Evinacumab, the first agent from a new class of lipid-lowering drugs, showed a “remarkable” and unprecedented level of LDL-cholesterol lowering in a pivotal trial with 65 patients with homozygous familial hypercholesterolemia.
Dr. Frederick Raal
Monthly intravenous infusions of evinacumab cut LDL cholesterol levels by an average of 135 mg/dL from baseline, a 47% mean reduction, after 24 weeks of treatment in 43 homozygous familial hypercholesterolemia (HoFH) patients, Frederick Raal, MBChB, said on March 30 in a video presentation of his research at the joint scientific sessions of the American College of Cardiology and the World Heart Federation, which was presented online this year. ACC organizers chose to present parts of the meeting virtually after COVID-19 concerns caused them to cancel the meeting.
Evinacumab is a human monoclonal antibody inhibitor of angiopoietin-like 3, a liver protein that boosts levels of LDL cholesterol and triglycerides (TG).
Another notable effect of the novel agent was that it was equally effective in the roughly one-third of patients with a minimal residual level of LDL receptor activity, patients know as having “null/null” mutations. “For the first time, we see HoFH patients getting to [lipid] targets that we never thought would be possible,” said Dr. Raal, professor and head of endocrinology and metabolism at the University of Witwatersrand in Johannesburg, South Africa. “This works in patients without residual LDL receptor function.” The drug was also generally very well tolerated, he said, causing no treatment-related serious adverse events during the brief treatment period of 24 weeks.
“One of the major, remarkable findings in this study was the effect on null/null patients,” which contrasts with the effects of other, more established drugs for treating dyslipidemia like statins and PCSK9 inhibitors, which work by increasing the number of LDL receptors on cells. The demonstrated efficacy and safety of evinacumab in null/null patients “is a definite advance,” commented Anne C. Goldberg, MD, a lipidologist and professor of medicine at Washington University in St. Louis.
The placebo-controlled trial randomized patients at 30 sites in 11 countries who were at least 12 years old and had documented mutations in both of their LDL receptor genes and a serum level of LDL cholesterol that was at least 500 mg/dL on no treatment. Patients averaged about 40 years of age; about 30% had null/null mutations, more than 90% were on statin treatment, and about three-quarters were receiving regular treatment with a PCSK9 inhibitor. At baseline, LDL cholesterol levels averaged about 250 mg/dL.
The study’s primary endpoint was the between-group percentage change in LDL cholesterol level after 24 weeks, which fell by 47% from baseline with evinacumab treatment and increased by an average of 2% among 22 patients who received placebo injections; so evinacumab cut this measure by 49%, compared with placebo after 24 weeks, a statistically significant difference. A cut of baseline LDL cholesterol by at least 50% occurred in 56% of the evinacumab-treated patients and in 5% of controls.
In addition to its LDL reduction, another notable effect of evinacumab was that it trimmed baseline triglyceride levels by half, consistent with prior reports of the drug’s effect on this measure, although average triglyceride levels in the enrolled patients fell within the normal range prior to treatment.
Evinacumab “will probably be very effective in treating patients with hypertriglyceridemia; those studies are ongoing,” noted Dr. Raal. But, he added, “this drug will probably be reserved for severe” dyslipidemia cases, not for “the garden variety of moderate hypertriglyceridemia or hypercholesterolemia.”
Dr. Dirk Blom
Evinacumab “may be a fairly broad-spectrum lipid-lowering drug, but it should be reserved for severe cases,” agreed Dirk Blom, MBChB, head of lipidology at the University of Capetown, South Africa. “This will likely remain a fairly expensive drug, and we wouldn’t want to use it across the board, but for difficult to treat patients with either severe hypercholesterolemia or hypertriglyceridemia, I think this will have very significant advantages,” he commented.
“Drugs that reduce triglycerides by large amounts may prove to have cardiovascular disease benefits, but that remains to be proven in large, long-term outcome trials,” commented Deepak Bhatt, MD, professor of medicine at Harvard Medical School and executive director of interventional cardiology programs at Brigham and Women’s Hospital, both in Boston. “But for right now, for most patients with more common forms of elevated LDL cholesterol, the treatment options include statins, ezetimibe [Zetia], and PCSK9 inhibitors, and for more common levels of elevated triglycerides, it’s icosapent ethyl [Vascepa],” Dr. Bhatt said.
Dr. Deepak L. Bhatt
The study was sponsored by Regeneron, the company developing evinacumab and which is partially owned by Sanofi. Dr. Raal has received personal fees and/or research funding from Regeneron, Sanofi Aventis, Amgen, and The Medicines Company. Dr. Goldberg has received research funding and/or consulting fees from Regeneron and Sanofi, Akcea, Amarin, Amgen, Esperion, Ionis, Merck, Novartis, and Pfizer. Dr. Blom has been a consultant to and/or received research funding from Regeneron, Sanofi, Aegerium, Akcea, Amgen, Amryt, AstraZeneca, Eli Lilly, Esperion, Gemphire, MSD, and Novo Nordisk. Dr. Bhatt has received research funding from many companies including Regeneron and Sanofi.
SOURCE: Raal F. ACC 20. Abstract 411-12.