Dendreon Announces Publication of Pivotal Phase 3 Study Highlighting Survival Benefit and Safety Profile of PROVENGE in Men with Advanced Prostate Cancer

-- First Cancer Immunotherapy to Demonstrate a Survival Benefit in a Randomized Phase 3 Study --
-- Company Plans to Submit BLA to U.S. Food and Drug Administration Later This Year --

SEATTLE, WA, June 29, 2006 – Dendreon Corporation (Nasdaq: DNDN) today announced the publication of the results of its pivotal Phase 3 study (D9901) of PROVENGE® (sipuleucel-T) in the July issue of the Journal of Clinical Oncology. The article highlights the significant survival benefit and favorable safety profile of PROVENGE, the Company's investigational active cellular immunotherapy, in men with advanced androgen-independent prostate cancer. The Company plans to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) later this year to obtain approval to market PROVENGE.

"This trial is an important milestone in the development of new treatments for prostate cancer patients. The survival benefit that was observed has the potential to offer important benefits to patients, and represents the first time an immunotherapy has provided a survival advantage in prostate cancer," said Eric J. Small, M.D., professor of medicine and urology at the University of California, San Francisco and lead author of the publication. "In addition to the observed survival benefit, PROVENGE has a very favorable toxicity and safety profile, with the most common side effects being low grade fevers and chills. A favorable benefit-to-risk profile will be appealing to patients with advanced stage prostate cancer who currently have few appealing treatment options available to them."

The double-blind, placebo-controlled Phase 3 Study D9901 showed that the group of men with asymptomatic, metastatic, androgen-independent prostate cancer who received PROVENGE had a median survival time 4.5 months longer than the median survival seen in the group that had been assigned to receive placebo. For the men who received PROVENGE, there was a 41 percent overall reduction in the risk of death (p-value = 0.010; HR = 1.7). In addition, 34 percent of patients receiving PROVENGE were alive 36 months after treatment compared to 11 percent of patients randomized to receive placebo. These data will form the basis of the Company's BLA to the FDA for marketing approval, which the Company plans to submit later this year.

Patients in the PROVENGE arm had a 31 percent delay in their time to disease progression compared to patients in the placebo arm (p-value = 0.052; HR = 1.45). Furthermore, patients receiving PROVENGE had an approximately 8-fold increase in their T-cell immunity after treatment compared to the placebo group (p<0.001).

"The survival benefit demonstrated in this trial, combined with the favorable safety profile of PROVENGE, will form the basis for our BLA submission to the FDA later this year," said Mark Frohlich, M.D., vice president of clinical affairs at Dendreon. "We look forward to making this active cellular immunotherapy available for the treatment of the many men with advanced prostate cancer."

The D9901 study was conducted at 19 institutions in the United States and enrolled 127 men with asymptomatic, metastatic androgen-independent (hormone-refractory) prostate cancer. Patients were randomized in a 2:1 ratio to receive three infusions of PROVENGE (n=82) or placebo (n=45) every two weeks for a total of three infusions over a one month period.

Treatment with PROVENGE was generally well tolerated. The majority of side effects were mild, including infusion-related fever and chills that were usually of low grade and typically lasted for one to two days following infusion.

About PROVENGE (sipuleucel-T)

PROVENGE (sipuleucel-T) is an investigational product that may represent the first in a new class of active cellular immunotherapies (ACIs) that are uniquely designed to stimulate a patient's own immune system. ACIs hold promise because they may provide patients with a meaningful survival benefit with low toxicities. PROVENGE targets the prostate cancer antigen, prostatic acid phosphatase (PAP), which is found in approximately 95 percent of prostate cancers. PROVENGE is in late-stage development for the treatment of patients with advanced prostate cancer. In clinical studies, patients typically received three infusions over a one-month period as a complete course of therapy.

About Prostate Cancer

Prostate cancer is the most common non-skin cancer in the United States and the third most common cancer worldwide. More than one million men in the United States have prostate cancer, with an estimated 232,000 new cases of prostate cancer diagnosed each year. More than 30,000 men die each year of the disease.

About Dendreon

Dendreon Corporation is a biotechnology company whose mission is to target cancer and transform lives through the discovery, development and commercialization of novel therapeutics that harness the immune system to fight cancer. The Company uses its experience in antigen identification, antigen engineering and antigen-presenting cell processing to produce active immunotherapy product candidates to potentially stimulate a cell-mediated immune response. PROVENGE (sipuleucel-T) is Dendreon's lead active cellular immunotherapy in Phase 3 development for prostate cancer. The Company also discovered Trp-p8, a cold receptor and transmembrane ion channel in pre-clinical development, which is over-expressed in breast, prostate, lung and colon cancers. For more information about the Company and its programs, visit www.dendreon.com .

Except for historical information contained herein, this news release contains forward-looking statements that are subject to risks and uncertainties surrounding the efficacy of PROVENGE to treat men suffering from prostate cancer, risks and uncertainties surrounding the presentation of data to the FDA and approval of product applications by the FDA and risks and uncertainties inherent in the process of discovering, developing and commercializing drugs that are safe and effective for use as human therapeutics. Factors that may cause such differences include risks related to our limited operating history, risks associated with completing our clinical trials, the risk that the safety and/or efficacy results of a clinical trial for PROVENGE will not support an application for a biologics license, the risk that the FDA may interpret data differently than we do or require more data or a more rigorous analysis of data than expected, the risk that the FDA will not approve a product for which a biologics license has been applied, the risk that the results of a clinical trial for PROVENGE or other product may not be indicative of results obtained in a later clinical trial, risks that we may lack the financial resources and access to capital to fund required clinical trials or commercialization of PROVENGE, our dependence on the efforts of third parties, and our dependence on intellectual property. Further information on the factors and risks that could affect Dendreon's business, financial condition and results of operations are contained in Dendreon's public disclosure filings with the U.S. Securities and Exchange Commission, which are available at www.sec.gov .

Contact:
Monique Greer
Dendreon Corporation
(206) 829-1500