Study protocol for a randomized controlled trial of fecal microbiota transplantation via different routes in children with moderate-to-severe autism spectrum disorder.

BACKGROUND

Fecal microbiota transplantation (FMT) shows promise for autism spectrum disorder (ASD) by modulating the gut-brain axis, but the optimal delivery route remains unknown. Our previous single-arm study suggested efficacy of nasojejunal FMT in children with moderate-to-severe ASD, yet could not exclude placebo effects or compare routes. This randomized controlled trial aims to determine the most effective and tolerable FMT administration route.

METHODS

This single-center, randomized, triple-blind, double-dummy, placebo-controlled, three-arm parallel-group trial will enroll 75 children (aged 3-16 years) with moderate-to-severe ASD [Childhood Autism Rating Scale, Second Edition (CARS-2) ≥36]. Participants are randomized 1:1:1 to: (1) FMT via nasojejunal tube + sham colonoscopy (FMT-NJT); (2) active FMT via colonoscopy with transendoscopic enteral tube placement (first session) + two subsequent infusions via the indwelling tube + sham nasojejunal intubation (FMT-C); (3) placebo via both routes (sham procedures). Three FMT/placebo sessions (5 mL/kg, max 100 mL) are administered over 5 days. Primary outcome is change in CARS-2 score from baseline to Week 24. Secondary outcomes include changes in Social Responsiveness Scale, Autism Behavior Checklist, Gastrointestinal Symptom Rating Scale, Short Sensory Profile, Children's Sleep Habits Questionnaire, gut metagenomic profiles (baseline, Weeks 2,6,12,24,48), and adverse events.

RESULTS

This is a study protocol; no results are available.

CONCLUSIONS

This first head-to-head comparison of FMT routes in pediatric ASD will provide high-level evidence to guide treatment standardization, directly addressing the translational gap identified in our preliminary work.