Abstract
IMPORTANCE: In individuals with heterozygous familial hypercholesterolemia (HeFH), it is uncertain whether and to what extent the reduction in low-density lipoprotein cholesterol (LDL-C) with proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor therapy is dependent on the residual functional activity of the LDLR gene carrying the pathogenic variant. OBJECTIVE: To evaluate the reduction in LDL-C achieved with PCSK9 inhibition according to FH genotype in a large cohort of patients with HeFH. DESIGN, SETTING, AND PARTICIPANTS: This nonrandomized clinical trial reports on a predefined, pooled subanalysis of participants with HeFH requiring additional lipid-lowering therapy in the open-label worldwide phase 3 study of the PSCK9 inhibitor lerodalcibep. This study included participants randomized to 5 phase 3 studies with the plasma PSCK9 inhibitor lerodalcibep and who participated in the open-label extension study from December 2020 to May 2025. Data were analyzed from March 2025 to February 2026. INTERVENTION: All participants received lerodalcibep 300 mg subcutaneously monthly for 72 weeks. MAIN OUTCOME AND MEASURES: The co-primary efficacy end points were LDL-C reduction at weeks 48 and 72. Secondary and exploratory end points included LDL-C response according to FH genotype and the achievement of currently recommended LDL-C goals. RESULTS: Among 703 included participants (mean [range] age, 53.8 [18-80] years; 372 male [52.9%]), 86 (12.2%) were Black, South Asian, or multiracial and 617 (87.8%) were White; 217 participants (72.3%) had atherosclerotic cardiovascular disease (ASCVD) or were at very high risk for ASCVD and 195 participants (27.7%) were at high risk for ASCVD. Despite most participants receiving treatment with statins or ezetimibe, the mean (SD) baseline LDL-C was 144.9 (61.9) mg/dL. Mean (SD) reductions in LDL-C associated with lerodalcibep were 50.3% (28.9%) and 50.3% (28.7%) (mean [SD] absolute change, -72.6 [50.5] mg/dL and -71.8 [48.0] mg/dL) at weeks 48 and 72, respectively. Of 740 participants (92.5%) who underwent genetic testing, monogenic FH-causing variants were found in 455 participants (61.5%), including 432 participants (95.7%) with the LDLR pathogenic variant. LDL-C reduction with lerodalcibep was independent of LDLR variant functional activity. More than 70% of participants achieved both a reduction in LDL-C of at least 50% and their ASCVD risk-based LDL-C goal. CONCLUSIONS AND RELEVANCE: These findings suggest that lerodalcibep was associated with significantly and consistently reduced LDL-C in patients with HeFH, with response found to be independent of LDLR function of the pathogenic variant. These findings support that LDL-C reductions in patients with HeFH with PCSK9 inhibition are predominantly mediated by upregulation of the unaffected wild-type LDLR. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04798430.