# EXPLORER-CN week 78: langetermijneffect en veiligheid van mavacamten bij Chinese patiënten met obstructieve HCM

*geplaatst 2026-06-03 · Hartfalen · Journal of the American Heart Association · doi 10.1161/JAHA.125.046251 · https://hartvaat.nl/2026/05/25/explorer-cn-week-78-langetermijneffect-en-veiligheid-van-mavacamten-bij-chinese-/*

Open-label langetermijnextensie van EXPLORER-CN bij 79 Chinese patiënten met obstructieve hypertrofische cardiomyopathie die de 30-weekse placebo-gecontroleerde periode hadden afgerond. Patiënten die mavacamten kregen behielden hun dosering (n=54); voormalige placebo-patiënten startten met 2,5 mg/dag (n=25). Tot week 78 bleven de eerder geboekte dalingen van de Valsalva- en rust-LVOT-gradiënt behouden (gemiddelde verandering -73,0 mmHg en -56,3 mmHg). Ook NYHA-klasse, Kansas City Cardiomyopathy Questionnaire-score en biomarkers vertoonden numerieke verbeteringen. Mavacamten werd goed verdragen; LVEF <50% kwam zelden voor. De Chinese gegevens bevestigen de langetermijnduurzaamheid en het veiligheidsprofiel van mavacamten bij obstructieve HCM.

## English: 

Open-label long-term extension of EXPLORER-CN in 79 Chinese patients with obstructive hypertrophic cardiomyopathy who completed the 30-week placebo-controlled period. Patients on mavacamten continued their dose (n=54); former placebo patients started 2.5 mg daily (n=25). Through week 78, previously achieved reductions in Valsalva and resting LVOT gradients were maintained (mean change -73.0 mm Hg and -56.3 mm Hg). NYHA class, Kansas City Cardiomyopathy Questionnaire score and cardiac biomarkers all showed numerical improvements. Mavacamten was well tolerated; LVEF <50% was rare. The Chinese data confirm long-term durability and safety of mavacamten in obstructive HCM.

## Abstract (original, from the publication)

BACKGROUND: Long-term efficacy and safety of mavacamten in Chinese patients with obstructive hypertrophic cardiomyopathy are unknown. METHODS: Patients who completed the 30-week, double-blind, placebo-controlled treatment period in EXPLORER-CN (A Study to Evaluate the Efficacy and Safety of Mavacamten in Chinese Adults With Symptomatic Obstructive HCM), with no active safety concerns, were eligible to enter the long-term extension period to receive 48-week mavacamten treatment. Patients previously on mavacamten continued mavacamten (dose at week 30; mavacamten-mavacamten group); patients previously on placebo received mavacamten (starting dose, 2.5 mg once daily; placebo-mavacamten group). Key efficacy end points included change from baseline in echocardiographic measures, New York Heart Association functional class, 23-item Kansas City Cardiomyopathy Questionnaire Clinical Summary Score, and cardiac biomarkers through week 78. Analyses were descriptive; no between-group hypothesis testing was performed. RESULTS: Seventy-nine patients (mean age, 51.6 years; 27.8% women) entered the long-term extension period (mavacamten-mavacamten, n=54; placebo-mavacamten, n=25). In the mavacamten-mavacamten group, numerical improvements in Valsalva and resting left ventricular outflow tract peak gradients were maintained through week 78 (mean change from baseline, -73.0 mm Hg [95% CI, -86.4 to -59.5]; and -56.3 mm Hg [95% CI, -67.1 to -45.5], respectively). Numerical improvements were also observed for other echocardiographic parameters, New York Heart Association class, Kansas City Cardiomyopathy Questionnaire Clinical Summary Score, and cardiac biomarkers through week 78. In the placebo-mavacamten group, numerical improvements with mavacamten in these parameters were noted from week 30 to week 78. Long-term mavacamten treatment appeared well tolerated; left ventricular ejection fraction <50% was rare. CONCLUSIONS: In this exploratory long-term extension study, 78-week mavacamten treatment appeared well-tolerated and was associated with numerical improvements from baseline in echocardiographic parameters, New York Heart Association class, patient-reported health status, and cardiac biomarkers in Chinese patients with obstructive hypertrophic cardiomyopathy. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT05174416.

Auteurs: Zhuang Tian, Xiaoyan Li, Liwen Li, Qing Zhang, Jian'an Wang, Yunqi Shi, Daoquan Peng, Wei Ma, Ping Yang, Xiang Cheng, Wei Jin, Fang Wang, Yimeng Xie, Beth Pan, Victoria Florea, Shuyang Zhang

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Bron: Journal of the American Heart Association, https://doi.org/10.1161/JAHA.125.046251. Bijgewerkt 2026-07-03T13:31:54Z. Citeer vrij, met bronvermelding en een link naar hartvaat.nl (de url van het record). Samenvattingen zijn redactioneel werk van HartVaat; de oorspronkelijke publicaties blijven van hun uitgevers (doi). Geen medisch advies.