Cytokinetics stock surges 40.45% on promising Aficamten results

Cytokinetics (CYTK) stock surged 40.45% on Tuesday after the company presented promising results from its study of Aficamten, a drug candidate for treating obstructive hypertrophic cardiomyopathy. Aficamten helped patients exercise better than those who took Metoprolol, with a larger effect on symptoms, functional class, and LVOT gradients. The FDA is reviewing Aficamten and a decision is expected by December 26, 2025.

Cytokinetics, Incorporated (CYTK) stock experienced a significant surge of 40.45% on Tuesday following the company's presentation of promising results from its study of Aficamten, an investigational drug candidate for treating obstructive hypertrophic cardiomyopathy (oHCM). The study, presented at the European Society of Cardiology Congress 2025 in Madrid, Spain, demonstrated that Aficamten outperformed the standard-of-care drug, Metoprolol, in improving exercise capacity and reducing symptoms in patients with oHCM.

The study, titled "MAPLE-HCM," showed that Aficamten was superior to Metoprolol in enhancing measures of diastolic function and reducing the likelihood of mitral valve systolic anterior motion (SAM) and mitral valve leaflet-septal contact, the primary contributors to left ventricular outflow tract (LVOT) obstruction. Additionally, there was a significant decrease in maximal wall thickness in patients treated with Aficamten compared to those treated with Metoprolol, although the reduction in left ventricular mass index (LVMI) was not significantly different between the two treatments [1].

The study also found that long-term treatment with Aficamten did not appear to increase the risk of atrial fibrillation (AF) in patients with oHCM. Among 173 patients followed for at least 48 weeks, four (2.9%) developed new-onset AF during follow-up, with an incidence rate of 1.5% per year, consistent with expected rates from validated prediction models [2].

The FDA is currently reviewing Aficamten under a New Drug Application (NDA) with a Prescription Drug User Fee Act (PDUFA) target action date of December 26, 2025. Cytokinetics will host an investor webcast on September 2, 2025, at 8:30 AM Eastern Time to discuss the primary results from MAPLE-HCM and other data presented at the European Society of Cardiology Congress 2025 [3].

References:
[1] https://ir.cytokinetics.com/press-releases/press-release-details/2025/Cytokinetics-Presents-New-Data-Related-to-Aficamten-at-the-European-Society-of-Cardiology-Congress-2025/default.aspx
[2] https://ir.cytokinetics.com/press-releases/press-release-details/2025/Cytokinetics-Presents-New-Data-Related-to-Aficamten-at-the-European-Society-of-Cardiology-Congress-2025/default.aspx
[3] https://ir.cytokinetics.com/press-releases/press-release-details/2025/Cytokinetics-Presents-New-Data-Related-to-Aficamten-at-the-European-Society-of-Cardiology-Congress-2025/default.aspx