Background/Purpose: To investigate whether clinical efficacy of abatacept (ABT) and tocilizumab (TCZ) differs depending on whether or not HLA-DRB1 Shared Epitope (SE) is present in patients with rheumatoid arthritis.

Methods: HLA-DRB1 genotype of patients treated with ABT(n=78) and TCZ (n=78) was identified. HLA-DRB1 0101,0102,0401,0404,0405,0408,1001 was defined as SE. Retention rate and clinical efficacy were assessed by Cox proportional hazard model and multiple regression analysis.

Results: The patients with SE positive were 51 in ABT (65%) and 53 in TCZ (68%). The retention rate of ABT was significantly higher in SE positive patients than in SE negatives. (p <0.0001,log rank),and the retention rate of TCZ was not significantly different in both group.

Average CDAI at 24 week was 3.5/10.7 in SE positive/negative group with ABT (p <0.0001, ANOVA), and 6.3/5.8 with TCZ (p = 0.87). Multivariable Cox hazard regression model, in which age, sex, disease duration, ACPA titer, RF titer , MHAQ, prior use of biological agents, MTX dose, oral steroid dose, and SDAI and CRP at baseline were adjusted, revealed that, compared with SE-positive, SE-negative had a higher abatacept discontinuation due to lack of efficacy (adjusted HR=9.2, 95% CI: 2.8-30.4), but was not significant in TCZ (p = 0.41). In addition, the predictor of CDAI at 24 week by multiple regression analysis was SE (p<0.0001) in ABT but SE was not predictive in TCZ.

Conclusion: ABT is effective in SE positive group, but TCZ is not relevant for SE.

« Back to 2017 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/relation-of-hla-drb1-genotype-to-the-efficacies-of-abatacept-and-tocilizumab-in-patients-with-rheumatoid-arthritis/