UPDATE: Dendreon Announces Prelim. Data for PROVENGE Shows Positive Immune Response

Dendreon Corporation

announced today that four abstracts featuring PROVENGE^® (sipuleucel-T) data from ongoing Phase II sequencing studies and the PROCEED registry, and two abstracts highlighting preliminary Phase II data of DN24-02, an investigational active cellular immunotherapy in patients with surgically resected HER2+ urothelial cancer, will be presented at the 49^th Annual Meeting of the American Society of Clinical Oncology (ASCO) from May 31-June 4, 2013 in Chicago, IL. Data from an open-label study demonstrate the presence of existing immunological memory in advanced prostate cancer patients retreated with PROVENGE several years after initial treatment for androgen dependent prostate cancer (ADPC) in the Phase III PROTECT study. In addition, the retreatment appeared to boost product potency compared with prior treatment. Separately, data from two Phase II studies indicate that PROVENGE can be combined with androgen deprivation therapy (ADT) or abiraterone acetate plus prednisone. “These studies help us understand how PROVENGE may be combined or sequenced with other advanced prostate cancer treatments,” said Mark Frohlich, M.D., executive vice president of research and development and chief medical officer at Dendreon. “We are also pleased with the preliminary data demonstrating that the antigen-presenting cell activity of DN24-02 for HER2+ urothelial cancer is similar to that of PROVENGE. The data highlight the promise of our active cellular immunotherapy platform and furthers Dendreon's position as a leader in personalized cancer therapies.” Studies evaluating PROVENGE and DN24-02 data at ASCO include: PROVENGE: * A Randomized Phase II Study Evaluating the Optimal Sequencing of Sipuleucel-T and Androgen Deprivation Therapy (ADT) in Biochemically-Recurrent Prostate Cancer (BRPC): Immune Results (Abstract 5016). Data suggest that combining ADT with sipuleucel-T may augment adaptive immunity. PROVENGE is not indicated for the treatment of biochemically-recurrent prostate cancer. Poster discussion session: Genitourinary Cancer, Saturday, June 1, 12:00 PM – 1:00 PM CDT., E Arie Crown Theater Lead Author: Emmanuel Stylianos Antonarakis, M.D., Sidney Kimmel Comprehensive Cancer Center at John Hopkins University, Baltimore, MD * A Randomized Phase II Trial of Sipuleucel-T with Concurrent or Sequential Abiraterone Acetate (AA) Plus Prednisone (P) in Metastatic Castrate-Resistant Prostate Cancer (mCRPC) (Abstract 5047). In a Phase II clinical study, the data suggest sipuleucel-T can be successfully manufactured during concurrent AA plus P with no significant changes in peripheral immune responses or alterations in adverse event profiles. General poster session: Genitourinary Cancer, Monday, June 3, 8:00 AM – 11:45 AM CDT., S Hall A2 Lead Author: Eric J. Small, M.D., Department of Medicine, University of California San Francisco, San Francisco, CA * Impact of Prior Docetaxel on Sipuleucel-T Product Parameters in PROCEED Patients (Abstract 5034). In an ongoing, Phase IV registry of patients administered sipuleucel-T regardless of prior docetaxel use, the data suggest that antigen presenting cell activation in sipuleucel-T is not impaired following docetaxel treatment. General poster session: Genitourinary Cancer, Monday, June 3, 8:00 AM – 11:45 AM CDT., S Hall A2 Lead Author: Celestia S. Higano, M.D., FACP Seattle Cancer Care Alliance, Seattle, WA * Open-Label, Multicenter Study of Sipuleucel-T in Men with Metastatic Castration-Resistant Prostate Cancer (mCRPC) Previously Treated with Sipuleucel-T: Evaluation of Antigen Presenting Cell (APC) Activation and ELISPOT Data (Abstract 5053). In a study designed to evaluate the product potency in the retreatment of patients with sipuleucel-T, the data indicate the presence of existing immunological memory to sipuleucel-T years following initial treatment, and retreatment appeared to boost product potency compared with prior treatment. The patients were initially treated with sipuleucel-T when they had ADPC, and were retreated after they developed mCPRC. PROVENGE is not indicated for the treatment of ADPC and the safety and effectiveness of retreatment have not been established. General poster session: Genitourinary Cancer, Monday, June 3, 8:00 AM – 11:45 AM CDT., S Hall A2 Lead Author: Tomasz M Beer, M.D., Oregon Health & Science University Knight Cancer Institute, Portland, OR DN24-02: * Preliminary Safety, Product Parameters, and Immune Response Assessments From A Phase II Randomized, Open-Label Trial of DN24-02, an Autologous Cellular Immunotherapy (ACI), In Patients with Surgically Resected HER2+ Urothelial Cancer at High Risk for Recurrence (Abstract 4547). In an ongoing Phase II study, preliminary data on the adverse events and immune response of DN24-02 indicate that antigen presenting cell activity is comparable to that of sipuleucel-T and positive immune responses were observed. General poster session: Genitourinary (Nonprostate) Cancer, Monday, June 3, 8:00 AM – 11:45 AM CDT., S Hall A2 Lead Author: Dean F. Bajorin, M.D., Memorial Sloan-Kettering Cancer Center, New York, NY * Preliminary HER2 Expression Data from NeuACT, the Phase II Randomized, Open-Label Trial of DN24-02 in Patients with Surgically Resected HER2+ Urothelial Cancer (UC) at High Risk for Recurrence (Abstract 4527). In an ongoing Phase II study, preliminary data on HER2 expression in urothelial cancer suggest a high incidence of HER2 expression (>74%) in urothelial cancer primary tumor and lymph node specimens from patients, with higher expression observed in lymph node specimens. Poster discussion session: Genitourinary (Nonprostate) Cancer, Tuesday, June 4, 11:30 AM – 12:30 PM CDT., E354a Lead Author: Michael Press, M.D., University of Southern California Norris Comprehensive Cancer Center, Los Angeles, CA