GSK2118436 is an orally administered, potent and selective small molecule BRAF inhibitor that is currently being developed for the treatment of BRAF mutation-positive tumors. This study is designed to evaluate the effects of particle size on the relative bioavailability of GSK2118436 (Cohort 1) and to evaluate the effects of a high-fat meal on the pharmacokinetics of GSK2118436 (Cohort 2). Subjects will randomly receive two of four possible regimens over two periods. Subjects enrolled in Cohort 1 will receive a single 150 mg dose of GSK2118436 as micronized particles fasted (gelatin capsule formulation) and a single 150 mg dose of GSK2118436 as non-micronized particles fasted (larger particle size). Subjects enrolled in Cohort 2 will receive a single 150 mg dose of GSK2118436 (HydroxyPropyl Methyl Cellulose (HPMC) capsule formulation) fasted and with a high-fat breakfast. GSK2118436 will be administered as the mesylate salt (equivalent to 150 mg free base). Safety and tolerability will also be evaluated. The study will be conducted at a sufficient number of centers to complete approximately 28 adult subjects (14 subjects per cohort) with BRAF mutation-positive tumors. Following completion of this study, subjects may continue dosing with GSK2118436 in the roll-over study, Protocol BRF114144.
The study is designed to evaluate the effects of a high fat meal on the pharmacokinetics of 150 mg of GSK2118436, as well as the effects of particle size on the relative bioavailability of GSK2118436.