The time of flare was significantly shorter in the placebo group compared to the baricitinib.
New data presented the 2022 American College of Rheumatology Convergence Meeting in Philadelphia shows baricitinib could be an effective treatment for juvenile idiopathic arthritis.
A team, led by Athimalaipet Ramanan, Bristol Royal Hospital for Children, evaluated the efficacy and safety of baricitinib in pediatric patients with juvenile idiopathic arthritis and an inadequate response to conventional synthetic or biologic disease-modifying antirheumatic drugs.
Baricitinib, a JAK1/2 selective inhibitor, is currently approved for rheumatoid arthritis, but not juvenile idiopathic arthritis.
In the phase 3, multicenter, double-blind, withdrawal, efficacy, and safety study, the investigators examined patients aged 2-17 with extended oligo- or poly-articular JIA, ERA, or JPsA, defined by the ILAR criteria. Each patient had inadequate response to 1 conventional synthetic or b-DMARDs.
The study included a 2-week pharmacokinetic/safety assessment, a 12 week open-label lead-in, and an up to 32 week double-blind withdrawal. The team confirmed dosage and safety in the pharmacokinetic/safety assessment and then in patients, including those in the pharmacokinetic/safety assessment, enrolled in the open-label lead-in. Each patient received age-based, oral, once daily doses of baricitinib.
Patients with a JIA-ACR30 response at week 12, the conclusion of the open-label lead-in, entered the double-blind withdrawal and were randomized to continue baricitinib treatment or placebo. This group remained until a flare or up to week 32.
The investigators sought a primary endpoint of the time to flare during the double-blind withdrawal and secondary endpoints included JIA-ACR30/50/70/90 response rates at week 12 and the proportion of patients with a flare during the double-blind withdrawal
The team estimated survival curves using the Kaplan-Meier method.
The study included 220 total patients, 29 in the pharmacokinetic/safety assessment, 219 in the open-label lead-in, and 163 in the double-blind withdrawal. The JIA-ACR30/50/70/90 response at week 12 was 76.3%/63.5%/46.1%/20.1%, respectively.
During the double-blind withdrawal, the time of flare was significantly shorter in the placebo group compared to the baricitinib (HR, 0.24; 95% CI, 0.13-0.45; P <0.001).
The proportion of patients with a flare during the double-blinded withdrawal was substantially lower in the baricitinib compared to placebo (n = 14; 17.1% vs. n = 41; 50.6%; P <0.001).
In the pharmakonetic/safety assessment and the open-label lead-in periods, 57.3% (n = 126) of patients reported at least 1 treatment emergent adverse event, while 2.7% (n = 6) reported at least 1 serious adverse event.
In the double-blind withdrawal, 46.9% (n = 38) and 65.9% (n = 54) patients reported at least 1 treatment-emergent adverse events for placebo and baricitinib, respectively. However, those with at least serious adverse events were 3.7% (n = 3) and 4.9% (n = 4).
The mean weeks of exposure was higher in the baricitinib compared placebo group during the double-blind withdrawal (26.34 vs 18.91) because of the study design.
There were no deaths, cardiovascular events or uveitis. However, there was 1 case of herpes zoster.
“Baricitinib significantly reduced time to and frequency of JIA flares in pts with JIA versus placebo, and improved JIA-ACR scores in the majority of patients within 12 weeks,” the authors wrote. “Safety findings were consistent with the known safety profile in adult rheumatoid arthritis indications. These findings support baricitinib as a treatment for signs and symptoms of JIA with an inadequate response to cs or b-DMARDs.”
The study, “Baricitinib in Juvenile Idiopathic Arthritis: A Phase 3, Double-Blind, Placebo-Controlled, Withdrawal, Efficacy and Safety Study,” was published online in ACR.
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