As filed with the Securities and Exchange Commission on November 9, 2017January 2, 2019

RegistrationNo. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORMS-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Aptevo Therapeutics Inc.

(Exact name of registrant as specified in its charter)

2401 4th Avenue, Suite 1050

Seattle, WA 98121

(206)838-0500

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Marvin L. White

President and Chief Executive Officer

Aptevo Therapeutics Inc.

2401 4th Avenue, Suite 1050

Seattle, WA 98121

(206)838-0500

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Sonya Erickson

Alan D. Hambelton

Cooley LLP

1700 Seventh Avenue, Suite 1900

Seattle, WA 98101

(206)452-8700

Approximate date of commencement of proposed sale to the public: From time to time after this Registration Statement becomes effective.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Formdelivery of the prospectus is a registration statement pursuantexpected to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commissionbe made pursuant to Rule 462(e) under the Securities Act,434, please check the following box.  ☐

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, anon-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company”company,” and “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 7(a)(2)(B) of the Securities Act. ☒

CALCULATION OF REGISTRATION FEE

The Registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment that specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until this registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement onForm S-3 that we filed with the Securities and Exchange Commission, or SEC, using the “shelf” registration process. Under this process, the selling stockholder may from time to time, in one or more offerings, sell the common stock described in this prospectus.

You should rely only on the information contained in, or incorporated by reference ininto, this prospectus (as supplemented and the applicable prospectus supplement,amended), along with the information contained in any free writing prospectuses we or the selling stockholder have authorized for use in connection with a specific offering. We have not authorized anyone to provide you with different information. We are not making an offerand the selling stockholder take no responsibility for, and can provide no assurances as to sell or seeking an offer to buy securities under this prospectus or the applicable prospectus supplement andreliability of, any related free writing prospectus in any jurisdiction where the offer or sale is not permitted.other information that others may give you. The information contained in this prospectus the applicable prospectus(and in any supplement or amendment to this prospectus) or any related free writing prospectus, and the documents incorporated by reference herein and therein, are accurate only as of their respective dates, regardless of the time of delivery of this prospectus, theany applicable prospectus supplement or any related free writing prospectus, or the time of any sale of a security.

About this Prospectus

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or the SEC, using a “shelf” registration process. Under this shelf registration statement, we may sell from timesecurity. We urge you to time in one or more offerings up to a total dollar amount of $150,000,000 of common stock, preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination with other securities as described in this prospectus. Each time we sell any type or series of securities underread carefully this prospectus we will provide a prospectus supplement that will contain more specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. A prospectus supplement(as supplemented and any related free writing prospectus may also add, update or change the information contained or incorporated by reference in this prospectus. This prospectus,amended), together with the applicable prospectus supplement, any related free writing prospectus and the documentsinformation incorporated herein by reference herein and therein, will include all material information relating to the applicable offering. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, together with the additional informationas described under “Where You Can Find Morethe heading “Incorporation of Certain Information” by Reference” before buyingdeciding whether to invest in any of the securitiescommon stock being offered.

THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the section entitled “Where You Can Find More Information.”

Except as otherwise indicated herein or as the context otherwise requires, references in this prospectus to “Aptevo,” “the Company,” “we,” “us,” “our” and similar references refer to Aptevo Therapeutics Inc., a corporation under the laws of the State of Delaware.  Delaware, and its subsidiaries on a consolidated basis.

This prospectus and the information incorporated herein by reference herein include trademarks, service marks and trade names owned by us or other companies. All trademarks, service marks and trade names included or incorporated by reference ininto this prospectus any applicable prospectus supplement or any related free writing prospectusand the information incorporated herein by reference are the property of their respective owners.

PROSPECTUS SUMMARY

i

Summary

The following summary highlights information contained elsewhere in this prospectus or incorporated by reference herein and does not contain all the information that may be important to purchasers of our securities. Prospective purchasers of our securities should carefully read thisthe entire prospectus, theany applicable prospectus supplement and any related free writing prospectus we or the selling stockholder have authorized for use in connection with a specific offering, including the risks of investing in our securities discussed under the heading “Risk Factors” contained in any applicable prospectus supplement and any related free writing prospectus, and under similar headings in the applicable prospectus supplement, any related free writing prospectus and theother documents that are incorporated by reference herein and therein.  into this prospectus. Prospective purchasers of our securities should also carefully read the information incorporated by reference ininto this prospectus, including our financial statements, and the exhibits to the registration statement of which this prospectus is a part.part.

Aptevo Therapeutics Inc.

Overview

We are a biotechnology company focused on novel oncology (cancer) and hematology (blood disease) therapeutics to meaningfully improve patients’ lives. Our core technology is the ADAPTIR™ (modular protein technology) platform. We currently have one revenue-generating product in the area of hematology, as well as various investigational stage product candidates in immuno-oncology.immuno-oncology and autoimmune and inflammatory diseases.

Our pipeline is composed ofWe have one marketed product, IXINITY^® coagulation factor IX (recombinant), indicated in adults and children 12 years of age and older with Hemophilia B for control and prevention of bleeding episodes, and management of bleeding during operations. We also have numerous investigational stage product candidates based on our ADAPTIR^TM (modular protein technology) platform. The ADAPTIR platform technology can produce monospecific and multispecific immunotherapeutic proteins that specifically bind to one or more targets, for example, bispecific therapeutic molecules, which may have structural and functional advantages over monoclonal antibodies. Our investigational stage product candidates otlertuzumab, APVO414, APVO210, and ALG.APV-527, a bispecific antibody candidate, featuring a novel mechanism of action targeting 4-1BB (CD137) and 5T4. The mechanisms of action for otlertuzumab, APVO414, APVO210, APVO436 and ALG.APV-527 include direct tumor cytotoxicity, antibody-dependent cell-cytotoxicity, redirected T-cell cytotoxicity (RTCC), costimulation of anti-tumor T cells and targeted cytokine delivery. The structural differences of ADAPTIR molecules over monoclonal antibodies allow for the development of other ADAPTIR immunotherapeutics that engage immune effector cells and disease targets in a novel manner to produce unique signaling responses.responses and ultimately kill tumors or modulate the immune system to kill tumors. We are skilled at product candidate generation, validation and subsequent preclinical and clinical development using the ADAPTIR platform. We have the ability to progress ADAPTIR molecules from concept to commercialization by way of our protein engineering, preclinical development and process development capabilities, cGMP manufacturing oversight and clinical development capabilities. We also have the ability to launch, market and commercialize these product candidates upon approval.

