This trial is conducted in the United States of America (USA). The aim of this trial is to determine the dose-response relationship for body weight and five escalating doses of NNC 90-1170 (liraglutide) in subjects with type 2 diabetes previously treated with an oral hypoglycemic agent (OHA).

Inclusion Criteria:

• Type 2 diabetic
• Treated with OHA (oral hypoglycaemic agent monotherapy for at least 3 months. Prior use of metformin is allowed
• Body Mass Index (BMI) between 27.0-42.0 kg/m^2 (inclusive)
• HbA1c maximum 10% based on analysis from central laboratory

Exclusion Criteria:

• Cardiac problems
• Uncontrolled treated/untreated hypertension
• Proliferative retinopathy or known autonomic neuropathy
• Recurrent severe hypoglycemia as judged by the investigator
• Known or suspected allergy to trial product or related products
• Use of any drug (except for OHAs), which in the investigators opinion could interfere with the glucose level or body weight or any contraindication to metformin use or intolerance to metformin 1000 mg (prior to trial entry or during run-in period). Stable doses, for 3 months or greater, of thyroid hormone replacement are allowed
• Known or suspected abuse of alcohol or narcotics
• Current treatment with thiazolidinediones or chronic daily use of insulin (more than 7 days) within three months in the absence of intercurrent illness
• TSH (thyroid stimulating hormone) below 0.2 or above 15 U/mL
• Type 1 or other specific causes of diabetes