Inclusion Criteria:

Patients meeting all of the following inclusion criteria at screening can be considered for admission to the study.

Stage 1 and Stage 2:

1. Male and female patients with, type 1 diabetes mellitus that are 18 through 70 years of age, or type 2 diabetes mellitus that are 30 through 70 years of age.
2. Patients who are insulin deficient and are diagnosed with type 1 or type 2 diabetes mellitus, and are currently well managed with insulin, with or without metformin.
3. Patients who have been on stable doses of insulin treatment for 90 days prior to study randomization.

Exclusion Criteria:

Patients meeting any of the following exclusion criteria at screening will not be enrolled in the study:

1. Patients with a history of any clinically significant retinopathy, symptomatic autonomic neuropathy, unstable angina, or kidney problems.
2. Patients with an uncontrolled or untreated significant pulmonary, neurological condition, or cardiovascular disease, including hypertension, congestive heart failure, angina, or peripheral vascular disease.
3. Patients who have received any investigational product within 30 days of admission into the study.
4. Patients with a history or clinical evidence of multiple organ autoimmune disorders.
5. Patients with a medical condition, serious intercurrent illness, or extenuating circumstance that would significantly decrease study compliance, including all prescribed follow-up.
6. Patients who are lactating and breastfeeding.