Evolocumab Treatment in Pediatric Patients With Homozygous Familial Hypercholesterolemia: Pooled Data From Three Open-Label Studies.

Background: Pediatric patients with homozygous familial hypercholesterolemia (HoFH) have an increased risk of atherosclerotic cardiovascular disease and difficulty meeting low-density lipoprotein cholesterol (LDL-C) goals. In this post hoc analysis, we evaluated pooled safety and efficacy data from 3 studies in pediatric patients with HoFH treated with the PCSK9 (proprotein convertase subtilisin/kexin type 9) monoclonal antibody inhibitor evolocumab.
Methods: Patients with HoFH aged 10 to 17 years received treatment with open-label evolocumab 420 mg subcutaneously monthly or biweekly in the TAUSSIG, RAMAN, or HAUSER-OLE clinical studies. All patients received background statins with or without ezetimibe. Study duration ranged from 12 to 260 weeks. The primary end point was treatment-emergent adverse events per 100 patient-years. Efficacy end points were changes from baseline to week 12 in lipids and PCSK9.
Results: Of the 39 patients in the pooled analysis, 69.2% were males, median age was 13.0 years, and 79.5% (31/39) had genotyped HoFH with LDLR pathogenic variants. Overall, median exposure to evolocumab was 18.2 (Q1, Q3: 3.0, 18.5) months. Treatment-emergent adverse events with an exposure-adjusted patient incidence rate of ≥5% were upper respiratory tract infection (6.6%), influenza (5.2%), and acne (5.0%) per 100 patient-years. Exposure-adjusted patient incidence of serious treatment-emergent adverse events was 13.3% per 100 patient-years. Excluding 4 patients receiving lipoprotein apheresis, week 12 median percentage change from baseline in LDL-C was -2.9% (Q1, Q3: -21.7, 1.5); however, 42.9% (15/35) of patients achieved ≥15% reduction in LDL-C from baseline. Residual LDLR (LDL receptor) activity was not associated with a reduction in LDL-C.
Conclusions: In this pooled data analysis from 3 studies in pediatric patients with HoFH, evolocumab was well tolerated, with no new safety signals reported. These safety findings are consistent with findings from previous studies of evolocumab. Patients showed marked variability in LDL-C reduction. Results from this pooled analysis support guidelines suggesting a trial of PCSK9 inhibitor therapy regardless of estimated residual LDLR function.
Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01624142, NCT03403374, and NCT02624869.
Competing Interests: Disclosures F.J. Raal has received research grants, honoraria, or consulting fees for professional input and lectures from Sanofi, Regeneron, Amgen, and Novartis; and travel support to attend the 2023 European Atherosclerosis Society (EAS) Congress from EAS. R.A. Hegele reports receiving consulting fees from Acasti, Aegerion, Akcea/Ionis, Amgen, Boston Heart, HLS Therapeutics, Novartis, Pfizer, Regeneron, Sanofi, and Ultragenyx; and lecture fees from Amgen, HLS Therapeutics, and Novartis. A. Ruzza is a former employee and a stockholder of Amgen. He is a current employee and a stockholder of GlaxoSmithKline. He holds a pending patent application PCT/US2021/034489 on PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors and methods of use thereof to treat cholesterol-related disorders. J.A.G. López, A.K. Bhatia, H. Wang, and J. Wu are employees and stockholders of Amgen. D. Gaudet reports receiving research grants, honoraria, or consulting fees for professional input and lectures from Alnylam, Amgen, Applied Therapeutics, Arrowhead, Boehringer Ingelhein, Chiesi (Amryt), CRISPR Therapeutics, Eli Lilly, Esperion, Ionis, Kowa, New Amsterdam Pharma, Novartis, Novo Nordisk, Pfizer, Regeneron, Sanofi, Ultragenyx, Uniqure, and Verve Therapeutics. A. Wiegman reports research support for pharmaceutical trials of lipid-lowering agents from Amgen, Sanofi-Regeneron Pharmaceuticals, Novartis, Silence Therapeutics, Esperion, and Ultragenyx; and is member of a safety board for Amryt. R.D. Santos reports receiving consulting fees and lecture fees from Abbott, Amgen, Amryt, AstraZeneca, Aché, Biolab, Getz Pharma, Eli Lilly, Libbs, Merck, PTC Therapeutics, Novo Nordisk, Novartis, and Sanofi-Regeneron Pharmaceuticals; and grant support from Amgen, Kowa, Esperion, Novartis, and Sanofi-Regeneron Pharmaceuticals. The other author reports no conflicts.