Randomized double-blind placebo-controlled trial of the effects of oral trehalose in spinocerebellar ataxia type 3: An interim analysis

INTRODUCTION: Spinocerebellar ataxia type 3 (SCA3) is a neurodegenerative disease characterized by increasingly worsening ataxia and non-ataxia features, negatively impacting patients' quality of life. This study was designed to test formally evaluate whether oral trehalose was effective in SCA3 patients.

METHODS: In this double-blind, randomized controlled trial, SCA3 patients received either 100 g oral trehalose or 30 g maltose to improve ataxia severity over six months. We also measured other clinical (non-ataxia), patient-reported (quality of life, motivations), and safety endpoints. An unscheduled interim analysis was conducted using two-way ANOVAs to analyze the interaction between time (baseline, 3-months, 6-months) and intervention (Trehalose vs. Placebo).

RESULTS: Fifteen participants (Trehalose = 7 vs. Placebo = 8) completed the study at the time of interim analysis. There was no interaction effect on the ataxia severity, and available data suggested an estimated sample size of 132 (66 per arm) SCA3 patients required to demonstrate changes in a 6-month trial. There were significant interaction effects for executive function (ƞ2 = 0.28-0.43). Safety data indicated that 100 g oral trehalose was well-tolerated.

CONCLUSION: We performed an unplanned interim analysis due to a slow recruitment rate. The new estimated sample size was deemed unfeasible, leading to premature termination of the clinical trial. In this small, current sample of SCA3 patients, 100 g oral trehalose did not differentially impact on ataxia severity compared to placebo. Interestingly, our findings may suggest an improvement in executive function. Future efforts will require a large multi-country, multi-center study to investigate the potential effect of trehalose.