collaboration Agreement is terminated and we are unable to raise additional capital or establish alternative collaborations with third-party collaboration partners for imetelstat, the development of imetelstat would be discontinued, which might cause us to cease operations. Additional financing through public or private equity financings, including pursuant to our sales agreement2015 Sales Agreement with MLV, prior to its expiration in October 2015, capital lease transactions or other financing sources may not be available on acceptable terms, or at all. We may raise equity capital at a stock price or on other terms that could result in substantial dilution of

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ownership for our stockholders. The receptivity of the public and private equity markets to proposed financings is substantially affected by the general economic, market and political climate and by other factors which are unpredictable and over which we have no control. In this regard, continued volatility and instability in the global financial markets and political climate could adversely affect our ability to raise additional funds through financings and the terms upon which we may raise those funds.

Our ability to raise additional funds will be severely impaired in the event of:

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any future clinical holds on any IND

further changes or delays in Janssen’s development plans for imetelstat;



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a failure or inability to show adequate safety or efficacy of imetelstat in existingcurrent or potential future clinical trials;trials, which may result in a decision by Janssen to delay or



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discontinue further development of imetelstat; or

a termination of the Collaboration Agreement or if our collaboration with Janssen is otherwise unsuccessful.

If sufficient capital is not available, we may be unable to fulfill our funding obligations under the Collaboration Agreement with Janssen, resulting in our breach of the Collaboration Agreement, which could lead to Janssen paying lower milestone payments and lower royalties to us under a reduced royalty tier which couldtier. This would have a material adverse effect on our results of operations and financial condition.

Moreover, in order to grow and diversify our business, we plan to diversifycontinue our sole product candidatebusiness development risk by identifyingefforts to identify and seekingseek to acquire and/or in-license newother oncology products, product opportunities for development.candidates, programs or companies. Acquisition or in-licensing opportunities that we may pursue could materially affect our liquidity and capital resources and may require us to incur indebtedness, seek equity capital or both.both, including pursuant to our 2015 Sales Agreement with MLV. In addition, there can be no assurance that sufficient additional capital would be available to us in order to pursue any of these opportunities.

The recently passed comprehensive tax reform bill could adversely affect our business and financial condition.

On December 22, 2017, President Trump signed into law new legislation that significantly revises the Internal Revenue Code of 1986, as amended. The newly enacted federal income tax law, among other things, contains significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%, limitation of the tax deduction for interest expense to 30% of adjusted earnings (except for certain small businesses), limitation of the deduction for net operating losses to 80% of current year taxable income and elimination of net operating loss carrybacks, one time taxation of offshore earnings at reduced rates regardless of whether they are repatriated, immediate deductions for certain new investments instead of deductions for depreciation expense over time, and modifying or repealing many business deductions and credits (including reducing the business tax credit for certain clinical testing expenses incurred in the testing of certain drugs for rare diseases or conditions). Notwithstanding the reduction in the corporate income tax rate, the overall impact of the new federal tax law is uncertain and our business and financial condition could be adversely affected. In addition, it is uncertain if and to what extent various states will conform to the newly enacted federal tax law. The impact of this tax reform on holders of our common stock is also uncertain and could be adverse. We urge our stockholders to consult with their legal and tax advisors with respect to this legislation and the potential tax consequences of investing in or holding our common stock.

Our ability to use our net operating loss carryforwards and certain other tax attributes may be limited.

Our net operating loss carryforwards could expire unused and be unavailable to offset future income tax liabilities. Under the newly enacted federal income tax law, federal net operating losses incurred in 2018 and in future years may be carried forward indefinitely, but the deductibility of such federal net operating losses is limited. It is uncertain if and to what extent various states will conform to the newly enacted federal tax law. In addition, under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code, and corresponding provisions of state law, if a corporation undergoes an "ownership“ownership change,"” generally defined as a greater than 50% change (by value) in its equity ownership over a three-year period, the corporation'scorporation’s ability to use its pre-change net operating loss carryforwards and other pre-change tax attributes (such as research tax credits) to offset its post-change taxable income or taxes may be limited. Changes in our stock ownership, some of which are outside of our control, may have resulted or could in the future result in an ownership change. If a limitation were to apply, utilization of a portion of our domestic net operating loss and tax credit carryforwards could be limited in future periods. In addition, a portion of the carryforwards may expire before being available to reduce future income tax liabilities.liabilities which could adversely impact our financial position.

