Abatacept reduces disease activity and ultrasound power Doppler in ACPA-negative undifferentiated arthritis: a proof-of-concept clinical and imaging study

• Published in: Rheumatology (Oxford, England) Vol. 56; no. 1; pp. 58 - 67
• Main Authors: Buch, Maya H, Hensor, Elizabeth M A, Rakieh, Chadi, Freeston, Jane E, Middleton, Edward, Horton, Sarah, Das, Sudipto, Peterfy, Charles, Tan, Ai Lyn, Wakefield, Richard J, Emery, Paul
• Format: Journal Article
• Language: English
• Published: England 01.01.2017
• Subjects: Abatacept - therapeutic use; Adult; Antirheumatic Agents - therapeutic use; Arthritis - diagnostic imaging; Arthritis - drug therapy; Arthritis - immunology; Arthritis, Rheumatoid - diagnostic imaging; Arthritis, Rheumatoid - drug therapy; Arthritis, Rheumatoid - immunology; Female; Hand Joints - diagnostic imaging; Humans; Knee Joint - diagnostic imaging; Male; Middle Aged; Patient Reported Outcome Measures; Peptides, Cyclic - immunology; Prospective Studies; Radiography; Remission Induction; Rheumatoid Factor - immunology; Severity of Illness Index; Synovitis - diagnostic imaging; Synovitis - drug therapy; Synovitis - immunology; Ultrasonography, Doppler; undifferentiated arthritis; ACPA; abatacept; ultrasound; inflammatory arthritis
• ISSN: 1462-0324; 1462-0332
• DOI: 10.1093/rheumatology/kew357

No proven treatment exists for ACPA-negative undifferentiated arthritis (UA). The aim of this study was to evaluate whether abatacept is effective in treating poor prognosis, ACPA-negative UA, including its effect on power Doppler on US (PDUS). A proof-of-concept, open-label, prospective study of 20 patients with DMARD-naïve, ACPA-negative UA (⩾2 joint synovitis) and PDUS ⩾ 1 with clinical and 20-joint US (grey scale/PDUS) assessments at baseline, 6, 12, 18 and 24 months. All patients received 12 months of abatacept (monotherapy for minimum first 6 months). The primary end point was a composite of the proportion of patients that at 6 months achieved DAS44 remission, a maximum of one swollen joint for at least 3 consecutive months and no radiographic progression (over 0-12 months). Twenty of the 23 patients screened were enrolled [14 female; mean (sd) age 53.4 (11.2) years, symptom duration 7.5 (0.9) months]. Two (10%) achieved the composite primary end point. A reduction in the mean (sd) DAS44 was observed from a baseline value of 2.66 (0.77) to 2.01 (0.81) at 6 months and to 1.78 (0.95) at 12 months. The DAS44 remission rates were 6/20 (30%; 95% CI: 15, 51%) at 6 months and 8/20 (40%; 95% CI: 22, 62%) at 12 months. A striking decrease in the median (interquartile range; IQR) total PDUS score was noted from 10 (4-23) at baseline to 3 (2-12) and 3 (0-5) at 6 and 12 months, respectively. This report is a first in potentially identifying an effective therapy, abatacept monotherapy, for poor-prognosis, ACPA-negative UA, supported by a clear reduction in PDUS. These data justify evaluation in a controlled study.