Earlier this week FDA deferred approval of Dendreon’s prostate cancer vaccine Provenge. It was a letdown for the company and patients, because an advisory panel had voted 13-4 in March to recommend approval. The company’s pivotal clinical trials demonstrated that the vaccine is safe, but the trials failed to meet their primary endpoints and there were also some “hints of an increased number of strokes,” according to the Wall Street Journal.
In a move typical of situations where a drug fails its endpoints, the company looked for any shred of evidence it could point to to claim the drug worked. It touted a 127 patient trial where those taking Provenge lived an extra 4.5 months. (Provenge is a therapaeutic vaccine, meaning it’s given to boost the body’s immune system once a patient is already sick. It’s not for disease prevention.)
Understandably, desperate patients with few good options are mad at FDA for not letting the drug into the market, especially after patient advocates were apparently able to influence the advisory panel. If I were a patient or a relative of a patient I’d probably feel the same way. But I think we should give the Agency the benefit of the doubt because the company doesn’t seem to have demonstrated efficacy with any degree of confidence. Maybe patients should be angry with Dendreon for poor trial design for picking the wrong endpoints. Provenge still has a chance for approval if an ongoing clinical trial demonstrates it works.
I don’t have a problem with FDA approving drugs that are efficacious but may be dangerous, as long as appropriate warnings are included. But I do think it’s reasonable to insist on some proof of efficacy. I’d really like Provenge to work, but that doesn’t mean it does.May 11, 2007