Roche’s Genentech Inc. unit enrolled all comers when it moved into Phase II in bladder cancer, the lead indication for Tecentriq (atezolizumab). It chose not to limit enrollment to patients with high levels of PD-L1 expression – unlike Merck & Co. Inc., which did not include low PD-L1 expressers in its Keytruda (pembrolizumab) lung cancer trials.
The tactic could have severely hindered Tecentriq’s chances, but when low PD-L1 expressers who didn’t have the high immune score by their data nonetheless responded, the Food and Drug Administration...