Group A, B, and C is made up of 8 participants per group. In each of these groups 6 participants will receive GSK2878175 and 2 participants will receive placebo. Group D is made up of 20 participants. 15 participants will receive GSK2878175 and 5 participants will receive placebo. The treatment groups will be dosed in sequence. Group A will be the first to take the study medication, then Group B, and so on. The plan is to dose subjects in Group A with 10 mg, Group B with 30 mg, Group C with 60 mg, and Group D with 60 mg of GSK2878175 or placebo. The next treatment group's actual dose will be decided after looking at the results from the previous group. The doses may therefore be higher or lower than planned depending on the previous group's results. The number of participants enrolled in the next group may also change depending on the results from the previous group.