Section 2.3.3: Information consolidated; Section 2.4: added Phase 1b study data and consolidated information; Section 4.4.1: Inclusion criterion 4 revised to require that women of child bearing potential use two highly effective forms of contraception; Section 6.2: added activity for site to telephone participants to remind them to complete diary; Sections 6.2 and 6.3: revised to define days at which participants should record stool frequency and rectal bleeding in their diary; Section 6.3.6: revised to state that study drug will be withheld in participants who exhibit any of the listed clinical laboratory elevations; Section 7.4: AE severity assessment revised to use NCI CTCAE grading; Section 7.5: revised to add sponsor medical monitor contact information and SAE reporting email and fax numbers; Section 7.11: revised to add individual stopping criteria based on abnormal echocardiogram findings of prolonged QT/QTc interval; Section 11.1: revised to remove statement that participants will be identified by their initials. Participant's initials are not being collected and therefore won’t be used for participant identification.

Section 1.0, 2.1, 2.2, 2.4: updated to include information on the Phase 1 study in patients with US who received LYC-30937-EC at single doses of 25 mg and 100 mg; Sections 1.0, 3.1.2, 3.2.2, 4.1, 4.5, 5.2, 6.1- 6.2.4, 7.6 and 8.4: revised due to extension of the open-label extension treatment period to up to 44 weeks, including the addition of study visits at Weeks 8, 20, 32, 44, and 46; Section 1.0: revised to add participating countries and to include the approximate last participant last visit timing date; Section 2.3.3: updated to include chronic toxicology information from rat and monkey studies; Section 4.4.1: Inclusion Criterion #2 revised to clarify that highly effective forms of contraception include hormonal contraceptives, which include the following forms oral, patch, long-acting injectable and implants; Section 4.5: revised to clarify that participants who withdraw should complete Visits 8 and 9; Section 5.3.3: revised to clarify that drug receipt is to be acknowledged in Interactive Web Response System upon receipt of drug; Sections 6.2 (Table 1 footnote), 6.2.1, 6.4.5,: updated to include body temperature log; Section 6.4.6: direction added to understand underlying baseline UC symptoms of abdominal pain and vomiting; Appendix A: revised the approximate blood volume collected.