Pharmacological and non-pharmacological treatments for refractory paediatric Still's disease: a scoping review

Management of systemic juvenile idiopathic arthritis, or Still's disease, has been transformed by the introduction of IL-1 and IL-6 antagonists. Despite this, a minority have refractory disease with three subtypes described: (1) persistent arthritis, (2) recurrent or difficult-to-treat macrophage activation syndrome (MAS), or (3) interstitial lung disease. This scoping review aimed to summarize available evidence for the treatment of refractory paediatric Still's.

Databases were searched using terms 'systemic JIA' or 'Still's disease' AND 'refractory', plus synonyms. Records were screened for papers on the treatment of refractory Still's, before reviewing full texts. Controlled trials, uncontrolled trials and case series/reports involving patients with disease onset <16 years were included. Data were extracted in tabulated form for study characteristics and outcome measures (survival, disease remission, reduction in corticosteroids, and adverse effects). Quality assessment was performed using the appropriate JBI checklist.

Thirty articles matched the inclusion criteria: 1 pilot study, 8 case series and 21 case reports. No controlled studies were identified with all three subtypes of refractory Still's represented. There were positive results in a pilot study of emapalumab (IFN-gamma inhibitor) for the treatment of refractory MAS, and beneficial results with combination biologics and Janus kinase (JAK) inhibitors for refractory Still's arthritis. There are reports of successful management with allogenic stem cell transplantation, although with significant risks.

Various treatment strategies are reported in refractory Still's, including emapalumab, JAK inhibitors, rituximab and combination biologics, although the evidence base is currently limited. Consistent outcome reporting and innovative trial designs are required to provide further evidence in these challenging subgroups.