Dendreon (DNDN) 424B5 Prospectus supplement for primary offering

Filed Pursuant to Rule 424(b)(5)

RegistrationNo. 333-127521

PROSPECTUS SUPPLEMENT (TO PROSPECTUS DATED OCTOBER 26, 2005)

9,890,110 Shares

Dendreon Corporation

Common Stock

Dendreon Corporation is offering up to 9,890,110 shares of its common stock directly to selected investors. Our common stock is quoted on the Nasdaq Global Market under the symbol “DNDN.” The last reported sale price of our common stock on the Nasdaq Global Market on November 14, 2006 was $5.18 per share.

Credit Suisse Securities (USA) LLC and Lazard Capital Markets LLC have agreed to act as joint lead placement agents in connection with this offering and to use their best efforts to solicit offers to purchase our securities in this offering.

Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning onpage S-7 of this prospectus supplement.

	Per Share		Total
Offering price	$	4.55	$	45,000,000
Placement agents’ fees	$	0.273	$	2,700,000
Offering proceeds to Dendreon Corporation, before expenses	$	4.277	$	42,300,000

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement is accurate or complete. Any representation to the contrary is a criminal offense.

We estimate the total expenses of this offering, excluding the placement agents’ fees, will be approximately $150,000. Because there is no minimum offering amount required as a condition to closing in this offering, the actual public offering amount, placement agents’ fees and net proceeds to us, if any, in this offering are not presently determinable and may be substantially less than the total maximum offering amount set forth above. The placement agents are not required to sell any specific number or dollar amount of the shares of common stock offered in this offering, but will use their best efforts to sell the shares of common stock offered. Pursuant to an escrow agreement among us, the placement agents and an escrow agent, a portion of the funds received in payment for the shares sold in this offering will be wired to an escrow account and held until we and the placement agents notify the escrow agent that the offering has closed, indicating the date on which the shares are to be delivered to the purchasers and the proceeds are to be delivered to us.

Credit Suisse Lazard Capital Markets

November 16, 2006

This document is in two parts. The first part is this prospectus supplement, which describes the terms of this offering of common stock and also adds to, updates and changes information contained in the accompanying prospectus and the documents incorporated by reference. The second part is the accompanying prospectus, which gives more general information. To the extent the information contained in this prospectus supplement differs or varies from the information contained in the accompanying prospectus or any document incorporated by reference, the information in this prospectus supplement will control.

You should rely only on the information contained in or incorporated by reference into this prospectus supplement and the accompanying prospectus. We have not authorized anyone to provide you with information that is different. This prospectus supplement is not an offer to sell or solicitation of an offer to buy these shares of common stock in any circumstances under which the offer or sale is unlawful. You should not assume that the information we have included in this prospectus supplement or the accompanying prospectus is accurate as of any date other than the date of this prospectus supplement or the accompanying prospectus or that any information we have incorporated by reference is accurate as of any date other than the date of the document incorporated by reference regardless of the time of delivery of this prospectus supplement or of any such shares of our common stock. Our financial condition, results of operations and business prospects may have changed since that date.

Information contained on our website does not constitute part of this prospectus supplement or the accompanying prospectus.

Dendreon^®, the Dendreon logo, Targeting Cancer, Transforming Lives, Provenge^®, Neuvenge^tm and the Antigen Delivery Cassette^tm are our trademarks. All other trademarks that may appear or be incorporated by reference into this prospectus supplement are the property of their respective owners.

TABLE OF CONTENTS

	Page
Prospectus Supplement
Summary		S-1
Forward Looking Statements		S-6
Risk Factors		S-7
Use of Proceeds		S-21
Description of Capital Stock		S-21
Plan of Distribution		S-22
Legal Matters		S-23
Experts		S-23
Where You Can Find Additional Information		S-23
Incorporation of Certain Information by Reference		S-23
Prospectus
About This Prospectus		1
Forward Looking Statements		1
Risk Factors		2
Our Business		2
Use of Proceeds		3
Plan of Distribution		3
Legal Matters		4
Experts		4
Where You Can Find Additional Information		5
Incorporation of Certain Information by Reference		5

SUMMARY

This summary highlights information contained elsewhere or incorporated by reference into this prospectus supplement and accompanying prospectus. This summary does not contain all the information that you should consider before investing in our common stock. You should carefully read the entire prospectus supplement and the accompanying prospectus, including the “Risk Factors” section, as well as the financial statements and the other information incorporated by reference herein before making an investment decision.

Overview

We are a biotechnology company focused on the discovery, development and commercialization of novel therapeutics that harness the immune system to fight cancer. Our product portfolio includes active cellular immunotherapy, monoclonal antibody and small molecule product candidates to treat a wide range of cancers. Our most advanced product candidate is Provenge (sipuleucel-T), an active cellular immunotherapy that has completed two Phase 3 trials for the treatment of asymptomatic, metastatic, androgen-independent prostate cancer. On November 9, 2006, we completed our submission of a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) for Provenge based upon the significant survival benefit seen in our completed studies for Provenge. We own worldwide commercialization rights for Provenge.

Provenge (sipuleucel-T)

Provenge is our active cellular immunotherapy that targets the prostate cancer antigen, prostatic acid phosphatase (PAP), which is found in approximately 95% of all prostate cancers. It combines patient-derived antigen-presenting cells (APC) and the engineered prostate cancer antigen in vitro. The antigen-loaded APC is then infused into patients to trigger a cell-mediated immune response to destroy tumors. Our Provenge clinical studies have primarily targeted asymptomatic, metastatic, androgen-independent prostate cancer. Androgen-independent prostate cancer is an advanced stage of prostate cancer in which the tumor growth is no longer regulated by androgens, or male hormones. Prostate cancer is the most common non-skin cancer among men in the United States, with over one million men currently diagnosed with the disease, and the second leading cause of cancer deaths in men in the United States. The American Cancer Society estimates that in 2006 approximately 234,500 new cases of prostate cancer will be diagnosed in the United States, and approximately 27,350 men are expected to die of prostate cancer.

Early-stage prostate cancer treatment generally involves surgery, radiation therapy or a combination of the two. Once the cancer becomes metastatic, or spreads outside the prostate gland, hormone ablation therapy is often used to try to control the cancer by limiting the supply of hormones that the cancer needs to grow. While most prostate cancer patients initially respond to hormone ablation therapy, the vast majority relapse after 18 to 24 months, becoming refractory to hormone treatment, or androgen-independent. For these androgen-independent patients, subsequent treatment involves a limited number of options, including chemotherapy and radiation therapy, which may not have the desired therapeutic effect and may result in significant side effects.

To be effective, cancer therapies must eliminate or control the growth of the cancer. There is only one FDA-approved chemotherapy drug that has been proven to prolong survival of androgen-independent prostate cancer patients. However, chemotherapy drugs are generally administered over the course of a number of months and are poorly tolerated due to significant side effects, including hair loss, fatigue, vomiting, and detrimental gastrointestinal effects.

We believe that Provenge addresses a significant unmet medical need for patients with asymptomatic, metastatic, androgen-independent prostate cancer and may provide considerable benefits compared to currently available treatment alternatives. The survival benefit shown in our Phase 3 clinical trials is greater than that observed to date in any published Phase 3 trial in asymptomatic, metastatic, androgen-independent prostate cancer. Provenge is administered over a four-week period consisting of three infusion

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treatments given on an outpatient basis each lasting about 30 to 60 minutes. Results from our Provenge clinical trials have shown that Provenge is well-tolerated with the most common side effects reported being fever and chills lasting for one to two days. The greater survival benefit in combination with these minimal side effects reflect a more favorablerisk-to-benefit profile than experienced with the current standard of care.

In September 2005, we announced plans to submit a BLA to the FDA to obtain regulatory approval for the commercialization of Provenge. This decision followed a pre-BLA meeting in which we reviewed safety and efficacy data with the FDA from our two completed Phase 3 clinical trials, D9901 and D9902A. In these discussions the FDA agreed that the survival benefit observed in the D9901 study in conjunction with the supportive data obtained from study D9902A and the absence of significant toxicity in both studies is sufficient to serve as the clinical basis of a BLA submission for Provenge. Provenge was granted Fast Track designation from the FDA for the treatment of asymptomatic, metastatic, androgen-independent prostate cancer patients, which enabled us to submit our BLA on a rolling basis. On August 24, 2006, we submitted the clinical and non-clinical sections of our BLA and on November 9, 2006, we submitted the chemistry, manufacturing and controls (CMC) section, completing our submission of our BLA to the FDA for Provenge. As part of the Provenge BLA submission, we have requested a Priority Review designation from the FDA, which, if granted, would give the FDA six months from the FDA’s receipt of the final section of the submission to take action on the application.

Our first Phase 3 clinical trial of Provenge, D9901, was a randomized double-blind placebo-controlled study in 127 men with asymptomatic, metastatic, androgen-independent (hormone refractory) prostate cancer. The trial was designed to measure a delay in time to disease progression. Time to the onset of disease related pain was a secondary endpoint that was to be evaluated in concert with the results from a second, identical companion trial, D9902. The protocols for both trials required patients to be followed for survival for three years after enrollment.

While trial D9901 approached, but did not meet, its primary endpoint of showing a significant delay in time to disease progression in the overall patient population in the study (p-value = 0.052, hazard ratio = 1.4) , we completed the planned three yearfollow-up for survival on the D9901 patients and disclosed in February 2005 that a significant survival advantage was seen in those patients who had been randomized to the Provenge arm compared to those who had been randomized to receive placebo. According to the final three yearintent-to-treat analysis, patients who received Provenge had a median survival of 25.9 months compared to 21.4 months for patients in the placebo arm, a 4.5 month or 21 percent improvement (p-value = 0.01, hazard ratio = 1.7). This hazard ratio implies that patients who received placebo have a relative risk of dying that is 70 percent higher than that of patients who received Provenge. In addition, 34 percent of patients who received Provenge were alive at 36 months compared to 11 percent of patients who received placebo. A Cox multivariate regression analysis was used to test the validity of the survival benefit seen in this study. The results showed that treatment with Provenge remained a strong independent predictor of survival after adjusting for prognostic factors. These results were published in the July 2006 issue of the Journal of Clinical Oncology. Recent additional analyses have demonstrated an improvement in prostate cancer specific survival for Provenge treated patients (p-value = 0.002; HR = 2.0). In addition, there is no evidence to suggest a delay in the use or timing of chemotherapy in the placebo arm relative to the Provenge arm. A separate analysis conducted by evaluating the integrated data from D9901/D9902A suggest the use of Provenge as a first-line treatment followed by chemotherapy docetaxel upon disease progression may provide patients with substantially prolonged survival. We have also demonstrated a correlation between overall survival and cumulative final product CD54 upregulation, a measure of antigen presenting cell activation which serves as the potency assay for Provenge.

