A Pilot Study Testing the Safety and Feasibility of Restorative Microbiota Therapy (RMT) in Patients With Refractory Immune-checkpoint Inhibitor-related Colitis

A single loading dose of RMT capsules containing \~5 x 10 11 bacteria on day 1 followed by 2 x 10 11 bacteria daily for 6 days. The RMT capsule preparation (\~2-5 capsules, size 00) is self-administered on an empty stomach with at least one glass of water. Clear liquids are allowed, and food can be resumed 2 hours after administration.

Participants will receive an identical looking placebo capsules daily for 7 days (i.e 5 placebo capsules on day 1), followed by 2 placebo capsules daily from Day 2-7. The placebo capsule preparation is self-administered on an empty stomach with at least one glass of water. Clear liquids are allowed, and food can be resumed 2 hours after administration.