Safety and Efficacy of CBX129801 in Patients With Type 1 Diabetes

Key Inclusion Criteria:

- Give informed consent;

- 18-65 years old;

- Have type 1 diabetes mellitus for a minimum of 5 years, with a stable diabetic
regimen (for at least 3 months);

- Have clinical signs of diabetic peripheral neuropathy at screening;

- Have abnormal sural nerve conduction observed bilaterally during screening;

- Be C-peptide deficient;

- Be in good general health (besides having type 1 diabetes mellitus);

- Practice effective contraception during and for at least 12 weeks after study
participation;

- Have a body mass index (BMI) ≥18.0 and <35.0 kg/m2.

Key Exclusion Criteria:

- Any significant cardiovascular, hematological, lymphatic, immunologic, urologic,
dermatologic, psychiatric, renal, hepatic, pulmonary, endocrine (except for diabetes
mellitus), central nervous, gastrointestinal, or other major disease;

- Unstable or inadequate glucose control;

- Any clinically significant laboratory value at screening;

- Occurrence of a severe, unexplainable hypoglycemic event (defined as requiring the
assistance of another individual) within 6 months of Day 0, or recurrent episodes of
non-severe hypoglycemia (≥3 per week on average) that are deemed clinically
significant by the Investigator;

- Have had an islet cell, kidney, and/or pancreas transplant;

- If female, is pregnant or lactating;

- History of alcohol or substance abuse within 2 years;

- Positive screen for hepatitis B, hepatitis C antibody, or human immunodeficiency
virus (HIV) antibody;

- Initiation of treatment or change of dose of medication that could affect peripheral
nerve function within 60 days;

- Previous treatment with CBX129801 or unmodified C-peptide;

- Receipt of an investigational product or therapeutic device, or participation in a
drug research study, within a period of 30 days;

- Chronic use of oral steroids or use of Ampyra (dalfampridine) within 60 days.