Impact of Evolocumab on the Effects of Clopidogrel in Patients With High On-Treatment Platelet Reactivity

Overview

Clopidogrel is the most widely used P2Y12 receptor inhibitor and is the only agent of this class currently recommended in patients with stable coronary artery disease (CAD) undergoing PCI, and for the treatment of stroke or PAD. Pharmacodynamic (PD) studies have shown that approximately 30-40% of patients experience high on-treatment platelet reactivity (HPR) while receiving clopidogrel treatment. Importantly HPR status has been strongly associated with an increased risk of ischemic events. Multiple approaches have been advocated to reduce HPR rates. In a previous study treatment with high-dose atorvastatin in addition to double-dose clopidogrel reduced platelet reactivity significantly more than double-dose clopidogrel alone in statin-naïve patients with stable CAD and HPR. To date, the exact biological mechanisms involved in the statin modulation of platelet function are not fully understood, although likely attributed to both its lipid-lowering and non-lipid-related effects. Evolocumab is a monoclonal antibody targeting proprotein convertase subtilisin/kexin type 9 (PCSK9). The use of evolocumab plus standard therapy, as compared with standard therapy alone, significantly reduced the incidence of cardiovascular events. Whether the reduction in cardiovascular events is simply due to LDL reduction or might be related to other mechanisms is currently subject of investigation. Although LDL reduction with statin therapies has been associated with reduction in platelet reactivity, to date the effects on platelet aggregation of adjunctive lipid lowering with evolocumab has not been explored. The aim of the present study is to investigate the effects of evolocumab in addition to statin therapy on HPR rates and platelet reactivity in patients with atherosclerotic cardiovascular disease (ASCVD) and HPR while on clopidogrel treatment.

Clopidogrel is the most widely used P2Y12 receptor inhibitor and is the only agent of this class currently recommended in patients with stable coronary artery disease (CAD) undergoing PCI, and for the treatment of stroke or PAD. Although the efficacy of DAPT with aspirin and clopidogrel has been consistently shown in different clinical settings, rates of ischemic recurrences remain elevated despite this treatment regimen, especially in high risk patients. This has been in part attributed to the high interindividual variability in responses to clopidogrel. Pharmacodynamic (PD) studies have shown that approximately 30-40% of patients experience high on-treatment platelet reactivity (HPR) while receiving clopidogrel treatment. Importantly HPR status has been strongly associated with an increased risk of ischemic events, in particular stent thrombosis, in patients with ACS and following PCI. This underscores the need for strategies aimed to reduce HPR rates in patients treated with clopidogrel. Multiple approaches have been advocated to reduce HPR rates. The pleiotropic effects associated with lipid lowering therapies, in particular statins, have been subject to extensive research. In a previous study treatment with high-dose atorvastatin in addition to double-dose clopidogrel reduced platelet reactivity significantly more than double-dose clopidogrel alone in statin-naïve patients with stable CAD and HPR. To date, the exact biological mechanisms involved in the statin modulation of platelet function are not fully understood, although likely attributed to both its lipid-lowering and non-lipid-related effects. Evolocumab is a monoclonal antibody targeting proprotein convertase subtilisin/kexin type 9 (PCSK9) that is administered subcutaneously (s.c.) at a dosage of 140 mg every 2 weeks or 420 mg once monthly. In clinical trials evolocumab was more effective than placebo and/or ezetimibe in reducing LDL cholesterol, including when added to statin therapy. The use of evolocumab plus standard therapy, as compared with standard therapy alone, significantly reduced the incidence of cardiovascular events. Whether the reduction in cardiovascular events is simply due to LDL reduction or might be related to other mechanisms is currently subject of investigation. Although LDL reduction with statin therapies has been associated with reduction in platelet reactivity, to date the effects on platelet aggregation of adjunctive lipid lowering with evolocumab has not been explored. The aim of the present study is to investigate the effects of evolocumab in addition to statin therapy on HPR rates and platelet reactivity in patients with atherosclerotic cardiovascular disease (ASCVD) and HPR while on clopidogrel treatment.