167with 73% having response at 10 weeks (after completion of induction dosing), and
the proportion of patients responding after randomization to 8- and 12-week infu-
sion intervals remained consistent during maintenance infusion (73% at 54 weeks,
1 partial, 15 complete). Nine patients developed perianal disease during treatment
with infliximab, but most (78%) had response with additional infusions. Cezard
et al. showed similar results in a subset of 12 patients with perianal fistula who
received three-dose induction regimen of infliximab, with all patients having clo-
sure of fistula by 3 months [ 6 ]. However, as 90% of the total study population expe-
rienced a relapse during the 12-month follow-up, it is possible that some patients
had recurrence of perianal disease without scheduled maintenance infusions.
Several factors may be associated with a positive response to infliximab therapy in
treatment of perianal disease in pediatric CD including shorter duration of disease
(<1 year), number of fistulas (≤1), and baseline HB index (<5) [ 16 , 17 ]. Prior to
initiating infliximab therapy for perianal disease, it is important to assess for com-
plicating factors such as rectal inflammation or complex fistula via colonoscopy and
pelvic magnetic resonance imaging (MRI) and/or rectal exam under anesthesia as
the combination of infliximab and surgery may lead to improved outcomes [ 18 ].
Infliximab for Pediatric Ulcerative Colitis
Infliximab was FDA approved for the treatment of moderate to severe pediatric
ulcerative colitis in 2011; however, similar to pediatric CD, this medication was
used off-label for pediatric patients with refractory colitis for several years prior to
approval based on adult data and smaller pediatric case series demonstrating effi-
cacy of this therapy. A preliminary case series by Mamula et al. showed that seven
of nine patients (77%) with moderate to severe UC that was refractory to traditional
therapy had a clinical response to infliximab as measured by the PGA, with six of
these patients having inactive disease 2 weeks after the infusion [ 19 ]. A steroid-
sparing effect was seen and 66% of these patients were able to discontinue cortico-
steroid therapy. Nine patients in this cohort were reevaluated after a minimum of
2 years of follow-up, and 73% of these patients were considered to be responders to
the initial dose [ 20 ]. Two of these patients lost response within 9 months, and the
remaining five responders had a sustained response, three of whom were doing well
without ongoing infliximab therapy. A clinical response rate of 88% was seen in an
additional eight patients with refractory UC treated with infliximab [ 20 ]. In total, 14
of 17 patients (82%) developed a short-term response, and 10 patients (63%) devel-
oped a long-term response to infliximab therapy. Another retrospective single- center
study evaluated the response to infliximab in 12 pediatric patients with UC, 3 with
fulminant colitis, 3 with an acute relapse of disease, 5 with steroid-dependent coli-
tis, and 1 with corticosteroid-refractory colitis [ 21 ]. Nine patients (75%) developed
a complete short-term response, two had a partial response, and eight patients had a
long-term response to infliximab (median follow-up 10.4 months). In this small
study, long-term response to infliximab therapy was more likely in patients who
11 Biologic Therapy in Pediatric Inflammatory Bowel Disease