Predicting Response to Standardized Pediatric Colitis Therapy

Inclusion Criteria: * Age ≥ 4years and ≤17 years at initiation of therapy (achieved 4th birthday, not yet 18th) * Weight ≥15 kg * New diagnosis of ulcerative colitis established by standard clinical, endoscopic, and histologic features at the PROTECT study site * Colitis extending beyond the rectosigmoid (Paris classification E2, E3, or E4)\[144\]. If a patient is seriously ill and the clinician does not advance the colonoscope beyond the sigmoid colon but the clinical condition of the patient highly suggests more extensive disease then that patient is eligible for study. * Disease activity by PUCAI of ≥10 at diagnosis * No therapy previously initiated to treat the newly diagnosed ulcerative colitis * Stool culture negative for routine enteric pathogens (Salmonella, Shigella, Campylobacter, E. coli 0157:H7) and Clostridium difficile toxin. Recent successful treatment for Clostridium difficile does not exclude a patient if toxin now absent. However, the patient must be a minimum of 5 weeks from the time treatment was started at the time toxin is absent. * Stool study negative for enteric parasites (ova and parasites) * Parent/guardian consent and patient assent * Ability to remain in follow-up for a minimum of one year from diagnosis * Female patients of child bearing age must have a negative urine pregnancy test and practice acceptable contraception (e.g., abstinence, intramuscular or hormonal contraception, two barrier methods (e.g., condom, diaphragm, or spermicide), intrauterine device, verbal report of the partner with history of vasectomy, or be surgically sterile). All female patients of childbearing potential (post-menarche) will undergo urine pregnancy testing at screening and must not be lactating. Exclusion Criteria: * Clinical, endoscopic, radiologic, or histologic evidence suggesting Crohn's disease (CD) consistent with Paris and North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) criteria \[144, 145\] * A previous diagnosis of inflammatory bowel disease for which treatment was given * Evidence of any active enteric infection at the time of study entry * Use of any oral CS for non-gastrointestinal indication within the past 4 weeks (e.g., asthma). Use of inhaled CS does not exclude a patient. * History of use of IM or anti-TNFα agent for other medical conditions (e.g., juvenile rheumatoid arthritis) within the past 6 months * Use of Accutane within the past 4 weeks * Use of any investigational drug within the past four weeks * Use of any 5-aminosalicylate within the past 4 weeks * Pregnancy * Subjects with poorly controlled medical conditions (e.g. diabetes, congestive heart failure) * Proctitis or proctosigmoiditis only (Paris classification E1) on colonoscopic evaluation * Chronic renal disease (BUN and serum creatinine \>1.5 times the upper normal limit) * Hepatic disease (AST or Alkaline phosphatase (ALP) greater than 3 times the upper normal limit in the absence of concomitant liver disease associated with IBD following full evaluation) * History of allergy or hypersensitivity to salicylates, aminosalicylates, or any component of the Pentasa capsule. * History of coexisting chronic illness or evidence of significant organic or psychiatric disease on medical history or physical examination, which, in the Investigator's opinion, would prevent participation in the study * History or presence of any condition causing malabsorption or an effect on gastrointestinal (GI) motility, or history of extensive small bowel resection (greater than half the length of the small intestine). * The finding of Helicobacter pylori at the time of evaluation does not exclude the patient from the study. Whether to treat this patient for Helicobacter pylori and when will be left to the discretion of the site.