Intravenous Golimumab in Patients with Polyarticular Juvenile Idiopathic Arthritis and Juvenile Psoriatic Arthritis and Subcutaneous Ustekinumab in Patients with Juvenile Psoriatic Arthritis: Extrapolation of Data from Studies in Adults and Adjacent Pediatric Populations

Objectives To describe the extrapolation approaches used to support intravenous (IV) golimumab for polyarticular juvenile idiopathic arthritis (pJIA) and juvenile psoriatic arthritis (jPsA) and subcutaneous (SC) ustekinumab for jPsA. Methods Pharmacokinetic, clinical response, and safety data from trials of IV golimumab and SC ustekinumab in polyarticular-course JIA (pc-JIA) (GO-VIVA) or pediatric psoriasis (PsO) (CADMUS and CADMUS Jr) and data from pivotal, phase 3 trials of these agents in adults with similar diseases were used to support extrapolation in pJIA and jPsA. In the phase 3 GO-VIVA trial, patients with pc-JIA aged 2 to < 18 years received IV golimumab 80 mg/m^{2} at weeks 0, 4, then every 8 weeks (Q8W). In the phase 3, randomized, placebo-controlled CADMUS trial, patients with PsO aged ≥ 12 to < 18 years received ustekinumab at weeks 0, 4, then Q12W. In the phase 3 CADMUS Jr trial, patients with PsO aged ≥ 6 to < 12 years received ustekinumab at weeks 0, 4, then Q12W. The ustekinumab analyses used data only from patients who received the standard ustekinumab dosing regimen (≤ 60 kg: 0.75 mg/kg; > 60 to ≤ 100 kg: 45 mg; > 100 kg: 90 mg). Results In the 127 patients with pc-JIA treated with IV golimumab (GO-VIVA), pharmacokinetic and exposure-response results were similar to those in adults with rheumatoid arthritis treated with IV golimumab. Additionally, pharmacokinetic and clinical response data from five patients with jPsA in GO-VIVA were comparable to those in adults with PsA treated with IV golimumab. No new safety signals were observed in GO-VIVA. Pharmacokinetic and clinical response data observed in the four pediatric patients with PsO and jPsA treated with ustekinumab in CADMUS and CADMUS Jr were similar to those in the 91 pediatric patients with PsO without jPsA in these trials and to those in adults with PsA treated with ustekinumab. Safety was extrapolated from CADMUS or CADMUS Jr; no new signals were observed. Conclusions These three sets of analyses corroborate similar exposure and efficacy of IV golimumab in pediatric patients with pc-JIA or jPsA and SC ustekinumab in patients with jPsA to support extrapolation of established adult efficacy. The overall safety profiles of IV golimumab in pediatric patients with pc-JIA or jPsA and SC ustekinumab in pediatric patients with PsO with or without jPsA were consistent with the safety profiles of these agents in the context of their clinical programs and cumulative use. Based on these analyses, the US Food and Drug Administration approved IV golimumab for polyarticular JIA and active PsA in patients 2 years and older and SC ustekinumab for pediatric PsA in patients 6 years and older, highlighting how use of an extrapolation approach can help streamline drug development for pediatric patient populations in whom larger clinical trials are not feasible. Clinical Trial Registration GO-VIVA (NCT02277444) was registered at clinicaltrials.gov on 29 October 2014; CADMUS (NCT01090427) was registered on 22 March 2010; and CADMUS Jr (NCT02698475) was registered on 3 March 2016. Supplementary Information The online version contains supplementary material available at 10.1007/s40272-022-00533-y.