Homozygous familial hypercholesterolemia (
HoFH) is an ultra-rare, life-threatening, genetic condition characterized by markedly elevated levels of
low-density lipoprotein cholesterol (
LDL-C). Standard
lipid-lowering
therapies minimally reduce
LDL-C in these patients, and lifelong serial
apheresis is the mainstay of treatment.
Evinacumab is a
monoclonal antibody against
angiopoietin-like protein 3 that lowers
LDL-C levels via a novel
LDL receptor-independent mechanism, and is US Food and Drug Administration approved for
HoFH in the United States. We present a pediatric
HoFH patient from Ontario who has been receiving
evinacumab through special access from Health Canada. A 17-year-old boy was diagnosed with severe
HoFH due to compound heterozygous LDLR pathogenic variants. Treatment has included a
statin,
ezetimibe, and
LDL apheresis every 2 weeks, with minimal overall effect on
LDL-C levels. He remains asymptomatic from a cardiovascular perspective. At age 16,
evinacumab infused intravenously every 4 weeks was added to his treatment. After 12 months, his time-averaged
LDL-C decreased by 53.4% from 8.75 mmol/L (338.4 mg/dL) to 4.08 mmol/L (157.8 mg/dL), despite reduced frequency of
LDL apheresis from biweekly to monthly. He has experienced no adverse events. Overall, treatment has increased quality of life for him and his family.
Evinacumab shows great promise for patients with
HoFH, a difficult-to-treat and potentially life-threatening condition.