In October 2005, we disclosed results from the second randomized Phase 3 trial, D9902A. Trial D9902A also did not meet its primary endpoint of showing a significant delay in time to disease progression. In the D9902A study, the three-year final survival analysis in theintent-to-treat population of the double-blind, placebo-controlled study of Provenge in 98 men with asymptomatic, metastatic, androgen-independent prostate cancer showed those patients who received Provenge had a median survival of 19.0 months compared to 15.7 months for patients in the placebo arm, a 3.3 month or 21 percent improvement (p-value

S-2

= 0.331, hazard ratio = 1.3). A Cox multivariate regression analysis of overall survival, which adjusts for the same prognostic factors known to influence survival utilized in D9901, met the criteria for statistical significance (p-value = 0.023; adjusted hazard ratio = 1.9). The hazard ratio observed in this analysis was similar to that seen in our D9901 trial. In addition, at the three-year final follow up, 32 percent of patients who received Provenge were alive compared to only 21 percent of the patients who received placebo, a 52 percent improvement in the survival rate.

An integrated analysis of the survival data from these two companion Phase 3 clinical studies, D9901 and D9902A, showed a significant survival benefit in the overallintent-to-treat population of 225 patients. In this analysis, those patients who received Provenge had a median survival of 23.2 months compared to 18.9 months for patients in the placebo arm (p-value = 0.011; hazard ratio = 1.5). A Cox multivariate regression analysis of the integrated data for overall survival also met the criteria for statistical significance (p-value = 0.0006; adjusted hazard ratio = 1.8). In addition, at the three-year final follow up, 33 percent of patients who received Provenge were alive compared to only 15% of the patients who received placebo. In both studies, Provenge was generally well tolerated. In controlled clinical trials, the most common adverse reactions associated with Provenge were chills, fever, headache, fatigue, shortness of breath, vomiting and tremor. These events were primarily grade 1 and 2, with a short duration of 1 to 2 days around the time of infusion. Less than 2% of patients were not able to receive a full course of Provenge (3 infusions) due to treatment-related adverse reactions.

The following table summarizes the survival results of the Provenge studies:

							Studies 1 and 2
	Study 1 (D9901)			Study 2 (D9902A)			Integrated
	N = 127			N = 98			N = 225
Median Survival in months:
Provenge		25.9			19.0			23.2
Placebo		21.4			15.7			18.9
Median Survival Benefit: % (months)		21	% (4.5)		21	% (3.3)		23	% (4.3)
Hazard Ratio		1.7			1.3			1.5
p-value (log rank)		p = 0.010			p = 0.331			p = 0.011
Hazard Ratio		2.1			1.9			1.8
p-value (Cox regression, adj.)		p = 0.002			p = 0.023			p = 0.0006
36-Month Survival: % (patients)
Provenge		34	%(28)		32	%(21)		33	%(49)
Placebo		11	%(5)		21	%(7)		15	%(12)

Other Provenge Clinical Trials

We are currently conducting another Phase 3 clinical trial of Provenge, called IMPACT (IMmunotherapy for Prostate AdenoCarcinoma Treatment) (D9902B) in metastatic androgen-independent prostate cancer. Based on the results of the two completed Phase 3 studies, D9901 and D9902A, we met with the FDA and have amended the D9902B Special Protocol Assessment agreement to open the trial to men regardless of Gleason score and to elevate survival to the primary endpoint. Approximately 500 men will be enrolled and men with asymptomatic or minimally symptomatic disease are eligible for the study. We expect to complete enrollment in the IMPACT study during 2007.

In July 2006, the results from a National Cancer Institute-sponsored Phase 2 study of Provenge in combination with Avastin were published in the journal Cancer. The research showed the combination immunotherapy significantly increased the prostate-specific antigen doubling-time (PSADT) in patients with prostate cancer that had relapsed after prior surgical and radiation therapy.

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In November 2006, we disclosed preliminary results from our ongoing PROTECT (PROvenge Treatment and Early Cancer Treatment)(P-11) clinical trial. The study was designed to explore the biologic activity of Provenge in patients with androgen-dependent (hormone sensitive) prostate cancer prior to the development of metastatic disease. These preliminary study results included assessments of PSA, PSADT, delays in the time to distant metastasis, and levels of immune response in patients randomized to receive Provenge compared to patients randomized to receive placebo. Per protocol, patients will continue to be followed for the clinical endpoints of distant failure and overall survival. The data from the patients in this study will supplement our overall safety database for Provenge as part of our BLA submission for men with advanced androgen-independent prostate cancer.

Neuvenge (lapuleucel-T)

Neuvenge is our investigational active cellular immunotherapy for the treatment of patients with breast, ovarian and other solid tumors expressing HER2/neu. In December 2004, we announced results from two Phase 1 studies of Neuvenge indicating that Neuvenge stimulated an immune response and may provide clinical benefit in patients with advanced, metastatic HER2/neu positive breast cancer. We are evaluating future development plans for Neuvenge.

Other Potential Product Candidates and Preclinical Research and Development Programs

In addition to other active immunotherapies in preclinical research and development, we have monoclonal antibody and small molecule product candidates in preclinical research and development programs. These also include product candidates being developed with our collaborators.

Manufacturing Developments

To support our commercialization efforts, including the potential commercialization of Provenge, we have invested in manufacturing facilities and related operations in preparation for anticipated clinical and commercial manufacturing activities. The initial build-out of our 158,242 square foot commercial manufacturing facility in Hanover, New Jersey was completed in July 2006.

As another integral part of our effort to prepare for the commercialization of Provenge, we are engaged with Diosynth RTP, Inc. in the production of the antigen used in the preparation of Provenge. Pursuant to this agreement, Diosynth completed conformance runs for the manufacturing process for the antigen in July 2006. On December 22, 2005, we entered into a long-term supply agreement with Diosynth covering the production of the antigen used in the preparation of Provenge. We have terminated our agreement with Gambro Healthcare, Inc. to act as provider of nationwide commercial leukapheresis services and are in active negotiations with several vendors for these services. We expect to complete negotiations and to have an established commercial leukapheresis supplier in place prior to FDA approval, if any, of Provenge.

Corporate Information

We are a Delaware corporation originally formed in 1992 as Activated Cell Therapy, Inc. Our executive offices are located at 3005 First Avenue, Seattle, Washington, 98121, and our telephone number is(206) 256-4545. Our website address is www.dendreon.com. Information contained on our website is not a part of this prospectus supplement or the accompanying prospectus.

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The Offering

Common stock offered by us	9,890,110 shares
Common stock to be outstanding after this offering	81,755,400 shares
Use of proceeds	We intend to use the net proceeds of this offering to finance our activities relating to the potential commercialization of Provenge; expand our manufacturing facilities for the commercial production of Provenge; fund ongoing and new clinical trials for Provenge and our other product candidates; support research and preclinical development activities for our other potential product candidates, and for general corporate purposes, including working capital.
Dividend policy	We currently intend to retain any future earnings to fund the development and growth of our business and do not anticipate paying cash dividends in the foreseeable future.
Nasdaq Global Market Symbol	DNDN

The number of shares of our common stock to be outstanding after this offering is based upon the number of our shares outstanding as of November 3, 2006 and excludes:

•  up to 5,360,868 shares that may be issued upon the exercise of outstanding options granted pursuant to our stock option plans at a weighted average exercise price of $7.84 per share; and

•  up to 19,688 shares that may be issued upon exercise of outstanding warrants at a weighted average exercise price of $14.73 per share.

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FORWARD LOOKING STATEMENTS

Some of the statements contained in this prospectus supplement or incorporated by reference into this prospectus supplement are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and are subject to the safe harbor created by the Securities Litigation Reform Act of 1995. We have based these forward-looking statements largely on our expectations and projections about future events and financial trends affecting the financial conditionand/or operating results of our business. Forward-looking statements involve risks and uncertainties, particularly those risks and uncertainties inherent in the process of discovering, developing and commercializing drugs that are safe and effective for use as human therapeutics. There are important factors that could cause actual results to be substantially different from the results expressed or implied by these forward-looking statements, including, among other things:

•  our ability to complete and achieve positive results in ongoing and new clinical trials;

•  having adequate financial resources and access to capital to fund development and commercialization of Provenge and our other potential product candidates;

•  our ability to obtain regulatory approval for our products that are under development and to comply with existing and future regulations affecting our business;

•  our ability to successfully commercialize our products that are under development and develop the infrastructure necessary to support commercialization if regulatory approvals are received;

•  our ability to successfully manufacture Provenge and other product candidates in necessary quantities with required quality;

•  our dependence on single-source vendors for some of the components used in our product candidates, including the Antigen Delivery Cassette for Provenge;

•  the extent to which the costs of any products that we are able to commercialize will be reimbursable by third-party payors;

•  the extent to which any products that we are able to commercialize will be accepted by the market;

•  our dependence on our intellectual property and ability to protect our proprietary rights and operate our business without conflicting with the rights of others;

•  the effect that any intellectual property litigation or product liability claims may have on our business and operating and financial performance;

•  our expectations and estimates concerning our future operating and financial performance;

•  the impact of competition and technological change on our business;

•  our ability to recruit and retain key personnel;

•  our ability to enter into future collaboration agreements;

•  anticipated trends in our business and the biotechnology industry generally; and

•  other factors set forth under “Factors that Could Affect Our Results of Operations and Financial Condition” contained in our most recent Annual Report onForm 10-K and in our future filings made with the Securities and Exchange Commission, which are incorporated by reference into this prospectus supplement, and the risk factors set forth in this prospectus supplement.

In addition, in this prospectus supplement and the documents incorporated by reference into this prospectus supplement, the words “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “plan,” “expect,” “potential,” “continue,” or “opportunity,” the negative of these words or similar expressions, as they relate to us, our business, future financial or operating performance or our management, are intended to identify forward-looking statements. We do not intend to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. Past financial or operating performance is not necessarily a reliable indicator of future performance and you should not use our historical performance to anticipate results or future period trends.

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RISK FACTORS

You should carefully consider the risks described below and all other information contained in or incorporated by reference into this prospectus supplement before purchasing our common stock. Some of the following risks relate principally to our business and the industry in which we operate. Other risks relate principally to the securities markets and ownership of our common stock. Additional risks and uncertainties not presently known to us, or risks that we currently consider immaterial, may also impair our operations or results. If any of the following risks actually occurs, we may not be able to conduct our business as currently planned, and our financial condition and operating results could be seriously harmed. In that case, the market price of our common stock could decline, and you could lose all or part of your investment.

Risks Relating to our Clinical and Commercialization Pursuits

Our near-term prospects are highly dependent on Provenge, our lead product candidate. If we fail to obtain FDA approval for Provenge or fail to successfully commercialize Provenge, our business would be harmed and our stock price would likely decline.

