Efficacy & Safety of TD-1473 in Ulcerative Colitis

Inclusion Criteria:

• Is at least 18 years of age at screening
• Has a history of UC for at least 3 months prior to screening
• Has moderately-to-severely active UC, as defined by a Mayo endoscopic subscore of ≥2points and an adapted Mayo score between 4 - 9 points inclusive
• Is corticosteroid-dependent or has demonstrated inadequate response, or intolerance toconventional therapy (aminosalicylates, corticosteroids, immunomodulators) orbiologics
• Willing to use highly-effective methods of contraception during the study and for 7days after the last dose
• Additional inclusion criteria apply

Exclusion Criteria:

• Has symptoms suggestive of fulminant colitis, megacolon or intestinal perforation
• Likely to require surgery for UC or other major surgeries
• Has previously received / is currently receiving prohibited medications withinspecified timeframe
• Is refractory to 3 biologics with ≥2 mechanisms of action
• Has a current bacterial, parasitic, fungal, or viral infection
• Has clinically significant abnormalities in laboratory evaluations
• Has had any prior exposure to an approved Janus kinase (JAK) inhibitor or potentialexposure to an investigational JAK inhibitor that was stopped due to intolerance orlack of efficacy
• Additional exclusion criteria apply