A Pharmacokinetic Study of Ustekinumab in Pediatric Subjects With Moderately to Severely Active Crohn's Disease

Inclusion Criteria:

- Be a pediatric subject 2 to less than (<) 18 years old in the US, 6 to <18 years old
elsewhere, of either gender with a body weight of greater than or equal to (>=) 10
kilogram (kg)

- Have Crohn's disease (CD) or fistulizing CD of at least 3 months duration, with active
colitis, ileitis, or ileocolitis, confirmed at any time in the past by radiography,
histology, and/or endoscopy

- Must have moderately to severely active CD defined by: Baseline pediatric Crohn's
disease activity index (PCDAI) score of greater than (>)30 and at least one of the
following: An abnormal C-reactive protein (CRP) >0.3 milligram per deciliter (mg/dL)
or 3.0 milligram per liter (mg/L) at screening) or fecal calprotectin >250 milligram
per kilogram (mg/kg) at screening or ileocolonoscopy with evidence of active CD
(defined as ulcerations in the ileum and/or colon) during screening into this study
including at the baseline visit

- Prior or current medication for CD must include at least 1 of the following: Current
treatment with at least 1 of the following therapies: oral corticosteroids, the
immunomodulators azathioprine, 6-MP, or methotrexate, or currently have or have had a
history of corticosteroid dependency, or have a history of failure to respond to, or
tolerate, at least 1 of the following therapies including oral or IV corticosteroids
or the immunomodulators 6-mercaptopurine, azathioprine, or methotrexate,or have
required more than 3 courses of oral or IV corticosteroids in the past year

- 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 study agent

Exclusion Criteria:

- Has complications of CD such as symptomatic strictures or stenosis, short gut
syndrome, or any other manifestation that might be anticipated to require surgery,
could preclude the use of the PCDAI to assess response to therapy, or would possibly
confound the ability to assess the effect of treatment with ustekinumab

- Currently has or is suspected to have an abscess. Recent cutaneous and perianal
abscesses are not exclusionary if drained and adequately treated at least 3 weeks
prior to baseline, or 8 weeks prior to baseline for intra-abdominal abscesses,
provided that there is no anticipated need for any further surgery. Participant with
active fistulas may be included if there is no anticipation of a need for surgery and
there are currently no abscesses identified

- Has had any kind of bowel resection within 6 months or any other intra-abdominal
surgery within 3 months prior to baseline

- Has a draining (that is (i.e.), functioning) stoma or ostomy

- Presence or history of any malignancy including presence or history of
lymphoproliferative disease including lymphoma, or signs and symptoms suggestive of
possible lymphoproliferative disease, such as lymphadenopathy of unusual size or
location (example, nodes in the posterior triangle of the neck, infraclavicular,
epitrochlear, or periaortic areas), or clinically significant hepatomegaly or
splenomegaly