A Phase 1 Study to Assess the Relative Bioavailability, Food Effect, and Safety of a Tablet Formulation of GSK2838232, a Novel HIV Maturation Inhibitor in Healthy Participants After Single and Repeated Doses

GSK2838232 is a novel, potent HIV-1 maturation inhibitor for use in regimen-based combination antiretroviral therapy from a once-daily oral dose boosted with a pharmacoenhancer (ritonavir or cobicistat). This phase 1 study in healthy participants was conducted in 2 parts. Part 1 (n = 14) assessed the relative bioavailability of single doses of a 200-mg GSK2838232 tablet and capsule formulation boosted with 100 mg ritonavir in fed and fasted (tablet-only) subjects. Part 2 (n = 10) assessed the pharmacokinetics of repeated 500-mg once-daily doses of GSK2838232 without a pharmacoenhancing boosting agent. In part 1, GSK2838232 demonstrated comparable bioavailability following a single dose of 200 mg GSK2838232 as capsule and tablet formulations in combination with ritonavir (RTV) under fed conditions, with lower intrasubject variability observed for the tablet formulation. In part 2, following administration of 500 mg GSK2838232 once daily for 11 days under fed conditions, C-max, AUC(0-tau), and C tau showed a small degree of accumulation (1.2- to 1.3-fold) of GSK2838232. The median t(max)was approximately 4 hours on both day 1 and day 11 when given with food. The mean t(1/2)was approximately 23 hours on day 11. Steady-state concentrations were achieved by day 3 with a geometric mean steady-state C tau on day 11 of 28 ng/mL. The tablet formulation was generally well tolerated as a single 200-mg dose with RTV under fed and fasted conditions and following administration of multiple daily doses (11 days) of 500 mg unboosted.