Our most advanced product candidate is Provenge, an active cellular immunotherapy for advanced prostate cancer. FDA approval of Provenge depends on, among other things, our manufacturing protocol and controls, composition of the product and the FDA finding the data from our completed Phase 3 clinical trials sufficient to support approval. On November 9, 2006, we completed our submission of a BLA for Provenge based primarily on the demonstration of a survival benefit over placebo with asymptomatic, metastatic androgen-independent prostate cancer in a Phase 3 study, D9901, as well as supportive evidence on survival from another Phase 3 study, D9902A. Although the FDA has indicated that the survival benefit observed in the D9901 study in conjunction with the supportive data obtained from study D9902A and the absence of significant toxicity in both studies is sufficient to serve as the clinical basis of a BLA submission for Provenge, the FDA may ultimately determine the data from these two studies fails to provide sufficient evidence of efficacy for Provenge and may require that we provide data from ongoing clinical trials, or commence additional trials to provide further supporting clinical dataand/or testing in a wider patient population. Survival was not originally a primary or secondary endpoint in either of these studies. Neither study achieved statistical significance on its prespecified primary endpoint, time to disease progression. In addition, our D9902A Phase 3 study did not show a statistically significant improvement in survival over placebo in a log-rank analysis. Even if we receive FDA approval, we might not be successful in commercializing Provenge. If any of these things occur, our business would be harmed and the price of our common stock would likely decline.

Provenge and our other product candidates are based on novel technologies, which may raise new regulatory issues that could delay or make FDA approval more difficult.

The process of obtaining required FDA and other regulatory approvals, including foreign approvals, is expensive, often takes many years and can vary substantially based upon the type, complexity and novelty of the products involved. Provenge and our other investigational active immunotherapies are novel; therefore, regulatory agencies may lack experience with them, which may lengthen the regulatory review process, increase our development costs and delay or prevent commercialization of Provenge and our other active immunotherapy products under development.

To date, the FDA has not approved for commercial sale in the United States any active immunotherapy designed to stimulate an immune response against cancer. Consequently, there is no precedent for the successful commercialization of products based on our technologies in this area. In addition, we have had only limited experience in filing and pursuing the applications necessary to gain regulatory approvals for marketing and commercial sale, which may impede our ability to obtain FDA approvals. We will not be able to commercialize any of our potential products until we obtain FDA approval.

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If testing of a particular product candidate does not yield successful results, then we will be unable to commercialize that product.

Our product candidates in clinical trials must meet rigorous testing standards. We must demonstrate the safety and efficacy of our potential products through extensive preclinical and clinical testing. Clinical trials are subject to continuing oversight by governmental regulatory authorities and institutional review boards and must meet the requirements of these authorities in the United States, including those for informed consent and good clinical practices. We may not be able to comply with these requirements, which could disqualify completed or ongoing clinical trials. We may experience numerous unforeseen events during, or as a result of, the testing process that could delay or prevent commercialization of Provenge or our other product candidates, including the following:

•  safety and efficacy results from human clinical trials may show the product candidate to be less effective or safe than desired or those results may not be replicated in later clinical trials;

•  the results of preclinical studies may be inconclusive or they may not be indicative of results that will be obtained in human clinical trials;

•  after reviewing relevant information, including preclinical testing or human clinical trial results, we may abandon or substantially restructure projects that we might previously have believed to be promising;

•  we or the FDA may suspend or terminate clinical trials if the participating patients are being exposed to unacceptable health risks or for other reasons; and

•  the effects of our product candidates may not be the desired effects or may include undesirable side effects or other characteristics that interrupt, delay or cause us or the FDA to halt clinical trials or cause the FDA or foreign regulatory authorities to deny approval of the product candidate for any or all target indications.

Data from our clinical trials may not be sufficient to support approval by the FDA for Provenge or our other product candidates. The clinical trials of Provenge or our other product candidates may not be completed as or when planned, and the FDA may not approve any of our product candidates for commercial sale. If we fail to demonstrate the safety or efficacy of a product candidate to the satisfaction of the FDA, this will delay or prevent regulatory approval of that product candidate. Therefore, any delay in obtaining, or inability to obtain, FDA approval of any of our product candidates could materially harm our business and cause our stock price to decline.

The FDA or its Advisory Committee may determine our clinical trials data regarding safety or efficacy are insufficient for regulatory approval.

We discuss with and obtain guidance from regulatory authorities on certain of our clinical development activities. These discussions are not binding obligations on the part of regulatory authorities. Under certain circumstances, regulatory authorities may revise or retract previous guidance during the course of our clinical activities or after the completion of our clinical trials. The FDA may also disqualify a clinical trial in whole or in part from consideration in support of approval of a potential product for commercial sale or otherwise deny approval of that product. Even if we obtain successful clinical safety and efficacy data, we may be required to conduct additional, expensive trials to obtain regulatory approval. Prior to regulatory approval, the FDA may elect to obtain advice from outside experts regarding scientific issuesand/or marketing applications under FDA review. These outside experts are convened through the FDA’s Advisory Committee process. An Advisory Committee will report to the FDA and make recommendations. Views of the Advisory Committee may differ from those of the FDA. We expect, based on preliminary discussions with the FDA, that Provenge will be reviewed by an Advisory Committee. We may experience delays in obtaining approval by the FDA because of the time associated with the Advisory Committee’s process, or we may not obtain approval of the BLA from the FDA because the Advisory Committee advises against it.

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We may take longer to complete our clinical trials than we project, or we may not be able to complete them at all.

A number of factors, including unexpected delays in the initiation of clinical sites, slower than projected enrollment, competition with ongoing clinical trials and scheduling conflicts with participating clinicians, regulatory requirements, limits on manufacturing capacity and failure of a product candidate to meet required standards for administration to humans may cause significant delays in the completion of our clinical trials. In addition, it may take longer than we project to achieve study endpoints and complete data analysis for a trial. Even if our product candidates proceed successfully through clinical trials and receive regulatory approval, there is no guarantee that an approved product can be manufactured in commercial quantities at reasonable cost or that such a product will be successfully marketed.

We rely on academic institutions, physician practices and clinical research organizations to conduct, supervise or monitor some or all aspects of clinical trials involving our product candidates. We have less control over the timing and other aspects of these clinical trials than if we conducted the monitoring and supervision entirely on our own. Third parties may not perform their responsibilities for our clinical trials on our anticipated schedule or consistent with a clinical trial protocol or applicable regulations. We also rely on clinical research organizations to perform much of our data management and analysis. They may not provide these services as required or in a timely manner.

If we fail to commence, complete or experience delays in any of our other present or planned clinical trials, our ability to conduct our business as currently planned could materially suffer. Our development costs will increase if we are required to complete additional or larger clinical trials for Provenge prior to FDA approval or with respect to other product candidates. If the delays or costs are significant, our financial results and our ability to commercialize Provenge or our other product candidates will be adversely affected.

If we encounter difficulties enrolling patients in our clinical trials, our trials could be delayed or otherwise adversely affected.

Clinical trials for our product candidates may require that we identify and enroll a large number of patients with the disease under investigation. We may not be able to enroll a sufficient number of patients to complete our clinical trials in a timely manner. We have in the past experienced some difficulty in enrollment in our clinical trials due to the criteria specified for eligibility for these trials, and we may encounter these difficulties in our ongoing clinical trials for Provenge or our other product candidates.

Patient enrollment is affected by factors including:

•  design of the trial protocol;

•  the size of the patient population;

•  eligibility criteria for the study in question;

•  perceived risks and benefits of the product candidate under study;

•  availability of competing therapies and clinical trials;

•  efforts to facilitate timely enrollment in clinical trials;

•  patient referral practices of physicians;

•  the ability to monitor patients adequately during and after treatment; and

•  proximity and availability of clinical trial sites for prospective patients.

If we have difficulty enrolling a sufficient number of patients to conduct our clinical trials as planned, we may need to delay or terminate ongoing or planned clinical trials, either of which would have a negative effect on our business.

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We must expand our operations to commercialize our products, which we may not be able to do.

We will need to expand and effectively manage our operations and facilities and develop the necessary infrastructure to commercialize Provenge and pursue development of our other product candidates. We will need to add manufacturing capabilities, information technology systems, a distribution network and personnel related to these functions. In July 2006, we completed the initial phased build-out of our facility in New Jersey that will provide manufacturing capabilities and related supporting facilities, as well as clean rooms. This facility will be inspected by the FDA as part of the BLA review. We will also need to add quality control, quality assurance, marketing and sales personnel, and personnel in all other areas of our operations, which may strain our existing managerial, operational, financial and other resources.

We have no experience in commercial-scale manufacturing, the installation and management of large-scale information technology systems, or the management of a large-scale distribution network. We also have no experience in sales, marketing or distribution of products in commercial quantities. As we begin to build our sales capability in anticipation of the approval and commercial launch of Provenge, we may be unable to successfully recruit an adequate number of qualified sales representatives or retain a third party to provide sales, marketing or distribution resources.

If we fail to manage our growth effectively, recruit required personnel or expand our operations within our planned time and budget, our product development and commercialization efforts for Provenge or our other product candidates could be curtailed or delayed.

Risks Relating to our Financial Position and Need for Additional Financing

We have a history of operating losses. We expect to continue to incur losses for the near future, and we may never become profitable.

At September 30, 2006, we had an accumulated deficit of $370.9 million. We do not have any products that generate revenue from commercial product sales. Operating losses have resulted principally from costs incurred in pursuing our research and development programs, clinical trials, manufacturing, marketing and general and administrative expenses in support of operations. We do not expect to achieve commercial product sales until and unless the FDA approves Provenge for commercial sale. We expect to incur additional operating losses over the next few years, and these losses may increase significantly as we continue preclinical research and clinical trials, apply for regulatory approvals, expand our operations and develop the manufacturing and marketing infrastructure to support commercialization of Provenge and our other potential product candidates. These losses have caused and may continue to cause our stockholders’ equity and working capital to decrease.

We may not be successful in commercializing any of our product candidates, and our operations may not be profitable even if any of our product candidates are commercialized.

We are likely to require additional funding, and our future access to capital is uncertain.

It is expensive to develop and commercialize cancer immunotherapy, monoclonal antibody and small molecule product candidates. We plan to continue to simultaneously conduct clinical trials and preclinical research for a number of product candidates. Our product development efforts may not lead to commercial products, either because our product candidates fail to be found safe or effective in clinical trials or because we lack the necessary financial or other resources or relationships to pursue our programs through commercialization. Even if commercialized, a product may not achieve revenues that exceed the costs of producing and selling it. Our capital and future cash flow may not be sufficient to support the expenses of our operations and we may need to raise additional capital depending on a number of factors, including the following:

•  the costs of developing the manufacturing, marketing and other supporting resources and systems to support FDA approval of Provenge;

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•  our timetable and costs for the development of marketing, manufacturing, information technology and other infrastructure and activities related to the commercialization of Provenge;

•  the rate of progress and cost of our research and development and clinical trial activities;

•  the introduction of competing products and other adverse market developments; and

•  whether we enter into a collaboration for the commercialization of Provenge.

