OR24-02 Case Series Of Canadian Patients With Homozygous Familial Hypercholesterolemia Treated With ANGPTL3 Inhibitor Evinacumab

Disclosure: I. Shamsudeen: None. B.W. McCrindle: Consulting Fee; Self; Jansen Pharmaceuticals, Amryt, Ultragenyx, Chiesi, Esperion. R.A. Hegele: Advisory Board Member; Self; Amgen Inc, HLS Pharmaceuticals, Novartis Pharmaceuticals. Consulting Fee; Self; Akcea Therapeutics, Ultragenyx, Medison, Acasti, Amgen Inc, Novartis Pharmaceuticals, Amryt, Amgen Inc, Pfizer, Inc., Arrowhead, Sanofi, HLS Pharmaceuticals, Regeneron Pharmaceuticals. Background: Homozygous familial hypercholesterolemia (HoFH) is an ultrarare, life-threatening condition characterized by markedly elevated levels of low-density lipoprotein cholesterol (LDL-C) due to biallelic LDL receptor variants. Patients have an increased risk of premature atherosclerotic cardiovascular disease (ASCVD). Traditional lipid-lowering agents are minimally effective and the gold standard treatment is serial apheresis. Recently, an angiopoietin-like protein 3 (ANGPTL3) inhibitor, evinacumab, was introduced as a promising new treatment for HoFH. It was FDA-approved in 2021, but is currently available in Canada only through clinical trials or special access programs. Case Presentations: The first five Canadian HoFH patients to receive evinacumab via special access are presented. Their mean age is 24.6 years (SD = 13.9). As of December 2022, they have received evinacumab 15 mg/kg intravenously every four weeks for a mean of 12.2 months (SD = 11.3). Their mean incremental LDL-C reduction is 49.4% (SD = 8.9) on evinacumab along with reduced apheresis frequency for those on serial apheresis. Safety labs for all patients are normal. Brief case summaries are as follows: (a) Patient A is a 36-year-old man with severe ASCVD who has been on evinacumab for 30 months, in addition to a statin, ezetimibe, evolocumab and LDL-apheresis. His time-averaged LDL-C has decreased by 46.2%, from 4.76 to 2.56 mmol/L (184 to 99 mg/dL), on evinacumab. (b) Patient B is a 17-year-old male with elevated LDL-C levels despite being on a statin, ezetimibe and LDL-apheresis. After 14 months on evinacumab, his time-averaged LDL-C reduced by 40.3%, from 8.75 to 5.22 mmol/L (338 to 202 mg/dL). (c) Patient C is a 30-year-old woman with ASCVD and xanthomas on a statin and ezetimibe, but not apheresis. She has been on evinacumab for 12 months with a 57.7% reduction in LDL-C, from 11.43 to 4.83 mmol/L (442 to 187 mg/dL). (d) Patient D is a 36-year-old man with ASCVD on a statin, ezetimibe, evolocumab and lomitapide in addition to plasmapheresis. He started evinacumab 2 months ago and has already had a 42.6% decrease in time-averaged LDL-C, from 4.34 to 2.49 mmol/L (168 to 96 mg/dL). (e) Patient E is a 4-year-old boy with HoFH and xanthomas on a statin, ezetimibe and plasmapheresis. After 3 months of treatment with evinacumab, his time-averaged LDL-C decreased by 59.9%, from 9.45 to 3.79 mmol/L (365 to 147 mg/dL). Concurrently, he has developed unexplained intermittent abdominal pain, with temporary suspension of evinacumab pending further assessment. Discussion: Five HoFH patients with distinctive histories, baseline treatments and ASCVD have all shown marked improvement in LDL-C levels with a mean reduction of 49.4% on evinacumab on top of existing therapy. Overall, observations from our case series suggest that evinacumab is an effective new treatment for HoFH, a life-threatening condition with few therapeutic options. Presentation: Saturday, June 17, 2023