To Investigate the Safety, Tolerability and Pharmacodynamics of GSK2890457 in Healthy Volunteers and Subjects With Type 2 Diabetes

This study is the first administration of GSK2890457 in humans. The study will be conducted in 3 parts: - Part A (conducted at a single investigative site) will determine the safety and tolerability of GSK2890457 alone in healthy subjects during six weeks of dosing, as well as evaluating the potential for a pharmacokinetic interaction with metformin. Part A consists of Screening, Treatment (6 weeks) and Follow-up periods. - Part B (conducted at multiple sites) will determine safety, tolerability, and pharmacodynamics (PD) in subjects with Type 2 diabetes (T2D) when co-dosed for six weeks with liraglutide (Victoza). Part B consists of Screening, Run-in (1 week), Stabilization (12 weeks), Treatment (6 weeks) and Follow-up periods. - Part C (conducted at multiple sites) will determine safety, tolerability, and PD in subjects with T2D when co-dosed for 6 weeks with metformin. Part C consists of Screening, Run-in (1 week), Stabilization (12 weeks), Treatment (6 weeks) and Follow-up periods.