This is a randomized, double-blind, placebo-controlled, first time in human (FTIH) study to evaluate the safety, tolerability and pharmacokinetics (PK) of single and repeat ascending doses of GSK2556286 following oral administration in healthy adult participants. A food effect (FE) cohort will investigate the influence of food on the PK of GSK2556286. The study will be conducted in two parts. Part A will be a single ascending dose (SAD), sequential, parallel cohort design including up to 8 cohorts (Cohort 1A to cohort 8A) and Part B will be a multiple ascending dose (MAD), sequential, parallel dose cohort design including up to 4 cohorts (Cohort 1B to cohort 4B). In each cohort of Part A and Part B, participants will be randomized to receive single and repeated oral doses, respectively, of either GSK2556286 or matching placebo, administered in a 3:1 ratio according to the randomization schedule in a blinded manner. In Part A, Cohort 1A till cohort 6A will be dosed under fasted conditions and Cohort 7A and cohort 8A will be dosed under fed conditions. Cohort 7A will investigate the effect of food administration (high fat meal) on safety, tolerability and PK after a single dose of GSK2556286. Based on emerging data, a second food effect cohort (Cohort 8A) may also be included using a higher dose of GSK2556286. Progression from Part A to Part B will be based on an acceptable safety, tolerability and PK profile in Part A. In Part B, participants in each cohort will receive a daily oral dose of GSK2556286 over a period of up to 14 days. Part B may include drug administration after either fed or fasted conditions, dependent on the results from Part A. Sentinel dosing will be used in each cohort in Part A and Part B. Participants can only take part in one dose cohort in either Part A or B of the study.