JAK-SPARE: Baricitinib Induces Glucocorticoid-Free Remission in Early PMR

Baricitinib efficacy in the JAK-SPARE trial

Baricitinib (Olumiant) met the primary endpoint of the phase 3 JAK-SPARE trial, inducing glucocorticoid (GC)-free remission in 65% (15/23) of patients with new-onset polymyalgia rheumatica (PMR) at week 16, compared with 17% (4/23) receiving placebo (P = .002).¹ Helga Lechner-Radner, Associate Professor of Rheumatology, Medical University Vienna, Austria, presented the randomized, double-blind data at the European Alliance of Associations for Rheumatology (EULAR), held in London in June.¹ Both arms received a standardized rapid oral GC taper from 20 mg to 0 mg over 11 weeks alongside baricitinib or placebo.¹

Sarilumab remains the only targeted agent carrying a specific indication for PMR, leaving clinicians with limited options for patients relapsing during glucocorticoid tapers.² JAK-SPARE is among the first phase 3, randomized, placebo-controlled trials evaluating an oral Janus kinase (JAK) inhibitor in new-onset PMR.¹ A positive result positions baricitinib as a potential oral glucocorticoid-sparing alternative pending regulatory review.

JAK-SPARE randomized patients with early PMR (diagnosed within three weeks, initial prednisone dose ≤25 mg/day) 1:1 to baricitinib 4 mg or placebo across five centers in Austria, Italy, and Czechia.¹ Both arms received the same 11-week rapid GC taper during the 16-week double-blind Part I.¹ After week 16, patients originally assigned to placebo crossed over to baricitinib 4 mg through week 28 (Part II), while the baricitinib arm continued unchanged.¹

Between July 2022 and May 2025, investigators screened 55 patients and randomized 46 to baricitinib (n=23) or placebo (n=23); last patient visit occurred in April 2026.¹ Mean age was similar between arms, at 65.1 years for baricitinib and 65.9 years for placebo, and nearly all participants in both groups identified as never-smokers.¹ Baseline PMR-Activity Scale scores, C-reactive protein levels, and prednisone dose were also comparable between arms.¹

The primary endpoint, GC-free remission at week 16 in the intention-to-treat population using non-responder imputation, was reached by 15 of 23 patients (65%) on baricitinib versus 4 of 23 (17%) on placebo (P = .002).¹ GC-free remission favored baricitinib as early as week 12, at 60.9% versus 26.1% with placebo (P < .01).¹

Baricitinib safety and secondary endpoints in PMR

Time to first relapse was significantly shorter with placebo than baricitinib (P = .035).¹ Median cumulative GC dose at week 16 was significantly higher with placebo, at 1183 mg (interquartile range [IQR], 1035-1392) versus 962 mg (IQR, 839-1076) with baricitinib (P = .007).¹ After crossover, GC-free remission in the former placebo arm rose to 65.2% by week 28, comparable to 78.3% in the original baricitinib arm (P = .514).¹

One serious adverse event occurred in each arm.¹ The baricitinib group had a case of prostate adenocarcinoma diagnosed at week 18, leading to treatment discontinuation, while the placebo group had a gastric ulcer at week 4.¹ Investigators did not report additional safety signals distinguishing baricitinib from placebo through week 16.¹

JAK-SPARE was funded by Eli Lilly and Company, the manufacturer of baricitinib.¹ Investigators concluded the data support baricitinib as an effective novel GC-sparing option in early PMR, though the drug does not yet carry a PMR indication.¹ Additional follow-up beyond week 28 will help clarify durability of remission after the placebo-to-baricitinib crossover.¹

References

1. Lechner-Radner H, Anderle K, Bond M, et al. Baricitinib for remission induction and glucocorticoid sparing in new-onset polymyalgia rheumatica (JAK-SPARE): a phase III randomized controlled trial. Ann Rheum Dis. 2026;85(suppl 1):LB0005. https://doi.org/10.1136/annrheumdis-2026-eular.LBA_B.61

2. Late-breaking studies at EULAR 2026. RheumNow. Published June 17, 2026. Accessed July 27, 2026. https://rheumnow.com/news/late-breaking-studies-eular-2026