Cytokinetics seeks broader use of heart drug after strong late-stage data

• 53% of patients on aficamten showed meaningful improvements in at least three of five key disease areas compared to just 13% on placebo in the 517-patient study
• Safety concerns emerged as 10% of patients experienced dangerous drops in heart pumping capacity and 12 heart failure events occurred during the study, attributed to rigid trial dosing protocols
• Cytokinetics is expected to hold the nHCM market alone for multiple years before Bristol Myers begins late-stage trials of rival drug Camzyos later this year

Cytokinetics Seeks Broader Approval for Heart Drug After Positive Late-Stage Results

Key Development: Cytokinetics announced detailed late-stage trial results for aficamten (brand name Myqorzo) showing significant improvements in patients with non-obstructive hypertrophic cardiomyopathy (nHCM), a genetic heart condition with no currently approved treatments. The company plans to file a supplemental U.S. marketing application in Q4 2026.

Trial Results: In the 517-patient study, 53% of patients taking aficamten showed meaningful improvements across at least three of five key disease areas—including stamina, symptom relief, and heart strain—compared to only 13% on placebo. The drug is already approved for the obstructive form of the condition (oHCM).

Market Implications: Barclays analysts forecast peak sales exceeding $5 billion for Myqorzo, projecting Cytokinetics will dominate the nHCM market for multiple years. This exclusivity is expected to create a "halo effect" boosting existing oHCM sales. The drug also serves as a crucial validation bridge for Cytokinetics' next-generation candidate, ulacamten, targeting the larger multi-billion dollar heart failure with preserved ejection fraction (HFpEF) market.

Safety Concerns: The trial revealed safety issues, with 10% of patients experiencing dangerous drops in heart pumping capacity and 12 heart failure events occurring during the study. Chief Medical Officer Steve Heitner attributed early events to rigid trial dosing protocols, stating real-world physician monitoring will mitigate risks.

Competition: Bristol Myers plans to initiate late-stage trials for rival drug Camzyos in nHCM patients later this year, setting up direct competition in both the nHCM and HFpEF markets.

Notable Limitation: The drug did not significantly improve heart structure or delay cardiovascular events.