CYTOKINETICS INC Revenue Disclosure

Revenue Participation Right Purchase Agreements

We have entered into certain revenue participation right purchase agreements with RPI ICAV, pursuant to which such investors purchased rights to royalties from aficamten and omecamtiv mecarbil revenue streams in exchange for consideration. We account for such agreements as liabilities to be amortized under the effective interest rate method over the life of the related royalty stream, when we have continuing involvement with the underlying R&D. We are required to update our estimates, at each reporting period, related to the amount and timing of future royalty payments to be paid to the counterparties of the revenue participation right purchase agreements. We have adopted an accounting policy to not reduce the effective borrowing rate below 0%. The estimates of the future royalty payment determine the measurement of the non-cash interest expense and the carrying value of the liability.

Revenue participation right purchase agreements are measured using significant unobservable inputs. The estimates of future royalties requires the use of several assumptions such as: the probability of clinical success, the probability of regulatory approval, the estimated date of a product launch, estimates of eligible patient populations, estimates of prescribing behavior and patient compliance behavior, estimates of pricing, payor reimbursement and coverage, and sales ramp. In December 2025, the FDA approved MYQORZO, 5 mg, 10 mg, 15 mg, and 20 mg tablets for the treatment of adults with oHCM to improve functional capacity and symptoms. As MYQORZO sales have not commenced and products containing omecamtiv mecarbil and ulacamten have not yet been approved as of December 31, 2025, the estimates are highly subjective.