Background/Purpose:

Abatacept is a new class of biologic agent for the treatment of rheumatoid arthritis (RA) that inhibits T cell activation by binding to CD80/86. Some evidences demonstrating that the abatacept may offer advantage on safety over the TNF inhibitors have been accumulated. Therefore, we sometimes tend to use abatacept in the elderly patients easily. We studied the clinical response and safety profile of abatacept in the real-world patients using the Japanese multicenter registry data.  

Methods:

Participants were the consecutive 508 RA patients treated with abatacept who were registered in the Tsurumai Biologics Communication Registry (TBCR). We divided the patients into three groups according to the tertile value of age. As the efficacy endpoints, we compared mean and categorical distribution of DAS28-CRP score and EULAR response rate between the young (<62 years), middle (62-72 years), and elderly (>72 years) group at baseline, 4, 12, 24, and 52 weeks. As the safety endpoints, we studied the incidence rate (Kaplan-Meier method) and the predictive factors (multivariate Cox regression analysis) of the discontinuation of abatacept due to adverse events for up to 4 years. We studied the safety endpoints separately in the patients with and without concomitant methotrexate (MTX) treatment, since the MTX usually affects the safety profile.

Results:

There was significant difference between the young, middle, and elderly groups in age (52.7, 67.7, and 78.1 years; p<0.001), eGFR value (108.5, 91.1, and 79.6 ml/min/1.73m²; p<0.001), and MTX usage rate (57.7, 44.9, and 32.2 %; p<0.001). There was no significant difference between three groups in all of the clinical efficacy endpoints (data not shown). For the safety analysis, we divided the patients into two groups according to the cut-off value (69.5 years) from the ROC curve for age in the MTX (-) patients (Fig. A). The elderly group (>69.5 years) demonstrated higher incidence rate of discontinuation due to adverse events (1.0 vs 4.9% at 24 weeks, p=0.005) in the MTX (-) patients (Fig. B). The age of >69.5 years was identified as an independent predictor of incidence of discontinuation due to adverse events in the MTX (-) patients (Fig. C). However, there was no such difference in the incidence rate (Fig. B) and the being elderly (>69.5 years) was not a predictor in the MTX (+) patients (Fig. C).

Conclusion:

It was remarkable that abatacept therapy demonstrated the comparative efficacy in the elderly patients. Similar to a case of other biologics, we should pay attention to the incidence of severe adverse events in the elderly patients without concomitant MTX. However, especially in the patients being treated with MTX concomitantly, abatacept would be a good treatment option in the elderly from the view point of both efficacy and safety.