Long-term Safety and Efficacy Profile of ABX464 in Subjects With Moderate to Severe Active Ulcerative Colitis

Inclusion Criteria: * Subjects who previously completed the ABX464-102 or ABX464-104 clinical studies * Subjects should be in endoscopic improvement with a rectal bleeding sub-score = 0 point at the end of treatment period in the previous study (ABX464-102 or ABX464-104). Endoscopic improvement is defined as: a Mayo endoscopic sub score of ≤1 ; * Subjects able and willing to comply with study visits and procedures; * Subjects must understand, sign and date the written voluntary informed consent form at the visit prior to any protocol-specific procedures; * 5\. Women of childbearing potential and men receiving the study treatment and their partners must agree to continue a highly effective contraceptive method during the study and for 6 months (180 days) after end of study or early termination. Women must be surgically sterile or if of childbearing potential must use a highly effective contraceptive method. Women of childbearing potential (WOCBP) will enter the study after confirmed menstrual period and a negative pregnancy test. Highly effective methods of contraception include true abstinence, intrauterine device (IUD) or hormonal contraception aiming at inhibition of ovulation, intrauterine hormone releasing system, bilateral tubal ligation, vasectomized partner. True abstinence is defined when this is in line with the preferred and usual lifestyle of the subject. In each case of delayed menstrual period (over one month between menstruations) confirmation of absence of pre…