Pfizer seeks silver lining in failed C. diff vaccine trial

Pfizer’s vaccine for Clostridium difficile (C. diff) looks like it may join a growing list of candidates that have been shelved or delayed, after the shot failed to meet its primary objective in a phase 3 trial.

The pharma company was quick to point out however that the CLOVER trial of PF-06425090 was undermined by a lower-than expected rate of C. diff infection (CDI) as a result of social isolation caused by the COVID-19 pandemic, and to highlight secondary endpoints in the trial that it said point to a “strong potential effect” for the shot.