New FDA guidance may lighten Prima’s regulatory load Nick...

New FDA guidance may lighten Prima’s regulatory load

Nick Evans
Tuesday, 22 September 2009

PRIMA Biomed’s path to market may have been boosted by the release last week of new draft guidance from the US Food and Drug Administration on the approval of therapeutic cancer vaccines.



While the guidance won’t be formally adopted by the FDA for some time, there are some indications that the regulator is rethinking the evidence it will require to approve therapeutic cancer vaccines such as Prima’s CVac and Dendreon’s Provenge.

Deutsche Bank, in a research note on Dendreon last week, said the FDA appeared to be moving towards allowing approval of therapeutic cancer vaccines on the basis of overall survival in clinical trials, rather than the more common mark of progression-free survival.

"The FDA guides that time to tumour progression may not be an appropriate end point for cancer vaccines. They note that the immune response launched against the tumour may take longer than the time it takes for a tumour to progress,” the bank noted.

The report said this implied the FDA would likely support Provenge approval even though it did not delay tumour progression but rather exhibited a survival benefit, according to US media reports.

The draft guidance also includes advice for companies planning trials and says the FDA may give consideration to trials that are closer to traditional Phase 1 drug trials in healthy patients, or those with a “minimal disease burden”, as these will allow “adequate time for the immune response elicited by the cancer vaccines to develop and manifest” – rather than companies relying on traditional early-stage cancer trials in patients at advanced and generally untreatable stages of the disease.

Prima Biomed director Martin Rogers said that, while he hadn’t had a chance to review the new guidance in detail, it looked as though it might benefit Prima.

“Deutsche Bank says it’s good for Dendreon and anything that’s good for Dendreon is good for us,” he said.

Rogers said Prima wouldn’t be reviewing the protocols for its soon-to-be-launched Phase 2 trial of CVac in light of the new guidance.

“We have both end points currently there – progression-free survival and overall survival,” he said.

“We’ll be measuring both and if the FDA decide one or the other is good enough, that won’t affect the way our trial is run.”