MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study.

Most elderly patients admitted for hip fracture suffer functional decline. Previous studies with MK-0677 in hip fracture patients suggested possible benefits to functional recovery. This is a randomized, double-blind study of 123 elderly hip fracture patients assigned to receive 25mg/day of MK-0677 (n = 62) or placebo (n = 61). Primary outcomes were a rank analysis of change during the study in objective functional performance measurements and insulin-like growth factor-1 (IGF-1) levels in blood. At 24-weeks, the mean stair climbing power increased by 12.5 W in the MK-0677 group (95% confidence interval (CI) = -10.95-35.88; p = 0.292) compared with placebo. Gait speed increased by a 0.7-score difference in the means (95% CI = 0.17-1.28; p = 0.011). There was no improvement in MK-0677 treated patients in several other functional performance measures. The MK-0677 group experienced fewer falls during the study compared to placebo and smaller number of patients who had any falls (p = 0.096). Levels of IGF-1 in treated patients increased by 51.4 ng/ml (95% CI = 34.42-68.44; p < 0.001) compared to placebo. Trial was terminated early due to a safety signal of congestive heart failure in a limited number of patients. In hip fracture patients treated with 25mg/day MK-0677, the increase in plasma IGF-1 levels was not paralleled by improvement in most functional performance measures. MK-0677 has an unfavorable safety profile in this patient population.