The Phase 3 trial could open new treatment doors for patients with a rare heart condition
Cytokinetics had a strong Tuesday on Wall Street. Shares of the biopharmaceutical company surged 28% after the firm announced that its drug aficamten had cleared critical targets in a major Phase 3 clinical trial, delivering a piece of welcome news for patients living with a heart condition that currently has no approved treatments specifically designed to address its root cause.
The results came from ACACIA-HCM, a pivotal Phase 3 study examining the effects of aficamten in patients with symptomatic non-obstructive hypertrophic cardiomyopathy, or nHCM, a chronic condition in which the heart muscle becomes abnormally thick, making it harder for the heart to pump blood effectively. Unlike the obstructive form of the disease, which already has approved therapies, the non-obstructive form has left patients with limited options beyond symptom management.
What the trial found
The ACACIA-HCM trial enrolled 516 participants, who were randomly assigned in equal numbers to receive either aficamten or a placebo. By Week 36, aficamten had met both of the trial’s dual primary endpoints, producing statistically significant improvements across two key measures.
The first tracked quality of life using the Kansas City Cardiomyopathy Questionnaire Clinical Summary Score, a patient-reported tool widely used to gauge the daily burden of heart disease. Participants on aficamten showed a 3.0-point improvement over those on placebo, reaching statistical significance with a p-value of 0.021. The second measured exercise capacity through peak oxygen uptake, a direct indicator of how efficiently the heart and lungs work during physical activity. Aficamten outperformed placebo by 0.67 mL/kg/min, with a p-value of 0.003.
Beyond those primary results, the drug also showed statistically significant gains across several secondary endpoints, including a meaningful increase in the proportion of participants who moved up at least one functional class on the New York Heart Association scale, a standard clinical tool for measuring heart failure severity.
Why this matters for patients
For the millions of people living with non-obstructive HCM, Tuesday’s announcement carried real weight. The condition causes the heart muscle to contract with excessive force, a state known as hypercontractility, which leads to reduced exercise tolerance, shortness of breath, and a diminished quality of life. No therapies have been approved specifically to target the underlying mechanism of the disease in this group. Aficamten works by acting on cardiac myosin, the molecular motor responsible for driving heart muscle contraction, with the aim of reducing that excessive force in a targeted way.
The safety data added to the encouraging picture. No new safety signals emerged during the trial, and completion rates were nearly identical between the two groups, with 88.4% of those on aficamten and 90.3% on placebo finishing the full 36-week study period, suggesting the drug was well tolerated throughout.
What comes next
Aficamten is already available in the U.S., China, and the European Union under the brand name MYQORZO, where it is approved to treat the obstructive form of hypertrophic cardiomyopathy. The ACACIA-HCM results now lay the groundwork for a potential label expansion to include the non-obstructive form, which would significantly broaden the number of patients who could benefit.
Cytokinetics said it plans to present the full trial data at an upcoming medical meeting and will bring the findings to the FDA and other regulatory authorities as it maps the path toward a potential new approval. For investors, the 28% single-day rally reflected how much may be at stake commercially if that expansion moves forward.
Source: Investing.com