Intestinal Microbiome Transplant in ALS

This is a 24-week study of intestinal microbiome transplant in people with ALS. All participants will be evaluated clinically in person for 4 visits. Blood and mailed/ fresh stool samples will also be collected. Blood samples will be used to determine changes in neurofilament light chain over time. Stool samples will be processed for microbiome analysis. Participants will have phone visits to further evaluate safety and tolerability. They will then undergo antibiotic conditioning and a standard bowel preparation before being assigned to the investigational product, MTP-101C .