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A Pilot Study of the Role of Methimazole in Patients With Polymyositis and Dermatomyositis

Phase 2
Not Enrolling
Dermatomyositis, Polymyositis

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Trial Information

A Pilot Study of the Role of Methimazole in Patients With Polymyositis and Dermatomyositis

This open label pilot study will assess the (1) activity of methimazole (MMI), a
down-regulator of MHC Class I transcription used in treatment of autoimmune thyroiditis
(AIT), on the tissue expression of HLA class I and its (2) efficacy as measured by serum
muscle enzyme levels and manual muscle testing in up to twenty patients with dermatomyositis
(DM) or polymyositis (PM). Participants will have persistent weakness, laboratory evidence
of inflammation and be on a stable regimen of medication to control their myopathy. MMI
will be administered orally at 30 mg twice a day for six months. Patients will be evaluated
for alteration of HLA Class I expression in muscle and peripheral blood lymphocytes (PBL)
and drug-related toxicities during the study and for three months after the discontinuation
of treatment.

Inclusion Criteria

Diagnosis of Polymyositis or Dermatomyositis.

Baseline muscle weakness score of less than or equal to 139 out of 160 on manual testing

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

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

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.

Type of Study:


Study Design:

Endpoint Classification: Safety/Efficacy Study, Primary Purpose: Treatment


United States: Federal Government

Study ID:




Start Date:

June 1995

Completion Date:

April 2001

Related Keywords:

  • Dermatomyositis
  • Polymyositis
  • Cytotoxicity
  • HLA Class I
  • Lymphocytes
  • Muscle
  • Myositis
  • Thionamides
  • Dermatomyositis
  • Polymyositis
  • Dermatomyositis
  • Polymyositis



National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) Bethesda, Maryland  20892