The Provenge data published in this week's New England Journal of Medicine might not be new. It has, after all, been presented at a conference and submitted to FDA in support of the newly approved prostate cancer vaccine. But the study is now down in black-and-white--under the auspices of the NEJM, no less--and is available for doctors everywhere.
The data shows that Provenge, developed and sold by Dendreon (NASDAQ: DNDN), prolongs survival of patients with advanced prostate cancer by about four months. Given that alternative treatments have only been proven to boost survival by two to three months, that's a definite plus for Provenge.
But the picture is a bit murky, as an NEJM editorial points out. The survival benefit is "important," writes Dan Longo, but the vaccine didn't show any measurable effect on tumors themselves. This raises the possibility that some "unmeasured prognostic variable" may have affected the study results, he adds. Plus, Provenge is expensive; some $93,000 for a course of treatment. "The high cost may affect use," Longo says.
The study's lead author says that Provenge could use more research. "I think we need to better detect how it works and how it can be made better," says Harvard Medical School's Philip Kantoff in an interview with Bloomberg. "This is really the first step in the field of immunotherapy."