2516 Use of Ustekinumab in Pediatric Crohn's Disease: A Report of Three Cases

Abstract

INTRODUCTION: Treatment options for pediatric IBD are limited. Use of non-FDA approved agents to manage difficult pediatric IBD patients (pts) may be considered. Ustekinumab (UST) is a humanized IgG1κ monoclonal antibody designed to block interleukin-12 and interleukin-23, suppressing cytokine activation and inflammatory response. While UST is approved for the treatment of moderate-to-severe Crohn's disease (CD) in adults, there are little safety and efficacy data in pediatric CD pts. We describe our experience with UST in pediatric CD. CASE DESCRIPTION/METHODS: Pt 1 is an 18 y/o female, diagnosed (dx) with CD in 2015. She was stable on infliximab (IFX) and methotrexate (MTX) but presented in Nov 2016 with worsening scalp psoriasis thought attributable to IFX. IFX was D/Ced and UST initiated in Dec 2016 (260 IV mg, then 90 mg q8wks) with concomitant MTX 15 mg weekly. By Feb 2017, CD was quiescent and psoriasis improving. She presented in Nov 2017 with abdominal cramping and loose stools after running out of MTX. CRP was 8.8 mg/L on UST alone; psoriasis had resolved. MTX was restarted at this time. Pt continued to do well until early Feb 2019 when she had a CD flare associated with a delay in UST dose. She responded to a prednisone taper and restarted therapy. UST serum level in Mar 2019 was 2.5 mg/L and the dose was increased to 90 mg q4wks. The patient continues to do well. Length of therapy (LOT) to date is 2.5 yrs. Pt 2 is an 18 y/o male, dx with CD in 2017. He has intermittently unstable CD, treated with various combinations of adalimumab (ADA), MTX, and prednisone in the past. In Aug 2018 ADA was D/Ced, and UST initiated (390 IV mg, then 90 mg IV q8wks). His CD responded well to UST with a reduction in CRP from 18 to 1.6 mg/L. In late Dec 2018 he reported frequent bloody stools but was otherwise stable. Colonoscopy and upper GI endoscopy in early Jan 2019 were unremarkable; hematochezia resolved with the addition of mesalamine. LOT to date is 10 mos. Pt 3 is a 15 y/o female, dx with CD in 2013. She was stable on ADA until Aug 2018 when she presented with increased symptoms. ADA was D/Ced and UST initiated in Sep 2018 (390 mg IV, then 90 mg IV q8wks). Significant improvement was noted (CRP 1.3 mg/L) in Dec 2018. LOT to date is 10 mos. DISCUSSION: Clinical improvement in CD was observed in these pts following conversion to UST, with no significant safety concerns observed. Further studies are warranted to determine the place in therapy for UST in unstable pediatric CD pts.