Our investigational stage product candidates are:

Company Information

On August 6, 2015, Emergent BioSolutions Inc., or Emergent, announced a plan to separate into two independent publicly traded companies. To accomplish this separation, Emergent created Aptevo Therapeutics Inc., or Aptevo, to be the parent company for the development-based biotechnology business focused on novel oncology and hematology therapeutics. Aptevo was incorporated in Delaware in February 2016 as a wholly owned subsidiary of Emergent. To effect the separation, Emergent made a pro rata distribution of Aptevo’s common stock to Emergent’s stockholders on August 1, 2016. Our common stock currently trades on the NASDAQNasdaq Global Select Market under the symbol “APVO.” Our primary executive offices are located at 2401 4th Avenue, Suite 1050, Seattle, Washington and our telephone number is (206)838-0500. Our website address is www.aptevotherapeutics.com. The information contained in, or that can be accessed through, our website is not a part of or incorporated by reference in this prospectus, and you should not consider it part of this prospectus or part of any prospectus supplement.supplement.

Risks Associated with our Business

Our business is subject to numerous risks, as described under the heading “Risk Factors” and under similar headings in theany applicable prospectus supplement, any related free writing prospectus and the documents incorporated by reference herein and therein.

The Offering

On December 20, 2018, we entered into a purchase agreement with Lincoln Park, which we refer to in this prospectus as the Purchase Agreement, pursuant to which Lincoln Park has agreed to purchase from us up to an aggregate of $35,000,000 of our common stock (subject to certain limitations) from time to time over the term of the Purchase Agreement. Also on December 20, 2018, we entered into a registration rights agreement with Lincoln Park, which we refer to in this prospectus as the Registration Rights Agreement, pursuant to which we have filed with the SEC the registration statement that includes this prospectus to register for resale under the Securities We May OfferAct of 1933, as amended, or the Securities Act, the shares of common stock that have been or may be issued to Lincoln Park under the Purchase Agreement.

We do not have the right to commence any sales of our common stock to Lincoln Park under the Purchase Agreement until certain conditions set forth in the Purchase Agreement, all of which are outside of Lincoln Park’s control, have been satisfied, including that the SEC has declared effective the registration statement that includes this prospectus. Thereafter, we may, offerfrom time to time and at our sole discretion, on any single business day, direct Lincoln Park to purchase shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination with other securities, with a total value ofamounts up to $150,000,000 from time100,000 shares, which amounts may be increased to time under this prospectus at prices andup to 200,000 shares depending on terms to be determinedthe market price of our common stock at the time of any offering. This prospectus provides you withsale and subject to a general descriptionmaximum commitment by Lincoln Park of the securities$2,000,000 per single purchase, which we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including,refer to the extent applicable:

The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained or incorporated by reference in this prospectus. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus atas “regular purchases”, plus other “accelerated amounts” and/or “additional accelerated amounts” under certain circumstances. We will control the timing and amount of any sales of our common stock to Lincoln Park. The purchase price of the shares that may be sold to Lincoln Park in regular purchases under the Purchase Agreement will be based on the market price of our common stock preceding the time of sale as computed under the effectivenessPurchase Agreement. The purchase price per share will be equitably adjusted for any reorganization, recapitalization,non-cash dividend, stock split, or other similar transaction occurring during the business days used to compute such price. We may at any time in our sole discretion terminate the Purchase Agreement without fee, penalty or cost upon one business day notice. There are no restrictions on future financings, rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement or Registration Rights Agreement, other than a prohibition on our entering into certain types of transactions that are defined in the Purchase Agreement as “Variable Rate Transactions.” Lincoln Park may not assign or transfer its rights and obligations under the Purchase Agreement.

In consideration for entering into the Purchase Agreement, we previously issued to Lincoln Park 105,467 shares of common stock as a commitment fee and shall issue an additional 195,867 commitment shares immediately upon the date that a registration statement covering the resale of shares of Common Stock that have been and may be issued under the Purchase Agreement, which the Company agreed to file with the Securities and Exchange Commission, or the SEC, pursuant to the Registration Rights Agreement is declared effective by the SEC and a final prospectus in connection therewith is filed and the other conditions set forth in the Purchase Agreement are satisfied, all of which this prospectusare outside the control of Lincoln Park (such date on which all of such conditions are satisfied is a part.referred to herein as the Commencement Date).

This prospectus may not be used to consummate a saleAs of securities unless it is accompanied by a prospectus supplement.

We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents, underwriters or dealers reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities to or through agents, underwriters or dealers, we will include in the applicable prospectus supplement:

Common Stock.

