The idea that vaccines might be used as therapies in some settings was first proposed by Robert Koch more than a century ago. But despite much study, there remains very little data suggesting any efficacy of vaccination against an established disease. The only approved uses of vaccines that might be considered vaguely therapeutic are rabies and smallpox when given very quickly after exposure (for a great overview on therapeutic vaccination see this presentation by Mike Lederman). Now, according to recent releases from a company called Dendreon, it appears that the US Food and Drug Administration may be on the verge of approving a therapeutic vaccine for prostrate cancer called Provenge. To quote from yesterday's press release from Dendreon:
"Dendreon recently held a pre-BLA meeting with the FDA to review safety and efficacy data from its two completed Phase 3 clinical trials of PROVENGE, D9901 and D9902A, in men with asymptomatic, metastatic, advanced prostate cancer. In these discussions, the FDA agreed that the survival benefit observed in the D9901 study in conjunction with the supportive data obtained from study D9902A and the absence of significant toxicity in both studies is sufficient to serve as the clinical basis of a BLA submission for PROVENGE. As a result of that meeting, Dendreon recently announced plans to submit a BLA to the FDA in 2006 to market PROVENGE for the treatment of men with asymptomatic, metastatic, androgen-independent prostate cancer."
A BLA is a Biologics License Application, the equivalent of a New Drug Application or NDA for biological products like vaccines and cytokine therapies. While unfortunately this does not mean that therapeutic vaccines for HIV are right around the corner, it does offer some hope that the immune system can be prodded into exerting useful therapeutic effects and may address the most commonly cited reason for pessimism about prospects for therapeutic vaccines: the lack of an effective precedent .