Predictors of Clinical Improvement in Rituximab‐Treated Refractory Adult and Juvenile Dermatomyositis and Adult Polymyositis1. Issue 3 (March 2014)

• Record Type: Journal Article
• Authors: Aggarwal, Rohit; Bandos, Andriy; Reed, Ann M.; Ascherman, Dana P.; Barohn, Richard J.; Feldman, Brian M.; Miller, Frederick W.; Rider, Lisa G.; Harris‐Love, Michael O.; Levesque, Marc C.; Oddis, Chester V.
• Is Part Of: Arthritis & rheumatology. Volume 66:Issue 3(2014)
• Page Start: 740
• Page End: 749
• Publication Date: 2014-03
• Subjects: Arthritis -- Periodicals; Rheumatism -- Periodicals; 616.72
• DOI: 10.1002/art.38270
• Languages: English
• ISSNs: 2326-5191

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="art38270-sec-0001" sec-type="section"> <title>Objective</title> <p>To identify the clinical and laboratory predictors of clinical improvement in a cohort of myositis patients treated with rituximab.</p> </sec> <sec id="art38270-sec-0002" sec-type="section"> <title>Methods</title> <p>We analyzed data for 195 patients with myositis (75 with adult polymyositis [PM], 72 with adult dermatomyositis [DM], and 48 with juvenile DM) in the Rituximab in Myositis trial. Clinical improvement was defined as 20% improvement in at least 3 of the following 6 core set measures of disease activity: physician's and patient's/parent's global assessment of disease activity, manual muscle testing, physical function, muscle enzymes, and extramuscular disease activity. We analyzed the association of the following baseline variables with improvement: myositis clinical subgroup, demographics, myositis damage, clinical and laboratory parameters, core set measures, rituximab treatment, and myositis autoantibodies (antisynthetase, anti–Mi‐2, anti–signal recognition particle, anti–transcription intermediary factor 1γ [TIF‐1γ], anti‐MJ, other autoantibodies, and no autoantibodies). All measures were univariately assessed for association with improvement using time‐to‐event analyses. A multivariable time‐dependent proportional hazards model was used to evaluate the association of individual predictive factors with improvement.</p> </sec> <sec id="art38270-sec-0003" sec-type="section"> <title>Results</title> <p>In the final multivariable model, the presence of an antisynthetase, primarily anti–Jo‐1 (hazard ratio [HR] 3.08, <italic>P</italic> < 0.01), anti–Mi‐2 (HR 2.5, <italic>P</italic> < 0.01), or other autoantibody (HR 1.4, <italic>P</italic> = 0.14) predicted a shorter time to improvement compared to the absence of autoantibodies. A lower physician's global assessment of damage (HR 2.32, <italic>P</italic> = 0.02) and juvenile DM (versus adult myositis) (HR 2.45, <italic>P</italic> = 0.01) also predicted improvement. Unlike autoantibody status, the predictive effect of physician's global assessment of damage and juvenile DM diminished by week 20. Rituximab treatment did not affect these associations.</p> </sec> <sec id="art38270-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Our findings indicate that the presence of antisynthetase and anti–Mi‐2 autoantibodies, juvenile DM subset, and lower disease damage strongly predict clinical improvement in patients with refractory myositis.</p> </sec> </abstract>