Impact of evolocumab on the pharmacodynamic profiles of clopidogrel in patients with atherosclerotic cardiovascular disease: a randomised, double-blind, placebo-controlled study.

Background: The impact of intense low-density lipoprotein cholesterol (LDL-C) reduction using a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor on profiles of platelet reactivity has yet to be explored.

Aims: Our aim was to investigate the effects of the PCSK9 inhibitor, evolocumab, on platelet reactivity in patients with atherosclerotic cardiovascular disease (ASCVD) on clopidogrel treatment.

Methods: This was a prospective, randomised, double-blind, placebo-controlled pharmacodynamic study in patients with ASCVD on clopidogrel treatment and with LDL-C levels ≥70 mg/dL despite a maximally tolerated statin dose. Patients were stratified according to levels of platelet reactivity using VerifyNow P2Y reactivity units (PRU) into high platelet reactivity (HPR; PRU >208) or normal platelet reactivity (NPR; PRU >85 and ≤208). Each cohort was randomised to receive evolocumab 420 mg or placebo. The primary endpoint was the difference in PRU at 30 days.

Results: A total of 84 patients (HPR, n=37 [19 evolocumab vs 18 placebo]; NPR, n=47 [22 evolocumab vs 25 placebo]) were included. Evolocumab significantly reduced LDL-C compared to placebo at 14 (p<0.001) and 30 (p=0.001) days. At 14 days, PRU levels were significantly lower with evolocumab compared to placebo in the HPR (218.2±29.7 vs 246.6±35.2; p=0.017), but not in the NPR cohort (141.2±42.8 vs 148.2±41.7; p=0.578). At 30 days, there were no significant differences in PRU in the HPR (219.3±38.3 vs 240.9±51.8; p=0.161) or NPR (141.5±54.3 vs 158.6±40.8; p=0.229) cohorts.

Conclusions: Compared to placebo, evolocumab in adjunct to statin therapy did not significantly reduce platelet reactivity at 30 days in ASCVD patients on clopidogrel treatment despite intense LDL-C reduction. ClinicalTrials.gov: NCT03096288.