Form 4 Filing for WIERENGA WENDELL

On December 22, 2025, WIERENGA WENDELL, a director at CYTOKINETICS INC, executed a Form 4 filing. The transactions included the acquisition of 20,000 shares of Common Stock at a price of $7.61 per share, and the disposal of 20,000 shares of Common Stock at $66.14 per share. Additionally, WENDELL exercised a non-qualified stock option to buy 20,000 shares of Common Stock, with an exercise price of $7.61 per share. Following these transactions, the post-transaction shares owned are reported as 52,444 and 32,444 for the non-derivative holdings, and 0 for the derivative holdings. The filing was signed by John O. Faurescu, attorney-in-fact for Dr. Wierenga, on December 23, 2025.