Effect of Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Inhibitors on Lipoprotein(a) Levels: An Umbrella Review of Meta-analyses of Randomized Controlled Trials

Elevated lipoprotein(a) [Lp(a)] is a genetically determined, causal risk factor for atherosclerotic cardiovascular disease, but effective therapies remain limited. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are primarily used to lower low-density lipoprotein cholesterol (LDL-C), yet their effects on Lp(a) have been inconsistently reported. This umbrella review synthesizes meta-analytic evidence on PCSK9 inhibitors and Lp(a).

We systematically searched PubMed, Embase, Web of Science, and Cochrane Library through April 2025 for meta-analyses of randomized controlled trials (RCTs) comparing PCSK9 inhibitors (alirocumab, evolocumab, inclisiran) with placebo or standard therapy. The primary outcome was mean percentage change in Lp(a). Methodological quality was assessed using the Assessment of Multiple Systematic Reviews 2 (AMSTAR-2), and evidence certainty was graded with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Overlap of primary trials was quantified using the Corrected Covered Area (CCA), and sensitivity analyses were performed to account for overlapping evidence.

Twenty-one meta-analyses (116 RCTs; 231,796 participants) were included. The PCSK9 inhibitors consistently reduced Lp(a): evolocumab (29.68–46.68%; high certainty), alirocumab (18.55–26.46%; high certainty), and inclisiran (18.00%; high certainty). Higher biweekly doses yielded larger decreases (e.g., alirocumab 150 mg: 24.6%; evolocumab 140 mg: 26.8%, high certainty). Reductions were dose-dependent and broadly consistent across populations, comparators, follow-up durations, and baseline Lp(a). The Lp(a) reductions correlated modestly with LDL-C (β = 0.28; 95% CI 0.07–0.49) and apolipoprotein B (apoB) (β = 0.33; 95% CI 0.03–0.63). Concomitant reductions in LDL-C, apoB, and major adverse cardiovascular events were supported by high and moderate certainty evidence. Safety was favorable, with injection-site reactions being the most common adverse event. Sensitivity analyses confirmed robustness of findings after accounting for overlapping trials.

The PCSK9 inhibitors, particularly evolocumab 140 mg every 2 weeks, significantly lower Lp(a) alongside LDL-C and apoB. These findings highlight the consistent Lp(a)-lowering effect of PCSK9 inhibitors. However, the observed cardiovascular benefits are largely attributable to concomitant LDL-C reduction, and the incremental contribution of Lp(a) lowering remains uncertain. Confirmation from outcome trials specifically designed to target Lp(a) is required.

PROSPERO CRD420251048597.