A229 USTEKINUMAB FOR THE TREATMENT OF REFRACTORY PEDIATRIC CROHN’S DISEASE: A SINGLE CENTRE EXPERIENCE

Abstract Background Despite the well-established efficacy of Tumor Necrosis Factor (TNF) antagonists as treatment options for Crohn’s Disease, many pediatric patients need a change in therapy due to adverse events, as well as primary and secondary loss of response, highlighting the necessity for medications with a different mechanism of action. Ustekinumab, a monoclonal antibody targeting IL-12 and IL-23, has been approved to treat psoriatic arthritis, plaque psoriasis, and adults with Crohn’s disease. While utekinumab has been shown to be effective in inducing clinical remission in adults with Crohn’s disease refractory to anti-TNF agents, minimal data exists in the pediatric population. Aims We retrospectively describe 11 pediatric patients who received ustekinumab at the Montreal Children’s Hospital with the goal of assessing its efficacy in inducing clinical, biochemical, and endoscopic remission. Methods We abstracted baseline data, prior treatment and response, indications for starting ustekinumab, clinical response, endoscopic data, and laboratory parameters pre- and post- therapy. Clinical response was defined as decrease in abbrPCDAI (Pediatric Crohn’s Disease Activity Index) score. Results Patients ranged in age from 12–17 years old upon initiation of treatment with ustekinumab and had all previously failed either one (N=8) or both (N=3) anti-TNF therapies. Follow-up ranged from 6 to 22 months. We examined three indices of response to ustekinumab: symptomatic improvement, biomarker normalization, and endoscopic changes. Five of eleven patients demonstrated a clinical response – two maintained clinical remission across available follow-up data, while the remaining three experienced a secondary loss of response. The other six patients studied were primary non-responders. Two of these patients had normal abbrPCDAI scores upon initiation of ustekinumab and terminated therapy due to persistent stricturing disease. The other four non-responders either remained unwell or demonstrated clinical worsening, as measured by the abbrPCDAI. Of the clinical responders, 3/5 had elevated CRP values prior to initiating ustekinumab therapy, all of which normalized within one month of clinical improvement. Endoscopic data both pre- and post- ustekinumab was available in two responders and two non-responders, with endoscopic improvement seen in both of the responders and in one of the two non-responders. Conclusions These results demonstrate that ustekinumab has the potential ability to induce not only clinical and biochemical remission, but also endoscopic improvement, in the pediatric population. An area of concern is the fact that only one patient maintained remission for longer than one year. Future research should focus on maximizing and lengthening the effect of ustekinumab, as well as determining factors that influence response to therapy. Funding Agencies None

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