MyoKardia has reported positive data from the Phase Ia clinical trial of MYK-491 in healthy volunteers.

MYK-491 is an oral, small molecule myosin activator that has been designed to boost contractility of the heart (systolic function) with minimal effects on myocardial relaxation (diastolic function). The therapeutic was found to be well tolerated without any dose-limiting toxicities.

According to the results, the drug candidate increased cardiac contractility by 5%-20% across various echocardiographic parameters at higher drug concentrations, with minimal impact on diastolic function.

MyoKardia executive vice-president and chief development officer June Lee said: “In developing MYK-491, we set out to target the underlying heart muscle proteins to increase contraction, with minimal impact on the heart’s ability to relax and fill with oxygenated blood between beats.

“Data from our Phase Ia study in healthy volunteers demonstrate that MYK-491 is achieving this desired effect, and these results have been confirmed by data from our Phase Ib study in patients with stable heart failure.”

The randomised, double-blind placebo-controlled, single-ascending dose Phase I trial evaluated the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of MYK-491 in 64 healthy volunteers, compared to placebo.

During the study, the most common adverse events (AE) observed was headaches, with no trend for increased AE frequency related to higher dose concentrations.

PK results demonstrated that the therapeutic may be amenable to once or twice-daily dosing.

MyoKardia presented these data at the European Society of Cardiology Heart Failure Congress in Athens, Greece.

The company is further studying MYK-491 in a Phase IIa multiple-ascending dose trial in patients with systolic heart failure. Top-line results from this trial are expected in the second half of this year.