FDA Approves First Immunotherapy Vaccine for Cancer

Provenge (sipuleucel-T), an autologous cellular immunotherapy for the treatment of asymptomatic or minimally symptomatic metastatic, castrate-resistant prostate cancer (also referred to as hormone-refractory), has become the first FDA-approved therapeutic vaccine for cancer. Provenge triggers an immune response against prostatic acid phosphatase, an antigen frequently expressed in prostate cancers. The highly anticipated approval follows nearly 2 decades of research and development that included a controversial rejection of the vaccine by the FDA in 2007.

With the approval of Provenge, Philip Kantoff, MD, director of the Lank Center for Genitourinary Oncology, chief of the Division of Solid Tumor Oncology and chief clinical research officer at Dana-Farber Cancer Institute, as well as a professor of medicine at Harvard Medical School, predicted, “Cancer immunotherapies that use the patient’s own immune system will likely create an entirely new treatment paradigm for patients with cancer.”

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The FDA based its approval of Provenge on three phase III studies, with the critical trial being the IMPACT (Immunotherapy for Prostate Adenocarcinoma Treatment) trial. This multicenter, randomized, double blind, placebo-controlled study evaluated a 512 men with asymptomatic or minimally symptomatic metastatic CRPC. In IMPACT, the median overall survival in the Provenge arm was 25.8 months compared with 21.7 months for the placebo group. The 4.1-month survival advantage for Provenge is approximately 1 month longer than the survival advantage over placebo with docetaxel, the only approved chemotherapy for advanced prostate cancer. Provenge reduced the risk of death by 22.5% (hazard ratio, 0.775; 95% confidence interval, 0.614-0.979; = .032), with a 3-year survival rate of 31.7%, compared with 23% for the control arm. In separate safety evaluations of Provenge, the most common adverse events reported were chills, fatigue, fever, back pain, nausea, joint ache, and headache. Although Provenge is approved, Dendreon Corporation, which manufactures the drug, says it will be conducting additional safety trials.

While the general reaction to Provenge has been positive, the vaccine’s steep price tag has drawn criticism. Provenge will cost between $70,000 to $100,000 for the 1-month course of therapy. Dendreon will almost certainly maintain that the high cost takes into consideration the expensive manufacturing requirements. The vaccine is custom made for each patient using dendritic cells from his tumor. This requires costly storage of biological material. To address concerns about the drug’s affordability, Dendreon plans to donate funds to a nonprofit organization that will provide copayment assistance to qualifying patients.

Oncology & Biotech News

Dendreon estimates Provenge may be appropriate for 103,000 current US patients. The company has been gearing up for production, anticipating FDA approval. Fifty centers, all previously approved as clinical trial sites, will administer the vaccine. Dendreon expects to increase capacity in mid-2011 and be ready for full-scale production as early as 2012. Watch for a more extensive report on Provenge and its likely impact on metastatic prostate cancer and immunotherapy in cancer in the June issue of .