Efficacy of Baricitinib in Long-term Therapy of Rheumatoid Arthritis
Baricitinib selectively and reversibly inhibits Janus kinases JAK1 and JAK2 and is used in the treatment of adults with active rheumatoid arthritis (RA). Its safety during long-term administration has already been demonstrated by previous analyses, with treatment durations of up to 7 years. Equally important is the long-term efficacy of this drug, which was the focus of work presented in June of this year at the annual European rheumatology congress EULAR 2020.
Baricitinib in Clinical Trials
Data were analyzed from monitoring patients with moderate to severe rheumatoid arthritis who had not been previously treated or had an inadequate response to methotrexate (MTX) treatment. The response data to baricitinib treatment at a dose of 4 mg daily were obtained from the RA-BEGIN clinical trial (patients previously untreated with MTX) and RA-BEAM (patients with inadequate response to MTX), which lasted 52 weeks, and further from the long-term extension of both studies (RA-BEYOND), comprising an additional 96 weeks of treatment (a total of 148 weeks). Efficacy was evaluated using the Simplified Disease Activity Index (SDAI) and the Health Assessment Questionnaire Disability Index (HAQ-DI). Low disease activity (LDA) was considered achieved with an SDAI score of ≤ 11.
Long-term Efficacy in Untreated Patients (RA-BEGIN)
In the RA-BEGIN study, which included 584 patients, baricitinib was administered alone or in combination with MTX, while the control group received only MTX. By the 24th week of the study, LDA was achieved in 62% of patients who took baricitinib (± MTX), compared to 40% in the MTX monotherapy group. During RA-BEYOND, all three groups were treated with baricitinib. The response rate recorded in the 24th week in the baricitinib-treated groups was maintained up to the 148th week of follow-up.
Long-term Efficacy in MTX Non-responders (RA-BEAM)
In the RA-BEAM study (1305 patients), LDA was confirmed in 52% of patients treated with baricitinib (+ MTX) and 50% of patients treated with the active comparator adalimumab (+ MTX) by the 24th week. In the control group treated with placebo (+ MTX), only 26% of patients achieved LDA. When transitioning to RA-BEYOND follow-up in the 52nd week, all patients were switched to baricitinib (patients from the placebo group were switched in the 24th week). The response rate observed in the 24th week in patients taking baricitinib and adalimumab was maintained up to the 148th week. No significant change in treatment efficacy was observed in patients who switched from adalimumab to baricitinib.
Conclusion
The analysis results indicate that long-term treatment with baricitinib at a dose of 4 mg daily maintains clinically relevant efficacy for up to 3 years. Results for LDA and physical function assessed using HAQ-DI were similar. Thus, baricitinib represents a suitable and effective therapeutic option in the treatment of moderate to severe rheumatoid arthritis.
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Source: Smolen J. S., Xie L., Jia B.et al. SAT0152 Efficacy of baricitinib in patients with moderate-to-severe rheumatoid arthritis with 3 years of treatment: results from a long-term study. Ann Rheum Dis 2020; 79: 1016.
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