We may not be able to obtain additional financing on favorable terms or at all. If we are unable to raise additional funds, we may have to delay, reduce or eliminate some of our clinical trials and our development programs. If we raise additional funds by issuing equity securities, further dilution to our existing stockholders will result.

We may elect to issue additional shares of our common stock, which could result in further dilution to our existing stockholders.

Assuming the sale of all of the shares offered in this offering, we may sell up to an additional $53.2 million of our common stock under our outstanding shelf registration statement. Future sales under this or any future shelf registration statement will depend primarily on the market price of our common stock, the interest in our company by institutional investors and our cash needs. In addition, we may register additional shares with the SEC for sale in the future. Each of our issuances of common stock to investors under a registration statement or otherwise will proportionately decrease our existing stockholders’ percentage ownership of our total outstanding equity interests and may reduce our stock price.

Risks Related to Regulation of our Industry

The industry within which we operate and our business is subject to extensive regulation, which is costly, time consuming and may subject us to unanticipated delays.

Our business, including preclinical studies, clinical trials and manufacturing, is subject to extensive regulation by the FDA and comparable authorities outside the United States. Preclinical studies involve laboratory evaluation of product characteristics and animal studies to assess the efficacy and safety of a potential product. The FDA regulates preclinical studies under a series of regulations called the current Good Laboratory Practices. If we violate these regulations, the FDA, in some cases, may not accept the studies and require that we replicate those studies.

An investigational new drug application, or IND, must become effective before human clinical trials may commence. The IND application is automatically effective 30 days after receipt by the FDA unless, before that time, the FDA raises concerns or questions about the product’s safety profile or the design of the trials as described in the application. In the latter case, any outstanding concerns must be resolved with the FDA before clinical trials can proceed. Thus, the submission of an IND may not result in FDA authorization to commence clinical trials in any given case. After authorization is received, the FDA retains authority to place the IND, and clinical trials under that IND, on clinical hold. If we are unable to commence clinical trials or clinical trials are delayed indefinitely, we would be unable to develop our product candidates and our business would be materially harmed.

Commercialization of our product candidates in the United States requires FDA approval, which may not be granted, and foreign commercialization requires similar approvals.

The FDA can delay, limit or withhold approval of a product candidate for many reasons, including the following:

•  a product candidate may not demonstrate sufficient safety in human trials or efficacy in treatment;

•  the FDA may interpret data from preclinical testing and clinical trials in different ways than we interpret the data or may require additionaland/or different categories of data than what we obtained in our clinical trials;

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•  the FDA may require additional information about the efficacy, safety, purity, stability, identity or functionality of a product candidate;

•  the FDA may not approve our manufacturing processes or facilities or the processes or facilities of our contract manufacturers; and

•  the FDA may change its approval policies or adopt new regulations.

The FDA also may approve a product for fewer indications than are requested or may condition approval on the performance of post-approval clinical studies. Even if we receive FDA and other regulatory approvals, our products may later exhibit adverse effects that limit or prevent their widespread use or that force us to withdraw those products from the market. Any product and its manufacturer will continue to be subject to strict regulations after approval, including but not limited to, the labeling, packaging, adverse event reporting, storage, advertising, promotion and record-keeping. Any problems with an approved product or any violation of regulations could result in restrictions on the product, including its withdrawal from the market. The process of obtaining approvals in foreign countries is subject to delay and failure for many of the same reasons.

Failure to comply with foreign regulatory requirements governing human clinical trials and marketing approval for product candidates could prevent us from selling our products in foreign markets, which may adversely affect our operating results and financial condition.

The requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement outside the United States vary greatly from country to country. The time required to obtain approvals outside the United States may differ from that required to obtain FDA approval. We may not obtain foreign regulatory approvals on a timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other countries, and approval by one foreign regulatory authority does not ensure approval by regulatory authorities in other countries or by the FDA and foreign regulatory authorities could require additional testing. Failure to comply with these regulatory requirements or obtain required approvals could impair our ability to develop foreign markets for our products and may have a material adverse effect on our results of operations and financial condition.

Even if approved, Provenge and any other product we may commercialize and market may be later withdrawn from the market or subject to promotional limitations.

We may not be able to obtain the labeling claims necessary or desirable for the promotion of our products. We may also be required to undertake post-marketing clinical trials. If the results of such post-marketing studies are not satisfactory, the FDA may withdraw marketing authorization or may condition continued marketing on commitments from us that may be expensiveand/or time consuming to fulfill. In addition, if we or others identify adverse side effects after any of our products are on the market, or if manufacturing problems occur, regulatory approval may be withdrawn and reformulation of our products, additional clinical trials, changes in labeling of our products and additional marketing applications may be required.

The availability and amount of reimbursement for our product candidates and the manner in which government and private payers may reimburse for our potential products is uncertain.

We expect that many of the patients who seek treatment with Provenge or any other of our products that are approved for marketing will be eligible for Medicare benefits. Other patients may be covered by private health plans or uninsured. The application of existing Medicare regulations, and interpretive coverage and payment determinations to newly approved products, especially novel products such as ours, is uncertain, and those regulations and interpretive determinations are subject to change. The Medicare Prescription Drug, Improvement, and Modernization Act (“Medicare Modernization Act”), enacted in December 2003, provides for a change in reimbursement methodology that reduces the Medicare reimbursement rates for many drugs, including oncology therapeutics, which may adversely affect reimbursement for Provenge, if it is approved for sale, or our other product candidates. If we are unable to

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obtain or retain adequate levels of reimbursement from Medicare or from private health plans, our ability to sell Provenge and our other potential products will be adversely affected. Medicare regulations and interpretive determinations also may determine who may be reimbursed for certain services. This may adversely affect our ability to market or sell Provenge or our other potential products, if approved.

Federal, state and foreign governments continue to propose legislation designed to contain or reduce health care costs. Legislation and regulations affecting the pricing of products like our potential products may change further or be adopted before Provenge or any of our potential products are approved for marketing. Cost control initiatives by governments or third party payers could decrease the price that we receive for any one or all of our potential products or increase patient coinsurance to a level that makes Provenge and our other products under development unaffordable. In addition, government and private health plans persistently challenge the price and cost-effectiveness of therapeutic products. Accordingly, these third parties may ultimately not consider Provenge or any or all of our products under development to be cost-effective, which could result in products not being covered under their health plans or covered only at a lower price. Any of these initiatives or developments could prevent us from successfully marketing and selling any of our potential products. We are unable to predict what impact the Medicare Modernization Act or other future regulation or third party payer initiatives, if any, relating to reimbursement for Provenge or any of our other potential products will have on sales of Provenge or those other product candidates, if any of them are approved for sale.

The pharmaceutical and medical device industries are subject to significant regulation in the United States.

In addition to FDA restrictions on marketing of pharmaceutical products, several other types of state and federal laws have been applied to restrict certain marketing practices in the pharmaceutical and medical device industries in recent years. These laws include antikickback statutes and false claims statutes.

The federal health care program antikickback statute prohibits, among other things, knowingly and willfully offering, paying, soliciting, or receiving remuneration to induce or in return for purchasing, leasing, ordering, or arranging for the purchase, lease, or order of any health care item or service reimbursable under Medicare, Medicaid, or other federally financed healthcare programs. This statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on one hand and prescribers, purchasers, and formulary managers on the other. Although there are a number of statutory exemptions and regulatory safe harbors protecting certain common activities from prosecution, the exemptions and safe harbors are drawn narrowly, and practices that involve remuneration intended to induce prescribing, purchases, or recommendations may be subject to scrutiny if they do not qualify for an exemption or safe harbor. Our practices may not in all cases meet all of the criteria for safe harbor protection from antikickback liability.

Federal false claims laws prohibit any person from knowingly presenting, or causing to be presented, a false claim for payment to the federal government, or knowingly making, or causing to be made, a false statement to get a false claim paid. Recently, several pharmaceutical and other health care companies have been prosecuted under these laws for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. Other companies have been prosecuted for causing false claims to be submitted because of the company’s marketing of the product for unapproved, and thus non-reimbursable, uses. The majority of states also have statutes or regulations similar to the federal antikickback law and false claims laws, which apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor. Sanctions under these federal and state laws may include civil monetary penalties, exclusion of a manufacturer’s products from reimbursement under government programs, criminal fines and imprisonment.

Because of the breadth of these laws and the narrowness of the safe harbors, it is possible that some of our business activities could be subject to challenge under one or more of these laws, which could have a material adverse effect on our business, financial condition and results of operations.

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Risks Relating to Manufacturing Activities

We have no commercial or other large-scale manufacturing experience.

To be successful, our product candidates must be capable of being manufactured in sufficient quantities, in compliance with regulatory requirements and at an acceptable cost. We have no commercial or other large-scale manufacturing experience. We currently rely on third parties for certain aspects of the commercial and clinical trial manufacture of Provenge and its components and our other product candidates. In July 2006, we completed the initial phased build out for our facility in Hanover, New Jersey, which includes commercial manufacturing space. We are required to hire and train a significant number of employees and comply with applicable regulations for our facilities, which are extensive. A limited number of contract manufacturers are capable of manufacturing the components of Provenge or the final manufacture of Provenge. If we encounter delays or difficulties with manufacturers and cannot manufacture the contracted components or product candidate ourselves, we may not be able to conduct clinical trials as planned or to meet demand for Provenge, if it is approved, any of which could harm our business.

We will need to demonstrate that Provenge manufactured at our new facility is comparable to Provenge used in clinical trials.

In addition to increased production efforts, we may make manufacturing changes to the components or to the manufacturing process for Provenge. These changes could result in delays in the development or regulatory approval of Provenge or in reduction or interruption of commercial sales, in the event Provenge is approved, any of which could materially harm our business. We will be required to demonstrate product comparability for each manufacturing site. The FDA may require additional testing beyond what we propose.

We intend to rely on results of preclinical studies and clinical trials performed using the form of the product candidate produced using the prior formulation or production method or at the prior scale. Depending upon the type and degree of differences between manufacturing processes or component substitutions for a product candidate, we may be required to conduct additional studies or clinical trials to demonstrate that the new method(s) or substitute component or product candidate is sufficiently similar to the previously produced material.

We and our contract manufacturers are subject to significant regulation with respect to manufacturing of our products.