We may issueDecember 21, 2018, there were 22,808,416 shares of our common stock from timeoutstanding, of which 18,185,752 shares were held bynon-affiliates. Although the Purchase Agreement provides that we may sell up to time. Each holder$35,000,000 of our common stock is entitled to one voteLincoln Park, only 6,000,000 shares of our common stock are being offered under this prospectus, which represents 5,698,666 shares that have been reserved for each shareissuance upon purchase under the Purchase Agreement plus 301,334 shares issued or to be issued as commitment shares. Depending on all matters submittedthe market prices of our common stock at the time we elect to a voteissue and sell shares to Lincoln Park under the Purchase Agreement, we may need to register for resale under the Securities Act additional shares of our common stock in order to receive aggregate gross proceeds equal to the $35,000,000 total commitment available to us under the Purchase Agreement. If all of the stockholders, including6,000,000 shares offered by Lincoln Park under this prospectus were issued and outstanding as of December 21, 2018, such shares would represent approximately 26% of the electiontotal number of directors. shares of our common stock outstanding and approximately 33% of the total number of outstanding shares held bynon-affiliates, in each case as of the date hereof. If we elect to issue and sell more than the 6,000,000 shares offered under this prospectus to Lincoln Park, which we have the right, but not the obligation, to do, we must first register for resale under the Securities Act any such additional shares, which could cause additional substantial dilution to our stockholders. The number of shares ultimately offered for resale by Lincoln Park is dependent upon the number of shares we sell to Lincoln Park under the Purchase Agreement.

Under our amended and restated certificateapplicable rules of incorporation,The Nasdaq Global Select Market, in no event may we issue or certificate of incorporation, and amended and restated bylaws, or bylaws, our stockholders do not have cumulative voting rights. Because of this,sell to Lincoln Park under the holders of a majorityPurchase Agreement more than 19.99% of the shares of our common stock entitledoutstanding immediately prior to vote in any election of directors can elect allthe execution of the directors standing for election, if they should so choose. SubjectPurchase Agreement (which is 4,538,320 shares based on 22,702,949 shares outstanding immediately prior to preferences that may be applicablethe execution of the Purchase Agreement), which limitation we refer to any then-outstanding preferred stock, holdersas the Exchange Cap, unless (i) we obtain stockholder approval to issue shares of common stock are entitled to receive ratably those dividends, if any, as may be declared from time to time by our boardin excess of directors outthe Exchange Cap or (ii) the average price of legally available funds. In the eventall applicable sales of our liquidation, dissolutioncommon stock to Lincoln Park under the Purchase Agreement equals or winding up, holdersexceeds $1.50 (which is based on the closing price of our common stock immediately prior to entering into the Purchase Agreement), such that issuances and sales of our common stock to Lincoln Park under the Purchase Agreement would be exempt from the Exchange Cap limitation under applicable Nasdaq rules. In any event, the Purchase Agreement specifically provides that we may not issue or sell any shares of our common stock under the Purchase Agreement if such issuance or sale would breach any applicable Nasdaq rules.

The Purchase Agreement also prohibits us from directing Lincoln Park to purchase any shares of common stock are entitled to share ratably in the net assets legally available for distribution to stockholders after the payment ofif those shares, when aggregated with all of our debts and other liabilities and the satisfaction of any liquidation preference granted to the holders of any then-outstanding shares of preferred stock. Holders of common stock have no preemptive, conversion or subscription rights and there are no redemption or sinking fund provisions applicable to the common stock. The rights, preferences and privileges of the holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate in the future.

Preferred Stock.

We may issue shares of our preferredcommon stock fromthen beneficially owned by Lincoln Park and its affiliates, would result in Lincoln Park and its affiliates having beneficial ownership, at any single point in time, to time, in one orof more series. Our board of directors will determine the designations, voting powers, preferences and rightsthan 9.99% of the preferredthen total outstanding shares of our common stock, as wellcalculated pursuant to Section 13(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, andRule 13d-3 thereunder, which limitation we refer to as the qualifications, limitationsBeneficial Ownership Cap.

Issuances of our common stock in this offering will not affect the rights or restrictions thereof, including dividend rights, conversion rights, preemptive rights, termsprivileges of redemption or repurchase, liquidation preferences, sinking fund termsour existing stockholders, except that the economic and voting interests of each of our existing stockholders will be diluted as a result of any such issuance. Although the number of shares constitutingof common stock that our existing stockholders own will not decrease, the shares owned by our existing stockholders will represent a smaller percentage of our total outstanding shares after any series or the designation of any series. Convertible preferred stock will be convertible intosuch issuance to Lincoln Park.

Securities Offered

RISK FACTORS

An investment in our common stock or exchangeable for other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

If we sell any series of preferred stock under this prospectus, we will fix the designations, voting powers, preferences and rights of such series of preferred stock, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Debt Securities.

We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common stock or other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

Any debt securities issued under this prospectus will be issued under one or more documents called indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. A form of indenture has been filed as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

Warrants.

We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities. In this prospectus, we have summarized certain general features of the warrants. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of warrants being offered, as well as any warrant agreements and warrant certificates that contain the terms of the warrants. We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants.

Any warrants issued under this prospectus may be evidenced by warrant certificates. Warrants also may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

Risk Factors

Investing in our securities involves a high degree of risk. Before deciding whetherPrior to investmaking a decision about investing in our securities,common stock, you should consider carefully the risks and uncertainties described underspecific risk factors discussed in the headingsections entitled “Risk Factors” contained in this prospectus and under similar headings in the applicable prospectus supplement, any related free writing prospectus and the documents incorporated by reference herein and therein (including our most recent Annual Report on Form10-K and our or Quarterly ReportsReport on Form10-Q, as filed with the SEC, which are incorporated in this prospectus by reference in their entirety, as well as any amendments theretoamendment or updates to our risk factors reflected in subsequent filings with the SEC), together with other information containedSEC, including any prospectus supplement hereto. These risks and incorporated by reference in the foregoing. The risks described in these documentsuncertainties are not the only onesrisks and uncertainties we face, but thoseface. Additional risks and uncertainties not presently known to us, or that we consider to be material. Therecurrently view as immaterial, may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects onalso impair our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods.business. If any of thesethe risks or uncertainties described in our SEC filings or any additional risks and uncertainties actually occurs,occur, our business, financial condition, results of operations orand cash flow could be seriously harmed. Thismaterially and adversely affected. In that case, the trading price of our common stock could decline and you might lose all or part of your investment.

