Effect of creatine monohydrate on motor function in children with facioscapulohumeral muscular dystrophy: A multicenter, randomized, double-blind placebo-controlled crossover trial.

backgroundFacioscapulohumeral muscular dystrophy (FSHD) is a rare, progressive muscle disease with no available disease-modifying therapy. Creatine monohydrate (CrM) has been shown to improve muscle strength in individuals with muscular dystrophies but has not been tested in young people with FSHD. This study aimed to explore the efficacy of CrM on motor function in children with FSHD.

methodsIn a randomized placebo-controlled double-blind crossover trial, powdered CrM at a dose of 100 mg/kg/day (maximum 10 g daily) was compared with placebo in two 12-week treatment periods with a 6-week washout between crossover arms. The primary outcome measure was the Motor Function Measure for Neuromuscular Disease (MFM-32) with secondary outcomes assessing safety, endurance, strength, patient-reported outcome measures, and muscle morphology measurements as assessed by whole-body magnetic resonance imaging (MRI).

resultsThirteen children were enrolled (mean (standard deviation, SD) 12.2 (2.67) years of age) and 11 patients completed both trial treatment periods. In an intention-to-treat analysis, no clinically meaningful difference was seen between treatment groups as measured by the mean difference in MFM-32 (0.19, 95% confidence interval (CI) -0.71 to 1.08). However, there was an improvement in 6-minute walk distance of 27.74 m (95% CI -1.41 to 56.88) and trends to improvement in the FSHD-Composite Outcome Measure for Pediatrics (FSHD-COM Peds), 10 meter walk/run, and in MRI measures. There were no serious adverse events. Serum creatinine increased by a mean 12.63 μmol/L (95% CI 1.14 to 24.12) post-CrM treatment, though this was presumed to reflect increased creatinine production. No participants discontinued CrM due to adverse events.

conclusionCrM is safe and well tolerated in children with FSHD. Although CrM had no effect on motor function as measured by the MFM-32 compared with placebo, there were trends toward improvement in the 6-minute walk distance and other secondary outcome measures. This study confirms the feasibility of conducting clinical trials in children with FSHD. Further assessment of the efficacy of CrM in pediatric FSHD is warranted in a larger randomized controlled clinical trial. Future studies may benefit from stratifying population cohorts according to functional ability or by MRI fat infiltration measurements.