RISKS RELATED TO OUR COMMON STOCK AND FINANCIAL REPORTING

Historically, our stock price has been extremely volatile.

Historically, our stock price has been extremely volatile. Between January 1, 20052008 and December 31, 2014,2017, our stock has traded as high as $12.18$9.24 per share and as low as $0.91 per share. Between January 1, 20122015 and December 31, 2014,2017, the price has ranged between a high of $7.79$5.30 per share and a low of $0.91$1.74 per share. The significant market price fluctuations of our common stock have been due to and may in the future be influenced by a variety of factors, including:

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announcements regarding the research and development of imetelstat, including results of, further delays in, discontinuation of, or further modifications or refinements to any clinical trials of imetelstat as a result of any internal data reviews or decisions by joint governance committees, and investor perceptions thereof;

not receiving timely regulatory clearances or approvals in any jurisdiction, whether within or outside of the United States, including, if we, Janssen or future investigators do not obtain regulatory clearance to commence, studiesconduct or continue clinical trials of imetelstat in MF, MDS or any additional hematologic myeloid malignancies in a timely manner or at all, includingor to amend any clinical trial protocol with respect to the Initial Phase 2 MF Study and the Initial Phase 2 MDS Study planned to be conducted by Janssen under the Collaboration Agreement;

Tableconduct of ContentsIMerge, IMbark or any future clinical trial of imetelstat;

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developments in our collaboration with Janssen, including the termination, modification or modificationamendment of the Collaboration Agreement, or disputes regarding the collaboration;





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announcements regarding the research and development of imetelstat, including results of or delays in any clinical trials of imetelstat, and investor perceptions thereof;



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announcements regarding the safety of imetelstat;

announcements regarding regulatory developments concerning imetelstat, including announcements similar to our March 2014 announcementsannouncement that the FDA had placed a full clinical hold on our IND for imetelstat and a partial clinical hold on imetelstat;

the investigator's IND for the MF Pilot Study due to safety concerns;



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announcements regarding our plans to discontinue certain programs or clinical trials, such as our prior announcements regarding the discontinuationexperimental nature of our stem cell programs and certain clinical trials;



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imetelstat;

perception by our stockholders about the adequacy of the consideration received for the divestiture of our stem cell assets to Asterias or potential payments we may receive under the Collaboration Agreement;



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the demand in the market for our common stock;



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the experimental nature of imetelstat;



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fluctuations in our operating results;



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our declining cash balance as a result of operating losses;



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general market conditions or market conditions relating to the biopharmaceutical and pharmaceutical industries;



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announcements of technological innovations, new commercial products, or clinical progress or lack thereof by us, our collaborators, licensees, partners or our competitors;



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fluctuations in our operating results;

our declining cash balance as a result of operating losses;

general market conditions or market conditions relating to the biopharmaceutical and pharmaceutical industries;

announcements concerning regulatory developments andimetelstat proprietary rights;



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comments by securities analysts;



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large stockholders exiting their position in our common stock;



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announcements of or developments concerning pending and/or potential future litigation;



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the issuance of common stock to partners, vendors or investors to raise additional capital;capital or to acquire other oncology products, product candidates, programs or companies; and



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the occurrence of any other risks and uncertainties discussed under the heading "Risk“Risk Factors."

Stock prices and trading volumes for many biopharmaceutical companies fluctuate widely for a number of reasons, including factors which may be unrelated to their businesses or results of operations, such as media coverage, statements made on message boards and social media forums, legislative and regulatory measures and the activities of various interest groups or organizations. In addition to otherthe risk factors described in this section, overall market volatility, as well as general domestic or international economic, market and political conditions, could materially and adversely affect the market price of our common stock and the return on your investment.

If we fail to continue to meet continuedthe listing standards of NASDAQ, our common stock may be delisted, which could have a material adverse effect on the liquidity of our common stock.

