The Endocyte (ECYT) catalysts -- the ovarian cancer approval decision in Europe and the phase II lung cancer study results -- were going to be close calls either way. Fortunately (for Endocyte bulls) both came up positive last Friday. What did the Endocyte bears miss? And where does the bear thesis go from here?
Predicting regulatory decisions is always difficult, but in this case, the Endocyte bears under-estimated the significance European regulators placed on the unmet medical need in platinum resistant ovarian cancer. The pairing of VynFinit with a diagnostic test to select ovarian cancer patients most likely to benefit was also something that helped sway European regulators in a positive direction. Endocyte bears didn't fully appreciate the importance of the diagnostic test.
In terms of the lung cancer data, the bears made a more fundamental mistake under-estimating the transitive properties of mathematics. Going into the data, we knew the vintafolide monotherapy arm was not going to be superior compared to docetaxel monotherapy. I think many read that as the monotherapy being worse, but that was not necessarily the case. We also knew data safety monitors in the trial allowed patients to continue on vintafolide mono therapy, and 80% chose this option. If vintafolide monotherapy was clearly inferior, I doubt patients would have been allowed to stay on treatment, nor would 80% choose to do so. As such, I inferred from these facts that vintafolide monotherapy was essentially equivalent to docetaxel if not very marginally better.