Safety and Efficacy of MMX Mesalamine/Mesalazine in Pediatric Subjects With Mild to Moderate Ulcerative Colitis

Inclusion Criteria:

1. Ability to voluntarily provide written, signed, and dated (personally or via a legallyauthorized representative [LAR]) informed consent or assent as applicable toparticipate in the study.
2. Subject's parent/LAR demonstrates an understanding, ability, and willingness to fullycomply with study procedures and restrictions.
3. Male and female children and adolescents aged 5-17 years, inclusive.
4. Body weight 18-90kg.
5. Male, or non-pregnant, non-lactating female who agrees to comply with any applicablecontraceptive requirements of the protocol or females of non-childbearing potential.
6. Diagnosed with mild to moderate UC, established by sigmoidoscopy or colonoscopy withcompatible histology. Screened subjects may also have an unconfirmed diagnosis of mildto moderate UC; however the diagnosis of mild to moderate UC must have beenestablished by sigmoidoscopy or colonoscopy with compatible histology prior tobaseline visit.
7. Subject is able to swallow the investigational product whole. Double-blind Acute Phase:
8. Partial UC-DAI score ≥2 (a combined rectal bleeding and stool frequency score ≥1 andPGA=1 or 2) at the Baseline Visit, for which 5-ASA would be used as part of normaltreatment.
9. If the subject is on 5-ASA treatment prior to study entry, then the dose must bestable. Stable therapy is defined as no change in dose, or no initiation of 5-ASA,from the onset of the current acute flare through discontinuation of therapy (requiredat the Baseline Visit). Double-blind Maintenance Phase:
10. Partial UC-DAI ≤1 (rectal bleeding=0, stool frequency ≤1, and PGA=0) at the BaselineVisit.

Exclusion Criteria:

1. Severe UC (defined by PGA=3).
2. Crohn's disease, bleeding disorders, active peptic ulcer disease, or UC known to beconfined to the rectum (isolated rectal proctitis).
3. Asthma, only if known to be 5 ASA sensitive.
4. Positive stool culture for enteric pathogens (including Salmonella, Shigella,Yersinia, Aeromonas, Plesiomonas, or Campylobacter). Clostridium difficile toxin, ova,or parasites present.
5. Systemic or rectal corticosteroid use within 4 weeks prior to the Screening Visit.Topical, intranasal, or inhaled use is not exclusionary.
6. Immunomodulator (6-mercaptopurine, azathioprine) use within 6 weeks prior to theScreening Visit.
7. History of biologic (eg, anti-tumor necrosis factor agents, integrin receptorantagonists) use at any time.
8. Antibiotic use within 7 days prior to the Screening Visit.
9. Any anti-inflammatory drugs, not including 5-ASA treatment but including non-steroidalanti-inflammatory drugs such as aspirin, COX-2 inhibitors or ibuprofen, within 7 daysprior to the Screening Visit unless used at over-the-counter levels for <3 days.However, prophylactic use of a stable dose of aspirin up to 325mg/day for cardiacdisease is permitted.
10. Prebiotic/probiotic use within 7 days prior to the Screening Visit. Yogurt productsare permitted.