This study is designed to evaluate the safety, tolerability, and pharmacokinetics (PK) of single-dose TD-3504 and single dose 15N2-tofacitinib in healthy subjects and subjects with UC. The relative bioavailability of tofacitinib released from TD-3504 compared to co-administered oral heavy-labeled tofacitinib (15N2-tofacitinib) will also be evaluated.

Inclusion Criteria:

• Male or female between 18 to 55 years old
• Male subjects must abstain from sexual intercourse or use a highly effective method of birth control
• Women of child bearing potential must have a negative pregnancy test and either abstain from sex or use a highly effective method of birth control
• Body Mass Index (BMI) 18 to 32 kg/m2
• Willing and able to give informed consent
• Additional inclusion criteria apply

Inclusion Criteria for Ulcerative Colitis (UC) subjects:

• Subject has a history of UC
• Subject is either not taking any medication for UC or has been taking a stable dose of ulcerative colitis medications for ≥ 14 days
• Additional inclusion criteria apply

Exclusion Criteria:

• Is positive for hepatitis A, B or C, HIV or tuberculosis
• Has clinically significant abnormalities in baseline laboratory evaluations
• Subject has a clinically significant abnormal electrocardiogram (ECG)
• Participated in another clinical trial of an investigational drug (or medical device) within 30 days prior to screening (or within 60 days prior to screening if investigational drug was a biologic, or is currently participating in another trial of an investigational drug (or medical device)
• Additional exclusion criteria apply

Exclusion Criteria for Healthy Subjects:

• Use of prescription drugs or any chronic over the counter medications within 14 days prior to clinic admission or requires continuing use during study participation, with the exception of hormonal contraceptives or hormone replacement therapy or standard daily multivitamin.
• Additional exclusion criteria apply

Theravance Biopharma, Inc. will not be sharing individual de-identified participant data or other relevant study documents.