In addition, you should carefully consider the following risks and other information in this prospectus in evaluating us and our common stock. Any of the following risks could materially and adversely affect Aptevo’s results of operations, financial condition or financial prospects.

The sale or issuance of our common stock to Lincoln Park may cause dilution and the sale of the shares of common stock acquired by Lincoln Park, or the perception that such sales may occur, could cause the price of our common stock to fall.

On December 20, 2018, we entered into the Purchase Agreement with Lincoln Park, pursuant to which Lincoln Park has committed to purchase up to $35,000,000 of our common stock. In consideration for entering into the Purchase Agreement, we previously issued to Lincoln Park 105,467 shares of common stock as a commitment fee and shall issue an additional 195,867 commitment shares immediately upon the Commencement Date. The remaining shares of our common stock that may be issued under the Purchase Agreement may be sold by us to Lincoln Park at our discretion from time to time over a36-month period commencing after the satisfaction of certain conditions set forth in the Purchase Agreement, including that the SEC has declared effective the registration statement that includes this prospectus. The purchase price for the shares that we may sell to Lincoln Park under the Purchase Agreement will fluctuate based on the price of our common stock. Depending on market liquidity at the time, sales of such shares may cause the trading price of our common stock to decline, resultingfall.

We generally have the right to control the timing and amount of any future sales of our shares to Lincoln Park. Additional sales of our common stock, if any, to Lincoln Park will depend upon market conditions and other factors to be determined by us. We may ultimately decide to sell to Lincoln Park all, some or none of the additional shares of our common stock that may be available for us to sell pursuant to the Purchase Agreement. If and when we do sell shares to Lincoln Park, after Lincoln Park has acquired the shares, Lincoln Park may resell all, some or none of those shares at any time or from time to time in its discretion. Therefore, sales to Lincoln Park by us could result in substantial dilution to the interests of other holders of our common stock. Additionally, the sale of a losssubstantial number of shares of our common stock to Lincoln Park, or the anticipation of such sales, could make it more difficult for us to sell equity or equity-related securities in the future at a time and at a price that we might otherwise wish to effect sales.

We may require additional financing to sustain our operations and without it we may not be able to continue operations.

We had an operating cash flow deficit of $44.1 million for the nine months ended September 30, 2018 and $26.2 million for the nine months ended September 30, 2017 and an operating cash flow deficit of $41.6 million for the year ended December 31, 2017 and $36.9 million for the year ended December 31, 2016. Although we expect our existing cash, cash equivalents, and short-term investments will be sufficient to fund our operations for at least twelve months from the date of this filing, we anticipate directing Lincoln Park to purchase shares of our common stock pursuant to the Purchase Agreement as a source of funding.

We may direct Lincoln Park to purchase up to $35,000,000 worth of shares of our common stock under our agreement over a36-month period generally in amounts up to 100,000 shares of our common stock, which may be increased to up to 200,000 shares of our common stock depending on the market price of our common stock at the time of sale and subject to a maximum limit of $2,000,000 per purchase, on any such business day. Assuming a purchase price of $1.27 per share (the closing sale price of the common stock on December 31, 2018) and the purchase by Lincoln Park of 27,559,055 purchase shares, proceeds to us would only be $34,999,999.85.

The extent we rely on Lincoln Park as a source of funding will depend on a number of factors including, the prevailing market price of our common stock and the extent to which we are able to secure working capital from other sources. If obtaining sufficient funding from Lincoln Park were to prove unavailable or prohibitively dilutive, we will need to secure another source of funding in order to satisfy our working capital needs. Even if we sell all $35,000,000 under the Purchase Agreement to Lincoln Park, we may still need additional capital to fully implement our business, operating and development plans. Should the financing we require to sustain our working capital needs be unavailable or part of your investment. Please also read carefullyprohibitively expensive when we require it, the section below entitled “Forward-Looking Statements.”consequences could be a material adverse effect on our business, operating results, financial condition and prospects, including on our ability to continue as a going concern.

Forward-Looking StatementsFORWARD-LOOKING STATEMENTS

This prospectus, including the documents that we incorporate by reference herein, contains, and any applicable prospectus supplement and anyor free writing prospectus, including the documents we incorporate by reference herein and therein, may contain, forward-looking statements, including statements regarding our future financial condition, business strategy and plans and objectives of management for future operations. Forward-looking statements include all statements that are not historical facts. In some cases, you can identify forward-looking statements by terminology such as “believe,” “will,” “may,” “estimate,” “continue,” “anticipate,” “intend,” “should,” “plan,” “might,” “approximately,” “expect,” “predict,” “could,” “potentially” or the negative of these terms or other similar expressions. Forward-looking statements appear in a number of places throughout this prospectus and the documents that we incorporate by reference herein, and include statements regarding our intentions, beliefs, projections, outlook, analyses or current expectations concerning, among other things, our outlook, financial performance or financial condition, our technologyongoing and related pipeline, collaborationplanned preclinical development and partnership opportunities, commercial portfolio, our future growth rates,clinical trials, the timing of and our ability to timely manufacture its products, spendingmake regulatory filings and obtain and maintain regulatory approvals for our current and future product candidates, our intellectual property position, the degree of the proceeds from this offering,clinical utility of our current and future product candidates, particularly in specific patient populations, our ability to develop commercial functions, expectations regarding clinical trial data, our results of operations, cash needs, financial condition, liquidity, prospects, growth and strategies, the industry in which we operate and the trends that may affect theour industry or us.

