Agency reaffirms safety and efficacy in atrial fibrillation patients despite use of faulty coagulation monitoring device in pivotal trial led by current FDA Commissioner Robert Califf when he was at Duke University.

Some members of FDA’s Cardiovascular and Renal Drugs Advisory Committee questioned whether the high rate of study dropouts and consent withdrawals in rivaroxaban’s pivotal trial for acute coronary syndromes resulted from elements of the trial’s design, including patient consent and follow-up procedures and the primary analysis.

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.