Novel assessment tools to evaluate clinical and laboratory responses in a subset of patients enrolled in the Rituximab in Myositis trial

Clin Exp Rheumatol. 2014 Sep-Oct;32(5):689-96. Epub 2014 Jul 28.

Abstract

Objectives: We aimed to assess changes in myositis core set measures and ancillary clinical and laboratory data from the National Institutes of Health's subset of patients enrolled in the Rituximab in Myositis trial.

Methods: Eighteen patients (5 dermatomyositis, 8 polymyositis, 5 juvenile dermatomyositis) completed more in-depth testing of muscle strength and cutaneous assessments, patient-reported outcomes, and laboratory tests before and after administration of rituximab. Percentage change in individual measures and in the definitions of improvement (DOIs) and standardized response means were examined over 44 weeks.

Results: Core set activity measures improved by 18-70% from weeks 0-44 and were sensitive to change. Fifteen patients met the DOI at week 44, 9 patients met a DOI 50% response, and 4 met a DOI 70% response. Muscle strength and function measures were more sensitive to change than cutaneous assessments. Constitutional, gastrointestinal, and pulmonary systems improved 44-70%. Patient-reported outcomes improved up to 28%. CD20+ B cells were depleted in the periphery, but B cell depletion was not associated with clinical improvement at week 16.

Conclusions: This subset of patients had high rates of clinical response to rituximab, similar to patients in the overall trial. Most measures were responsive, and muscle strength had a greater degree of change than cutaneous assessments. Several novel assessment tools, including measures of strength and function, extra-muscular organ activity, fatigue, and health-related quality of life, are promising for use in future myositis trials. Further study of B cell-depleting therapies in myositis, particularly in treatment-naïve patients, is warranted.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anti-Inflammatory Agents / therapeutic use*
  • Antibodies, Monoclonal, Murine-Derived / therapeutic use*
  • B-Lymphocytes / drug effects
  • B-Lymphocytes / immunology
  • Biomarkers / blood
  • Child
  • Female
  • Health Status Indicators
  • Humans
  • Male
  • Middle Aged
  • Muscle Strength / drug effects
  • Myositis / blood
  • Myositis / diagnosis
  • Myositis / drug therapy*
  • Myositis / physiopathology
  • Predictive Value of Tests
  • Recovery of Function
  • Remission Induction
  • Rituximab
  • Skin / drug effects
  • Skin / pathology
  • Surveys and Questionnaires
  • Time Factors
  • Treatment Outcome

Substances

  • Anti-Inflammatory Agents
  • Antibodies, Monoclonal, Murine-Derived
  • Biomarkers
  • Rituximab