Discussions containing these forward-looking statements may be found, among other places, in the Sectionssections entitled “Business,” “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” incorporated by reference from our most recent Annual Report onForm 10-K and in our Quarterly Reports onForm 10-Q, as well as any amendments thereto, filed with the SEC. These statements relate to future events or our future financial performance and involve known and unknown risks, uncertainties and other factors that could cause our actual results, levels of activity, performance or achievement to differ materially from those expressed or implied by these forward-looking statements. We discuss in greater detail, and incorporate by reference into this prospectus in their entirety, many of these risks and uncertainties under the heading “Risk Factors” contained in any applicable prospectus supplement, in any free writing prospectus we or the selling stockholder may authorize for use in connection with a specific offering, and in our most recent Annual Report on Form10-K and in our most recent Quarterly Report on Form10-Q, as well as any amendments thereto reflected in subsequent filings with the SEC. These statements reflect our current views with respect to future events and are based on assumptions and subject to risks and uncertainties. Given these uncertainties, you should not place undue reliance on these forward-looking statements. These forward-looking statements represent our estimates and assumptions only as of the date of the document containing the applicable statement and, except as required by law, we undertake no obligation to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise.

THE LINCOLN PARK TRANSACTION

General

On December 20, 2018, we entered into the Purchase Agreement and the Registration Rights Agreement with Lincoln Park. Pursuant to the terms of the Purchase Agreement, Lincoln Park has agreed to purchase from us up to $35,000,000 of our common stock (subject to certain limitations) from time to time during the term of the Purchase Agreement. Pursuant to the terms of the Registration Rights Agreement, we have filed with the SEC the registration statement that includes this prospectus to register for resale under the Securities Act the shares that have been or may be issued to Lincoln Park under the Purchase Agreement.

We do not have the right to commence any sales to Lincoln Park under the Purchase Agreement until certain conditions set forth in the Purchase Agreement, all of which are outside of Lincoln Park’s control, have been satisfied, including the registration statement that includes this prospectus being declared effective by the SEC. Thereafter, we may, from time to time and at our sole discretion, on any single business day, direct Lincoln Park to purchase shares of our common stock in amounts up to 100,000 shares, which amounts may be increased to up to 200,000 shares depending on the market price of our common stock at the time of sale and subject to a maximum commitment by Lincoln Park of $2,000,000 per single purchase, which we refer to in this prospectus as “regular purchases”, plus other “accelerated amounts” and/or “additional accelerated amounts” under certain circumstances.    The purchase price per share sold in regular purchases will be based on the market price of our common stock immediately preceding the time of sale as computed under the Purchase Agreement. Lincoln Park may not assign or transfer its rights and 15,000,000 shares of preferred stock, $0.001 par value per share. As of November 8, 2017, 21,428,468obligations under the Purchase Agreement.

In consideration for entering into the Purchase Agreement, we previously issued to Lincoln Park 105,467 shares of common stock were outstandingas a commitment fee and shall issue an additional 195,867 commitment shares upon the Commencement Date.

Under applicable rules of The Nasdaq Global Select Market, in no shares of preferred stock were outstanding.

The following summary describesevent may we issue or sell to Lincoln Park under the material terms of our capital stock. The summary is qualified in its entirety by reference to our certificate of incorporation and our bylaws.

Common Stock

Voting Rights.  

Each holderPurchase Agreement share of our common stock is entitled to one vote for each share on all matters submitted to a votein excess of the stockholders, including the election of directors. Under our certificate of incorporation and bylaws, our stockholders do not have cumulative voting rights. Because of this, the holders of a majorityExchange Cap (which is 4,538,320 shares, or 19.99% of the shares of our common stock entitledoutstanding immediately prior to vote in any election of directors can elect allthe execution of the directors standing for election, if they should so choose.

Dividends.  

SubjectPurchase Agreement), unless (i) we obtain stockholder approval to preferences that may be applicable to any then-outstanding preferred stock, holders of common stock are entitled to receive ratably those dividends, if any, as may be declared from time to time by our board of directors out of legally available funds.

Liquidation.

In the event of our liquidation, dissolution or winding up, holders of common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities and the satisfaction of any liquidation preference granted to the holders of any then-outstanding shares of preferred stock.

Rights and Preferences.  

Holders of common stock have no preemptive, conversion or subscription rights and there are no redemption or sinking fund provisions applicable to our common stock. The rights, preferences and privileges of the holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate in the future.

Fully Paid and Nonassessable.

All of our outstandingissue shares of common stock are fully paid and nonassessable.

Preferred Stock

Under our certificate of incorporation, our board of directors is authorized by resolution to divide the preferred stock into one or more series and, with respect to each series, to determine the designations, powers, preferences, rights, qualifications, limitations and restrictions thereof, including the dividend rights, conversion or exchange rights, voting rights, redemption rights and terms, liquidation preferences, sinking fund provisions and the number of shares constituting the series. Our board of directors can, without stockholder approval but subject to the terms of our certificate of incorporation, issue preferred stock with voting and other rights that could adversely affect the voting powerin excess of the holdersExchange Cap or (ii) the average price of all applicable sales of our common stock to Lincoln Park under the Purchase Agreement equals or exceeds $1.50 (which is based on the closing price of our common stock immediately prior to entering into the Purchase Agreement), such that issuances and which could have certain anti-takeover effects. Beforesales of our common stock to Lincoln Park under the Purchase Agreement would be exempt from the Exchange Cap limitation under applicable Nasdaq rules. In any event, the Purchase Agreement specifically provides that we may not issue or sell any seriesshares of preferredour common stock our board of directors will be required to adopt resolutions creating and designatingunder the Purchase Agreement if such series of preferred stock.issuance or sale would breach any applicable Nasdaq rules.

The following summaryPurchase Agreement also prohibits us from directing Lincoln Park to purchase any shares of termscommon stock if those shares, when aggregated with all other shares of our preferredcommon stock is not complete. You should refer tothen beneficially owned by Lincoln Park and its affiliates, would result in Lincoln Park exceeding the provisionsBeneficial Ownership Cap.

Purchase of our certificateShares Under the Purchase Agreement

Under the Purchase Agreement, following effectiveness of incorporation, our bylaws and the resolutions containing the terms of each series of preferred stock, which have been or will be filed with the SEC at or prior to the time of issuance of such series and described in the applicable prospectus supplement. The applicable prospectus supplement may also state that any of the terms set forth herein are inapplicable to such series of preferred stock, provided that the information set forth in such prospectus supplement does not constitute a material change to the information herein such that it alters the nature of the offering or the securities being offered.

