This randomized, double-blind, placebo-controlled study will assess the efficacy, safety, tolerability, pharmacokinetics and pharmacodynamics of RO5095932 in patients with type 2 diabetes mellitus. Patients will be randomized to receive either RO5095932 subcutaneously once weekly or placebo for 4 weeks (part 1) or 6 weeks (part 2), in addition to their current stable doses of metformin.

Inclusion Criteria:

• adult patients, 18-65 years of age
• females who are either surgically sterile or post-menopausal
• type 2 diabetes treated with a stable dose of metformin
• BMI between 25-39kg/m2
• HbA1c between 7 and 10%
• fasting plasma glucose between 7 and 13.3mmol/L

Exclusion Criteria:

• history of clinically significant cardiovascular disease
• history of clinically significant hepatic or renal disease or impairment
• recent therapy with insulin, thiazolidinedione, glucagon-like peptide-1 analogues, amylin analogues and/or DPP-IV inhibitors