There was a nice discussion on the Biotech values board between iwfal and p3analyze about PFS . It was spurred on by some commentary made when SNTA presented at the JPM conference, and it spurred me to listen to the rebroadcast. The point of discussion regarded the comment about PFS in the NSCLC trial. Specifically, PFS in the Docetaxel only population was due to new lesions forming, whereas few in the Ganetespib + Docetaxel population showed such new lesions.
As a follow up, Iwfal found a few papers which were retrospectively assessing this phenomenon. While still early, it does lend support to the idea that the ability to block new lesions from forming may be a very good predictor of a drugs chances for success. Hopefully, rather than a simple PFS report, we can dissect the PFS to include the metric of new lesion formation to another new metric, measurements of circulating tumor cells (CTCs), as better early indicators of OS improvement.