The oral Janus kinase (JAK) inhibitor baricitinib has demonstrated efficacy in inducing and maintaining glucocorticoid-free remission in patients with early polymyalgia rheumatica, according to the phase III JAK-Spare trial.
At week 16, the primary endpoint of glucocorticoid-free remission occurred in 65.2 percent patients in the baricitinib arm as opposed to 17.4 percent in the placebo arm (p<0.01), reported lead investigator Dr Study Helga Lechner-Radner from the Medical University of Vienna in Vienna, Austria. [EULAR 2026, abstract LB0005]
“This significant difference was already present at week 12 (60.9 percent vs 26.1 percent; p<0.01), very shortly after the withdrawal of glucocorticoids,” Lechner-Radner added.
When patients in the placebo arm crossed over to treatment with baricitinib, the rate of glucocorticoid-free remission dramatically rose to 65.2 percent at week 28. In the baricitinib arm, the rate increased to 78.3 percent. Time to relapse was significantly longer with baricitinib vs placebo (p=0.008).
Median cumulative steroid doses were also significantly lower in the baricitinib arm than in the placebo arm, at 736 vs 1,065 mg at week 16 (p=0.015) and 736 vs 1,086 mg at week 28 (p=0.013).
For patients in the placebo arm who crossed over to baricitinib treatment, the cumulative steroid dose remained stable from week 16 through week 28, demonstrating that no further glucocorticoid additions were necessary, according to Lechner-Radner.
“These findings support the use of baricitinib as an effective novel glucocorticoid-sparing treatment option in early polymyalgia rheumatica,” the investigator said.
This has important clinical implications, given that while the majority of patients do respond very well to glucocorticoids, relapses frequently occur during tapering or discontinuation, she added.
The JAK-Spare trial
Conducted across five centres across Europe, JAK-Spare included 46 polymyalgia rheumatica patients at a very early disease stage (≤3 weeks duration) who had not been exposed to more than 25 mg of glucocorticoids since their diagnosis. The average age of the patients was 65 years, and slightly more than half were men. The average disease duration before enrolment was 16 days, and the average glucocorticoid dose was 18 mg.
The trial was conducted in three parts:
· Part 1: The patients were randomly assigned to receive treatment with either baricitinib 4 mg or placebo orally for 16 weeks, on top of a standardized rapid oral glucocorticoid taper (from 20 to 0 mg over 11 weeks).
· Part 2: At week 16, patients in the placebo arm crossed over to baricitinib 4 mg until week 28, while those in the baricitinib arm continued the same treatment dose.
· Part 3: At week 28, patients who achieved glucocorticoid-free remission were randomly assigned either to continue treatment with baricitinib 4 mg through week 44 or to lower their dose of baricitinib to 2 mg and then stop it altogether from 36 to 44 weeks.
Results for part 3 of the trial showed that 93.3 percent of patients who continued receiving baricitinib 4 mg maintained glucocorticoid-free remission as opposed to 72.2 percent of those who tapered and withdrew their medication (p=0.186).
Lechner-Radner pointed out that while the difference was not significant, only around 7 percent of patients who continued with baricitinib 4 mg arm lost their state of glucocorticoid-free remission, whereas almost 30 percent in those who tapered and withdrew treatment did. “This is also reflected in the relapse free survival course.”
In terms of safety, only four serious adverse events (AEs) occurred during the trial, all of which were unlikely related or not related to the investigational drug, she said. “We had a very well-balanced number of AEs across the placebo and the baricitinib arms, and all AEs were regarded as either mild or moderate in severity.”