Ustekinumab therapy for moderately to severely active pediatric Crohn’s disease: UNITI Jr study safety and efficacy results in patients weighing at least 40 kg

BACKGROUND: UNITI Jr is a phase 3 study evaluating the efficacy, safety, and pharmacokinetics of ustekinumab, an interleukin-12/-23 antagonist, in pediatric patients with moderately to severely active Crohn's disease. Results from patients weighing at least 40 kg are reported. METHODS: Patients at least 40 kg and aged less than 18 years with a Pediatric Crohn's Disease Activity Index score of >30 received a single intravenous weight-tiered induction dose of ustekinumab. After 8 weeks, patients were randomized to subcutaneous ustekinumab 90 mg every 8 or 12 weeks. The primary endpoint was clinical remission at Week 8. Secondary endpoints included clinical response (Weeks 8, 52), endoscopic response (Weeks 16, 52), clinical remission, and corticosteroid-free remission (Week 52). RESULTS: Of 48 patients, median age was 15.0 years (interquartile range: 14.0-16.0). At Week 8, 52.1% (25/48) achieved clinical remission and 93.8% (45/48) achieved clinical response. At Week 16, 29.8% (14/47) achieved endoscopic response. Clinical remission at Week 52 was achieved in 15/25 (60.0%; every 12 weeks) and 10/23 (43.5%; every 8 weeks). Three patients (6.3%) discontinued ustekinumab between Weeks 8 and 52. Ustekinumab was safe and well-tolerated; adverse event rates were similar between groups. Immunogenicity was low; trough median (mean) steady-state serum ustekinumab concentrations following 8 weeks of dosing were 1.38 (2.08) to 1.74 (2.32) μg/mL and were comparable to levels in adult patients: 2.83 (2.05) μg/mL. CONCLUSIONS: Ustekinumab induction and maintenance therapy was effective and safe through 52 weeks in pediatric patients weighing at least 40 kg with moderately to severely active Crohn's disease. TRIAL REGISTRATION NUMBERS: NCT04673357.