Cytokinetics has shared positive top-line results from a late-stage study of its investigational oral cardiac myosin inhibitor aficamten in hypertrophic cardiomyopathy (HCM).
The phase 3 MAPLE-HCM trial has been comparing the candidate against standard-of-care beta blocker metoprolol in more than 170 patients with symptomatic obstructive HCM.
As many as one in 500 people in the UK and US are living with HCM, a common form of genetic heart disease. Some patients do not experience symptoms, causing a large percentage of cases to remain undiagnosed, while others may only feel symptoms such chest pain and shortness of breath during exercise.
Approximately two-third of HCM patients have the obstructive form of the condition, in which the thickened part of the heart muscle blocks or reduces the blood flow from the heart, while non-obstructive HCM, when the heart muscle is thickened but does not block blood flow out of the heart, is less common.
Aficamten is designed to reduce the hypercontractility associated with HCM by blocking myosin, a motor protein that plays a key role in muscle contraction, from pulling.
MAPLE-HCM met its primary endpoint, with aficamten monotherapy significantly improving peak oxygen uptake, measured by cardiopulmonary exercise testing, compared to metoprolol monotherapy from baseline to week 24.
The safety and tolerability profile of Cytokinetics’ drug was also shown to be favourable in comparison to metoprolol.
The company’s executive vice president of research and development, Fady Malik, said the results “represent the first evidence that aficamten may be used as monotherapy to deliver clinically meaningful improvements in people living with obstructive HCM”.
“Importantly, the results from MAPLE-HCM provide important context to the benefit of this potential new medicine compared to the current standard of care,” he added.
Aficamten, which is also being evaluated in non-obstructive HCM, is currently under regulatory review by the US Food and Drug Administration, with a decision expected by 26 December. The drug is also being assessed by the European Medicines Agency.