RxTrials Institute Drug Pipeline Alert

Dendreon: Did Provenge Spark Early Fireworks? (Pharma’s Market)
In his blog, Mike Huckman discusses the recent success of Dendreon with its prostate cancer vaccine, Provenge. Although the company’s product has received criticism because it does not prevent the disease, researchers are seeing the value of products that stimulate the immune system to combat pre-existing cancers.

Huckman writes, “An FDA Advisory Committee recently recommended approval of Provenge. But the FDA delayed making a decision unless or until it sees positive survival data from an ongoing, large clinical trial. Dendreon says interim results won’t be available until the middle of the second half of next year. And final results won’t be out for two to three years from now. However, the company says the FDA may accept positive interim results for possible approval.

“Some patients in earlier Provenge tests lived, on average, four-and-a-half months longer than those who got sanofi-aventis’ Taxotere and hormone therapy. But detecting a survival benefit wasn’t the goal of those studies, prompting critics to cast aspersions on the small size of the trials and the analysis.”

Although the American Association of Cancer Research claimed the drug did not meet its primary endpoints and had little therapeutic value, others disagree, according to Huckman.

Huckman continues,“While there is no conclusive evidence to explain why a vaccine may lead to better patient survival, Jeffrey Schlom, head of the National Cancer Institute’s Laboratory of Tumor Immunology and Biology, believes the evidence suggests that vaccines are, in fact, priming the immune system. And Schlom is quoted as saying, ‘Vaccines are not passive, they induce a dynamic process of immune response that, in many cases may keep the tumor in check and enhance the effectiveness of subsequent therapies.’”