Rituximab in the treatment of dermatomyositis: an open-label pilot study

Arthritis Rheum. 2005 Feb;52(2):601-7. doi: 10.1002/art.20849.


Objective: To test the hypothesis that B cells play a role in the pathophysiology of dermatomyositis (DM) by examining the effect of B cell depletion in patients with symptomatic DM. Patients were treated with rituximab, a CD20+ B cell-depleting monoclonal antibody.

Methods: This was an open-label uncontrolled pilot trial in 7 adult patients with DM, 6 of whom had longstanding illness that was responding inadequately to a number of currently available immunosuppressive agents. All patients received 4 intravenous infusions of rituximab given at weekly intervals. Patients were followed up for up to 1 year without further treatment with rituximab. One patient was lost to followup. The principal efficacy outcome was muscle strength, measured by quantitative dynomometry.

Results: All 6 evaluable patients exhibited major clinical improvement, with muscle strength increasing over baseline by 36-113%. Maximal improvements in muscle strength occurred as early as 12 weeks after the initial infusion of rituximab. CD20+ B cells were effectively depleted in all patients by 12 weeks. Four patients experienced a return of symptoms that coincided with the return of B cells before the 52-week end point. Two patients maintained their increased muscle strength at 52 weeks, and 1 of these patients maintained this strength even after the return of B cells. Other symptoms of DM, including rash, alopecia, and reduced forced vital capacity, improved markedly in patients with these symptoms. Rituximab was well tolerated, with no treatment-related severe or serious adverse events during the observation period of this study.

Conclusion: This small open-label study of DM patients treated with rituximab provided sufficiently encouraging results to justify a more formal evaluation of the value of B cell depletion therapy in the treatment of DM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antibodies, Monoclonal / administration & dosage
  • Antibodies, Monoclonal / therapeutic use*
  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD20 / analysis
  • B-Lymphocytes / physiology
  • Dermatomyositis / drug therapy*
  • Dermatomyositis / physiopathology
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Muscle, Skeletal / physiopathology
  • Pilot Projects
  • Rituximab
  • Treatment Outcome


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD20
  • Rituximab