A Phase II clinical trial of Cytokinetics’ investigational drug candidate, CK-3773274 (CK-274), has shown positive top-line data from first and second cohorts in hypertrophic cardiomyopathy (HCM) patients.

Data from the REDWOOD-HCM trial revealed statistically significant decreases in the average resting left ventricular outflow tract pressure gradient (LVOT-G) and the average post-Valsalva LVOT-G from baseline when treated with CK-274 for ten weeks.

Compared to placebo, most of the CK-274-treated participants reached the target treatment goal, determined as resting gradient and post-Valsalva gradient of less than 30mmHg and 50mmHg, respectively, at week ten.

LVOT-G reductions were observed in two weeks of starting the CK-274 treatment. These effects were maximised in two to six weeks of the dose titration initiation and maintained until the end of the ten-week treatment period.

The LVOT-G reductions were also reported to be dose-dependent and patients experienced higher decreases with increasing CK-274 doses.

CK-274 was generally well-tolerated during the trial with the occurrence of adverse events being similar between treatment groups. The drug candidate was not associated with any serious adverse events.

Cytokinetics Research & Development executive vice-president Fady Malik said: “The combined data from Cohorts 1 and 2 in REDWOOD-HCM met our high expectations for this trial of CK-274 in patients with obstructive HCM, given the observed onset of response to initiation of treatment, magnitude and breadth of response, reversibility of LVEF decreases and favourable tolerability profile.”

CK-274 is an oral, small-molecule inhibitor of cardiac myosin intended to mitigate hypercontractility related to HCM.

A multi-centre, randomised, placebo-controlled, double-blind, dose-finding Phase II trial, REDWOOD-HCM assessed the drug in symptomatic obstructive HCM patients receiving background treatment.

Safety and tolerability of CK-274 were the primary objectives while secondary objectives were the concentration-response link between CK-274 and the resting and post-Valsalva LVOT-G, established using echocardiography over the treatment period.

The REDWOOD-HCM data inform dose selection and back the entry of CK-274 into a planned Phase III registrational trial set to commence before year-end.

In October 2020, Cytokinetics and its partners Amgen and Servier announced mixed results from the Phase III GALACTIC-HF trial of omecamtiv mecarbil in patients with heart failure with reduced ejection fraction.