Xarelto Tested FDA’s Comparative Efficacy Powers, But Conservative View Prevailed

J&J/Bayer’s Xarelto tested the limits of FDA’s policy on comparative efficacy, thanks to suboptimal use of the active comparator, warfarin, and the introduction of a new competitor, Pradaxa. In the medical reviewers’ view, new therapies should be as effective as existing therapies used skillfully, but division leadership would withhold approval only if the new drug were clearly inferior to approved agents.