TUESDAY, Aug. 29, 2023 (HealthDay News) — In patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM), mavacamten reduces the need for septal reduction therapy (SRT) at week 56, according to a study published online Aug. 28 in JAMA Cardiology to coincide with the European Society of Cardiology Congress 2023, held from Aug. 25 to 28 in Amsterdam.
Milind Y. Desai, M.D., from the Cleveland Clinic, and colleagues examined the cumulative longer-term effect of mavacamten on the need for SRT through week 56 in a double-blind, placebo-controlled, randomized clinical trial. The analysis included 112 patients with symptomatic HCM who were either randomly assigned to mavacamten at baseline for 56 weeks or assigned to placebo with crossover to mavacamten from week 16 to week 56 (40-week exposure).
The researchers found that at week 56, five of 56 patients in the original mavacamten group and 10 of 52 patients in the placebo crossover group met composite SRT criteria, and 96 of 108 patients continued taking mavacamten long term. After 56 weeks, there was a sustained reduction in resting (mean difference, −34.0 mmHg and −33.2 mmHg in mavacamten and placebo-to-mavacamten groups, respectively) and Valsalva (mean difference, −45.6 mmHg and −54.6 mmHg) left ventricular outflow tract gradients. There was also an improvement in New York Heart Association class 1 or higher in 51 of 55 patients in the original mavacamten group and in 37 of 51 patients in the crossover group. A left ventricular ejection fraction <50 percent was seen in 11.1 percent of patients overall, representing 12.5 percent in the original mavacamten group and 9.6 percent in the placebo crossover group.
“Although this represents a useful therapeutic option, given the potential risk of LV systolic dysfunction, there is a continued need for close monitoring,” the authors write.
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