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Hypertrophic CardiomyopathySeptember 2025Summary reviewed June 2026

What the MAPLE-HCM Trial Found — Aficamten for Obstructive Heart Muscle Disease

Researchers compared aficamten, a newer heart medication, to metoprolol, a common beta-blocker, in 175 adults with obstructive hypertrophic cardiomyopathy. After 24 weeks, people taking aficamten improved their exercise capacity and symptoms more than those on metoprolol.

What the trial was testing

The MAPLE-HCM enrolled 175 patients with hypertrophic cardiomyopathy. The study was sponsored by Cytokinetics and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

Aficamten improved peak oxygen uptake by 2.3 ml/kg/min more than metoprolol.

The New England journal of medicine · 2025 · NCT05767346

These findings — that people on aficamten gained more exercise capacity than those on the standard treatment — were published in the The New England journal of medicine and represent the headline result of the study.

Researchers tracked outcomes across 175 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with hypertrophic cardiomyopathy, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

Aficamten is FDA-approved for obstructive hypertrophic cardiomyopathy. This trial showed it works better than metoprolol (a standard beta-blocker) at improving exercise capacity and quality of life. If you have this condition, ask your cardiologist whether aficamten might be right for you.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.

Open hypertrophic cardiomyopathy trials

RecruitingTesting effectiveness

A Trial to Evaluate the Efficacy and Safety of Ninerafaxstat in Patients With Symptomatic Non-obstructive Hypertrophic Cardiomyopathy

FORTITUDE-HCM is a global, multicenter, double-blind, parallel-group, placebo-controlled Phase 2b study that will assess the efficacy and safety of ninerafaxstat compared to placebo on top of Standard of Care in patients with symptomatic nHCM

La Jolla, California, United States +24 more
RecruitingObservational study

Multimodal and Multidisciplinary Approach to Optimize Diagnostic, Prognostic, and Therapeutic Management of Patients with Non-ischemic Cardiomyopathies and Arrhythmogenic-inflammatory Phenotypes: a Multicenter, Observational, Retrospective and Prospective Registry Study.

Non-ischemic cardiomyopathies (NICM) represent a heterogeneous group of pathologies characterized by absence of obstructive disease of the epicardial coronary vessels and distinct structural and functional changes of the myocardium. The main identified forms include dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), and arrhythmogenic cardiomyopathy proper (ACM). More recently, further forms of cardiomyopathy have been described, less common and not uniquely classifiable, including: uncompressed myocardium (LVNC), peripartum cardiomyopathy (PPCM), structural correlates of arrhythmogenic mitral valve prolapse (AMVP), Anderson-Fabry disease (AFD), NICM associated with multi- system neuromuscular or autoimmune diseases, lysosomal diseases, glycogenosis, mitochondrial cytopathies and canal diseases with structural substrates. Finally, there are "overlap" forms, characterized by the sharing in the same subject of characteristic aspects of two or more of the above- mentioned diseases; and of the "undefined" forms, which to date do not reach the diagnostic criteria for any of the above-mentioned diseases. To the best of current knowledge, there are two points discovered in scientific research, namely the description of the arrhythmogenic and "inflammatory" phenotypes in a broad sense, which are summarized here with the acronym AINICM. In detail: 1. Arrhythmic manifestations account for the arrhythmogenic component of AINICM, which is not limited to ACM proper. In fact, most of the above diseases have a non-arrhythmic clinical presentation and a prevailing tendency to evolve towards a picture of cardiovascular decompensation. Although sudden arrhythmic death has been described throughout the spectrum of AINICM, early arrhythmic manifestations of such diseases have an unknown prevalence, an uncertain association with different disease genotypes and phenotypes, and still uncertain predictivity of long-term arrhythmic risk. At the same time, optimal diagnostic and therapeutic pathways in arrhythmias associated with AINICM are still being studied. 2. Myocardial inflammation (M-Infl) accounts for the inflammatory component of AINICM, and has recently been described in association with many AINICM on a genetic basis, including undefined and arrhythmic forms. The data is of high interest not only in the diagnostic, but also in prognostic and therapeutic field. In fact, on the one hand the presence of M-Infl seems to have a physio- pathological role in AINICM; on the other, as already known in myocarditis, the optimal therapeutic paths of arrhythmias may differ in patients with and without M-Infl; in particular, also in the light of the preliminary data available in adult and paediatric AINICM, the inflammatory forms are expected to respond better to immunosuppressive therapy, the arrhythmogenic ones to an ablative therapy with frequent need of implantation of cardiac devices. Based on the clinical presentation, NICM patients will be divided into arrhythmic (AINICM) and non-arrhythmic patients as study and control groups , respectively. The AINICM group will include presentation with ventricular fibrillation (VF), either sustained or non-sustained ventricular tachycardia (VT; NSVT), frequent premature ventricular complexes (PVC), supraventricular arrhythmias (SVA) and bradyarrhythmias (BA). Clinical presentations other than arrhythmic, including chest pain and heart failure, will define the control group. In parallel, as shown in Figure 1, patients with any evidence of M-Infl will be compared with those showing no signs of M-Infl.

Milan, Milano, Italy