Predictors of the effectiveness of first-line CTLA4-Ig in patients with RA: the FIRST registry.

Abstract

This study aimed to elucidate which bio-naïve patients with RA are suitable for treatment with CTLA4-Ig. This study enrolled 953 patients with RA who were administered their first biological DMARD (CTLA4-Ig, n = 328; tumour necrosis factor inhibitor [TNFi], n = 625) from July 2013 to August 2022. The primary outcome was the Clinical Disease Activity Index (CDAI) remission rate at week 24 in each group, adjusted using propensity score (PS)-based inverse probability of treatment weighting (IPTW). After minimizing selection bias using PS-based IPTW, the CDAI remission showed no significant difference between the CTLA4-Ig and TNFi groups (P = 0.464). Multivariable logistic regression analysis identified low baseline HAQ-Disability Index (DI) scores as a contributing factor to the CDAI remission rate at week 24 in both groups, along with high baseline ACPA levels in the CTLA4-Ig group. However, among patients with high baseline HAQ-DI scores and low baseline ACPA levels (≦57.2), the CDAI remission rate was significantly higher in the TNFi group (29.8%) compared with the CTLA4-Ig group (5.9%, P < 0.0001). Among patients with high baseline HAQ-DI scores and ACPA levels (>57.2), the CDAI remission rate was significantly higher in the CTLA4-Ig group (35.6%) compared with the TNFi group (22.1%, P = 0.0057). Bio-naive RA patients with low HAQ-DI scores showed high treatment efficacy with no significant difference between CTLA4-Ig and TNFi. Among patients with high baseline HAQ-DI scores, TNFi and CTLA4-Ig were more likely to be effective in those with lower and higher baseline ACPA levels, respectively.