Effect of fecal microbiota transplantation on patients with sporadic amyotrophic lateral sclerosis: a randomized, double-blind, placebo-controlled trial.

Background: Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder marked by the progressive loss of motor neurons. Recent insights into ALS pathogenesis underscore the pivotal role of the gut microbiome, prompting an investigation into the potential therapeutic impact of fecal microbiota transplantation (FMT) on sporadic ALS patients.

Methods: Conducted as a double-blind, placebo-controlled, parallel-group, randomized clinical trial, the study enrolled 27 participants from October 2022 to April 2023. The participants were followed up for 6 months from February 2023 to October 2023, during in-person visits at baseline, week 15, week 23, and week 35. The participants, evenly randomized, received either healthy donor FMT (FMT, n = 14) or a mixture of 0.9% saline and food coloring (E150c) as sham transplantation (placebo, n = 13). The primary outcome measured the change in the ALS Functional Rating Scale-Revised (ALSFRS-R) total score from baseline to week 35. Secondary outcomes included changes in gastrointestinal and respiratory functions, muscle strength, autonomic function, cognition, quality of life, intestinal microbiome composition, and plasm neurofilament light chain protein (NFL). Efficacy and safety outcomes were assessed in the intention-to-treat population.

Results: A total of 27 randomized patients (47% women; mean age, 67.2 years), 24 participants completed the entire study. Notably, ALSFRS-R score changes exhibited no significant differences between FMT (6.1 [SD, 3.11]) and placebo (6.41[SD, 2.73]) groups from baseline to week 35. Secondary efficacy outcomes, encompassing respiratory function, muscle strength, autonomic function, cognition, quality of life, and plasm NFL, showed no significant differences. Nevertheless, the FMT group exhibited improvements in constipation, depression, and anxiety symptoms. FMT induced a shift in gut microbiome community composition, marked by increased abundance of Bifidobacterium, which persisted until week 15 (95% CI, 0.04 to 0.28; p = 0.01). Gastrointestinal adverse events were the primary manifestations of FMT-related side effects.

Conclusions: In this clinical trial involving 27 sporadic ALS patients, FMT did not significantly slow the decline in ALSFRS-R score. Larger multicenter trials are needed to confirm the efficacy of FMT in sporadic ALS patients and to explore the underlying biological mechanisms.

Trial registration: Chinese Clinical Trial Registry Identifier: ChiCTR 2200064504.