To examine the efficacy of abatacept in patients with rheumatoid arthritis (RA) using magnetic resonance imaging (MRI) of bilateral hands.
This prospective study included 35 RA patients. MRI of bilateral hands was performed at baseline and after 12 months of treatment with intravenous abatacept. MRI images were scored for synovitis, osteitis, erosion and joint space narrowing (JSN) according to the RA MRI Scoring System (RAMRIS). The primary endpoint was the change in RAMRIS score from baseline. Repair of erosion was defined as a negative change in the erosion score that was greater than the smallest detectable changes (SDCs).
Thirty-one patients completed the study. Median synovitis and osteitis scores showed statistically significant reductions at Month 12 when compared to baseline (synovitis score, -5.5 [P < 0.0001]; osteitis score, -0.5 [P = 0.03]). However, median erosion and JSN scores did not significantly change. At Month 12, 83% of patients showed no progression of erosion scores and repair of erosion was observed in 11% of patients. All patients with repair of erosion achieved functional remission (Health Assessment Questionnaire-Disability Index ≤ 0.5). The Simplified Disease Activity Index response rate at Month 1 was identified as an independent factor predicting changes in the erosion scores at Month 12.
Abatacept treatment reduced synovitis and osteitis scores and did not worsen erosion and JSN scores at Month 12. Over 10% of patients experienced repair of erosion.