The Lancet ( ) published recently results from a Phase 2 clinical trial evaluating omecamtiv mecarbil in patients with chronic heart failure. The COSMIC-HF (Chronic Oral Study of Myosin Activation to Increase Contractility in Heart Failure) trial met its primary pharmacokinetic objective and showed statistically significant improvements in all pre-specified secondary measures of cardiac function in the treatment group receiving pharmacokinetic-based dose titration. It is a double-blind, randomized, placebo-controlled, multicenter, Phase 2 trial.

The trial, which evaluated 448 patients with chronic heart failure and left ventricular systolic dysfunction, showed that dose titration controlled patient exposure to omecamtiv mecarbil. Patients were randomized 1:1:1 to receive either placebo or treatment with omecamtiv mecarbil dosed as 25 mg twice daily or 25 mg with dose escalation to 50 mg twice daily, depending on plasma concentrations of omecamtiv mecarbil after two weeks of treatment. The pharmacokinetic-based dose titration strategy was designed to maintain patient exposure to omecamtiv mecarbil in the targeted plasma concentration range. Approximately 53 percent of patients in the dose titration group were escalated to a dose of 50 mg twice daily. Following 20 weeks of treatment, statistically significant improvements were observed in all pre-specified secondary endpoint measures of cardiac function in the dose titration group, compared to placebo. Systolic ejection time increased by 25.0 msec (p<0.0001), stroke volume increased by 3.6 mL (p=0.0217) and heart rate decreased by 3.0 beats per min (p=0.0070). Left ventricular end-systolic and end-diastolic dimensions decreased by 1.8 mm (p=0.0027) and 1.3 mm (p=0.0128), respectively, and were associated with statistically significant reductions in left ventricular end-systolic and end-diastolic volumes. N-terminal pro-brain natriuretic peptide (NT-proBNP) decreased by 970 pg/mL (p=0.0069). In pre-specified exploratory analyses of the dose titration group, placebo-corrected reductions in NT-proBNP persisted four weeks after stopping omecamtiv mecarbil, decreasing further to 1,306 pg/mL (p=0.0006). The data also showed increases in fractional shortening at week 20 compared to placebo in the dose titration group.