Dec. 19, 2025 was the day Cytokinetics stopped being a clinical-stage company. The FDA’s clearance of aficamten that afternoon ended a 27-year run during which the Brisbane, California biotech had watched an ALS program fail, seen its heart failure drug rejected in 2023, and built a scientific reputation in cardiac muscle biology without ever having a product on the market. MYQORZO, the brand name for aficamten, became available by prescription in the United States on Jan. 27, 2026. Armistice Capital holds a position in Cytokinetics alongside BlackRock, Fidelity, Vanguard, T. Rowe Price, Deep Track Capital, and roughly 449 reported institutional holders in total.
What the Drug Treats
MYQORZO is approved for adults with symptomatic obstructive hypertrophic cardiomyopathy, a condition in which an abnormally thickened cardiac muscle obstructs blood flow out of the heart. The obstruction limits exercise capacity, produces breathlessness and chest pain, and in severe cases raises the risk of sudden cardiac death. Cytokinetics estimates at least 100,000 patients in the United States are eligible for treatment.
Aficamten works as an allosteric, reversible inhibitor of cardiac myosin motor activity, reducing the force of ventricular contraction and lowering the left ventricular outflow tract gradient that defines the obstructive form of the disease. The FDA approval rested on data from the SEQUOIA-HCM Phase 3 trial, in which patients on aficamten improved peak oxygen uptake by 1.8 milliliters per kilogram on average, compared to no detectable improvement in the placebo group, the primary exercise capacity measure used to assess functional severity in this patient population.
MYQORZO carries a Risk Evaluation and Mitigation Strategy. Prescribers must obtain echocardiographic assessments of left ventricular ejection fraction before initiating treatment and at defined intervals during dose titration. Aficamten reduces LVEF and carries a boxed warning for heart failure risk; initiation is not recommended for patients with LVEF below 55%. Within weeks of the January launch, more than 700 cardiologists had completed REMS registration and training.
One Drug, Two REMS Protocols
MYQORZO enters a market Bristol Myers Squibb’s Camzyos has occupied since 2022. The BMS cardiac myosin inhibitor generated more than $1 billion in combined U.S. and European sales in 2025. Both drugs act on the same molecular mechanism. The competitive distinction that has drawn the most attention from prescribers and investors lies in how differently the two REMS protocols operate.
Camzyos requires regular echocardiograms, mandatory drug-drug interaction screening, and dose interruption requirements that impose a real administrative burden on prescribers, patients, and dispensing pharmacies. MYQORZO’s label includes more flexible echocardiography timing during up-titration, no required drug-interaction monitoring, and dose adjustment rather than full interruption in most scenarios. RBC Capital Markets analyst Leonid Timashev wrote following the FDA decision that those distinctions should “materially lower barriers to prescribing” for MYQORZO relative to Camzyos.
Cytokinetics has set a commercial target of more than 50% new-to-brand prescription share among patients entering the cardiac myosin inhibitor class in 2026. More than 80% of the eligible obstructive HCM population remains untreated with either drug. Both companies are only beginning to reach that population.
Building the Prescriber Base
Cytokinetics deployed more than 125 U.S. field sales colleagues at launch, concentrating early resources on approximately 750 high-volume prescribers who account for roughly 80% of current cardiac myosin inhibitor prescriptions. Broader outreach extends to approximately 11,000 cardiologists across the country, most of whom have not yet written a prescription in the category.
At the 25th Annual Needham Virtual Healthcare Conference in April 2026, Cytokinetics management described early prescribing activity among REMS-enrolled physicians as encouraging, with positive reimbursement outcomes for commercially insured patients. A bridge program supplies up to 12 months of free drug for commercially insured patients without active payer coverage, and up to two months for Medicare patients awaiting formulary decisions. Commercial insurance access comparable to Camzyos is projected by the fourth quarter of 2026. The company entered 2026 with approximately $1.2 billion in cash, enough to fund operations through that access-building period.
Europe and the ACACIA-HCM Readout
Cytokinetics is targeting Germany for a MYQORZO launch in the second quarter of 2026 under the AMNOG pricing framework, with additional Western European markets expected later in the year. The European Commission issued its marketing authorization in early 2026 following a positive recommendation from the EMA’s Committee for Medicinal Products for Human Use.
Running concurrently is ACACIA-HCM, a registrational Phase 3 trial testing aficamten in patients with symptomatic non-obstructive HCM. Non-obstructive disease accounts for roughly half the total diagnosed and symptomatic HCM population in the United States and has no approved treatment. Bristol Myers Squibb’s attempt to expand Camzyos into that setting failed in Phase 3. A positive ACACIA-HCM readout, expected in the second quarter of 2026, would position Cytokinetics as the only company with an approved therapy across both forms of the disease, a materially different commercial and competitive situation than the one it manages today.
