Growth is the question paediatric rheumatologists ask of any JAK inhibitor, because growth hormone signals through JAK2. In 225 children with JIA followed for a median of 3.6 years on tofacitinib, height stayed close to age-appropriate norms, younger children grew faster than the WHO reference, and IGF-1, IGFBP3 and osteocalcin did not fall. It is a post hoc analysis with no untreated comparator, so it reassures rather than proves.
An individual patient data meta-analysis of 16 phase 3 trials and 11,883 patients shows JAK inhibitor response falls in a graded way as BMI rises — roughly 18 fewer ACR20 responders per 100 treated at class 3 obesity. Crucially, no such gradient appears in the placebo arms, and within-trial interaction analyses confirm obesity modifies the treatment effect rather than simply marking worse disease.
SELECT-SWITCH is the first double-blind RCT to test mechanism-of-action switching (to the JAK inhibitor upadacitinib) versus cycling to a second TNF inhibitor (adalimumab) after a first TNFi fails in RA. At 12 weeks, upadacitinib roughly doubled low-disease-activity rates and beat adalimumab on the primary endpoint and 4 of 5 ranked secondaries — though HAQ-DI function did not separate and safety was comparable.
The 2025 EULAR update streamlines RA management to 5 overarching principles and 9 recommendations, abandons post-methotrexate prognostic risk stratification, and keeps JAK inhibitors co-equal with biologics after individual risk assessment.
The VALOR phase 3 trial shows that brepocitinib 30 mg daily — a selective TYK2–JAK1 inhibitor — significantly improves composite disease activity, skin involvement, and muscle strength while enabling steroid discontinuation in adults with treatment-refractory dermatomyositis, marking the first successful phase 3 RCT of an oral targeted agent in this disease.