Study for Participants With Ulcerative Colitis Previously Enrolled in Etrolizumab Phase II/III Studies

Inclusion Criteria:

Part 1 (Open-label Extension)

• Participants previously enrolled in the Phase II OLE study or Phase III controlledstudies who meet the eligibility criteria for open-label etrolizumab for thosestudies as described in the protocol

Part 2 (Safety Monitoring)

• Participants whose safety follow-up or PML follow-up is not completed within StudyGA27927 and participants who had their last dose of etrolizumab in July 2016 inStudy GA27927 and are not eligible or willing to enroll in Part 1 (OLE)

• Participants who participated in one of the etrolizumab Phase III studies and arenot eligible or willing to enter Part 1 (OLE)

• Participants who transfer from Part 1 (OLE)

• Completion of the 12-week safety follow-up prior to entering.

Exclusion Criteria:

Part 1 (Open-label Extension)

• Withdrawal of consent from and participant not compliant in the Phase II OLE studyor any of the Phase III studies

• Participant who discontinued etrolizumab/etrolizumab placebo prior to Week 10 or didnot perform the Week 10 visit of the Phase III Studies GA28948, GA28949, GA29102,and GA29103

• Participant who discontinued etrolizumab/etrolizumab placebo prior to Week 14 or didnot perform the Week 14 visit of the Phase III Study GA28950

• Any new, significant, uncontrolled condition