Inclusion Criteria

Patients entering this study:

• Are between the ages of 18-80 years old.
• Legal residents of the United States or Canada.
• Have a history of a chronic onset of a progressive motor weakness of less than 24 months duration.
• Fulfill El Escorial criteria of probable or definite ALS.
• If female, are surgically sterile, two years postmenopausal, or if of child-bearing potential, must be using a medically acceptable method of birth control and agree to continue use of this method for the duration of the study. Acceptable methods include a barrier method with spermicide, oral contraceptives (normal doses are acceptable; low dose oral contraceptives or contraceptive implants must be used with a barrier method), IUD, or abstinence. Have a negative pregnancy test.
• Are able to comply with protocol requirements.
• Can provide written informed consent.
• Have a manual muscle testing score of less than 8.
• Have a forced vital capacity by pulmonary function testing *60% predicted.

Exclusion Criteria:

Patients entering this study will not:

• Have any of the following conditions:renal disease (Creatine > 2.0) or other active systemic disease
• Have any clinically significant abnormalities on the prestudy laboratory evaluation, physical examination, ECG, chest x-ray or ophthalmologic exam.
• Have any clinically significant medical condition (e.g., within six months of baseline, had myocardial infarction, angina pectoris, and/or congestive heart failure) that, in the opinion of the investigator, would compromise the safety of patient.
• Have Type I or Type II diabetes.
• Have a history of cancer including melanoma with the exception of localized skin cancers (with no evidence of metastasis, significant invasion, or re-occurrence within three years of baseline) and carcinoma in-situ of the cervix (women only).
• Have used an investigational drug within 30 days of baseline visit.
• Have had a tracheostomy.
• Have a Beck's Depression Inventory score * 12.
• Have legal residency outside of the United States or Canada.
• Be pregnant or breast-feeding.