SOUTH SAN FRANCISCO, Calif. — May 5, 2026 — Leads & Copy — Cytokinetics, Incorporated (Nasdaq: CYTK) announced positive topline results from the ACACIA-HCM Phase 3 clinical trial of aficamten in patients with symptomatic non-obstructive hypertrophic cardiomyopathy (HCM).
ACACIA-HCM met both dual primary endpoints, demonstrating statistically significant improvements from baseline to Week 36 compared to placebo in both Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS) and maximal exercise performance (pVO2).
The improvement in KCCQ was consistent throughout the treatment period in participants on aficamten. Following washout, KCCQ decreased for participants on aficamten to match the placebo group. At Week 36, pVO2 increased for participants on aficamten, while it remained unchanged for participants on placebo, consistent with prior trials of aficamten in obstructive HCM (oHCM).
Statistically significant (p<0.001) improvements compared to placebo were observed in key secondary endpoints including the proportion of participants with improvements in New York Heart Association (NYHA) Functional Class, the composite z-score of ventilatory efficiency and pVO2, and NT-proBNP.
There were no new safety signals identified. The percentage of participants completing planned dosing was similar in those receiving aficamten or placebo (88.4% vs. 90.3%, respectively). Left ventricular ejection fraction (LVEF) <50% occurred in 27 (10%) participants taking aficamten and in two (1%) participants taking placebo. Two participants on aficamten experienced a serious adverse event of heart failure associated with LVEF <50%. Treatment interruptions due to LVEF <40% occurred in 3% of participants taking aficamten.
“Patients with non-obstructive HCM have no therapies approved to treat the underlying hypercontractility associated with the disease. We hope that will change with ACACIA-HCM which is the first clinical trial to demonstrate statistically significant improvements in exercise capacity and symptom burden in patients with non-obstructive HCM,” said Fady I. Malik, M.D., Ph.D., Cytokinetics’ Executive Vice President of Research & Development. “We believe that the totality and consistency of evidence favoring aficamten across multiple patient-reported and physician-assessed endpoints of symptom improvement and physical function are clinically meaningful for patients with non-obstructive HCM.”
Cytokinetics will host an investor conference call on May 5, 2026, at 8:00 AM Eastern Time to discuss the topline results from ACACIA-HCM. Interested parties can register online at ACACIA-HCM Topline Results. The live webcast will be available on the Investors & Media section of the Cytokinetics website. A replay of the webcast will be archived on the Cytokinetics website for six months.
ACACIA-HCM was a Phase 3, multi-center, randomized, double-blind, placebo-controlled clinical trial designed to evaluate the effect of aficamten compared to placebo in patients with symptomatic non-obstructive hypertrophic cardiomyopathy (nHCM). The dual primary endpoint was the change in Kansas City Cardiomyopathy Questionnaire (KCCQ) Clinical Summary Score and change in maximal exercise performance (pVO2) from baseline to Week 36.
Secondary endpoints included the proportion of participants with ≥1 class improvement in New York Heart Association (NYHA) functional class, and changes in the composite z-score of two cardiopulmonary exercise testing (CPET) parameters of sub-maximal exercise performance (VE/VCO2 and pVO2), NT-proBNP, and left atrial volume index (LAVI) from baseline to Week 36. After 36 weeks of treatment, participants continued treatment with aficamten or placebo for up to 72 weeks to evaluate additional secondary and exploratory analyses including the time to first cardiovascular event. The trial (outside Japan) concluded when at least 200 participants completed 52 weeks of treatment.
ACACIA-HCM randomized and treated 516 participants (outside Japan) on a 1:1 basis with aficamten or placebo. At screening, participants enrolled in ACACIA-HCM were required to have resting left ventricular outflow tract gradient (LVOT-G) <30 mmHg and post-Valsalva LVOT-G <50 mmHg in addition to left ventricular ejection fraction (LVEF) ≥60%, respiratory exchange ratio (RER) ≥1.00 and peak VO2 ≤90% predicted, NT-proBNP ≥300 pg/mL or ≥900 pg/mL if atrial fibrillation or atrial flutter were present at screening, NYHA functional class II or III and KCCQ Clinical Summary Score ≤85.
Each patient received up to four escalating doses of aficamten or placebo based on echocardiographic guidance. Participants who received aficamten began with 5 mg dosed once daily. At weeks 2, 4 and 6 participants received an echocardiogram to determine if they would be up-titrated to escalating doses of 10, 15 or 20 mg. Dose escalation occurred only if a participant had an LVEF ≥60%. Participants who did not meet escalation criteria continued the same dose or were down-titrated if their LVEF was <50%.
MYQORZO® (aficamten) is a cardiac myosin inhibitor approved in the U.S., China and European Union for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (oHCM). In patients with oHCM, myosin inhibition with MYQORZO reduces cardiac contractility and consequently, left ventricular outflow tract (LVOT) obstruction. Aficamten is also under clinical investigation in CEDAR-HCM, in a pediatric population with oHCM. Aficamten has not been deemed safe or effective for use in this patient population. In addition, aficamten is being studied in FOREST-HCM, an open-label extension clinical study.
Cytokinetics is a specialty cardiovascular biopharmaceutical company, building on its over 25 years of pioneering scientific innovations in muscle biology, and advancing a pipeline of potential new medicines for patients suffering from diseases of cardiac muscle dysfunction. Cytokinetics’ MYQORZO® (aficamten) is a cardiac myosin inhibitor approved in the U.S., European Union and China for the treatment of adults with symptomatic obstructive hypertrophic cardiomyopathy (oHCM). Cytokinetics is also developing omecamtiv mecarbil, an investigational cardiac myosin activator for the potential treatment of patients with heart failure with severely reduced ejection fraction and ulacamten, an investigational cardiac myosin inhibitor for the potential treatment of heart failure with preserved ejection fraction, while continuing pre-clinical research and development in muscle biology.
Source: Cytokinetics
