Progression-Free Survival Versus Overall Survival in Ovarian Cancer: Where Are We Now?

Excerpt

Our commentary is prompted by the recent release of information on the two most promising areas of drug development in the treatment of ovarian cancer: the vascular endothelial growth factor inhibitor bevacizumab and the poly(adenosine diphosphate ribose) polymerase (PARP) inhibitor olaparib. Firstly, positive results, chiefly in terms of progression-free survival (PFS), have now been reported for bevacizumab in both first-line and recurrent/resistant disease settings. This has led many clinicians to conclude that the agent should now be incorporated into the standard management of this disease. On the other hand, a press release in December 2011 indicated that the development of olaparib in serous ovarian cancer was in question following a review of an interim analysis of a phase II study (Study 19) [1]. This had indicated that in a maintenance therapy trial, the previously reported PFS benefit was unlikely to translate into an overall survival (OS) benefit. This press release led to a degree of confusion; however, AstraZeneca recently announced that the development of olaparib was to continue, although limited to patients with BRCA mutations. These events prompted us to revisit the use of PFS and OS both for regulatory purposes and as end points for drug development in the era of targeted therapies for ovarian cancer. …