<p>This review will summarize clinical, genetic and pathophysiologic characteristics that are shared between children with enthesitis related arthritis (ERA) with axial involvement and adults with non-radiographic, and in some cases radiographic, axial spondyloarthritis (SpA); and between children with ERA and primarily peripheral disease manifestations and adults with peripheral SpA. Due to the differences in classification criteria for children with ERA and adults with axial and peripheral SpA, the FDA granted automatic full waivers of studies in children for new medications for "axial spondyloarthropathies including ankylosing spondylitis" up until July 2020. Thus, although current juvenile idiopathic arthritis (JIA) treatment guidelines recommend the use of biologic disease modifying anti-rheumatic drugs (DMARDs) as part of the early treatment for patients with ERA, none of the FDA-approved therapies for peripheral SpA or non-radiographic axial SpA (certolizumab pegol, ixekizumab, and secukinumab) have been studied or are labelled for use in children with ERA. Considering the similarities between adult spondyloarthritis and ERA in terms of etiology, genetics, pathogenesis and clinical manifestations summarized in this review, medications approved for axial SpA or peripheral SpA should also be studied in children with active ERA involving axial or peripheral joints, respectively, with the intent to achieve labeling for use in children. Considering the current lack of effective FDA-approved therapies for ERA, the FDA should also consider requiring pediatric studies for medications that have already been approved for the treatment of adults with SpA.</p>

<p>The pediatric rheumatic diseases are a heterogeneous group of rare diseases, posing a number of challenges for the use of traditional clinical and translational research approaches. Innovative comparative effectiveness approaches are needed to efficiently study treatment approaches and disease outcomes. The Childhood Arthritis and Rheumatology Research Alliance (CARRA) developed the consensus treatment plan (CTP) approach as a comparative effectiveness tool for research in pediatric rheumatology. CTPs are treatment strategies, developed by consensus methods among CARRA members, intended to reduce variation in treatment approaches, standardize outcome measurements, and allow for comparison of the effectiveness of different approaches with the goal of improving disease outcomes. To date, CTPs have been published for 7 different diseases and disease manifestations. The approach has been successfully piloted for juvenile localized scleroderma, systemic onset juvenile idiopathic arthritis (JIA), polyarticular JIA, dermatomyositis, and lupus nephritis. Large-scale studies are underway for systemic JIA and polyarticular JIA, with the CARRA patient registry serving as the data collection platform. These studies have been designed with stakeholder involvement, including active input from CARRA providers, patients, and parents, with the goal of increasing the feasibility and ensuring the relevance of the outcomes. These studies include ancillary biospecimen collection intended to support additional translational and mechanistic studies. Data from these ongoing CTP studies will provide more information on the ability of this approach to identify effective treatment strategies and improve outcomes for the pediatric rheumatic diseases. This article is protected by copyright. All rights reserved.</p>