Efficacy of baricitinib in patients with moderateto-severe rheumatoid arthritis with 3 years of treatment: results from a long-term study

Aim: Baricitinib (BARI) is an oral, selective, reversible Janus kinase 1/2 inhibitor approved for treatment of adults with active rheumatoid arthritis (RA). Evaluation of long‐term efficacy of once‐daily BARI4mg in methotrexate (MTX)‐na�ve/inadequately responding (IR) patients with active RA. Methods: Analyses were performed on data from RA‐BEGIN (MTXna�ve) and RA‐BEAM (MTX‐IR) for 52weeks, and from the long‐term extension (LTE) study (RA‐BEYOND) for an additional 96weeks (148weeks total). At week52, MTX‐na�ve patients initially treated with MTX, BARI4mg, or BARI4mg+MTX (RA‐BEGIN) switched to open‐label BARI4mg monotherapy in the LTE. At week52, MTX‐IR patients initially treated with BARI4mg or adalimumab (ADA)+MTX in RA‐BEAM were switched to open‐label BARI4mg (+MTX) treatment in the LTE. Placebo (+MTX)‐treated patients switched to openlabel BARI4mg (+MTX) at week24. The analyses of efficacy (SDAI) and physical function (HAQ‐DI) were conducted on all patients randomized into RA‐BEGIN and RA‐BEAM receiving?1 dose of study drug (mITT population). The proportion of patients reaching low disease activity (LDA), measured by SDAI?11, was evaluated, along with change from baseline in HAQ‐DI. The non‐responder imputation (NRI) was used for the categorical analysis. Results: By week24 in RA‐BEGIN (N = 584), 62%of BARI4mg or BARI4mg+MTX‐treated patients achieved SDAI LDA compared to 40%of MTX group; response rates for BARI groups were maintained through week148. By week24 in RA‐BEAM (N = 1305), 52%of BARI4mg (+MTX)‐treated, and 50% of ADA (+MTX)‐treated patients achieved SDAI LDA compared to 26%of PBO (+MTX)‐treated patients. BARI4mg and ADA week24 response rates were maintained through week148 even after ADA‐to‐BARI4mg switch at week52. Improvement and maintenance of physical function measured by HAQ‐DI were demonstrated. The overall discontinuation rate (DR) across treatment groups from RA‐BEGIN (19.5%) and RA‐BEAM (14.2%) have been published. In LTE, BARI‐treated DR was13.7%for RA‐BEGIN (1.1%due to lack of efficacy, 6.4%due to safety) and 12.6%for RABEAM (1.8%due to lack of efficacy, 5.9%due to safety). Conclusions: Long‐term BARI4mg treatment demonstrated the maintenance of clinically‐relevant outcomes for up to 3years. Low discontinuation rates during the LTE indicate that BARI4mg treatment was well‐tolerated.