Cytokinetics' heart failure drug improves exercise capacity, sending shares soaring in long-awaited win

Cytokinetics’ Christmas wish has come true. Cardiomyopathy treatment aficamten has improved exercise capacity in a pivotal phase 3 trial, sending the biotech’s shares soaring by more than 50% in pre-market trading Wednesday.

It’s been a long time coming for Cytokinetics, which has been trying to get a drug approved for 25 years. After many clinical stumbles, the biotech now seems to have a winner on its hands with the late-stage data from the SEQUOIA-HCM trial, which also showed a win on all secondary endpoints, according to a Wednesday morning release.

The company's shares spiked to $68.88 Wednesday morning compared to $44.60 at close on December 26. The shares hit a low of $26 in October. 

The update was brief, with Cytokinetics promising more details in a conference call this morning with full results to be revealed at a future medical conference. Aficamten was being tested in patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM), which is characterized by a thickening of the wall between the left and right ventricles.

Aficamten improved exercise capacity as measured by increasing peak oxygen uptake as measured by cardiopulmonary exercise testing when compared to placebo. Cytokinetics said the treatment effect was consistent across all prespecified subgroups including patients who were receiving background beta-blocker therapy and those who were not.

The company also said the results show a statistically significant improvement on all of the 10 prespecificed secondary endpoints, including measures of heart failure improvement, stages of heart failure and change in provoked left ventricular outflow tract gradient. There were also improvements in exercise workflow.

As for safety, Cytokinetics reported that aficamten was well tolerated and the adverse event profile compared to placebo. There were eight treatment emergent serious adverse events in the aficamten arm and 13 in placebo.

Cytokinetics’ Fady Malik, M.D., Ph.D., executive vice president of R&D, said on a conference call this morning that the company is “extremely pleased with these results [which] meet our high expectations for the trial.”

CEO Robert Blum said the biotech already has one meeting with the FDA in the diary in the first quarter of next year to discuss the results with a view to filing an approval application later in 2024. Blum also placed the SEQUOIA-HCM results in the context of its other ongoing trials, including a phase 3 head-to-head with approved hypertension drug metoprolol.

“As we move forward with FDA and EMA discussions and our plans to file marketing applications in the second half of 2024, we continue the conduct of MAPLE-HCM to elucidate the potential benefit of aficamten versus metoprolol for the treatment of patients with obstructive HCM, as well as ACACIA-HCM evaluating aficamten for the potential treatment of non-obstructive HCM,” the CEO said on the call. 

The positive data are a much-needed jolt of good news for Cytokinetics, which has been rumored to be an M&A target among Big Pharmas. But any deal hinged on the SEQUOIA-HCM trial. The results come after years of clinical and regulatory stumbles for Cytokinetics, which got close to FDA approval last year with heart failure candidate omecamtiv mecarbil before the FDA rejected it in February.

Then in May, the company’s amyotrophic lateral sclerosis medicine was shown to be ineffective in a phase 3 trial and ultimately discontinued.