Study to Evaluate the Safety, Tolerability, PK and PD of PB2452 in Healthy Younger, Older and Elderly Subjects

This is a Phase 2A, randomized, double-blind, placebo-controlled, single dose, sequential group study to evaluate the safety, tolerability, PK, and PD of PB2452 vs matching placebo with ticagrelor (with or without acetylsalicylic acid (ASA)) pretreatment when various dose levels and administration regimens are administered to healthy younger (ages 18 to 50), older (ages 50 to 64 years) and elderly (ages 65 to 80 years) male and female subjects. Up to 5 dose levels and/or administration regimens will be evaluated in up to 5 cohorts. Each cohort will include approximately 8 to 12 subjects randomized in a 3:1 ratio (PB2452:placebo).