The impact of IMPACT

May 7, 2009

Although significant questions remain, the recently released IMPACT study is a major victory for Dendreon's prostate cancer vaccine, Provenge. Two years ago, Provenge was denied FDA approval causing a wave of public outcry. Now, all eyes are on FDA as Dendreon gears up to once again tackle the approval process.

Despite well-publicized and controversial approval setbacks that ignited a firestorm of protests from advocacy groups, it appears that Dendreon's prostate cancer vaccine, Provenge, might very well be on its way to FDA approval. Results from the phase III IMPACT study presented at the recent American Urological Association annual meeting in Chicago, showed that Provenge significantly improved survival in men with advanced prostate cancer.

The 512-patient study showed that Provenge extended median survival by 4.1 months compared to placebo [25.8 months versus 21.7 months] and, more impressive, the treatment improved 3-year survival by 38% compared to placebo [31.7% versus 23.0%]. Moreover, Provenge exhibited a favorable safety profile consistent with prior trials.

However, Provenge represents the first of its class in the emerging field of active cellular immunotherapies, so the burden of proof is expected to be high. It's also important to note that in October of last year, the IMPACT interim results failed to meet the primary endpoint of overall survival-Provenge demonstrated a 20% reduction in risk of death but was short of the 22% mark that FDA was looking for.

Dendreon spokespersons say that they're gearing up to submit its Special Protocol Assessment to FDA in the fourth quarter of 2009. According to Forbes Magazine, Dendreon's future is riding on Provenge. The company has only one other drug in clinical trials, and, as of its last quarterly report, it had just $102 million in cash; the company posted a $70 million loss for the year.

Oncology NEWS Today contributor Judd Moul, MD, Director of Duke University Prostate Center, said, "As a prostate cancer advocate I'm for anything that extends my patients' lives, but when I put my public health hat on I also want to know what the cost is going to be for a year of life saved. By all accounts, this will be a very expensive treatment, and given the current strain on our health care dollars, it's important to look at the big picture."

It is predicted that the three-infusion Provenge therapy will cost about $20,000 per infusion, elevating Provenge into the rarefied dollar range of new biologic such as Avastin. Dr. Moul also pointed out that the treatment delivery is complicated by the need for apheresis.

"Another factor to look at, perhaps a little politically incorrect, is what will the reimbursement status be. In other words, will the effort involved be worth it to financially stressed community docs?"

Scott Riccio, Director of Accelerate Progress, a not-for-profit action-tank "focused on bringing new promising and potentially life-saving therapies to cancer patients more quickly and efficiently." Mr. Riccio weighed in on the recent Provenge study results: "It was good news for the prostate cancer patients we know. The news further validated many of the issues we raised two years ago about the broken regulatory process that initially denied approval for Provenge. It is also tragic that since then we have lost 60,000 men thanks to FDA's bungling of the review. Obviously not all of those men would have benefited from Provenge, but it's just as obvious that none of them benefited from not having Provenge help them fight for their lives."

The nuances of the FDA approval system are often overlooked by ardent supporters of cancer patients' rights who feel that people with no other hope should not be denied "experimental" therapies. The truth is, most of the so called "experimental" therapies are not approved for a simple reason-they don't work. FDA has a public charter to maintain efficacy and safety standards and the agency's charter cannot bend in the winds of public passion no matter how strongly they blow.