Cytokinetics rockets on positive heart drug trial

Shares in US biotech Cytokinetics have popped after a report that its aficamten drug improved symptoms in people with a rare and progressive form of heart disease.

Treatment with the cardiac myosin inhibitor significantly improved exercise capacity in patients with obstructive hypertrophic cardiomyopathy (HCM), an inherited disorder in which the heart muscle becomes thickened and can obstruct blood flow. It is one of the most common reasons for sudden cardiac death in people who are younger than 35.

The results of the 300-patient SEQUOIA-HCM study suggest Cytokinetics is on track to bring aficamten to market as a rival to Bristol-Myers Squibb’s Camzyos (mavacamten), which is currently the only FDA-approved treatment for HCM and has been tipped as a future blockbuster. First approved in April 2022, Camzyos made $142 million in sales in the first nine months of 2023.

In the aficamten trial, patients taking the drug saw an increase in peak oxygen uptake (pVO2) measured by cardiopulmonary exercise testing (CPET), measured 24 weeks after baseline, and the benefit was seen whether or not the subjects were taking background beta-blocker therapy.

That was accompanied by significant and “clinically meaningful” improvements in a series of secondary endpoints, including patient- and investigator-reported measures of symptoms at weeks 12 and 24, the change in provoked left ventricular outflow tract gradient (LVOT-G), a key measure of heart function, and exercise workload capacity.

There was also a very low rate of worsening left ventricular ejection fraction (LVEF) or treatment interruptions caused by LVEF reductions, which have been reported with BMS’ drug.

Cytokinetics said that the broad efficacy and encouraging safety profile of aficamten give it a chance of becoming the “cardiac myosin inhibitor of choice among physicians and patients.”

Cytokinetics said the data will be reported at a future medical congress and will form the basis of regulatory filings for aficamten in HCM in the second half of next year, along with data from its phase 2 REDWOOD-HCM study reported in 2021 and an ongoing open-label extension trial called FOREST-HCM.

Shares in Cytokinetics leapt almost 83% after the top-line results were announced, driving its valuation north of $8 billion.

Speculation has already started that the company may become a takeover target on the strength of the data, with AstraZeneca and Novartis – both of which have cardiovascular franchises – mentioned as potentially being interested in a deal.

Check out a video interview with Cytokinetics from earlier this year below.