Cytokinetics Announces Start of MAPLE-HCM, a Phase 3 Clinical Trial of Aficamten Compared to Metoprolol in Patients With Symptomatic Obstructive Hypertrophic Cardiomyopathy

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Cytokinetics, Incorporated
Cytokinetics, Incorporated

First Phase 3 Trial Evaluating Monotherapy with a Cardiac Myosin Inhibitor Compared to Monotherapy with a Beta Blocker in Adults with Symptomatic Obstructive Hypertrophic Cardiomyopathy

SOUTH SAN FRANCISCO, Calif., June 20, 2023 (GLOBE NEWSWIRE) -- Cytokinetics, Incorporated (Nasdaq: CYTK) today announced that MAPLE-HCM (Metoprolol vs Aficamten in Patients with LVOT Obstruction on Exercise Capacity in HCM), a Phase 3 clinical trial comparing aficamten as monotherapy to metoprolol as monotherapy in patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM), is open to enrollment. Aficamten is a next-in-class cardiac myosin inhibitor in development for the potential treatment of HCM.

“We are pleased to further expand the development program for aficamten with the start of MAPLE-HCM, a Phase 3 trial assessing for the potential superiority of aficamten compared to a commonly prescribed beta blocker, metoprolol,” said Fady I. Malik, M.D., Ph.D., Cytokinetics’ Executive Vice President of Research & Development. “MAPLE-HCM is, to date, the first and only clinical trial directly comparing a cardiac myosin inhibitor to what is considered the standard of care therapy in patients with HCM. While beta-blockers like metoprolol can reduce the left ventricular outflow tract gradient (LVOT-G) and improve patient symptoms, they are often associated with undesirable side effects and have not been shown to improve exercise capacity, a desired treatment outcome for patients suffering from HCM. We hope that MAPLE-HCM will generate evidence showing treatment with aficamten as first-line monotherapy is superior to monotherapy with metoprolol, which may help offer a simplified treatment approach in HCM.”

MAPLE-HCM: Clinical Trial Design

MAPLE-HCM is a Phase 3, multi-center, randomized, double-blind active-comparator clinical trial of aficamten compared to metoprolol in patients with symptomatic obstructive HCM. The primary endpoint is the change in peak oxygen uptake (pVO2) from baseline to Week 24 measured by cardiopulmonary exercise testing (CPET). Secondary endpoints include the change from baseline to Week 24 in Kansas City Cardiomyopathy Questionnaire (KCCQ) score, the proportion of patients with ≥1 class improvement in New York Heart Association (NYHA) functional class, and changes in left ventricular mass index (LVMI), left atrial volume index (LAVI), post-Valsalva left ventricular outflow tract gradient (LVOT-G) and NT-proBNP.

MAPLE-HCM is expected to enroll 170 patients, randomized on a 1:1 basis to receive aficamten or metoprolol. Randomization will be stratified by CPET exercise modality (treadmill or bicycle) and recently diagnosed versus chronic obstructive HCM. At screening, patients enrolled in MAPLE-HCM must have a resting LVOT-G ≥30 mmHg and/or post-Valsalva LVOT-G ≥50 mmHg in addition to left ventricular ejection fraction (LVEF) ≥ 60%, respiratory exchange ratio (RER) ≥ 1.05 and pVO2 <100% predicted, NYHA functional class II or III and a KCCQ Clinical Summary Score (KCCQ-CSS) score ≥ 35 and ≤ 90. Following the initial screening visit, all participants on standard of care (SOC) therapy will undergo a washout period of up to 14 days of weaning from SOC therapy, followed by an additional 7 days with no SOC therapy prior to the second screening visit. Each patient will receive up to four escalating doses of aficamten or metoprolol based on echocardiographic guidance. Patients receiving aficamten will begin with 5 mg dosed once daily. At weeks 2, 4 and 6 patients will receive an echocardiogram to determine if they will be up-titrated to escalating doses of 10, 15 or 20 mg. Patients receiving metoprolol will begin with 50 mg dosed once daily. At weeks 2, 4 and 6 patients will receive an echocardiogram to determine if they will be up-titrated to escalating doses of 100, 150 or 200 mg. Patients who complete MAPLE-HCM will be eligible to participate in the open-label extension clinical study, FOREST-HCM (Follow-Up, Open-Label, Research Evaluation of Sustained Treatment with Aficamten in HCM). Additional information can be found on www.clinicaltrials.gov.