All of those involved in the preparation of a therapeutic drug for clinical trials or commercial sale, including our existing contract manufacturer for the Antigen Delivery Cassette used in Provenge, and clinical trial investigators, are subject to extensive regulation by the FDA. Components of a finished therapeutic product approved for commercial sale or used in late-stage clinical trials must be manufactured in accordance with cGMP, a series of complex regulations. These regulations govern manufacturing processes and procedures and the implementation and operation of quality systems to control and assure the quality of investigational products and products approved for sale. Our facilities and quality systems and the facilities and quality systems of some or all of our third party contractors must pass a pre-approval inspection for compliance with the applicable regulations as a condition of FDA approval of Provenge or any of our other potential products. In addition, the FDA may, at any time, audit or inspect a manufacturing facility involved with the preparation of Provenge or our other potential products or the associated quality systems for compliance with the regulations applicable to the activities being conducted. The FDA also may, at any time following approval of a product for sale, audit our manufacturing facilities or those of our third party contractors. If any such inspection or audit identifies a failure to comply with applicable regulations or if a violation of our product specifications or applicable regulation occurs independent of such an inspection or audit, we or the FDA may require remedial measures that may be costlyand/or time consuming for us or a third party to implement and that may include the temporary or permanent suspension of a clinical trial or commercial sales or the temporary or permanent closure of a facility. Any such remedial measures imposed upon us or third parties with whom we contract could harm our business.

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If we make changes in our manufacturing processes for a product candidate, or change components of a drug, the FDA and corresponding foreign authorities may require us to demonstrate that the changes have not caused the product candidate to differ significantly from that previously produced. Expansion of our production capabilities or facilities might also require reexamination of our manufacturing processes.

We must rely at present on relationships with third-party contract manufacturers, which will limit our ability to control the availability of, and manufacturing costs for, our product candidates in thenear-term.

We will rely upon contract manufacturers for components of Provenge for commercial sale, if it is approved for sale. We have contracts with contract manufacturers for commercial level production for some, but not all, of these components. While we plan to negotiate contracts for commercial level production with contract manufacturers for all components that we do not produce ourselves, there is no assurance that we will be able to do so on acceptable terms or at all. Failure to negotiate such contracts and to maintain sufficient capacity under these arrangements for manufacturing needs could cause inventory shortfalls, and delay or prevent the successful commercialization of Provenge.

In addition, problems with any of our or our contract manufacturers’ facilities or processes could result in failure to produce or a delay in production of adequate supplies of antigen, components or finished Provenge. This could delay or reduce commercial sales and harm our business. Any prolonged interruption in the operations of our or our contract manufacturers’ facilities could result in cancellation of shipments, loss of components in the process of being manufactured or a shortfall in availability of a product. A number of factors could cause interruptions, including the inability of a supplier to provide raw materials, equipment malfunctions or failures, damage to a facility due to natural disasters, changes in FDA regulatory requirements or standards that require modifications to our manufacturing processes, action by the FDA or by us that results in the halting or slowdown of production of components or finished product due to regulatory issues, a contract manufacturer going out of business or failing to produce product as contractually required or other similar factors. Because manufacturing processes are highly complex and are subject to a lengthy FDA approval process, alternative qualified production capacity may not be available on a timely basis or at all. Difficulties or delays in our contract manufacturers’ manufacturing and supply of components could delay our clinical trials, increase our costs, damage our reputation and, for Provenge, if it is approved for sale, cause us to lose revenue or market share if we are unable to timely meet market demands.

If our contract manufacturers are not in compliance with regulatory requirements at any stage, including post-marketing approval, we may be fined, forced to remove a product from the marketand/or experience other adverse consequences, including delays, which could materially harm our financial results.

We use hazardous materials in our business and must comply with environmental laws and regulations, which can be expensive.

Our operations produce hazardous waste products, including chemicals and radioactive and biological materials. We are subject to a variety of federal, state and local regulations relating to the use, handling, storage and disposal of these materials. Although we believe that our safety procedures for handling and disposing of these materials complies with the standards prescribed by state and federal regulations, the risk of accidental contamination or injury from these materials cannot be eliminated. We generally contract with third parties for the disposal of such substances and store our low level radioactive waste at our facilities until the materials are no longer considered radioactive. We may be required to incur further costs to comply with current or future environmental and safety regulations. In addition, in the event of accidental contamination or injury from these materials, we could be held liable for any damages that result and any such liability could exceed our resources.

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Risks from Competitive Factors

Our competitors may develop and market products that are less expensive, more effective, safer or reach the market sooner, which may diminish or eliminate the commercial success of any products we may commercialize.

Competition in the cancer therapeutics field is intense and is accentuated by the rapid pace of advancements in product development. We anticipate that we will face increased competition in the future as new companies enter our markets. Some competitors are pursuing a product development strategy competitive with ours. Certain of these competitive products may be in a more advanced stage of product development and clinical trials. In addition, we compete with other clinical-stage companies and institutions for clinical trial participants, which could reduce our ability to recruit participants for our clinical trials. Delay in recruiting clinical trial participants could adversely affect our ability to bring a product to market prior to our competitors. Further, research and discoveries by others may result in breakthroughs that render Provenge or our other potential products obsolete even before they begin to generate any revenue.

There are products currently under development by others that could compete with Provenge or other products that we are developing. For example, Cell Genesys, Inc. is developing prostate cancer therapeutics that could potentially compete with Provenge. Cell Genesys, Inc. has initiated Phase 3 clinical trials of its prostate cancer immunotherapy. Other products such as chemotherapeutics, antisense compounds, angiogenesis inhibitors and gene therapies for cancer are also under development by a number of companies and could potentially compete with Provenge and our other product candidates. A chemotherapeutic, Taxotere^® (docetaxel) Injection Concentrate, was approved by the FDA in 2004 for the therapeutic treatment of metastatic androgen-independent prostate cancer.

Some of our competitors in the cancer therapeutics field have substantially greater research and development capabilities and manufacturing, marketing, financial and managerial resources than we do. In addition, our competitors may obtain patent protection or FDA approval and commercialize products more rapidly than we do, which may impact future sales of our products. If we are permitted by the FDA to commence commercial sales of products, we will also be competing with respect to marketing capabilities and manufacturing efficiency, areas in which we have limited or no experience. We expect that competition among products approved for sale will be based, among other things, on product efficacy, price, safety, reliability, availability, patent protection, and sales, marketing and distribution capabilities. Our profitability and financial position will suffer if our products receive regulatory approval, but cannot compete effectively in the marketplace.

Our products may not be accepted in the marketplace; therefore, we may not be able to generate significant revenue, if any.

Even if Provenge or any of our other potential products is approved and sold, physicians and the medical community may not ultimately use it or may use it only in applications more restricted than we expect. Our products, if successfully developed, will compete with a number of traditional products and immunotherapies manufactured and marketed by major pharmaceutical and other biotechnology companies. Our products will also compete with new products currently under development by such companies and others. Physicians will only prescribe a product if they determine, based on experience, clinical data, side effect profiles and other factors, that it is beneficial and preferable to other products currently in use. Many other factors influence the adoption of new products, including marketing and distribution restrictions, course of treatment, adverse publicity, product pricing, the views of thought leaders in the medical community, and reimbursement by government and private third party payers.

Failure to retain key personnel could impede our ability to develop our products and to obtain new collaborations or other sources of funding.

We depend, to a significant extent, on the efforts of our key employees, including senior management and senior scientific, clinical, regulatory and other personnel. The development of new therapeutic products requires expertise from a number of different disciplines, some of which are not widely available. We

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depend upon our scientific staff to discover new product candidates and to develop and conduct preclinical studies of those new potential products. Our clinical and regulatory staff is responsible for the design and execution of clinical trials in accordance with FDA requirements and for the advancement of our product candidates toward FDA approval and submission of data supporting approval. The quality and reputation of our scientific, clinical and regulatory staff, especially the senior staff, and their success in performing their responsibilities, may directly influence the success of our product development programs. In addition, our Chief Executive Officer and other executive officers are involved in a broad range of critical activities, including providing strategic and operational guidance. The loss of these individuals, or our inability to retain or recruit other key management and scientific, clinical, regulatory and other personnel, may delay or prevent us from achieving our business objectives. We face intense competition for personnel from other companies, universities, public and private research institutions, government entities and other organizations.

Risks Relating to Collaboration Arrangements

If we fail to enter into any needed collaboration agreements for our product candidates, we may be unable to commercialize them effectively or at all.

To successfully commercialize Provenge, we will need substantial financial resources and we will need to develop or access expertise and physical resources and systems, including expanding our manufacturing facilities, a distribution network, an information technology platform and sales and marketing and other resources that we currently do not have or may be in the process of developing. We may elect to develop some or all of these physical resources and systems and expertise ourselves or we may seek to collaborate with another biotechnology or pharmaceutical company that can provide some or all of such physical resources and systems as well as financial resources and expertise. Such collaborations are complex and any potential discussions may not result in a definitive agreement for many reasons. For example, whether we reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration, and the proposed collaborator’s evaluation of a number of factors. Those factors may include the design or results of our Provenge clinical trials, the potential market for Provenge, the costs and complexities of manufacturing and delivering Provenge to patients, the potential of competing products, the existence of uncertainty with respect to our ownership of technology, which can exist if there is a challenge to such ownership without regard to the merits of the challenge and industry and market conditions generally. If we were to determine that a collaboration for Provenge is necessary and were unable to enter into such a collaboration on acceptable terms, we might elect to delay or scale back the commercialization of Provenge in order to preserve our financial resources or to allow us adequate time to develop the required physical resources and systems and expertise ourselves.

If we enter into a collaboration agreement we consider acceptable, the collaboration may not proceed as quickly, smoothly or successfully as we plan. The risks in a collaboration agreement for Provenge include the following:

•  the collaborator may not apply the expected financial resources or required expertise in developing the physical resources and systems necessary to successfully commercialize Provenge;

•  the collaborator may not invest in the development of a sales and marketing force and the related infrastructure at levels that ensure that sales of Provenge reach their full potential;

•  disputes may arise between us and a collaborator that delay the commercialization of Provenge or adversely affect its sales or profitability; or

•  the collaborator may independently develop, or develop with third parties, products that could compete with Provenge.

