FDA: 'rare' subset driving axitinib PFS benefit

FDA said Inlyta axitinib's two-month progression-free survival benefit over Nexavar sorafenib in a Phase III trial was driven by a group of patients previously treated with cytokines, a subset of the advanced renal cell carcinoma (RCC) population the agency called "rare" in the U.S. The comments came in briefing documents posted ahead of Wednesday's Oncologic Drugs Advisory Committee meeting to discuss the Pfizer Inc. (NYSE:PFE) drug.

FDA plans to ask the committee whether the "more meager" PFS benefit in patients previously treated with Pfizer's Sutent sunitinib would affect Inlyta's overall benefit-risk assessment. The increase in median PFS for patients previously treated with cytokines was 5.6 months (p<0.0001), while the increase in patients previously treated with Sutent was 1.4 months (p=0.011). The trial's overall population consisted of about 54% previously treated with Sutent and 34% with cytokines, including IL-2 and interferon-alpha. The trial's North American population consisted of 68% previously treated with Sutent and 20% with cytokines. FDA added that the PFS benefit likely will not translate to an overall survival benefit. OS data are expected 1Q12. FDA said axitinib showed a safety profile similar to that of other approved VEGF inhibitors. ...