A study to look at the long-term safety of a medicine, efmarodocokin alfa, in people with ulcerative colitis

Inclusion Criteria for Study Entry:

• Prior enrollment in Study GA29469 or Study GA39925 and meeting protocol defined entry criteria

Inclusion Criteria for Study Entry and Study Re-Entry:

• Ability to comply with requirements of the study, in the investigator's judgment
• For women and men: use of highly effective contraception as defined by the protocol.

Exclusion Criteria for Study Entry:

• Withdrawal of consent from parent study
• Discontinuation of study drug as required by the parent study protocol
• Discontinuation of study drug and withdrawal from Study GA29469 prior to Day 85 or from Study GA39925 prior to Week 8
• Noncompliance in the parent study, specifically defined as missing scheduled visits or non-adherence with background medications and concomitant medications

Exclusion Criteria for Study Entry and Study Re-Entry:

• Pregnant or breastfeeding, or intending to become pregnant during the study or within 8 weeks after the final dose of study drug or within 18 weeks after the final dose of study drug from GA39925, whichever is longer
• Any new malignancy, significant uncontrolled comorbidity, such as cardiac, pulmonary, renal, hepatic, endocrine, or gastrointestinal disorders, or signs or symptoms of infection judged by the investigator to be clinically significant since enrolling in the parent study
• Use of prohibited therapies as defined in the parent study
• Abnormal laboratory values, as defined in the protocol, recorded at the last visit in the parent study

Exclusion Criterion for Study Re-Entry:

• Use of prohibited concomitant therapy since enrolling in the extension study