Concomitant methotrexate and tacrolimus augment the clinical response to abatacept in patients with rheumatoid arthritis with a prior history of biological DMARD use.

This observational retrospective study examined whether abatacept efficacy could be augmented with concomitant methotrexate (MTX) or tacrolimus (TAC) in patients with rheumatoid arthritis (RA) who experienced failure with prior biological disease-modifying antirheumatic drugs (DMARDs) and in whom favorable therapeutic efficacy is difficult to achieve. All patients with a prior biological DMARD history who were treated with abatacept for 52 weeks and registered in a Japanese multicentre registry were included. Clinical efficacy and safety of abatacept according to the concomitant drug used, i.e., none (ABT-mono), MTX (ABT-MTX), and TAC (ABT-TAC), were compared. A greater mean percent change of DAS28-ESR was observed in the ABT-TAC group compared with the ABT-mono group at weeks 12 (-20.5 vs. -5.4 %, p = 0.035) and 24 (-25.0 vs. -11.0 %, p = 0.036). ABT-MTX and ABT-TAC groups had a significantly higher proportion of patients who achieved low disease activity (LDA) within 52 weeks compared with the respective baselines, while no significant change was observed in the ABT-mono group. A higher proportion of patients in the ABT-TAC group achieved EULAR moderate response compared with the ABT-mono group at week 52 (66.7 vs. 35.0 %, p = 0.025). Multivariate logistic regression analysis revealed that concomitant TAC use was independently associated with the achievement of LDA and EULAR response at 52 weeks, while concomitant MTX use was not. Concomitant TAC use may offer a suitable option for RA patients treated with abatacept after prior biological DMARD failure, likely because both abatacept and TAC affect T cell activation.