Yesterday, told the public that CBER (Center for Biologics Evaluation & Research) granted a complete response to its BLA (Biologic License Application) for Provenge. Complete response letters for BLAs are essentially the equivalent of approvable letters for NDAs. Dendreon did not provide details on the CR letter, except to note that FDA requested further information related to efficacy and CMC issues.
The company’s stock, which had soared from just over $5/sh prior to the Advisory Committee meeting in late March to just over $25/sh at its peak, predictably fell on the news yesterday and is currently trading at just under $7/sh.
Although Dendreon chose not to disclose specific data requests, questions around efficacy that persist after the first review cycle nearly always require additional clinical data (or additional analyses of existing data) to address. In Dendreon’s case, it appears that the only source of significantly additive clinical data would be an ongoing Phase 3 study [IMPACT], which is why investors have reacted so harshly to this news.
Based on the information I had after the advisory committee meeting, I felt that FDA should have given approval to market the drug narrowly. Sure, the evidence of efficacy wasn’t overwhelming, and it’s reasonable to worry when the endpoint selected as the basis for approval isn’t even a pre-specified trial endpoint.
But approval, it seemed to me, had little downside for patients and would have made obtaining the therapy much easier. FDA’s advisory committee supported approval, and FDA usually follows its committees’ recommendations. Was there information the committee didn’t have that swayed FDA? If so, why didn’t the committee have this information? What other advisors, internal (e.g. Division of Oncologic Drug Products at CDER) or external (e.g. ODAC members) were involved in FDA’s decision-making process? Whose opinions were given the most weight and why? Until the public has answers to these questions, speculating on a larger meaning behind this decision is foolish.
DNDN 1-yr chart: