The Food and Drug Administration has approved sipuleucel-T for treatment of advanced prostate cancer in a much-anticipated ruling that marks the first approval of a vaccine for cancer treatment.
The indication is for use in patients with “asymptomatic or minimally symptomatic prostate cancer that has spread to other parts of the body and is resistant to standard hormone treatment,” according to the FDA announcement.
Sipuleucel-T will be marketed as Provenge by manufacturer Dendreon Corp.
The company announced the vaccine will be available initially at 50 oncology and urology centers that were approved clinical trial sites. Executives said in an investors' call that they expected to serve 2,000 patients within the first 12 months. Initially, the individually tailored vaccine will be manufactured only in the company's New Jersey facility, but Dendreon plans to add facilities in Atlanta and in Orange County, Calif. by mid-2011.
Pricing has been set at $31,000 per infusion, or a total of $93,000 for the therapy. The company has set up a patient-access program to help men who cannot afford co-payments.
The granting of the indication follows a long and tumultuous review process in which protestors icketed after an FDA advisory committee rejected Dendreon's initial application for the vaccine. Early results from a key trial designed to address issues raised by the panel failed to show an improvement in progression-free survival, but researchers were eventually able to demonstrate that men lived longer when treated with sipuleucel-T.
The pivotal Dendreon-sponsored, phase III IMPACT (Immunotherapy for Prostate Adenocarcinoma Treatment) trial randomized 512 men with metastatic castration-resistant prostate cancer to sipuleucel-T or placebo. At a median follow-up of 3 years, the vaccine was credited with a 4.1-month gain in overall survival, with men on the vaccine living a median of 25.8 months vs. 21.7 months in the control group.
Adverse events occurred in almost all patients, with chills, fatigue, fever, back pain, nausea, joint ache, and headache being common reactions. Most side effects were mild or moderate, but the FDA noted that about a quarter of patients had serious adverse reactions, including some acute infusion reactions and stroke.
“Cerebrovascular events, including hemorrhagic and ischemic strokes, were observed in 3.5% of patients in the Provenge group, compared with 2.6% of patients in the control group,” it said.
The company announced that it has committed to conducting “a registry of approximately 1,500 patients to further evaluate a small potential safety signal of cerebrovascular events.”
An autologous cellular immunotherapy, sipuleucel-T delivers a patient's own immune cells, extracted via leukapheresis, in a vaccine designed to stimulate an immune response against prostatic acid phosphatase (PAP), an antigen expressed in most prostate cancers. Men received three doses of the vaccine in intravenous injections given at about 2-week intervals.”
“The availability of Provenge provides a new treatment option for men with advanced prostate cancer, who currently have limited effective therapies available,” said Dr. Karen Midthun, acting director of the FDA's Center for Biologics Evaluation and Research, in the FDA announcement.
The International Society for Biological Therapy of Cancer issued a statement hailing the approval as “a significant advance in the development of biological therapy [also called immunotherapy] for cancer treatment.”
Bernard Fox, Ph.D., the society's president, noted that the search for a way to harness the immune system against cancer has lasted more than a century. Dr. Fox had no relevant financial conflicts to disclose.
Emily Hayes of the Pink Sheet contributed to this report. The Pink Sheet and this publication are owned by Elseiver.