FDA questions Brilinta efficacy discrepancies

In briefing documents posted ahead of Wednesday's Cardiovascular and Renal Drugs Advisory Committee, FDA questioned the regional efficacy differences observed in the Phase III PLATO trial of acute coronary syndrome (ACS) candidate Brilinta ticagrelor from AstraZeneca plc (LSE:AZN; NYSE:AZN). The documents noted that the trial showed worse results for Brilinta in the U.S. for all efficacy measures. Brilinta had a non-significant higher hazard ratio on the trial's primary endpoint of time to first occurrence of any event from the composite of cardiovascular death, myocardial infarction and stroke compared to Plavix clopidogrel in the U.S. compared to outside the U.S. (HR: 1.27 vs. HR: 0.81).

AstraZeneca attributed the difference to U.S. patients receiving higher doses of concurrent aspirin than ex-U.S. patients, but FDA asserted in the documents that the pharma's model for explaining the difference did not appear robust. However, a reviewer in FDA's Office of Clinical Pharmacology did recommend approval of Brilinta with a post-marketing trial to reconcile the data from the U.S. ...