Methimazole to Treat Polymyositis and Dermatomyositis

Inclusion Criteria

• •Diagnosis of Polymyositis or Dermatomyositis.
• •Baseline muscle weakness score of less than or equal to 139 out of 160 on manual testing (MMT).
• •Baseline functional assessment score of less than or equal to 82 out of 91.
• •Ability to provide informed consent to all aspects of the study after full information is provided.
• •Age equal to or older than 18.
• •A diagnosis of classic or definite polymyositis or dermatomyositis (Critieria A and B plus at least one of the three other criteria):
• •1. Symmetrical proximal muscle weakness;
• •2. Muscle biopsy abnormalities at some time during their disease:
• •i. degeneration and regeneration of muscle fibers
• •ii. necrosis
• •iii. phagocytosis
• •iv. interstitial mononuclear infiltration;
• •c. Elevation of serum creatinine phosphokinase (CPK), transaminases, lactic dehydrogenase (LDH) or aldolase activity;
• •d. Electromyography (EMG) triad of changes
• •i. small amplitude, short duration polyphasic motor unit potentials
• •ii. fibrillations, positive sharp waves, increased insertional irritability
• •iii. spontaneous bizarre high frequency discharges;
• •e. Typical skin rash of DM.
• •Willingness to undergo 2 muscle biopsies.
• •Evidence of active disease as measured by weakness, and an elevated CK or an active MRI.
• •Must be tapered to a stable dose of steroid equal to or less than 0.50 mg/kg/day equivalent of prednisone for one month prior to the study.
• •If on additional immunosuppressive drugs, the drugs must be maintained at a stable dose for 1 month prior to the initiation of therapy and will be maintained throughout the trial.
• •Women of childbearing potential and men whose partners are of childbearing potential must practice an acceptable form of contraception. No pregnant females or nursing mothers.
• •No history of hepatitis or abnormal liver function tests.
• •No history of prior thyroid disease.
• •No active acute or chronic infections requiring antimicrobial therapy, or serious viral or fungal infections.
• •No preexisting or coexisting malignancy other than basal cell and localized squamous cell carcinoma of the skin.
• •No history of cerebrovascular accidents, seizure disorder, aseptic meningitis, transverse myelitis or central nervous system disease.
• •No history of documented coronary artery disease, cardiomyopathy, greater than first-degree heart block, or dysrhythmia requiring therapy.
• •No confounding medical illness that in the judgement of the investigators would pose added risk for study participants.
• •No anemia requiring maintenance blood transfusions; leukoplakia with WBC less than 3,000 micrograms or absolute neutrophil count less than 2,000 micrograms; and platelet count less than 100,000 micrograms on at least two different occasions.
• •No history of (or current) autoimmune hemolytic anemia.
• •No current anticoagulant therapy.