We will fix the designations, voting powers, preferences and rights of each series of preferred stock that we issue under this prospectus, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference herein from reports that we file with the SEC, the formmay direct Lincoln Park to purchase up to 100,000 shares of any certificate of designation that describes the terms of the series of preferred stock we are offering. We will describe in the applicable prospectus supplement the terms of the series of preferred stock being offered, including, to the extent applicable:

If we issue shares of preferred stock under this prospectus, the shares will be fully paid and non-assessable.

The issuance of preferred stock could adversely affect the voting power of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation. The issuance could have the effect of decreasing the market price of the common stock. The issuance of preferred stock also could have the effect of delaying, deterring or preventing a change in control of us.

Options and Restricted Stock Units

As of November 8, 2017, (i) optionsRegular Purchase notice directing Lincoln Park to purchase an aggregate of 1,553,718 shares of common stock were outstanding under our 2016 Converted Equity Awards Incentive Plan, (ii) 442,993 restricted stock units were outstanding under our 2016 Converted Equity Awards Incentive Plan, (iii) options to purchase an aggregate of 1,421,864 shares of common stock were outstanding under our 2016 Stock Incentive Plan, (iv) 780,084 restricted stock units were outstanding under our 2016 Stock Incentive Plan and (v) an additional 1,332,990 shares were reserved for future issuance under our 2016 Stock Incentive Plan.

Stockholder Registration Rights

Certain holdersthe maximum number of shares of our common stock that we are entitledthen permitted to certain rights with respectinclude in a single Regular Purchase notice and the closing sale price of our common stock on such business day is not below the lower of (i) $1.50 per share or (ii) $1.50 per share adjusted for any reorganization, recapitalization,non-cash dividend, stock split, reverse stock split or other similar transaction as provided in the Purchase Agreement to registrationpurchase an additional amount of such shares under the Securities Act of 1933, as amended, or the Securities Act. These shares are referredour common stock, which we refer to as registrable securities. The holdersan Accelerated Purchase, not to exceed the lesser of:

The purchase price per share for each such Accelerated Purchase will be equal to the lower of:

We will pay the registration expenses, othermay also direct Lincoln Park, not later than underwriting discounts, selling commissions1:00 p.m., Eastern time, on a business day on which an Accelerated Purchase has been completed and stock transfer taxes,all of the shares registeredto be purchased thereunder (and under the corresponding Regular Purchase) have been properly delivered to Lincoln Park in accordance with the Purchase Agreement prior to such time on such business day, and provided that the closing price of our common stock on the business day immediately preceding such business day is not less than $1.50 per share (subject to adjustment for any reorganization, recapitalization,non-cash dividend, stock split, reverse stock split or other similar transaction as provided in the Purchase Agreement), to purchase an additional amount of our common stock, which we refer to as an Additional Accelerated Purchase, of up to the lesser of:

We may, in our sole discretion, submit multiple Additional Accelerated Purchase notices to Lincoln Park prior to 1:00 p.m., Eastern time, on a single Accelerated Purchase date, provided that all prior Accelerated Purchases and piggyback registration rights described below.

Generally,Additional Accelerated Purchases (including those that have occurred earlier on the same day) have been completed and all of the shares to be purchased thereunder (and under the corresponding Regular Purchase) have been properly delivered to Lincoln Park in an underwritten offering,accordance with the managing underwriter, if any, has the right, subject to specified conditions, to limit the number of shares the holders may include.

Demand Registration RightsPurchase Agreement.

The holderspurchase price per share for each such Additional Accelerated Purchase will be equal to the lower of:

In the case of the registrable securities, on not moreRegular Purchases, Accelerated Purchases and Additional Accelerated Purchases, the purchase price per share will be equitably adjusted for any reorganization, recapitalization,non-cash dividend, stock split, reverse stock split or other similar transaction occurring during the business days used to compute the purchase price.

Other than two occasions, may request thatas described above, there are no trading volume requirements or restrictions under the Purchase Agreement, and we register all or a portionwill control the timing and amount of their shares, subjectany sales of our common stock to certain specified exceptions. Such request for registration must cover securitiesLincoln Park.

Events of Default

Events of default under the aggregate offering price of which, before payment of underwriting discounts and commissions, exceeds $10,000,000.Purchase Agreement include the following:

Piggyback Registration Rights

upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction began, excluding for purposes of determining the voting stock outstanding (but not the outstanding voting stock owned by the interested stockholder) those shares owned (1) by persons who are directors and also officers and (2) employee stock plans in which employee participants doLincoln Park does not have the right to determine confidentially whether shares held subject toterminate the plan will be tendered in a tender or exchange offer; or

PLAN OF DISTRIBUTION

The common stock preferred stock or debt securities and may be issued in one or more series. Warrants may be offered independently or in combination with common stock, preferred stock or debt securities offered by any prospectus supplement. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The following description of warrants will apply to the warrants offered by this prospectus unless we provide otherwise inis being offered by the applicable prospectus supplement.selling stockholder, Lincoln Park. The applicable prospectus supplement for a particular series of warrants may specify different or additional terms.

We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants thatcommon stock may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part,sold or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants. The following summaries of material terms and provisions of the warrants are subject to, and qualified in their entirety by reference to, all the provisions of the form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements applicable to a particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplement related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectus, and the complete form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements, that contain the terms of the warrants.

General

We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including, to the extent applicable:

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants by delivering the warrant or warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent, if applicable, in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of any warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to any warrant agent in connection with the exercise of the warrant.