With respect to a collaboration for Provenge or any of our other product candidates, we are dependent on the success of our collaborators in performing their respective responsibilities and the continued cooperation of our collaborators. Our collaborators may not cooperate with us to perform their obligations

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under our agreements with them. We cannot control the amount and timing of our collaborators’ resources that will be devoted to activities related to our collaborative agreements with them. Our collaborators may choose to pursue existing or alternative technologies in preference to those being developed in collaboration with us. Disputes may arise between us and our collaborators that delay the development and commercialization of our product candidates. In addition, a collaborator for Provenge may have the right to terminate the collaboration at its discretion. Any termination may require us to seek a new collaborator, which we may not be able to do on a timely basis, if at all, or require us to delay or scale back the commercialization efforts. The occurrence of any of these events could adversely affect the commercialization of Provenge and harm our business and stock price by delaying the date on which sales of the product may begin, if it is approved by the FDA, by slowing the pace of growth of such sales, by reducing the profitability of the product or by adversely affecting the reputation of the product in the market.

Risks in Protecting our Intellectual Property

If we are unable to protect our proprietary rights or to defend against infringement claims, we may not be able to compete effectively or operate profitably.

We invent and develop technologies that are the basis for or incorporated in our potential products. We protect our technology through United States and foreign patent filings, trademarks and trade secrets. We have a number of issued patents, and applications for U.S. and foreign patents in various stages of prosecution. We expect that we will continue to file and prosecute patent applications and that our success depends in part on our ability to establish and defend our proprietary rights in the technologies that are the subject of issued patents and patent applications.

The fact that we have filed a patent application or that a patent has issued, however, does not ensure that we will have meaningful protection from competition with regard to the underlying technology or product. Patents, if issued, may be challenged, invalidated, declared unenforceable or circumvented. In addition, our pending patent applications as well as those we may file in the future may not result in issued patents. Patents may not provide us with adequate proprietary protection or advantages against competitors with, or who could develop, similar or competing technologies or who could design around our patents.

We also rely on trade secrets and unpatentable know-how that we seek to protect, in part, by using confidentiality agreements. Our policy is to require our officers, employees, consultants, contractors, manufacturers, outside scientific collaborators and sponsored researchers and other advisors to execute confidentiality agreements. These agreements provide that all confidential information developed or made known to the individual during the course of the individual’s relationship with us be kept confidential and not disclosed to third parties except in specific limited circumstances. We also require signed confidentiality agreements from companies that receive our confidential data. For employees, consultants and contractors, we require confidentiality agreements providing that all inventions conceived while rendering services to us shall be assigned to us as our exclusive property. It is possible, however, that these parties may breach those agreements, and we may not have adequate remedies for any breach. It is also possible that our trade secrets or unpatentable know-how will otherwise become known to or be independently developed by competitors.

From time to time, we have received invitations to license third party patents. We are also subject to the risk of claims, whether meritorious or not, that our immunotherapy candidates infringe or misappropriate third party intellectual property rights. If we are found to infringe or misappropriate third party intellectual property, we could be required to seek a license or discontinue our products or cease using certain technologies or delay commercialization of the affected product(s), and we could be required to pay substantial damages, which could materially harm our business.

We may be subject to litigation that will be costly to defend or pursue and uncertain in its outcome.

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

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involved in litigation brought by or against us. That litigation is likely to be expensive and may require a significant amount of management’s time and attention, at the expense of other aspects of our business.

Litigation relating to the ownership and use of intellectual property is expensive, and our position as a relatively small company in an industry dominated by very large companies may cause us to be at a disadvantage in defending our intellectual property rights and in defending against claims that our immunotherapy candidates infringe or misappropriate third party intellectual property rights. Even if we are able to defend our position, the cost of doing so may adversely affect our profitability. We have not yet experienced patent litigation. This may reflect, however, the fact that we have not yet commercialized any products. We may in the future be subject to such litigation and may not be able to protect our intellectual property at a reasonable cost if such litigation is initiated. The outcome of litigation is always uncertain, and in some cases could include judgments against us that require us to pay damages, enjoin us from certain activities or otherwise affect our legal or contractual rights, which could have a significant adverse effect on our business.

We are exposed to potential product liability claims, and insurance against these claims may not be available to us at a reasonable rate in the future.

Our business exposes us to potential product liability risks that are inherent in the testing, manufacturing, marketing and sale of therapeutic products. We have clinical trial insurance coverage, and we intend to obtain commercial product liability insurance coverage in the future. However, this insurance coverage may not be adequate to cover claims against us or available to us at an acceptable cost, if at all. Regardless of their merit or eventual outcome, product liability claims may result in decreased demand for a product, injury to our reputation, withdrawal of clinical trial volunteers and loss of revenues. Thus, whether or not we are insured, a product liability claim or product recall may result in losses that could be material.

Risks Relating to an Investment in Our Common Stock

Market volatility may affect our stock price, and the value of your investment in our common stock may be subject to sudden decreases.

The trading price for our common stock has been, and we expect it to continue to be, volatile. The price at which our common stock trades depends on a number of factors, including the following, many of which are beyond our control:

•  timing and outcome of FDA review of our product development activities and of our BLA submitted for Provenge;

•  preclinical and clinical trial results;

•  our historical and anticipated operating results, including fluctuations in our financial and operating results;

•  changes in government regulations affecting product approvals, reimbursement or other aspects of our or our competitors’ businesses;

•  announcements of technological innovations or new commercial products by us or our competitors;

•  developments concerning our key personnel and intellectual property rights;

•  announcements regarding significant collaborations or strategic alliances;

•  publicity regarding actual or potential performance of products under development by us or our competitors;

•  market perception of the prospects for biotechnology companies as an industry sector; and

•  general market and economic conditions.

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In addition, the stock market has from time to time experienced extreme price and volume fluctuations. These broad market fluctuations may lower the market price of our common stock and affect the volume of trading in our stock. During periods of stock market price volatility, share prices of many biotechnology companies have often fluctuated in a manner not necessarily related to their individual operating performance. Accordingly, our common stock may be subject to greater price volatility than the stock market as a whole.

Anti-takeover provisions in our charter documents and under Delaware law and our stockholders’ rights plan could make an acquisition of us, which may be beneficial to our stockholders, more difficult.

Provisions of our certificate of incorporation and bylaws will make it more difficult for a third party to acquire us on terms not approved by our board of directors and may have the effect of deterring hostile takeover attempts. Our certificate of incorporation authorizes our board of directors to issue up to 10,000,000 shares of preferred stock, of which 1,000,000 shares have been designated as “Series A Junior Participating Preferred Stock,” and to fix the price, rights, preferences, privileges and restrictions, including voting rights, of those shares without any further vote or action by the stockholders. The rights of the holders of our common stock will be subject to, and may be junior to the rights of the holders of any preferred stock that may be issued in the future. The issuance of preferred stock could reduce the voting power of the holders of our common stock and the likelihood that common stockholders will receive payments upon liquidation.

In addition, our certificate of incorporation divides our board of directors into three classes having staggered terms. This may delay any attempt to replace our board of directors. We have also implemented a stockholders’ rights plan, also called a poison pill, which would substantially reduce or eliminate the expected economic benefit to an acquirer from acquiring us in a manner or on terms not approved by our board of directors. These and other impediments to a third party acquisition or change of control could limit the price investors are willing to pay in the future for shares of our common stock. Our board of directors adopted a Change of Control Executive Severance Plan providing severance benefits for participants in the event that their employment terminates involuntarily without cause or for good reason within twelve months after a change of control of us. This plan could affect the terms of a third party acquisition.

We are also subject to provisions of Delaware law that could have the effect of delaying, deferring or preventing a change in control of our company. One of these provisions prevents us from engaging in a business combination with any interested stockholder for a period of three years from the date the person becomes an interested stockholder, unless specified conditions are satisfied.

We have broad discretion in how we use the net proceeds of this offering, and we may not use these proceeds effectively.

We currently intend to use the net proceeds from the sale of the common stock by us to finance our activities relating to the potential commercialization of Provenge; expand our manufacturing facilities for the commercial production of Provenge; fund ongoing and new clinical trials for Provenge and our other product candidates; support research and preclinical development activities for our other potential product candidates, and for general corporate purposes, including working capital. However, our management will have broad discretion as to the application of the net proceeds received by us and could use them for purposes other than those contemplated at the time of this offering, including, for example, in-licensing or acquisitions of complementary companies. Our stockholders may not agree with the manner in which our management chooses to allocate and spend the net proceeds received by us. Moreover, our management may use the net proceeds received by us for corporate purposes that may not increase our profitability or our market value.

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USE OF PROCEEDS

We estimate the net proceeds to us from this offering will be approximately $42,150,000, after deducting the placement agents’ fees and estimated expenses of this offering.

We intend to use the net proceeds of this offering to finance our activities relating to the potential commercialization of Provenge; expand our manufacturing facilities for the commercial production of Provenge; fund ongoing and new clinical trials for Provenge and our other product candidates; support research and preclinical development activities for our other potential product candidates, and for general corporate purposes, including working capital.

Pending such uses, we may invest the net proceeds in short-term, investment-grade, interest-bearing securities or guaranteed obligations of the United States government or other securities.

DESCRIPTION OF CAPITAL STOCK

The description of our common stock is incorporated by reference from our registration statement onForm 8-A, which was filed on May 22, 2000.

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PLAN OF DISTRIBUTION

We have engaged Credit Suisse Securities (USA) LLC and Lazard Capital Markets LLC as joint lead placement agents to use their best efforts to solicit offers to purchase an aggregate of 9,890,110 shares of our common stock, as provided on the cover of this prospectus supplement. Credit Suisse Securities (USA) LLC and Lazard Capital Markets LLC are not obligated to, and have advised us that they will not, purchase or sell any shares of our common stock for their own accounts nor are they required to arrange for the purchase or sale of any specific number or dollar amount of shares. We will enter into subscription agreements directly with the investors in connection with this offering.

The shares of common stock sold in this offering will be listed on the Nasdaq Global Market, subject to official notice of issuance.

The closing of the offering is subject to customary conditions and it is possible that not all of the shares offered pursuant to this prospectus supplement and accompanying prospectus will be sold, in which case our net proceeds would be reduced.

The compensation of Credit Suisse Securities (USA) LLC and Lazard Capital Markets LLC for acting as placement agents for this offering will consist of the placement fees and reimbursement of theirout-of-pocket expenses in certain circumstances. The following table sets forth the placement fees to be paid to Credit Suisse Securities (USA) LLC and Lazard Capital Markets LLC for this offering, which will equal 6% of $45,000,000, the maximum gross offering proceeds from the sale of shares of our common stock. In compliance with NASD guidelines, the maximum compensation to the placement agents in connection with the sale of common stock pursuant to this prospectus supplement and the accompanying prospectus will not exceed 8% of the total offering price to the public of such common stock as set forth on the cover page of this prospectus supplement. Lazard Frères & Co. LLC referred this transaction to Lazard Capital Markets LLC and will receive a fee from Lazard Capital Markets LLC in connection therewith.

