Hypothesis: The responder rate of the MAX-002 will be superior to placebo after 6 weeks of treatment in patients with mild to moderate ulcerative proctitis.

Summary: The primary purpose of this study is to evaluate the efficacy and safety of new mesalamine suppositories (MAX-002) as compared to placebo after 6 weeks of treatment in adults with mild to moderate ulcerative proctitis.

Prior to randomization, all inclusion and exclusion criteria will be verified to confirm eligibility. Patients found to be eligible will be randomized in a 1:1:1 scheme to receive either MAX-002 1 g, Canasa® 1 g, or Placebo suppository once daily at bedtime for 6 weeks in a double-blind fashion. Completers at Study Week 6 will be offered to receive MAX-002 1 g suppositories on a voluntary basis during the next 8 weeks of the open-label phase. Regardless of the treatment groups, all patients will be evaluated through phone calls at Study Weeks 1 and 2 followed by clinical visits at Study Weeks 3, 6, and 14. Study-specific procedures include but are not limited to the following: flexible proctosigmoidoscopy; disease activity assessment; smoking habits description; health-related quality of life; compliance to treatment check and safety evaluations (physical examinations, ECG, vitals signs, clinical laboratory analyses). All patients will complete daily diaries and will be asked general open questions about any occurrence of adverse events/concurrent medical conditions, use of adjunctive therapy/procedure, and their intake of concomitant medication.