Clinical effectiveness and safety of additional administration of tacrolimus in rheumatoid arthritis patients with an inadequate response to abatacept: A retrospective cohort study

OBJECTIVE: Abatacept (ABT) demonstrates good clinical efficacy and retention in rheumatoid arthritis (RA) patients. However, no rescue treatment option against inadequate response to ABT exists. Since tacrolimus (TAC) and ABT suppress T lymphocytes via different mechanisms and a combination of these agents could potentially be effective, this study aimed to examine the efficacy and safety of add-on TAC therapy in RA patients with inadequate response to ABT. METHODS: Of 550 patients treated with ABT and registered in a Japanese multicenter registry, 25 consecutive patients who underwent add-on TAC therapy and were followed for longer than 24 weeks were included in this study. RESULTS: Mean patient age was 67.0 years, disease duration was 16.2 years, and duration of ABT treatment was 1.2 years at the initiation of add-on TAC therapy. Mean TAC dose was 1.2 mg/d at baseline and 1.6 mg/d at week 24. Mean Disease Activity Score of 28 joints - erythrocyte sedimentation rate was significantly improved at week 24 (3.35) relative to baseline (4.97). The proportion of patients who achieved low disease activity or remission was 40.0%, and the European League Against Rheumatism moderate or good response was 72.0%. ABT retention rate was 92.0% at week 24, as calculated by Kaplan-Meier analysis. Only one patient discontinued add-on TAC therapy due to an adverse event (itching sensation). CONCLUSION: This is the first report describing the efficacy and safety profile of add-on TAC therapy with a focus on RA patients with inadequate response to ABT. Our findings suggest that add-on TAC therapy is a worthwhile complementary treatment option in daily clinical practice.