Dose-Ranging Phase 2b Study of ABX464 in Moderate to Severe Ulcerative Colitis

Inclusion Criteria

• Men or women age 18 - 75 years;
• Diagnosis of moderate to severe active UC (including ulcerative proctitis if proximal extension of disease occurs beyond 10 cm) confirmed by endoscopy and histology at least 12 Weeks prior to screening visit. Moderate to severe active UC defined by Modified Mayo Score (MMS) of 5 to 9 inclusive (on a scale of 0-9). Moderate to severe active UC should be confirmed at screening visit with a centrally read endoscopy sub-score of at least 2 (on a scale of 0-3);
• Patients having either a documented inadequate response, no response, a loss of response, or an intolerance (defined as the occurrence of at least one Adverse Reaction leading to treatment discontinuation) to either immunosuppressant treatment (i.e., azathioprine, 6-mercaptopurine, methotrexate), tumor necrosis factor [TNF] inhibitors, vedolizumab, JAK inhibitors and/or corticosteroid treatment. Inadequate response, no response, loss of response is defined as:

i. Active disease or relapse in spite of thiopurines or methotrexate given at an appropriate dose for at least 3 months (i.e. azathioprine 2-2.5 mg/kg/day or mercaptopurine 1-1.5 mg/kg/day in the absence of leukopenia), and/or ii. Active disease despite corticosteroids treatment (prednisolone up to 0.75 mg/kg/day) over a period of 4 Weeks, and/or iii. Active disease or relapse in spite of adequate treatment (as defined in the SmPC) with tumor necrosis factor [TNF] inhibitors or vedolizumab, and/or iv. Active disease or relapse in spite of adequate treatment with JAK inhibitors over a period of at least 6 Weeks.

• Patients receiving oral corticosteroids must have been on a stable dose of prednisone or prednisone equivalent (≤20 mg/day) or on beclomethasone diproprionate (≤5mg/day) or on budesonide MMX (≤9 mg/day) for at least 2 Weeks prior to the screening visit;
• Topical corticosteroids and topical 5-aminosalicylic acid preparations must have been withdrawn at least 2 Weeks prior to the screening visit;
• Patients who are on oral 5-aminosalicylic acid must have been on a stable dose for at least 4 Weeks prior to the screening visit;
• Patients who are receiving immunosuppressants in the form of azathioprine, 6-mercaptopurine, or methotrexate needed to be on a stable dose for at least 4 Weeks prior to screening visit. Patients taking methotrexate also are advised to take folic acid 1 mg/day (or equivalent) supplementation if there is no contraindication;
• Patients on probiotics (e.g., Culturelle® [Lactobacillus GG, i-Health, Inc.], Saccharomyces boulardii) must be on stable doses for at least 2 Weeks prior to the screening visit;
• Patients on antidiarrheals (e.g., loperamide, diphenoxylate with atropine) must be on stable doses for at least 2 Weeks prior to the screening visit;
• Patients who have received tumor necrosis factor [TNF] inhibitors, vedolizumab or other biologics must have discontinued therapy at least 8 Weeks prior to the screening visit due to lack or insufficient efficacy or intolerance;
• Patients previously treated with cyclosporine, tacrolimus or JAK inhibitors must have discontinued therapy at least 4 Weeks prior to the screening visit due to lack or insufficient efficacy or intolerance;
• Patients previously treated with tube feeding, defined formula diets, or parenteral alimentation/nutrition must have discontinued treatment 3 Weeks before the screening visit and must be able to take, orally, appropriate amount of food (calories) and liquids to maintain body weight;
• Patients with surveillance colonoscopy defined as per ECCO guidelines;
• Patients with the following hematological and biochemical laboratory parameters obtained at screening:

i. Hemoglobin > 9.0 g dL-1; ii. Absolute neutrophil count ≥ 750 mm-3; iii. Platelets ≥ 100,000 mm-3; iv. Total serum creatinine ≤ 1.3 x ULN (upper limit of normal); v. Creatinine clearance > 90 mL min-1 by the Cockcroft-Gault equation within 60 days prior to baseline; vi. Total serum bilirubin < 1.5