Rheumatoid arthritis (RA) is the most common form of chronic inflammatory arthritis. Characteristic radiographic findings of RA include periarticular osteopenia, joint space loss, and marginal joint erosions. These changes are often not seen in early disease; as such, magnetic resonance imaging (MRI) and ultrasonography have been shown to be more sensitive than radiography for the detection of changes resulting from synovitis.1,2 Ultrasound imaging has been compared with standard radiographic imaging and has been shown to be superior at detecting bone erosions early in the course of RA.3

In an open-label, multicenter, single-arm study published in the Annals of Rheumatic Diseases, D’Agostino and colleagues analyzed data from 89 patients with RA who completed a 24-week treatment period with abatacept.4 Abatacept is a fully human, soluble fusion protein that consists of the extracellular domain of human cytotoxic T-lymphocyte antigen 4 (CTLA-4) and the Fc portion of IgG1, which selectively modulates the CD80/CD86:CD28 costimulatory signals and interactions between activated T cells and antigen-presenting cells.  Individual joints were evaluated with a composite power Doppler ultrasound (PDUS) score developed by the Outcome Measures in Rheumatology-European League Against Rheumatism (OMERACT-EULAR) Ultrasound Task Force. Maximal scores for each joint were added to a Global OMERACT-EULAR Synovitis Score (GLOESS) for bilateral metacarpophalangeal joints 2 through 5 at baseline. Other joint sets were evaluated for comparison, and additional screening occurred at 1, 2, 4, 6, 8, 12, 16, 20, and 24 weeks.

Signs of improvement were observed on PDUS as early as 1 week after initiation of treatment, with a mean reduction from baseline GLOESS of 0.7. Similar trends in PDUS scores were observed in synovitis in individual joints, with statistically significant improvements noted at week 1. A significant reduction in synovial hyperplasia was seen by week 2, while joint effusion showed statistically significant reductions at week 4.


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Based on these promising results, the authors suggest performing ultrasound evaluation as early as possible to assess the response to abatacept treatment.

Summary and Clinical Applicability

Power Doppler ultrasound (PDUS) is a sensitive diagnostic tool to detect early improvement in synovitis with abatacept treatment in patients with RA.  Further studies will be needed to validate its use with other tumor necrosis factor (TNF) inhibitor treatments.  Early joint examination with PDUS after initiation of TNF inhibitor treatment should be considered to assess treatment efficacy.

References

1. McQueen FM. The use of MRI in early RA. Rheumatology (Oxford). 2008; 47:1597-1599.

2. Terslev L, Torp-Pedersen S, Savnik A, et al. Doppler ultrasound and magnetic resonance imaging of synovial inflammation of the hand in rheumatoid arthritis: a comparative study. Arthritis Rheum. 2003;48:2434-2441.

3. Wakefield RJ, Gibbon WW, Conaghan PG, et al. The value of sonography in the detection of bone erosions in patients with rheumatoid arthritis. Arthritis Rheumatism. 2000;43:2672-2770.

4. D’Agostino MA, Wakefield RJ, Berner-Hammer H, et al; for the OMERACT-EULAR-Ultrasound Task Force.  Value of ultrasonography as a marker of early response to abatacept in patients with rheumatoid arthritis and an inadequate response to methotrexate: results from the APPRAISE study. Ann Rheum Dis. 2015; Nov 20. pii: annrheumdis-2015-207709. doi: 10.1136/annrheumdis-2015-207709. [Epub ahead of print]