EDP-1503

This study is being done to determine if orally administered EDP1503 will enhance the response to standard immunotherapy treatment (pembrolizumab) in participants with advanced melanoma.
The study will involve initial administration of EDP1503 for a run-in period (2 weeks) followed by administration of both EDP1503 (twice daily) and pembrolizumab (every 3 weeks).
Mandatory biopsies are required before starting study treatment and after 2 weeks of EDP1503 dosing.