The FDA's Cardiovascular and Renal Drugs Advisory Committee today recommended against the approval of cangrelor, the investigational new antiplatelet drug from the Medicines Company. In a 7-2 vote the panel first rejected an indication for the reduction of thrombotic cardiovascular events including stent thrombosis in patients undergoing PCI.
The panel also voted unanimously to reject a second indication, for the maintenance of antiplatelet therapy in patients with acute coronary syndromes or patients with stents who have discontinued antiplatelet therapy because they are awaiting surgery and are at high risk for thrombotic events. FDA reviewers, who had delivered mixed opinions for the first indication, had recommended a complete response letter for the second indication, since the company had failed to perform a trial showing clinical benefit for the indication.
Throughout the day panel members wrestled with problems with the pivotal CHAMPION PHOENIX trial, which attempted to remedy the deficiencies of two earlier negative trials. Although most panel members agreed that PHOENIX showed a benefit compared to the clopidogrel control group, the benefit appeared small and the committee was concerned that cangrelor may have received an unfair advantage because in the control group clopidogrel was not used ideally, since many did not receive preloaded high-dose clopidogrel. An additional concern was that most of the difference between the groups was due to a reduction in periprocedural MIs. Panelists once again raised the question of the clinical relevance of this finding. Finally, the higher risk of bleeding with clopidogrel appeared to largely offset the observed benefits.
Panel member Milton Packer, who voted against approval, said that he wanted to vote yes and that he thought an antiplatelet agent with rapid on/off properties might well prove useful. But, he said, the sponsor had not demonstrated that cangrelor was superior to full dose clopidogrel and that the effect on cardiac enzyme elevations was clinically meaningful.
