Effects of an oral growth hormone secretagogue in older adults.

Author(s): White HK, Petrie CD, Landschulz W, MacLean D, Taylor A, Lyles K, Wei JY, Hoffman AR, Salvatori R, Ettinger MP, Morey MC, Blackman MR, Merriam GR, Capromorelin Study Group

Affiliation(s): Duke University School of Medicine and Geriatric Research Education and Clinical Center, Durham Veterans Affairs Medical Center, Durham, North Carolina 27710, USA. White031@mc.duke.edu

Publication date & source: 2009-04, J Clin Endocrinol Metab., 94(4):1198-206. Epub 2009 Jan 27.

Publication type: Multicenter Study; Randomized Controlled Trial; Research Support, Non-U.S. Gov't

CONTEXT: GH secretion declines with age, possibly contributing to reduced muscle mass, strength, and function. GH secretagogues (GHS) may increase muscle mass and physical performance. OBJECTIVES/DESIGN: We conducted a randomized, double-masked, placebo-controlled, multicenter study to investigate the hormonal, body composition, and physical performance effects and the safety of the orally active GHS capromorelin in older adults with mild functional limitation. INTERVENTION/PARTICIPANTS: A total of 395 men and women aged 65-84 yr were randomized for an intended 2 yr of treatment to four dosing groups (10 mg three times/week, 3 mg twice a day, 10 mg each night, and 10 mg twice a day) or placebo. Although the study was terminated early according to predetermined treatment effect criteria, 315 subjects completed 6 months of treatment, and 284 completed 12 months. RESULTS: A sustained dose-related rise in IGF-I concentrations occurred in all active treatment groups. Each capromorelin dose prompted a rise in peak nocturnal GH, which was greatest with the least frequent dosing. At 6 months, body weight increased 1.4 kg in subjects receiving capromorelin and decreased 0.2 kg in those receiving placebo (P = 0.006). Lean body mass increased 1.4 vs. 0.3 kg (P = 0.001), and tandem walk improved by 0.9 sec (P = 0.02) in the pooled treatment vs. placebo groups. By 12 months, stair climb also improved (P = 0.04). Adverse events included fatigue, insomnia, and small increases in fasting glucose, glycosylated hemoglobin, and indices of insulin resistance. CONCLUSIONS: In healthy older adults at risk for functional decline, administration of the oral GHS capromorelin may improve body composition and physical function.