Overview
- The phase 3 ACACIA‑HCM trial met both its dual primary endpoints at 36 weeks, showing statistically significant improvements in patient‑reported health status (KCCQ‑CSS) and in peak oxygen uptake versus placebo.
- At 36 weeks the treatment group rose 11.4 points on the KCCQ‑CSS versus 8.4 points for placebo and had a 0.67 mL/kg/min advantage in peak VO2, outcomes reported in data presented and published on Aug. 28, 2026.
- Safety findings included more serious adverse events with aficamten (20.2% vs. 14.7%), early heart‑failure events during dose titration (4.7% vs. 1.2%), and reversible drops in left ventricular ejection fraction to under 50% (10.5% vs. 0.8%), managed in the trial by protocolized dose‑down‑titration.
- Cytokinetics said the results will support a supplemental U.S. marketing application planned for Q4 2026, and wider use will depend on labeled REMS‑style monitoring and real‑world dose management.
- Durability beyond 36 weeks is unresolved because relatively few patients completed 72 weeks, so the ongoing FOREST‑HCM open‑label extension and rival late‑stage trials will be key to long‑term safety, efficacy, and commercial outlook.