Positive Topline Data for Aficamten in Obstructive HCM

Megan Brooks

February 01, 2022

The investigational, next-generation cardiac myosin inhibitor aficamten (previously CK-274, Cytokinetics) continues to show promise as a potential treatment for hypertrophic cardiomyopathy (HCM).

Today, the company announced positive topline results from cohort 3 of the REDWOOD-HCM phase 2 clinical trial, which included 13 patients with symptomatic obstructive HCM and a resting or post-Valsalva left ventricular outflow tract pressure gradient (LVOT-G) of 50 mm Hg or greater whose background therapy included disopyramide.

Treatment with aficamten led to substantial reductions in the average resting LVOT-G, as well as the post-Valsalva LVOT-G (defined as resting gradient <30 mm Hg and post-Valsalva gradient <50 mm Hg), the company reported.

These "clinically relevant" decreases in pressure gradients were achieved with only modest decreases in average left ventricular ejection fraction (LVEF), the company said. 

In no patient did LVEF fall below the prespecified safety threshold of 50%.

New York Heart Association (NYHA) functional class was improved in most patients.

The safety and tolerability of aficamten in cohort 3 were consistent with previous experience in the REDWOOD-HCM trial, with no treatment interruptions and no serious treatment-related adverse events.

The pharmacokinetic data from cohort 3 are similar to those observed in REDWOOD-HCM cohorts 1 and 2, which included HCM patients taking background medications exclusive of disopyramide, as reported previously by theheart.org | Medscape Cardiology .

"We are encouraged by the clinically relevant reductions in the LVOT gradient observed in these medically refractory patients and are pleased with the safety profile of aficamten when administered in combination with disopyramide," Fady Malik, MD, PhD, Cytokinetics' executive vice president of research and development, said in a news release.

"These results represent the first report of patients with obstructive HCM treated with a combination of a cardiac myosin inhibitor and disopyramide and support our plan to include this patient population in SEQUOIA-HCM, our phase 3 trial, which is important, given these patients have exhausted other available medical therapies," Malik said.

These results from cohort 3 of the REDWOOD-HCM trial will be presented at the upcoming American College of Cardiology Annual Meeting in April.


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