Cytokinetics Gains on Positive Late-Stage Cardiomyopathy Study Results

Cytokinetics, Incorporated's (CYTK) shares surged 40.4% on Sept. 2, driven by positive results from a phase III study on cardiovascular candidate aficamten.

On Aug. 30, Cytokinetics presented primary results from the late-stage MAPLE-HCM study in a Hot Line Session at the European Society of Cardiology Congress 2025 in Madrid, Spain. The results were simultaneously published in The New England Journal of Medicine.

Results demonstrated the superiority of aficamten to the standard-of-care beta-blocker metoprolol.

Cytokinetics’ shares have gained 5.4% year to date compared with the industry’s 5.1% gain.

More on CYTK’s MAPLE-HCM Study

MAPLE-HCM is a phase III randomized, double-blind, active-comparator clinical study of aficamten compared to metoprolol in patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM).

Aficamten is an investigational selective, small molecule cardiac myosin inhibitor, while metoprolol is a beta-blocker.

The study enrolled 175 patients who were randomized equally to receive either aficamten or metoprolol as monotherapy. This study was designed to include patients with less severe oHCM, enrolling patients without obstruction at rest and with higher predicted peak oxygen uptake (pVO2) as compared to the other study, SEQUOIA-HCM.

Results showed that aficamten is superior to metoprolol on all clinically relevant efficacy endpoints. The primary endpoint in MAPLE-HCM was the mean change from baseline in pVO2 for aficamten compared to metoprolol after 24 weeks of treatment. The mean change in pVO2 from baseline to week 24 was +1.1 mL/kg/min for aficamten and -1.2 mL/kg/min for metoprolol.

The primary endpoint was statistically significant with a least-squares mean (LSM) difference between groups of 2.3 mL/kg/min. The effect of aficamten on pVO2 was consistent across all prespecified subgroups, including patients who were newly diagnosed or treatment naïve.

Aficamten also showed superiority to metoprolol in five of six secondary endpoints. It had a larger effect on measures of symptoms, functional class, and left ventricular outflow tract (LVOT) gradients as compared to first-line standard-of-care metoprolol. Aficamten substantially improved functional class and reduced patient symptom burden.

51% of patients receiving aficamten showed an improvement of one or more functional class in New York Heart Association (“NYHA”) Functional Class compared to 26% receiving metoprolol. Aficamten significantly improved resting LVOT gradient and Valsalva LVOT-G with a modest reduction in left ventricular ejection fraction (LVEF) and only one patient experiencedLVEF <50% per core laboratory.

Cytokinetics noted that these effects were achieved in a broader patient population with oHCM than previously studied in SEQUOIA-HCM.

On Aug. 31, Cytokinetics presented additional data on aficamten. The additional data from MAPLE-HCM showed that aficamten improved cardiac structure and function compared to metoprolol. New analysis showed the annual incidence rate of atrial fibrillation with aficamten is 1.5%. Cytokinetics also presented longer-term data, which were consistent with the previously reported safety profile of aficamten.

CYTK Eyes a Potential Approval of Aficamten

Aficamten is under regulatory review in the United States. The FDA has set a target action date of Dec. 26, 2025.

The FDA had earlier set a target action date of Sept. 26, 2025. However, the regulatory body extended the target action date for the new drug application (NDA) to Dec. 26, 2025. Cytokinetics submitted the NDA for aficamten in obstructive HCM without an accompanying REMS, and the FDA accepted the same following pre-NDA discussions (wherein safety and risk mitigation were discussed).

During the NDA review, the FDA requested that Cytokinetics submit a REMS consistent with the inherent characteristics of aficamten, which the company provided. The submission of a REMS has now been determined by the FDA to be a major amendment to the NDA, resulting in a standard three-month extension to the original target action date. Nonetheless, no additional clinical data or studies have been requested by the FDA.

Upon approval, aficamten will face competition from Camzyos (mavacamten), a first-in-class cardiac myosin inhibitor marketed by Bristol Myers Squibb (BMY).

BMY obtained FDA approval of the drug in 2022 for the treatment of adults with symptomatic New York Heart Association class II-III obstructive HCM to improve functional capacity and symptoms.

Camzyos has put up a stellar performance. BMY also has a promising candidate, milvexian, in its cardiovascular pipeline.

CYTK’s Zacks Rank & Key Picks

Cytokinetics currently carries a Zacks Rank #3 (Hold). Some better-ranked stocks in the biotech sector are CorMedix (CRMD) and Kiniksa Pharmaceuticals (KNSA), both sporting a Zacks Rank #1 (Strong Buy) at present. You can see the complete list of today’s Zacks #1 Rank stocks here.

In the past 60 days, estimates for CorMedix’s earnings per share have increased from $1.10 to $1.49 for 2025. During the same time, earnings per share estimates for 2026 have increased from $1.46 to $2.16. Year to date, shares of CRMD have surged 80.7%.

In the past 60 days, estimates for Kiniksa Pharmaceuticals’ 2025 earnings per share have increased from 74 cents to $1.03. Earnings per share estimates for 2026 have increased from $1.19 to $1.60 during the same period. KNSA stock has surged 73.3% year to date.

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