A Study to Evaluate the Safety, Tolerability and Pharmacokinetics/Pharmacodynamics of Oral Doses of H008

This will be a Phase I, randomized, double-blind, positive- and placebo-controlled study to evaluate the safety, tolerability, and PK/PD of multiple oral doses of H008 in healthy adult subjects. Two dose levels of H008 at 20 mg and 40 mg will be studied in two sequential cohorts. Each cohort will be enrolled with 12 subjects (8 on H008, 2 on placebo and 2 on positive control drug). Subjects are only allowed to participate in one of the two cohorts. Both the investigational product and placebo will be given in a double blinded manner, while the positive control drug will be given in an open-label manner.Dose escalation to the next cohort will be permitted only when safety data until follow-up and PK data until 48 hours post-last dose, from all subjects in previous cohorts are reviewed, and the investigational product is deemed well tolerated. The study will consist of a screening period, a baseline period, a 7-day repeated-dose period and a safety follow-up period.