Our common stock is currently traded on the Nasdaq Global Select Market. The NASDAQ Stock Market LLC has requirements that a company must meet in order to remain listed on NASDAQ. In particular, NASDAQ rules require us to maintain a minimum bid price of $1.00 per share of our common stock. If the closing bid price of our common stock were to fall below $1.00 per share for 30 consecutive trading days or we do not meet other listing requirements, we would fail to be in

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compliance with NASDAQ'sNASDAQ’s listing standards. There can be no assurance that we will continue to meet the minimum bid price requirement, or any other requirement in the future. If we fail to meet the minimum bid price requirement, The NASDAQ Stock Market LLC may initiate the delisting process with a notification letter. If we were to receive such a notification, we would be afforded a grace period of 180 calendar days to regain compliance with the minimum bid price requirement. In order to regain compliance, shares of our common stock would need to maintain a minimum closing bid price of at least $1.00 per share for a minimum of 10 consecutive trading days. In addition, we may be unable to meet other applicable NASDAQ listing requirements, including maintaining minimum levels of stockholders'stockholders’ equity or market values of our common stock, in which case our common stock could be delisted. If our common stock were to be delisted, the liquidity of our common stock would be adversely affected and the market price of our common stock could decrease.

The sale of a substantial number of shares may adversely affect the market price of our common stock.

        The sale of a substantial number of shares of our common stock in the public market, or the perception that such sales could occur, could significantly and negatively affect the market price of our common stock. As of December 31, 2014,2017, we had 300,000,000 shares of common stock authorized for issuance and 157,429,871159,877,239 shares of common stock outstanding. In addition, we had reserved 32,327,34530,044,457 shares of our common stock for future issuance pursuant to our option and equity incentive plans and outstanding warrants as of December 31, 2014. Issuing additional shares could negatively affect2017. In addition, under the market priceuniversal shelf registration statement filed by us in August 2015 and declared effective by the SEC in September 2015, we may sell any combination of our common stock, preferred stock, debt securities and the return on your investment.warrants in one or more offerings, up to a cumulative value of $250 million.

Future sales of our common stock or the perception that such sales could occur, including pursuant to our sales agreement2015 Sales Agreement with MLV, prior to its expiration in October 2015, or the issuance of common stock to satisfy our current or future cash payment obligations or to acquire technology, property, or other businesses, could cause immediate dilution and adversely affect the market price of our common stock. In addition, under the universal shelf registration statement filed by us in July 2012 and declared effective by the SEC in October 2012, we may sell any combination of common stock, preferred stock, debt securities and warrants in one or more offerings, up to a cumulative value of $96.5 million. The sale or issuance of our securities, as well as the existence of outstanding options and shares of common stock reserved for issuance under our option and equity incentive plans and outstanding warrants, also may adversely affect the terms upon which we are able to obtain additional capital through the sale of equity securities, which could negatively affect the market price of our common stock and the return on your investment.

Our undesignated preferred stock may inhibit potential acquisition bids; this may adversely affect the market price of our common stock and the voting rights of holders of our common stock.

Our certificate of incorporation provides our board of directors with the authority to issue up to 3,000,000 shares of undesignated preferred stock and to determine or alter the rights, preferences, privileges and restrictions granted to or imported upon these shares without further vote or action by our stockholders. The issuance of shares of preferred stock may delay or prevent a change in control transaction without further action by our stockholders. As a result, the market price of our common stock may be adversely affected.

In addition, if in the future, we issue preferred stock that has preference over our common stock with respect to the payment of dividends or upon our liquidation, dissolution or winding up, or if we issue preferred stock with voting rights that dilute the voting power of our common stock, the rights of holders of our common stock or the market price of our common stock could be adversely affected.

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Provisions in our charter, bylaws and Delaware law may inhibit potential acquisition bids for us, which may prevent holders of our common stock from benefiting from what they believe may be the positive aspects of acquisitions and takeovers.

Provisions of our charter documents and bylaws may make it substantially more difficult for a third party to acquire control of us and may prevent changes in our management, including provisions that:

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prevent stockholders from taking actions by written consent;



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divide the board of directors into separate classes with terms of office that are structured to prevent all of the directors from being elected in any one year; and



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set forth procedures for nominating directors and submitting proposals for consideration at stockholders'stockholders’ meetings.