Upon receipt of payment and the warrant or warrant certificate, as applicable, properly completed and duly executed at the corporate trust office of the warrant agent, if any, or any other office, including ours, indicated in the prospectus supplement, we will, as soon as practicable, issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants (or the warrants represented by such warrant certificate) are exercised, a new warrant or a new warrant certificate, as applicable, will be issued for the remaining warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements, and any claim, controversy or dispute arising under or related to the warrants or warrant agreements, will be governed by and construed in accordance with the laws of the State of New York.

Enforceability of Rights by Holders of Warrants

Each warrant agent, if any, will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

Legal Ownership of Securities

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a global security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

Street Name Holders

We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any applicable trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the legal holder, we have no further responsibility for the payment or notice even if that legal holder is required, under agreements with its participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the legal holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the legal holders contact the indirect holders is up to the legal holders.

Special Considerations for Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form because the securities are represented by one or more global securities or in street name, you should check with your own institution to find out:

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we issue to, deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, DTC will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under “Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations for Global Securities

The rights of an indirect holder relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only in the form of a global security, an investor should be aware of the following:

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When a Global Security Will Be Terminated

In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks, brokers or other financial institutions to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

The prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

Plan of Distribution

We may sell our securities covered by this prospectus in any of three ways (or in any combination):

Webrokers, dealers, or underwriters who may distribute the securities:

Each time we offer and sell securities coveredprices, or at fixed prices, which may be changed. The sale of the common stock offered by this prospectus we will provide a prospectus supplement or supplements that will describe the method of distribution and set forth the terms of the offering, including:

Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time. We may determine the price or other terms of the securities offered under this prospectus by use of an electronic auction. We will describe how any auction will determine the price or any other terms, how potential investors may participate in the auction and the nature of the obligations of the underwriter, dealer or agent in the applicable prospectus supplement.

Underwriters or dealers may offer and sell the offered securities from time to timeeffected in one or more of the following methods:

In order to comply with the securities laws of certain states, if applicable, the shares may be sold only through registered or licensed brokers or dealers. In addition, in certain states, the shares may not be sold unless they have been registered or qualified for sale in the state or an exemption from the state’s registration or qualification requirement is available and complied with.

Lincoln Park is an “underwriter” within the meaning of Section 2(a)(11) of the Securities Act.

Lincoln Park has informed us that it intends to use an unaffiliated broker-dealer to effectuate all sales, if any, of the common stock that it may purchase from us pursuant to the Purchase Agreement. Such sales will be made at a fixed public offering priceprices and at terms then prevailing or at varying prices determined atrelated to the then current market price. Each such unaffiliated broker-dealer will be an underwriter within the meaning of Section 2(a)(11) of the Securities Act. Lincoln Park has informed us that each such broker-dealer will receive commissions from Lincoln Park that will not exceed customary brokerage commissions.

Brokers, dealers, underwriters or agents participating in the distribution of the shares as agents may receive compensation in the form of commissions, discounts, or concessions from the selling stockholder and/or purchasers of the common stock for whom the broker-dealers may act as agent. The compensation paid to a particular broker-dealer may be less than or in excess of customary commissions. Neither we nor Lincoln Park can presently estimate the amount of compensation that any agent will receive.

We know of no existing arrangements between Lincoln Park or any other stockholder, broker, dealer, underwriter or agent relating to the sale or distribution of the shares offered by this prospectus. At the time a particular offer of sale. Ifshares is made, a prospectus supplement, if required, will be distributed that will set forth the names of any agents, underwriters or dealers are used inand any compensation from the sale ofselling stockholder, and any securities,other required information.

We will pay the securities will be acquired by the underwriters or dealers for their own account and may be resold from time to time in one or more transactions described above. The securities may be either offeredexpenses incident to the public through underwriting syndicates represented by managing underwriters, or directly by underwriters or dealers. Generally, the underwriters’ or dealers’ obligations to purchase the securities will be subject to certain conditions precedent. The underwriters or dealers will be obligated to purchase all of the securities if they purchase any of the securities, unless otherwise specified in the prospectus supplement. We may use underwriters with whom we have a material relationship. We will describe the nature of any such relationship in the prospectus supplement, naming the underwriter.

We may sell the securities through agents from time to time. The prospectus supplement will name any agent involved in the offer orregistration, offering, and sale of the securitiesshares to Lincoln Park. We have agreed to indemnify Lincoln Park and any commissions we pay to them. Generally, any agent will be acting on a best efforts basis for the period of its appointment. We may authorize underwriters, dealers or agents to solicit offers by certain purchasers to purchase the securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. The contracts will be subject only to those conditions set forth in the prospectus supplement, and the prospectus supplement will set forth any commissions we pay for solicitation of these contracts.

Agents, dealers and underwriters may be entitled to indemnification by usother persons against certain civil liabilities in connection with the offering of shares of common stock offered hereby, including liabilities arising under the Securities Act or, if such indemnity is unavailable, to contribute amounts required to be paid in respect of such liabilities. Lincoln Park has agreed to indemnify us against liabilities under the Securities Act that may arise from certain written information furnished to us by Lincoln Park specifically for use in this prospectus or, if such indemnity is unavailable, to contributioncontribute amounts required to be paid in respect of such liabilities.

Lincoln Park has represented to us that at no time prior to the Purchase Agreement has Lincoln Park or its agents, representatives or affiliates engaged in or effected, in any manner whatsoever, directly or indirectly, any short sale (as such term is defined in Rule 200 of Regulation SHO of the Exchange Act) of our common stock or any hedging transaction, which establishes a net short position with respect to payments whichour common stock. Lincoln Park agreed that during the term of the Purchase Agreement, it, its agents, dealersrepresentatives or underwriters may beaffiliates will not enter into or effect, directly or indirectly, any of the foregoing transactions.

We have advised Lincoln Park that it is required to make in respect thereof. Agents, dealers and underwriters may be customers of, engage in transactions with, or perform services for us in the ordinary course of business.

