{"id":"67f367049d91","type":"article","url":"https://hartvaat.nl/2026/05/25/explorer-cn-week-78-langetermijneffect-en-veiligheid-van-mavacamten-bij-chinese-/","title":"EXPLORER-CN week 78: langetermijneffect en veiligheid van mavacamten bij Chinese patiënten met obstructieve HCM","title_en":"","category":"hartfalen","category_label":"Hartfalen","professions":["apotheker","cardioloog"],"tags":["hypertrofische-cardiomyopathie"],"journal":"Journal of the American Heart Association","doi":"10.1161/JAHA.125.046251","source_url":"https://doi.org/10.1161/JAHA.125.046251","authors":["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"],"significance":7,"published":"2026-06-03","source_date":"2026-05-25","image":"","kennis":["https://hartvaat.nl/kennis/hartfalen/hypertrofische-cardiomyopathie/","https://hartvaat.nl/kennis/hartfalen/hartfalen-stadiumindeling-nyha/"],"congress":"","summary_en":"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.","created":"2026-07-03T10:32:59Z","updated":"2026-07-03T13:31:54Z","licence":"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.","body_markdown":"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.","abstract_original":"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."}