Is the FDA softening their stance on approving drugs using progression radiographic progression-free survival (rPFS) (how long it takes for the disease to progress based on scans) as opposed to only survival? The answer is maybe, under certain circumstances.

An article in Clinical Cancer Research looked into the US Food and Drug Administration’s thinking about the approval of abiraterone acetate (Zytiga) for the treatment of chemotherapy-naive patients with metastatic, castration-resistant prostate cancer (mCRPC).

The article written by Kleutz et al., entitled “Abiraterone shows radiographic improvement in PFS for metastatic castration-resistant prostate cancer; survival benefit uncertain,” looks at the FDA’s decision and their commentary used in the approval of abiraterone acetate + prednisone for the treatment of men with chemotherapy-naive mCRPC in December 2012.

The FDA’s approval was based on the results of the clinical trial (COU-AA-302). It looked at men with asymptomatic or mildly symptomatic, chemotherapy-naïve mCRPC who were randomized to treatment with either abiraterone acetate + prednisone (N = 546) or placebo + prednisone (N = 542). The trial was structured to have two endpoints; radiographic progression-free survival (rPFS) and overall survival (OS).

The trial showed that the median time to rPFS was 8.3 months in the placebo arm and the median time had not yet been