Placement Fees	Per Share		Total
Common stock offered hereby	$	0.273	$	2,700,000

The expenses directly related to this offering, excluding the placement fees, are estimated to be approximately $150,000 and will be paid by us. Expenses of the offering, exclusive of the placement fees, include legal and accounting fees, our transfer agent fees and other miscellaneous fees.

We have agreed to indemnify Credit Suisse Securities (USA) LLC and Lazard Capital Markets LLC and certain affiliated persons from and against, and to make contributions for payments made by such person with respect to, certain liabilities, including liabilities arising under the Securities Act. Credit Suisse Securities (USA) LLC and Lazard Capital Markets LLC may be deemed “underwriters” within the meaning of the Securities Act.

Confirmations and definitive prospectuses will be distributed to all investors who agree to purchase the shares of our common stock offered hereby, informing investors of the closing date as to such shares. We currently anticipate that closing of the sale of 9,890,110 shares of common stock will take place on or about November 21, 2006. Investors will also be informed of the date and manner in which they must transmit the purchase price for their shares.

We and each of our executive officers and directors have agreed to lock-up provisions regarding future transfers or sales of our capital stock for a period of 90 days after this offering, as described in our agreement with the placement agents. However, if (1) during the last 17 days of the initial lock-up period, we release earnings results or material news or a material event relating to us occurs or (2) prior to the expiration of the initial lock-up period, we announce that we will release earnings results during the16-day period beginning on the last day of the initial lock-up period, then in each case the lock-up period will be extended until the expiration of the18-day period beginning on the date of release of the earnings results or the occurrence of the material news or material event, as applicable, unless the placement agents waive, in writing, such extension.

The placement agents may distribute prospectuses electronically.

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LEGAL MATTERS

Jones Day will pass upon the validity of the issuance of the shares being sold in this offering. Certain matters will be passed upon for the placement agents by Shearman & Sterling LLP, San Francisco, California.

EXPERTS

The consolidated financial statements of Dendreon Corporation appearing in Dendreon Corporation’s Annual Report(Form 10-K) for the year ended December 31, 2005 and Dendreon Corporation management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2005 included therein, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in its reports thereon, included therein, and incorporated herein by reference. Such consolidated financial statements and management’s assessment are incorporated herein by reference in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.

WHERE YOU CAN FIND ADDITIONAL INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any reports, statements and other information filed by us at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. Please call1-800-SEC-0330 for further information on the Public Reference Room. The SEC maintains an Internet web site that contains reports, proxy and information statements and other information regarding issuers, including us, that file electronically with the SEC. The address for the SEC’s website ishttp://www.sec.gov.

We make available, free of charge, through our investor relations website, our annual reports onForm 10-K, quarterly reports onForm 10-Q, current reports onForm 8-K, statements of changes in beneficial ownership of securities, and amendments to those reports and statements as soon as reasonably practicable after they are filed with the SEC. The address for our web site ishttp://www.dendreon.com and the address for the investor relations page of our web site ishttp://investor.dendreon.com/edgar.cfm. The contents of our website are not part of this prospectus supplement, and the reference to our website does not constitute incorporation by reference into this prospectus supplement of the information contained at that site.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers or persons controlling the registrant pursuant to the foregoing provisions, the registrant has been informed 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.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus supplement the information in documents we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be a part of this prospectus supplement, and information that we file later with the SEC will automatically update and supersede this information. Any statement contained in any document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in or omitted from this prospectus supplement, or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superceded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement. We incorporate by reference the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act until the offering is completed:

•  The description of our common stock set forth in the registration statement onForm 8-A, which was filed on May 22, 2000 (FileNo. 000-30681);

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•  The description of our Series A junior participating preferred stock, as set forth in our Current Report onForm 8-K, which was filed on September 25, 2002 (FileNo. 000-30681);

•  Our Annual Report onForm 10-K for the fiscal year ended December 31, 2005, as filed with the SEC on March 15, 2006 (File No.000-30681), including certain information incorporated by reference from our Definitive Proxy Statement for our 2006 Annual Meeting of Stockholders filed with the SEC on April 28, 2006;

•  Our Quarterly Report onForm 10-Q for the quarter ended March 31, 2006, as filed with the SEC on May 9, 2006, our Quarterly Report onForm 10-Q (excluding Items 1 and 2) for the quarter ended June 30, 2006, as filed with the SEC on August 8, 2006, our Quarterly Report onForm 10-Q/A for the quarter ended June 30, 2006, as filed with the SEC on October 11, 2006 and our Quarterly Report onForm 10-Q for the quarter ended September 30, 2006, as filed with the SEC on November 8, 2006 (FileNo. 000-30681); and

•  Our Current Reports onForm 8-K as filed on January 5, 2006, January 24, 2006, February 3, 2006, February 10, 2006, March 14, 2006 (Item 8.01 only), March 21, 2006, March 29, 2006, April 7, 2006, October 11, 2006, November 8, 2006 (Item 8.01 only) and November 13, 2006 (File No.000-30681).

You may request, and we will provide to you, a copy of these filings at no cost, by writing or telephoning us at the following address:

Dendreon Corporation
3005 First Avenue
Seattle, Washington 98121
(206) 256-4545
Attention: Investor Relations

We have filed with the SEC a registration statement onForm S-3 under the Securities Act covering the shares of common stock to be offered and sold by this prospectus supplement. This prospectus supplement does not contain all of the information included in the registration statement, some of which is contained in exhibits to the registration statement. The registration statement, including the exhibits, can be read at the SEC web site or at the SEC offices referred to above. Any statement made in this prospectus supplement concerning the contents of any contract, agreement or other document is only a summary of the actual contract, agreement or other document. If we have filed any contract, agreement or other document as an exhibit to the registration statement, you should read the exhibit for a more complete understanding of the document or matter involved. Each statement regarding a contract, agreement or other document is qualified in its entirety by reference to the actual document.

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PROSPECTUS

$150,000,000

Common Stock

Dendreon Corporation intends to sell common stock over time in one or more offerings up to a maximum aggregate offering price of $150,000,000. We will specify in an accompanying prospectus supplement the terms of any offering. Our common stock is traded on The Nasdaq National Market under the symbol “DNDN.” On October 26, 2005, the last reported sale price of our common stock on The Nasdaq National Market was $6.69 per share.

You should read this prospectus, the prospectus supplement and the documents incorporated by reference in this prospectus and any prospectus supplement carefully before you invest.This prospectus may not be used to offer or sell any of the common stock unless accompanied by a prospectus supplement.

Investing in our common stock involves risks and you should carefully consider those risk factors included in a prospectus supplement and our most recently filed Annual Report onForm 10-K and our most recently filed Quarterly Report onForm 10-Q.

We may offer these securities through agents, underwriters or dealers or directly to investors. See “Plan of Distribution.” Each prospectus supplement will provide the amount, price and terms of the plan of distribution relating to the shares of common stock to be sold pursuant to such prospectus supplement. We will set forth the names of any underwriters or agents in the accompanying prospectus supplement, as well as the net proceeds we expect to receive from such sale.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is October 26, 2005.

TABLE OF CONTENTS

	Page
ABOUT THIS PROSPECTUS		1
FORWARD LOOKING STATEMENTS		1
RISK FACTORS		2
OUR BUSINESS		2
USE OF PROCEEDS		3
PLAN OF DISTRIBUTION		3
LEGAL MATTERS		4
EXPERTS		4
WHERE YOU CAN FIND ADDITIONAL INFORMATION		5
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE		5

You should rely only on the information contained or incorporated by reference into this prospectus or any applicable prospectus supplement. We have not authorized anyone to provide you with different information. You must not rely upon any unauthorized information or representation. We are not making an offer of the common stock to be sold under this prospectus in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained in this prospectus or any applicable prospectus supplement is accurate as of any date other than the date on the front cover of the prospectus or the prospectus supplement or that the information contained in any document incorporated by reference is accurate as of any date other than the date of the document incorporated by reference.

Dendreon^®, the Dendreon logo, DACS^®, Provenge^®, Mylovenge^tm, Myezenium^tm, Neuvenge^tm, Neuzenium^tm, Prozenium^tm and the Antigen Delivery Cassette^tm are our trademarks. All other trademarks appearing or incorporated by reference into this prospectus and the accompanying prospectus supplement are the property of their respective owners.

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, or SEC, using a “shelf” registration process. Under this shelf registration process, we may sell common stock over time in one or more offerings up to a total dollar amount of $150,000,000. Each time we sell any common stock under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of that offering. We may also add, update or change in a prospectus supplement any of the information contained in this prospectus or in documents we have incorporated by reference into this prospectus. This prospectus may not be used to sell any of the common stock unless accompanied by a prospectus supplement. You should carefully read both this prospectus and the applicable prospectus supplement together with the additional information described under the section entitled “Where You Can Find Additional Information” in this prospectus, before you invest in our common stock.

FORWARD LOOKING STATEMENTS

Some of the statements contained in this prospectus and the accompanying prospectus supplement or incorporated by reference into this prospectus are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and are subject to the safe harbor created by the Securities Litigation Reform Act of 1995. We have based these forward-looking statements largely on our expectations and projections about future events and financial trends affecting the financial conditionand/or operating results of our business. Forward-looking statements involve risks and uncertainties, particularly those risks and uncertainties inherent in the process of discovering, developing and commercializing drugs that are safe and effective for use as human therapeutics. There are important factors that could cause actual results to be substantially different from the results expressed or implied by these forward-looking statements, including, among other things:

•  our ability to complete and achieve positive results in clinical trials;

•  our possessing adequate financial resources and access to capital to fund development and commercialization of Provenge and our other product candidates;

•  our ability to comply with existing and future regulations affecting our business and obtain regulatory approvals for our products that are under development;

•  our ability to successfully commercialize our products that are under development and develop the infrastructure necessary to support commercialization;

•  the extent to which the costs of any products that we are able to commercialize will be reimbursable by third-party payors;

•  the ability to successfully manufacture Provenge and other product candidates in necessary quantities with required quality;

•  the extent to which any products that we are able to commercialize will be accepted by the market;

•  our dependence on our intellectual property and ability to protect our proprietary rights and operate our business without conflicting with the rights of others;

•  the effect that any intellectual property litigation or product liability claims may have on our business and operating and financial performance;

•  our expectations and estimates concerning our future operating and financial performance, ability to finance our business, and financing plans;

•  our reliance on corporate collaborators for research and development, manufacturing, clinical trials management and other activities, and technology licenses;

•  our dependence on single-source vendors for some of our components;

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•  the impact of competition and technological change on our business;

•  our ability to recruit and retain key personnel;

•  our ability to enter into future collaboration agreements;

•  anticipated trends in our business;

•  risks related to our limited operating history; and

•  other factors set forth under “Factors that Could Affect Our Results of Operations and Financial Condition” contained in our most recent Annual Report onForm 10-K and most recent Quarterly Report onForm 10-Q and in our future filings made with the Securities and Exchange Commission, which are incorporated by reference in this prospectus, and the risk factors set forth in the accompanying prospectus supplement.