Provisions of Delaware law may also inhibit potential acquisition bids for us or prevent us from engaging in business combinations. In addition, we have severance agreements with several employees and a company-wide severance plan, either of which could require a potential acquirer to pay a higher price. Either collectively or individually, these provisions may prevent holders of our common stock from benefiting from what they may believe are the positive aspects of acquisitions and takeovers, including the potential realization of a higher rate of return on their investment from these types of transactions.

We do not intend to pay cash dividends on our common stock in the foreseeable future.

We do not anticipate paying cash dividends on our common stock in the foreseeable future. Any payment of cash dividends will depend upon our financial condition, results of operations, capital requirements and other factors and will be at the discretion of our board of directors.

Failure to achieve and maintain effective internal controls in accordance with Section 404 of the Sarbanes-Oxley Act of 2002 could have a material adverse effect on our business and stock price.

Section 404 of the Sarbanes-Oxley Act of 2002, or Section 404, requires that we establish and maintain an adequate internal control structure and procedures for financial reporting. Our annual reports on Form 10-K must contain an annual assessment by management of the effectiveness of our internal control over financial reporting and must include disclosure of any material weaknesses in internal control over financial reporting that we have identified. In addition, our independent registered public accounting firm must annually provide an opinion annually on the effectiveness of our internal control over financial reporting.

The requirements of Section 404 are ongoing and also apply to future years. We expect that our internal control over financial reporting will continue to evolve as our business develops. Although we are committed to continue to improve our internal control processes and we will continue to diligently and vigorously review our internal control over financial reporting in order to ensure compliance with Section 404 requirements, any control system, regardless of how well designed, operated and evaluated, can provide only reasonable, not absolute, assurance that its objectives will be met. Therefore, we cannot be certain that in the future material weaknesses or significant deficiencies will not exist or otherwise be discovered.discovered in the future. If material weaknesses or other significant deficiencies occur, thesesuch weaknesses or deficiencies could result in misstatements of our results of operations, restatements of our financial statements, a decline in our stock price, or other material adverse effects on our business, reputation, results of operations, financial condition or liquidity.

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RISKS RELATED TO COMPETITIVE FACTORS

Competitors may develop technologies that are superior to or more cost-effective than ours, which may significantly impact the commercial viability of imetelstat, which could cause Janssen to terminate the Collaboration Agreement and damage our ability to sustain operations.

The pharmaceutical and biotechnology industries are intensely competitive. Other pharmaceutical and biotechnology companies and research organizations currently engage in or have in the past engaged in efforts related to the biological mechanisms related to imetelstat, including the study of telomeres, telomerase, andor our proprietary oligonucleotide chemistry, and the research and development of therapies for the treatment of hematologic myeloid malignancies. In addition, other products and therapies that could directly compete with imetelstat currently exist or are being developed by pharmaceutical and biopharmaceutical companies and by academic institutions, government agencies and other public and private research organizations. We expect Janssen’s decisions regarding continued development and/or commercialization, if any, of imetelstat, including completing IMerge and/or IMbark, its Continuation Decision or the termination of the Collaboration Agreement, to be informed in part by what Janssen believes is the estimated commercial potential of imetelstat for the treatment of hematologic malignancies, such as MF or MDS.

