PCSK9 Inhibitor with Statin Therapy for Intracranial Artery Stenosis ( PISTIAS): Rationale and design of a multicenter randomized controlled trial.

Rationale: Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors enable an additional 54-75% reduction in low-density lipoprotein cholesterol (LDL-C) in statin-treated patients, demonstrating plaque regression in coronary artery disease. However, the impact of achieving an extremely low level of LDL-C with PCSK9 inhibitors (e.g. Evolocumab) on symptomatic intracranial atherosclerosis remains unexplored.

Aim and hypothesis: To determine whether combining Evolocumab and statins achieves a more significant symptomatic intracranial plaque regression than statin therapy alone.

Sample size estimates: With a sample size of 1000 subjects, a two-sided α of 0.05, and 20% lost to follow-up, the study will have 83.3% power to detect the difference in intracranial plaque burden.

Methods and design: This is an investigator-initiated multicenter, randomized, open-label, outcome assessor-blinded trial, evaluating the impact of combining Evolocumab and statins on intracranial plaque burden assessed by high-resolution magnetic resonance imaging at baseline in patients undergoing a clinically indicated acute stroke or transient ischemic attack due to intracranial artery stenosis, and after 24 weeks of treatment. Subjects (n = 1000) were randomized 1:1 into two groups to receive either Evolocumab 140 mg every 2 weeks with statin therapy or statin therapy alone.

Study outcomes: The primary endpoint is the change in intracranial plaque burden assessed by high-resolution magnetic resonance imaging, performed at baseline and at the end of the 24-week treatment period.

Discussion: This trial will explore whether more significant intracranial plaque regression is achievable with the treatment of combining Evolocumab and statins, providing information about efficacy and safety data.

Trial registration number: ChiCTR2300068868; https://www.chictr.org.cn/.