Dendreon Announces Publication of Phase 1 Study Highlighting Immunologic and Clinical Activity of Lapuleucel-T (Neuvenge(R)) in Advanced Breast Cancer Patients

Dendreon Corporation (Nasdaq: DNDN) today announced publication of results from a Phase 1 study of NEUVENGE, an investigational active cellular immunotherapy, in the August 20 issue of the Journal of Clinical Oncology. The article highlights the safety profile, immune response and clinical activity of NEUVENGE in women with HER2/neu-positive breast cancer who have failed standard therapy.

"In addition to demonstrating that NEUVENGE was safe and well tolerated, the T-cell responses seen in these patients and the prolonged disease stabilization in the absence of other anti-cancer therapies in many patients is promising," said John W. Park, M.D., associate clinical professor of medicine and neurosurgery at the University of California, San Francisco and lead author of the publication. "These observations are encouraging and are suggestive of the clinical benefit of NEUVENGE, particularly in light of the aggressive cancer seen in these patients who had progressed while on standard therapy. The findings warrant additional studies of NEUVENGE for the many women with advanced breast cancer who have exhausted many of their treatment options."

Study Design

The Phase 1 study (D2000-2) was conducted to evaluate the safety and immunologic activity of NEUVENGE in patients with HER2-overexpressing metastatic breast cancer who had failed standard therapy, including prior treatment with chemotherapy and trastuzumab. All patients had experienced disease progression while on standard therapy. There were 19 patients enrolled in the study with 18 patients receiving treatment with NEUVENGE. Patients underwent three infusions of NEUVENGE at Weeks 0, 2, and 4 following randomization. Patients who achieved a partial response, or had stable disease lasting through Week 52, were eligible for re-treatment, a booster, using the same protocol and dose as the initial treatment. Endpoints included safety, immunologic activity and antitumor activity.

Study Results

Treatment with NEUVENGE 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. No patient discontinued the trial because of toxicity.

Treatment with NEUVENGE stimulated significant immune responses, which were shown to be enhanced following booster infusions. Twenty-two percent of patients had evidence of anti-cancer activity. This included one patient who experienced a partial response lasting approximately 6 months and three patients who had stable disease for over a year (74.9-94.0 weeks) without the addition of any other cancer therapy other than the continuation of bisphonates. Two additional patients had stable disease for up to 20 weeks. The study concluded that NEUVENGE was feasible, well-tolerated and showed evidence of anti-cancer activity.

"We are pleased that the results from this Phase I study of NEUVENGE demonstrate its potential as a treatment for advanced breast cancer patients," said Mark Frohlich, M.D., vice president of clinical affairs at Dendreon. "These data, together with the data we have published on the use of Provenge(R) (sipuleucel-T) in prostate cancer, further substantiate the promise of active cellular immunotherapies as new treatments for different types of cancer."

About NEUVENGE

NEUVENGE (lapuleucel-T) is an investigational product 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 clinical benefit with low toxicities. NEUVENGE is designed to stimulate cellular immune responses against HER2/neu. HER2/neu is over-expressed in a variety of solid tumors, including breast, colorectal and ovarian cancer. In clinical studies, patients typically received three infusions over a one-month period as a complete course of therapy.

About Breast Cancer

Breast cancer is the most common non-skin cancer among women. The chance of developing invasive breast cancer at some point in a women's life is about 1 in 8 or 13% of women. It is estimated that in 2007 about 178,480 new cases of invasive breast cancer will be diagnosed among women in the United States. Breast cancer is the second leading cause of cancer death in women, exceeded only by lung cancer.

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 applies its expertise in antigen identification, engineering and cell processing to produce active cellular immunotherapy product candidates designed to stimulate an immune response. Active cellular immunotherapy holds promise because it may provide patients with a meaningful clinical benefit, such as survival, combined with low toxicity. The Company has its headquarters in Seattle and is traded on the Nasdaq Global Market under the symbol DNDN. For more information about the Company and its programs, visit http://www.dendreon.com.

Except for historical information contained herein, this news release contains forward-looking statements that are subject to risks and uncertainties. Factors that could affect these forward-looking statements include, but are not limited to, the efficacy of PROVENGE or sipuleucel-T, the company's lead product candidate to treat men suffering from prostate cancer, the efficacy of NEUVENGE or lapuleucel-T, 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 associated with completing our clinical trials, the risk that the safety and/or efficacy results of existing clinical trials or from additional clinical trials for PROVENGE or NEUVENGE will not support approval 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 results of a clinical trial for PROVENGE, NEUVENGE 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 http://www.sec.gov.