All securities we may offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids in accordancecomply with Regulation M promulgated under the Securities Exchange Act of 1934, as amended. Overallotment involves salesAct. With certain exceptions, Regulation M precludes the selling stockholder, any affiliated purchasers, and any broker-dealer or other person who participates in excessthe distribution from bidding for or purchasing, or attempting to induce any person to bid for or purchase any security which is the subject of the offering size, which create a short position. This short sales position may involve either “covered” short salesdistribution until the entire distribution is complete. Regulation M also prohibits any bids or “naked” short sales. Covered short sales are short salespurchases made in an amount not greater than the underwriters’ over-allotment optionorder to purchase additional securities in this offering described above. The underwriters may close out any covered short position either by exercising their over-allotment option or by purchasing securities in the open market. To determine how they will close the covered short position, the underwriters will consider, among other things,stabilize the price of securities available for purchasea security in connection with the open market, as compared to the price at which they may purchase securities through the over-allotment option. Naked short sales are short sales in excessdistribution of that security. All of the over-allotment option. The underwriters must close out any naked short position by purchasing securities inforegoing may affect the open market. A naked short position is more likely to be created if the underwriters are concerned that, in the open market after pricing, there may be downward pressure on the price of the securities that could adversely affect investors who purchase securities in this offering. Stabilizing transactions permit bids to purchase the underlying security for the purpose of fixing the price of the security so long as the stabilizing bids do not exceed a specified maximum. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions.

Any underwriters who are qualified market makers on the NASDAQ Global Market may engage in passive market making transactions in our common stock, preferred stock, warrants and debt securities, as applicable, on the NASDAQ Global Market in accordance with Rule 103 of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded.

In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

Similar to other purchase transactions, an underwriter’s purchase to cover the syndicate short sales or to stabilize the market price of our securities may have the effect of raising or maintaining the market price of our securities or preventing or mitigating a decline in the market price of our securities. As a result, the price of our securities may be higher than the price that might otherwise exist in the open market. The imposition of a penalty bid might also have an effect on the price of the securities if it discourages resales of the securities.

Neither we nor the underwriters make any representation or prediction as to the effect that the transactions described above may have on the price of the securities. If such transactions are commenced, they may be discontinued without notice at any time.

Legal Matters

Unless otherwise indicated in the applicable prospectus supplement, the validitymarketability of the securities offered by this prospectus.

This offering will terminate upon the date that all shares offered by this prospectus and any supplement thereto, will behave been sold by Lincoln Park.

Our common stock is quoted on The Nasdaq Global Select Market under the symbol “APVO.”

LEGAL MATTERS

The validity of the common stock being offered hereby was passed upon for us by Cooley LLP, Seattle, Washington.

ExpertsEXPERTS

The consolidated financial statements of Aptevo Therapeutics Inc. appearing in our Annual Report (Form10-K) for the year ended December 31, 2016,2017, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in itstheir report thereon, included therein,herein, and incorporated herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such reportsreport given on the authority of such firm as experts in accounting and auditing.

Where You Can Find More InformationWHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of a registration statement on FormS-3 we filed with the SEC. This prospectus does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of the securities offered by this prospectus.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any document we file with the SEC at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C., 20549. Please call the SEC at 1.800.SEC.0330 for further information on the operation of the public reference room. Our SEC filings are also available to the public at the SEC’s website at http://www.sec.gov.

Item 17. Undertakings

The undersigned registrant hereby undertakes:

(a) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) to include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) to reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) to include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (i), (ii) and (iii) of this section do not apply if the registration statement is on FormS-1, FormS-3, FormSF-3 or FormF-3 and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or, as to a registration statement on FormS-3, FormSF-3 or Form F03, is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(b) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(c) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(d) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(i) Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5) or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.date; and

(e) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary(iii) Each prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus424(b) as part of a registration statement relating to an offering, other than registration statements relying on Rule 430B or other than prospectuses filed in reliance on Rule 430A, shall be deemed to be part of and included in the offering prepared by or on behalfregistration statement as of the undersigned registrantdate it is first used after effectiveness.Provided, however, that no statement made in a registration statement or used or referred to by the undersigned registrant;

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(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalfthat is part of the undersigned registrant; and

(iv) Any other communicationregistration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is an offerpart of the registration statement will, as to a purchaser with a time of contract of sale prior to such first use, supersede or modify any statement that was made in the offeringregistration statement or prospectus that was part of the registration statement or made by the undersigned registrantin any such document immediately prior to the purchaser.such date of first use

(f) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(g) That, for purposes of determining any liability under the Securities Act, (i) the information omitted from the form of prospectus filed as part of the registration statement in reliance upon Rule 430A and contained in the form of prospectus filed by the registrant pursuant to Rule 424(b)(l) or (4) or 497(h) under the Securities Act shall be deemed to be a part of the registration statement as of the time it was declared effective; and (ii) each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(h) To file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the Commission under Section 305(b)(2) of the Trust Indenture Act.II-2

(g) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is therefore unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on FormS-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Seattle, Washington, on November 9, 2017.January 2, 2019.

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Marvin L. White and Jeffrey G. Lamothe, and Shawnte Mitchell, his or her true and lawful agent, proxy andattorney-in-fact, each acting alone, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to (i) act on, sign, and file with the SEC any and all amendments (including post-effective amendments) to this registration statement together with all schedules and exhibits thereto, (ii) act on, sign and file such certificates, instruments, agreements and other documents as may be necessary or appropriate in connection therewith, (iii) act on and file any supplement to any prospectus included in this registration statement or any such amendment or any subsequent registration statement filed pursuant to Rule 462(b) under the Securities Act, and (iv) take any and all actions which may be necessary or appropriate to be done, as fully for all intents and purposes as he or she might or could do in person, hereby approving, ratifying and confirming all that such agent, proxy andattorney-in-fact or any of his substitutes may lawfully do or cause to be done by virtue thereof.

Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated:

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