In addition, in this prospectus and the prospectus supplement and the documents incorporated by reference into this prospectus, the words “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “plan,” “expect,” “potential,” “continue,” or “opportunity,” the negative of these words or similar expressions, as they relate to us, our business, future financial or operating performance or our management, are intended to identify forward-looking statements. We do not intend to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. Past financial or operating performance is not necessarily a reliable indicator of future performance and you should not use our historical performance to anticipate results or future period trends.

RISK FACTORS

An investment in our common stock involves a high degree of risk. You should carefully consider the risk factors contained in a prospectus supplement as well as those set forth in our most recently filed Annual Report onForm 10-K and most recently filed Quarterly Report onForm 10-Q. You should also refer to the other information in this prospectus and any applicable prospectus supplement, including our financial statements and the related notes incorporated by reference into this prospectus. Additional risks and uncertainties that are not yet identified may also materially harm our business, operating results and financial condition and could result in a complete loss of your investment.

OUR BUSINESS

We are a Delaware corporation originally formed in 1992 as Activated Cell Therapy, Inc. We are a biotechnology company focused on the discovery, development and commercialization of targeted therapies for cancer. Our portfolio of product candidates includes active immunotherapies, monoclonal antibodies and small molecules to treat a wide range of cancers. The product candidates most advanced in development are active immunotherapies designed to stimulate a patient’s immune system for the treatment of cancer.

Our executive offices are located at 3005 First Avenue, Seattle, Washington, 98121, and our telephone number is(206) 256-4545.

Product Candidates

Our most advanced product candidate is Provenge, an active immunotherapy for the treatment of prostate cancer. Provenge is designed to stimulate a patient’s immune system against prostate cancer. It is developed through our proprietary Antigen Delivery Cassette technology, which utilizes a recombinant form of an antigen found in 95 percent of prostate cancers, prostatic acid phosphatase . Our first two Phase 3 clinical trials for Provenge, D9901 and D9902A, were double-blind placebo controlled clinical trials in men with asymptomatic, metastatic, androgen-independent prostate cancer. Results from these trials were reported in the first half of 2005.

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Provenge is being further evaluated in an ongoing Phase 3 study in asymptomatic, metastatic, androgen-independent prostate cancer, D9902B. It is also being evaluated in a Phase 3 trial, known as PROTECT orP-11, in men with early stage prostate cancer. We own commercialization rights for Provenge worldwide.

Neuvenge is our investigational immunotherapy for the treatment of patients with breast, ovarian and other solid tumors expressing HER2/neu. We are presently designing Phase 2 trials of Neuvenge in women with metastatic breast cancer.

Preclinical Research and Development Programs

In addition to our immunotherapies in clinical and preclinical development for a variety of cancers, our product pipeline also includes monoclonal antibody and small molecule product candidates. We have research and development alliances for these monoclonal antibody and small molecule product candidates with Genentech, Inc., Abgenix, Inc. and Dyax Corp.

USE OF PROCEEDS

Except as otherwise described in any applicable prospectus supplement, we intend to use the net proceeds from the sale of our common stock to fund clinical trials, research, preclinical development and commercialization activities for our active immunotherapies, monoclonal antibodies, and small molecule products, increase our antigen-presenting cell processing capacity, satisfy third party obligations, and for general corporate purposes, including working capital. We also may use a portion of the net proceeds to acquire complementary technologies or products, although we currently have no agreements or commitments in this regard. We have not determined the amount of net proceeds from sales of our common stock pursuant to this prospectus and any prospectus supplement that we will use for each of these purposes.

Pending such uses, we may invest the net proceeds in short-term, investment-grade, interest-bearing securities or guaranteed obligations of the United States government or other securities.

We may not receive any cash proceeds from the sale of our common stock pursuant to this prospectus and the prospectus supplement where we issue shares as consideration for services performed or goods provided to us or in payment of outstanding indebtedness.

PLAN OF DISTRIBUTION

We may sell common stock pursuant to this prospectus and the accompanying prospectus supplement:

•  through one or more underwriters or dealers;

•  through agents;

•  directly to one or more purchasers; or

•  through a combination of the above.

We may distribute the common stock:

•  from time to time in one or more transactions at a fixed price or prices, which may be changed from time to time;

•  at market prices prevailing at the times of sale;

•  at prices related to such prevailing market prices; or

•  at negotiated prices.

We will describe the method of distribution of the common stock in the applicable prospectus supplement.

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Underwriters, dealers or agents may receive compensation in the form of discounts, concessions or commissions from us or our purchasers (as their agents in connection with the sale of the common stock). In addition, underwriters may sell common stock to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwritersand/or commissions from the purchasers for whom they act as agent. These underwriters, dealers or agents may be considered to be underwriters under the Securities Act. As a result, discounts, commissions, or profits on resale received by the underwriters, dealers or agents may be treated as underwriting discounts and commissions. Each applicable prospectus supplement will identify any such underwriter, dealer or agent, and describe any compensation received by them from us. Any initial public offering price and any discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time.

We may enter into agreements that provide for indemnification against certain civil liabilities, including liabilities under the Securities Act, or for contribution with respect to payments made by the underwriters, dealers or agents and to reimburse these persons for certain expenses.

We may grant underwriters who participate in the distribution of the common stock an option to purchase additional shares of common stock to cover over-allotments, if any, in connection with the distribution. Underwriters or agents and their associates may be customers of, engage in transactions with, or perform services for us in the ordinary course of business.

In connection with the offering of the common stock, certain underwriters and selling group members and their respective affiliates, may engage in transactions that stabilize, maintain or otherwise affect the market price of the common stock. These transactions may include stabilization transactions effected in accordance with Rule 104 of Regulation M promulgated by the SEC pursuant to which these persons may bid for or purchase common stock for the purpose of stabilizing its market price.

The underwriters in an offering of the common stock may also create a “short position” for their account by selling more common stock in connection with the offering than they are committed to purchase from us. In that case, the underwriters could cover all or a portion of the short position by either purchasing common stock in the open market or by exercising any over-allotment option granted to them by us. In addition, any managing underwriter may impose “penalty bids” under contractual arrangements with other underwriters, which means that they can reclaim from an underwriter (or any selling group member participating in the offering) for the account of the other underwriters, the selling concession for the common stock that are distributed in the offering but subsequently purchased for the account of the underwriters in the open market. Any of the transactions described in this paragraph or comparable transactions that are described in any accompanying prospectus supplement may result in the maintenance of the price of the common stock at a level above that which might otherwise prevail in the open market. None of the transactions described in this paragraph or in an accompanying prospectus supplement are required to be taken by any underwriters and, if they are undertaken, may be discontinued at any time.

LEGAL MATTERS

Jones Day will pass upon the validity of the common stock being offered hereby.

EXPERTS

The consolidated financial statements of Dendreon Corporation appearing in Dendreon Corporation’s Annual Report(Form 10-K) for the year ended December 31, 2004 and Dendreon Corporation management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2004 included therein, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in its report thereon (which conclude, among other things, that Dendreon Corporation did not maintain effective internal control over financial reporting as of December 31, 2004, based on Internal Control — Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission, because of the effects of the material weakness described therein), included therein, and incorporated herein by reference. Such financial statements and management’s assessment have been incorporated herein by

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reference in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.

WHERE YOU CAN FIND ADDITIONAL INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any reports, statements and other information filed by us at the SEC’s Public Reference Room at 450 Fifth Street, N.W., Washington, D.C. 20549. Please call1-800- SEC-0330 for further information on the Public Reference Room. The SEC maintains an Internet web site that contains reports, proxy and information statements and other information regarding issuers, including us, that file electronically with the SEC. The address for the SEC’s website ishttp://www.sec.gov.

We make available, free of charge, through our investor relations web site, our annual reports onForm 10-K, quarterly reports onForm 10-Q, current reports onForm 8-K, statements of changes in beneficial ownership of securities, and amendments to those reports and statements as soon as reasonably practicable after they are filed with the SEC. The address for our web site ishttp://www.dendreon.comand the address for the investor relations page of our web site ishttp://investor.dendreon.com/edgar.cfm. The contents of our web site are not part of this prospectus, and the reference to our web site does not constitute incorporation by reference into this prospectus of the information contained at that site.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information in documents we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be a part of this prospectus, and information that we file later with the SEC will automatically update and supersede this information. Any statement contained in any document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in or omitted from this prospectus or any accompanying prospectus supplement, or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superceded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus. We incorporate by reference the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act until the offering is completed:

•  The description of our common stock set forth in the registration statement onForm 8-A, which was filed on May 22, 2000 (FileNo. 000-30681);

•  The description of our Series A junior participating preferred stock, as set forth in our Current Report onForm 8-K, which was filed on September 25, 2002 (FileNo. 000-30681);

•  Our Annual Report onForm 10-K for the fiscal year ended December 31, 2004, as filed with the SEC on March 16, 2005 (FileNo. 000-30681), including certain information incorporated by reference from our Definitive Proxy Statement for our 2005 Annual Meeting of Stockholders filed with the SEC on April 15, 2005;

•  Our Quarterly Report onForm 10-Q for the quarter ended March 31, 2005, as filed with the SEC on May 9, 2005 and our Quarterly Report onForm 10-Q for the quarter ended June 30, 2005, as filed with the SEC on August 8, 2005 (File No.000-30681); and

•  Our Current Reports onForm 8-K which were filed on January 11, February 17, June 13, 2005, July 13, 2005 and July 21, 2005 (File Nos.000-30681).

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You may request, and we will provide to you, a copy of these filings at no cost, by writing or telephoning us at the following address:

Dendreon Corporation
3005 First Avenue
Seattle, Washington 98121
(206) 256-4545
Attention: Investor Relations

We have filed with the SEC a registration statement onForm S-3 under the Securities Act covering the shares of common stock to be offered and sold by this prospectus and the applicable prospectus supplement. This prospectus does not contain all of the information included in the registration statement, some of which is contained in exhibits to the registration statement. The registration statement, including the exhibits, can be read at the SEC web site or at the SEC offices referred to above. Any statement made in this prospectus or the prospectus supplement concerning the contents of any contract, agreement or other document is only a summary of the actual contract, agreement or other document. If we have filed any contract, agreement or other document as an exhibit to the registration statement, you should read the exhibit for a more complete understanding of the document or matter involved. Each statement regarding a contract, agreement or other document is qualified in its entirety by reference to the actual document.

6

9,890,110 Shares

Dendreon Corporation

Common Stock

PROSPECTUS SUPPLEMENT

NOVEMBER 16, 2006

Credit Suisse Lazard Capital Markets