Rituximab as therapy for refractory polymyositis and dermatomyositis.
We describe response to rituximab treatment of refractory inflammatory myopathy. Three patients with long-standing polymyositis (PM) or dermatomyositis (DM) poorly responsive to prednisone combined with several immunosuppressants were given intravenous rituximab 1,000 mg on Days 0 and 14. Prior to rituximab, each had significant proximal weakness with creatine phosphokinase (CPK) elevation to>3 times the normal upper limit (range 789-3,123 U/l). Patients were receiving prednisone plus methotrexate (MTX) or azathioprine. CPK decrease was observed 1 month post-infusion, with normalization of levels averaging 4.6 months (range 2.6-7.7 mo). Muscle strength improved in all, with strength returning to normal in 2. Average daily prednisone dose decreased from 16.7 mg (range 10-20 mg) to 4 mg (range 0-7 mg) after infusion. MTX dose was tapered by 50% in 2 patients. The third patient eventually discontinued all additional therapies. Percentage of CD19+ cells in each were suppressed at 0-1% 5 to 6 months after infusion (normal 5-21%). Elevated CPK with return of clinical symptoms occurred in 2 patients 6 and 10 months post-infusion, requiring rituximab retreatment. CD19+ cells remained suppressed at 1% in one patient, but were almost normal at 4% in the other. The third patient remains disease-free 12 months after initial treatment, even though her CD19+ cells are now normal at 8%. Thus, short-term beneficial effects with rituximab were observed in patients with DM and PM. However, the need for retreatment did not correlate with levels of CD19+ cells.
Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital, and Harvard University School of Medicine, Boston, Massachusetts; and The Center for Rheumatology, Albany, New York, USA.
Erika H
EH
Noss
Dorota L
DL
Hausner-Sypek
Michael E
ME
Weinblatt
D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D058846:Antibodies, Monoclonal, Murine-Derived; D018941:Antigens, CD19 / Q000032:analysis; D001379:Azathioprine / Q000627:therapeutic use; D001402:B-Lymphocytes / Q000737:chemistry / Q000473:pathology / Q000502:physiology; D003402:Creatine Kinase / Q000032:analysis; D003882:Dermatomyositis / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology; D017285:Polymyositis / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D011241:Prednisone / Q000627:therapeutic use; D000069283:Rituximab; D013997:Time Factors
D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D018941:Antigens, CD19; D007166:Immunosuppressive Agents; D000069283:Rituximab; D003402:Creatine Kinase; D001379:Azathioprine; D011241:Prednisone; D008727:Methotrexate