Material Event (Form 8-K)

Item 8.01 Other Events.

Regulatory Updates

On September 15, 2025, Cytokinetics, Incorporated (the "Company") participated in a Late Cycle Meeting with the United States Food and Drug Administration ("FDA") in connection with the Company's New Drug Application ("NDA") foraficamtenin obstructive hypertrophic cardiomyopathy ("oHCM"). In that meeting, the Company discussed its proposed REMS program, including Elements to Assure Safe Use ("ETASU") and anticipated post-marketing requirements with respect to aficamten. Prior to the Late Cycle Meeting, the Company received FDA's response to the Company's proposed REMS and label for aficamten. Based on the Company's discussions and communications with FDA to date, the Company continues to expect a differentiated label and risk mitigation profile foraficamten, if approved by the FDA. As previously announced, the Company completed all Good Clinical Practice ("GCP") inspections for aficamtenand received communications from FDA that no observations were noted. There have been no Good Manufacturing Practice ("GMP") inspections for aficamtenscheduled. The Prescription Drug User Fee Act ("PDUFA") target action date for the NDA foraficamtenremains December 26, 2025. In addition, the Company recently submitted responses to Day 120 List of Questions from the Committee for Medicinal Products for Human Use ("CHMP") from European Medicines Agency ("EMA") with respect to the potential approval ofaficamtenin the European Union.

Royalty Pharma Development Funding Loan Agreement

As previously disclosed, the Company is entitled to draw up to $100.0 million of Tranche 5 term loans at any time prior to November 25, 2025 under the Development Funding Loan Agreement (the "Loan Agreement") with Royalty Pharma Development Funding, LLC and the other parties thereto. The Company intends to draw the full $100.0 million of the Tranche 5 term loans on or about October 1, 2025.