 CAMBRIDGE, Mass.--BUSINESS WIRE--Seres Therapeutics, Inc. Nasdaq: MCRB today announced that it has dosed the first patient in its Phase 1b trial evaluating SER-301 for the treatment of active mild-to-moderate ulcerative colitis UC. SER-301 is an oral, rationally-designed microbiome therapeutic designed to dampen the aberrant gastrointestinal inflammation central to ulcerative colitis and induce clinical remission in patients suffering from active UC. SER-301 is designed to modify the gast 