A Study to Investigate the Safety, Tolerability, and Pharmacokinetics of ALS-008176 in Healthy Japanese Adult Participants

This is a double-blind (test or experiment in which neither the person giving the treatment nor the patient knows which treatment the patient is receiving), placebo-controlled, randomized (study medication assigned to participants by chance) and single-center study of ALS-008176. The duration of study will be approximately 6 weeks for each participant. The study consists of 3 parts: Screening Phase (28 days before study commences on Day 1); double-blind Treatment Phase (single oral dose of ALS-008176 or placebo on Day 1 under fasted condition); and Follow up Phase (up to 14 days after study drug administration). All the eligible participants will be randomly assigned to receive either a single oral dose of ALS-008176 or placebo in each group. The planned doses will be escalated in a stepwise fashion if the safety and tolerability in the preceding dose is found acceptable. Participants in Group 1 will receive ALS-008176, 250 milligram (mg) or placebo, Group 2 will receive ALS-008176, 500 mg or placebo and Group 3 will receive ALS-008176, 750 mg or placebo. Study drug will be administered following a 10-hour overnight fast. Blood samples will be collected for evaluation of pharmacokinetics at pre-dose and post-dose of study treatment. Pharmacokinetics of ALS-008176, ALS-008206, ALS-008112, and its metabolite ALS 008144 will be evaluated primarily. Participants' safety will be monitored throughout the study.