Many companies are developing alternative therapies to treat hematologic myeloid malignancies and, in this regard, are competitors of ours and Janssen.malignancies. For example, if approved for commercial sale for the treatment of MF, imetelstat would compete against Incyte Corporation'sCorporation’s ruxolitinib, or Jakafi®, which is orally administered. In clinical trials, Jakafi® reduced spleen size, abdominal discomfort, early satiety, bone pain, night sweats and itching in MF patients. Recently, there have also been reports of overall survival benefit as well as improvement in bone marrow fibrosis from Jakafi® treatment. Other treatment modalities for MF include hydroxyurea for the management of splenomegaly, leukocytosis, thrombocytosis and constitutional symptoms; splenectomy and splenic irradiation for the management of splenomegaly and co-existing cytopenias, or low blood cell counts; chemotherapy and pegylated interferon. Drugs for the treatment of MF-associated anemia include erythropoiesis-stimulating agents, androgens, danazol, corticosteroids, thalidomide and lenalidomide. There are other investigational treatments for MF further along in development than imetelstat, such as momelotinib by Gilead Sciences, Inc. and pacritinib by Cell Therapeutics,CTI Biopharma Corporation, or CTI Biopharma, and fedratinib by Impact Biomedicines, Inc., acquired by Celgene Corporation, or Celgene, which are currently inhave reported results from Phase 3 clinical trials, and othertrials. Other investigational treatments for MF include inhibitors of the JAK-STAT pathway, as well as several investigational treatments in early phase testing such as NS-018 by NS Pharma, Inc.; histone deacetylase inhibitors,inhibitors; interleukin-3 receptor targeted agents; inhibitors of heat shock protein 90,90; hypomethylating agents,agents; PI3 Kinase and mTOR inhibitors,inhibitors; anti-fibrosis antibodies, such as PRM-151 from Promedior, Inc.; hedgehog inhibitors,and SMO inhibitors; PIM kinase inhibitors; IAP inhibitors; anti-LOX2 inhibitors,inhibitors; recombinant pentraxin 2 protein,protein; KIP-1 activators,activators; TGF-beta superfamily inhibitors, such as sotatercept and luspatercept by Acceleron Pharma, Inc., or Acceleron, in collaboration with Celgene; FLT inhibitors,inhibitors; and other tyrosine kinase inhibitors.

If approved for commercial sale for the treatment of lower risk MDS, imetelstat would compete against a number of treatment options, including erythropoiesis stimulating agents and other hematopoietic growth factors; immunomodulators, such as lenalidomide by Celgene; hypomethylating agents, such as azacitidine by Celgene and decitabine by Janssen; in addition to investigational treatments that may be further along in development than imetelstat, such as oral versions of azacitidine; histone deacetylase inhibitors; TGF-beta superfamily inhibitors, such as luspatercept by Acceleron, in collaboration with Celgene; PI3 Kinase inhibitors; aminopeptidase inhibitors, such as tosedostat by CTI Biopharma; TLR2-specific antibodies; anti-CD33 antibodies; anti-CD38 antibodies, such as daratumumab by Genmab A/S in collaboration with Janssen; anti-CD123 antibodies, such as talacotuzumab by Janssen; retinoic acid receptor alpha agonists, such as SY-1425 by Syros Pharmaceuticals; hypoxia-inducible factor prolyl hydroxylase inhibitors, such as roxadustat by FibroGen, Inc.; Fas ligand inhibitors; and JAK-STAT pathway inhibitors.

Independently, Janssen is developing therapies for hematologic malignancies, including AML, MDS, MMmultiple myeloma and ABC-subtype diffuse large B-cell lymphoma. Molecular and cellular pathways of interest include:

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cell surface targets for immune-directed therapy;



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immune checkpoint inhibition;



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leukemia stem cells;



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pathway addiction (genetic alterations, cell-type specific pathways);



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conditional sensitivity (stress, protein-producing tumors);



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targeting of T-cells and natural killer "NK"“NK” cells to tumors;



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identification of novel tumor-specific antigens; and



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progression from early MDS to AML and cancer interception.

Success by Janssen in any of these approaches may compete with imetelstat or render imetelstat obsolete or noncompetitive, which could lead to a decision by Janssen to discontinue the imetelstat program and terminate the Collaboration Agreement, which would materially and adversely affect our business and business prospects.

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Smaller companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. We anticipate increased competition in the future as new companies explore treatments for hematologic myeloid malignancies, which may significantly impact the commercial viability of imetelstat. Academic institutions, government agencies and other public and private research organizations may also conduct research, seek patent protection and establish collaborative arrangements for research, clinical development and marketing of products similar to ours.imetelstat. These companies and institutions compete with us in recruiting and retaining qualified scientificdevelopment and management personnel as well as in acquiring technologies complementary to ourthe imetelstat program.

In addition to the above factors, we and Janssen expect toimetelstat will face competition in the following areas:based on:

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product efficacy and safety;



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convenience of product administration;



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cost of manufacturing;



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the timing and scope of regulatory consents;



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status of reimbursement coverage;



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coverage and level of reimbursement;

price; and



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patent position, including potentially dominant patent positions of others.