An Efficacy and Safety Study of Infliximab Dose Escalation in Pediatric Participants With Inflammatory Bowel Disease

The purpose of this study is to evaluate whether trough serum infliximab concentrations at the time of loss of clinical response will identify pediatric participants with inflammatory bowel disease (IBD) who would benefit (regain clinical response) from dose escalation above the currently approved dose \[5 milligram (mg)/kilogram (kg) every 8 weeks (q8wk)\] and the safety of that dose escalation.

This is a multicenter (when more than one hospital or medical school team work on a medical research study), prospective (study following participants forward in time), open-label (all people know the identity of the intervention) study of infliximab in pediatric participants with inflammatory bowel disease. The study consists of 3 Phases: screening Phase (up to 4 weeks), open-label treatment Phase (56 weeks) and follow up safety Phase (8 weeks). The duration of participation in the study for each participant is approximately up to 68 weeks (including screening period). Participants' efficacy and safety outcomes will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* Must have a biopsy-confirmed diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) prior to study entry
* Must meet concomitant medication stability criteria as specified in protocol
* Is considered eligible according to the tuberculosis (TB) Screening criteria specified in protocol
* Must have negative stool results for enteric pathogens. Stool studies must include a stool culture and Clostridium difficile toxin assay. These must have been performed during Screening or the current episode of disease exacerbation as long as the stool studies were performed within 4 months prior to the first administration of infliximab at Week 0
* Must have screening laboratory test results as specfied in the protocol
* Must be up to date with all immunizations in agreement with current local immunization guidelines for immunosuppressed participants prior to Screening
* Must not have discontinued infliximab therapy

Exclusion Criteria:

* Must not require, or must not have required, within the 2 months prior to Screening, surgery for active gastrointestinal bleeding, peritonitis, intestinal obstruction, or intraabdominal or pancreatic abscess requiring surgical drainage, or other conditions possibly confounding the evaluation of benefit from infliximab treatment
* Must not have presence or history of colonic or small bowel obstruction within 6 months prior to Screening, confirmed by objective radiographic or endoscopic evidence of a stricture with resulting obstruction (example, dilation of the colon or small bowel proximal to the stricture on barium radiograph or an inability to traverse the stricture at endoscopy)
* Must not have local manifestations of CD, such as fistulae, strictures, abscesses, or other disease complications for which surgery might be indicated. Enterocutaneuous fistulae for which surgery is not indicated, are allowed
* Must not have presence of a stoma
* Must not have documented short bowel syndrome (more than 100 centimeter in total of small bowel resected)