Summary

This randomized, double-blind, placebo-controlled, parallel-group trial (BACHELOR) evaluated the efficacy and safety of baricitinib, a Janus kinase 1/2 inhibitor, in patients with recent-onset polymyalgia rheumatica (PMR) without initial use of oral glucocorticoids. Conducted across six expert centers in France, the study enrolled 34 glucocorticoid-naive participants with active PMR (CRP PMR-AS >17) of less than 6 months' duration. Participants were randomized 1:1 to receive either 4 mg oral baricitinib or placebo for 12 weeks, followed by 2 mg baricitinib or placebo for another 12 weeks. Subdeltoid glucocorticoid injections were allowed at weeks 1 and 4, but oral glucocorticoids were reserved as rescue therapy based on disease activity.

Impact on Patient Treatment and Future Perspectives

The primary endpoint—achieving low disease activity (CRP PMR-AS ≤10) at week 12 without oral glucocorticoid use—was met by 78% of the baricitinib group compared to 13% of the placebo group (relative risk 5.8, adjusted p<0.0001). Baricitinib treatment showed rapid efficacy, with over half of treated patients achieving low disease activity by week 2, and maintained benefits through week 24. Notably, no disease flares were observed up to week 36 despite cessation of baricitinib after 24 weeks. Secondary outcomes demonstrated improved quality-of-life measures (SF-36, EQ-5D) and reduced pain in the baricitinib group. Adverse events were consistent with the known safety profile of baricitinib, predominantly musculoskeletal disorders, with no new safety signals or major cardiovascular events reported.

Clinical relevance:

This study presents the first evidence that early PMR can be effectively managed without initial oral glucocorticoids by using baricitinib, potentially mitigating glucocorticoid-related adverse events common in the elderly. These findings address a significant unmet need in PMR treatment and suggest that targeted JAK inhibition offers a viable alternative to traditional glucocorticoid therapy, especially for patients at risk of glucocorticoid toxicity. Larger trials are warranted to confirm these findings and optimize dosing strategies.

References

Saraux A et al. Lancet Rheumatol 2025

Composed by

PD Dr. med. Thomas Neumann, Stv. Chefarzt, Kantonsspital St. Gallen