Abstract
OBJECTIVES: T cells play a key role in the pathogenesis of early systemic sclerosis. This study assessed the safety and efficacy of abatacept in patients with diffuse cutaneous systemic sclerosis (dcSSc).
METHODS: A 12-month, randomized, double-blind, placebo-controlled trial with participants randomized in a 1:1 ratio to either abatacept 125 mg subcutaneous or matching placebo, stratified by duration of dcSSc. Escape therapy was allowed at six months for worsening disease. The co-primary end points were change in modified Rodnan skin score (mRSS) and safety over 12 months. Treatment differences in longitudinal outcomes were assessed using linear mixed models, with outcomes censored after initiation of escape therapy. Baseline skin tissue was classified into intrinsic gene expression subsets.
RESULTS: Among 88 participants, the adjusted mean change in mRSS at 12 months was -6.24 units in the abatacept and -4.49 units in the placebo, with adjusted mean treatment difference of -1.75 units (p=0.28). Two secondary outcome measures (HAQ-DI and a composite measure) were clinically and statistically significant favoring abatacept. A larger proportion of placebo subjects required escape therapy relative to abatacept (36% vs. 16%). Decline in mRSS over 12 months was clinically and significantly higher in abatacept vs. placebo for the Inflammatory (p<0.001) and Normal-like skin gene expression subsets (p=0.03). 35 participants in the abatacept versus 40 in the placebo had adverse events (AEs), including two and one deaths, respectively.
CONCLUSIONS: In this Phase 2 trial, abatacept was well tolerated, but change in mRSS was not statistically significant. Secondary outcome measures, including gene expression subsets, showed some evidence in favor of abatacept. These data should be confirmed in a Phase 3 trial. This article is protected by copyright. All rights reserved.
Khanna, Dinesh