This is a Phase 1, randomized, double-blind, placebo-controlled, parallel group study to evaluate the safety and tolerability, pharmacodynamics (PD) and pharmacokinetics (PK) of ALT-801 and its effects on glucose control in overweight and obese subjects with type 2 diabetes mellitus (T2DM).

Inclusion Criteria:

• Written informed consent signed prior to the performance of any study procedures
• Male or female volunteers, age 18 to 65 years, inclusive
• Overweight to obese (BMI >/=28.0 kg/m2)
• Type 2 diabetes mellitus (T2DM), on stable regimen, for at least 3 months prior to screening, of any combination of (1) diet and exercise, (2) metformin with absent or mild gastrointestinal symptoms (nausea, vomiting or diarrhea), and/or (3) sodium glucose cotransporter-2 (SGLT-2) therapy
• Female subjects of childbearing potential who are not pregnant or breastfeeding, do not plan to become pregnant during the study, and agree to use effective birth control

Exclusion Criteria:

• Type 1 diabetes mellitus (DM) and/or insulin-dependent T2DM, or uncontrolled T2DM defined as hemoglobin A1c (HbA1c) ≥ 9.5% or C-peptide ≤ 8 ng/mL
• History of acute or chronic pancreatitis or hypersensitivity reaction to GLP-1 analogues