AstraZeneca has suffered a setback with advisors to the US Food and Drug Administration recommending against accelerated approval of olaparib for ovarian cancer.

The agency’s Oncologic Drugs Advisory Committee has voted 11 to 2 that current evidence does not support early approval for use of olaparib as a maintenance treatment for platinum-sensitive relapsed ovarian cancer in women who have the germline BRCA mutation, and who are in complete or partial response to platinum-based chemotherapy. The vote comes after FDA staffers expressed concern about a subgroup retrospective analysis of Phase II data on the poly ADP-ribose polymerase (PARP) inhibitor which revealed a 7.1 month median improvement in progression-free survival.

AstraZeneca decided, in December 2011, not to progress olaparib into Phase III, but reversed that decision on the basis of results for the aforementioned subgroup. It received priority review status in April from the FDA but the latter’s staffers have questioned whether the reanalysis skewed the results.

The panel also mentioned safety issues such as bone marrow suppression, fatigue, nausea and abdominal pain and cases of myelodysplastic syndrome and acute myeloid leukaemia in study participants that had a small risk of being linked to olaparib.

Briggs Morrison, AstraZeneca’s chief medical officer, said that patients “have few options available to treat this disease” and “we are disappointed with [the] recommendation”. He added that “we strongly believe that olaparib has the potential to provide patients…and their doctors with a much-needed treatment option”.

However this is not the end of the road for olaparib as Dr Morrison said the firm is continuing with its Phase III clinical programme to evaluate the benefit of the drug for this patient population. “We aim to have completed this study by the end of 2015,” he added.

Nevertheless, the decision is indeed disappointing given that AstraZeneca, when fending off the advances of Pfizer earlier this year, had predicted peak sales potential of olaparib at $2 billion.