Baricitinib Effectively Reduces Frequency of Flares in Patients with JIA

Results from a University of Bristol-led analysis of a phase 3 trial are providing clinicians with insight into use of baricitinib in the management of juvenile idiopathic arthritis (JIA).

The study, which assessed data from the JUVE-BASIS trial, suggests baricitinib significantly reduced both the time to and frequency of flares in patients with JIA when compared with placebo (PBO), with improvements in JIA-ACR scores observed in the majority of patients by week 12.

“Baricitinib is a Janus kinase (JAK)1/2 selective inhibitor approved for the treatment of rheumatoid arthritis,” investigators explained. “JIA is a group of diseases characterized by immune mediated chronic arthritis which often requires treatment with conventional synthetic or biologic disease-modifying antirheumatic drugs (cs or b-DMARDs).

To investigate efficacy and safety of baricitinib in patients with JIA with an inadequate response to cs or b-DMARDs, patients aged 2 to <18 years with extended oligo- or poly-articular JIA, enthesitis-related arthritis (ERA), or juvenile psoriatic arthritis (JPsA) were included in the multicenter, double-blind, withdrawal study (NCT03773978). Eligible patients met International League of Associations for Rheumatology (ILAR) criteria and had an inadequate response to 1 or more cs and/or b-DMARDs.

The study was categorized into 3 periods: a 2-week pharmacokinetic/safety assessment (PKS), a 12-week open-label lead-in (OLLI), and an up-to a 32-week double-blind withdrawal (DBW) period. Both dosage and safety were established in the PKS first, and then all patients, including those enrolled in the OLLI who were receiving age-based, oral, once daily doses of baricitinib. Those with a JIA-ACR30 response at week 12, the end of OLLI, were then entered into the DBW and randomized 1:1 to either continue baricitinib or begin PBO, remaining until flare or up to week 32. The primary endpoint was time to flare during the withdrawal period. Secondary endpoints included the JIA-ACR30/50/70/90 response at week 12, as well as the proportion of patients who experienced a flare during the DBW.

Of the 220 patients were enrolled in the study, with 29 in the PKS group, 219 entered the OLLI, and 163 participated in the DBW. The JIA-ACR30/50/70/90 response at week 12 was 76.3%, 63.5%, 46.1%, and 20.1%, respectively. Time was significantly shorter with PBO compared with baricitinib (hazard ratio 0.24 [95% CI 0.13,0.45], P<0.001) and flares were significantly lower in patients receiving baricitinib when compared with placebo (14 (17.1%) vs 41 (50.6%), P<0.001) throughout the DBW.

During the PKS and OLLI periods, 57.3% (n=126) of patients reported 1 or more treatment emergent adverse event (TEAE), and 2.7% (n=6) of patients had 1 or more serious adverse event (SAE). In the DBW period, 46.9% (n=38) patients receiving placebo and 65.9% (n=54) patients receiving baricitinib reported at least 1 TEAE, and 3.7% (n=3). A total of 4.9% (n=4) reported 1 or more SAE, respectively. The mean weeks of exposure was higher in participants in the baricitinib group when compared with placebo during DBW (26.34 vs 18.91, respectively) due to the study design. There were no deaths, cardiovascular events, or uveitis, and safety was consistent with the known safety profile in adult patients with rheumatoid arthritis.

“These findings support baricitinib as a treatment for signs and symptoms of JIA with an inadequate response to cs or b-DMARDs,” investigators concluded.

The study, “Baricitinib in Juvenile Idiopathic Arthritis: A Phase 3, Double-Blind, Placebo-Controlled, Withdrawal, Efficacy and Safety Study,” was presented at the EULAR 2022.