Impact of <i>CYP2C19</i> Genotype Variants on <scp>PCSK9</scp> Inhibitor Efficacy in Lipid‐Lowering Among Patients With Symptomatic Intracranial Atherosclerotic Stenosis

Ischemic stroke is frequently associated with symptomatic intracranial atherosclerotic stenosis (sICAS), is a leading cause of global disability and mortality. Current guidelines recommend dual antiplatelet and intensive statin therapies. Proprotein convertase subtilisin 9/kexin type 9 (PCSK9) inhibitors have emerged as a potent lipid-lowering therapy, potentially influenced by genetic variations, particularly in the CYP2C19 gene. This study at Xuzhou Central Hospital from January 2021 to December 2023 included 151 patients divided into a statin group (n = 73) and a PCSK9 inhibitor (PCSK9i) group (n = 78). It evaluated lipid profiles, inflammatory markers, neurological function, and clinical outcomes over a 180-day follow-up period, with additional analysis stratified by CYP2C19 genotype. The PCSK9i group demonstrated significant improvements in lipid parameters compared to the statin group, including greater reductions in low-density lipoprotein cholesterol (LDL-C) (p = 0.008), total cholesterol (TC) (p < 0.001), and triacylglycerols (TAG) (p = 0.041), along with apolipoprotein A1 (ApoA1) and apolipoprotein B (ApoB) (both p < 0.001). Inflammatory markers, particularly interleukin-6 (IL-6), significantly reduced in the PCSK9i group (p < 0.001). In the PCSK9i group, CYP2C19 rapid metabolizers achieved greater reductions in LDL-C (p = 0.021), ApoB (p = 0.003), and IL-6 levels (p = 0.041) compared to slow metabolizers. Post-treatment modified Rankin Scale (mRS) scores were significantly lower in rapid metabolizers compared to slow metabolizers (p = 0.018), though clinical events occurred infrequently in both subgroups. This study demonstrates that PCSK9 inhibitor therapy combined with statins provides enhanced lipid-lowering and anti-inflammatory effects compared to statin monotherapy in sICAS patients. While the CYP2C19 genotype may influence specific treatment responses, particularly lipid parameters, its impact on clinical outcomes requires further investigation.