The aim of this study is to investigate the safety and feasibility of daily subcutaneous injections of recombinant IGF1 complexed with IGF binding protein 3 (SomatoKine-INSMED) as a treatment for muscle wasting and weakness in myotonic dystrophy type 1.

Inclusion Criteria:

• A clinical diagnosis of DM-1 according to accepted clinical research criteria.23 The clinical research criteria require each of the following: (1) clinically evident myotonia; (2) muscle weakness in a characteristic distribution (distal predominant); and (3) similar findings in a first degree relative.

• Age 21 to 60 years (inclusive).

• Ability to walk 30 feet without assistance (cane and leg bracing is permitted).

• Weakness of sufficient severity to justify treatment and provide a reasonable opportunity to observe a therapeutic effect. At the eligibility evaluation, eligible patients must show both of the following:

  1. muscle strength in a distal muscle group (ankle dorsiflexors or deep flexors of the fingers) which is less than or equal to grade 4 (Medical Research Council grade).
  2. muscle strength in a proximal or mid-limb muscle group (flexors or extensors of the knee, elbow, shoulder, or hip) which is which is greater than or equal to 4- (Medical Research Council grade).

• For patients that are not within driving distance to Rochester, a local health care provider in their area must be able to complete their home visits.

• Competent, willing, and able to give informed consent.

• Able to self-administer study medication by subcutaneous injection or caregiver available to administer study medication.

Exclusion Criteria:

• Congenital DM-1. Congenital disease constitutes ~10% of all cases of DM-1. Early in life, the weakness in individuals with congenital DM-1 derives from maldevelopment of skeletal muscle rather than muscle degeneration. Later in life, these individuals are also subject to the added effects of a wasting process similar to classical DM-1. However, it is difficult to determine which of these phenomena are mainly to blame for weakness in a particular patient. Furthermore, more than 75% of patients with congenital DM-1 have mental retardation.
• Prior treatment with glucocorticoids, anabolic steroids, testosterone, growth hormone, or IGF-I within 1 year of entry; or any investigational agent within 60 days of entry.
• Any history of malignancy except for surgically cured skin cancer or pilomatricoma (benign tumor of the hair follicle that is associated with DM-1).
• Women of childbearing potential who are not using effective birth control; women who are pregnant or lactating.
• Medical illness which would prevent assessment of muscle strength or function. This exclusion would include individuals with orthopedic, cardiac, or pulmonary disorders which preclude proper positioning on the myometry testing table, or restrict their ability to tolerate repeated maximum muscle contractions.
• Known allergy to tetracycline.
• Diaphragmatic weakness such that patients are unable to tolerate supine position, or swallowing impairment such that patients are unable to maintain nutrition without use of gastrostomy.
• Symptomatic liver or kidney disease, insulin requiring diabetes or type 2 diabetes requiring oral anti-diabetic agents.
• Untreated thyroid disease (hypo or hyperthyroidism)
• Major psychiatric illness (major depression, bipolar disorder, or schizophrenia) within twelve months of entry.
• History of non-compliance with other therapies.
• Drug or alcohol abuse within 12 months of enrollment.
• In men, evidence of a mass lesion on clinical examination by their primary care physician within twelve months prior to entry into the study (specifically prostate or testicular mass on clinical exam or other signs of mass lesion) or evidence of mass lesion on chest x-ray. In men 50 years of age or older, prostate specific antigen (PSA) elevation above normal.
• In women, evidence for mass lesion on clinical examination by their primary care physician or gynecologist (specifically breast & pelvic exam) within 12 months of entry into the study or evidence of mass lesion on chest x-ray. In women 40 years of age or older, evidence of mass lesion on mammogram. Women with Gail Scores > 1.7 will be excluded due to their increased risk of developing cancer.
• Atrial fibrillation/flutter; 2nd or 3rd degree heart block without pacemaker treatment
• Weight greater than 100 kilograms(kg).
• Body Mass Index greater than 30.
• History of bleeding diathesis or use of anticoagulant medications. Patients taking nonsteroidal anti-inflammatory agents will be asked to discontinue these medications 3 days prior to muscle biopsy.