The study will consist of a Screening/Pre-treatment period, an on-site assignment to study treatment and administration, a Follow-up visit on (Day 3 and Day 7) and a Final Follow-up visit (Day 35). Infusion of PB2452 will be initiated on Day 1 and will continue for approximately 16 hours for a total of 18 g.

On Day 1, subjects who meet all the inclusion criteria and none of the exclusion criteria will receive an intravenous (IV) infusion comprised of an initial IV bolus of 6 grams (g) infused over 10 minutes for rapid reversal, followed immediately by a 6g IV loading infusion over 4 hours and then a 6g IV maintenance infusion over 12 hours. This PB2452 regimen is expected to provide immediate reversal of the antiplatelet effects of ticagrelor within 5 minutes of the initiation of infusion that is sustained for 20-24 hours.

In subjects with potential drug interaction from concomitant use of moderate or strong CYP3A inhibitors with ticagrelor, an alternative regimen may be used comprising administration of 36 g over an active treatment period of 24 hours and 10 min. (This alternative regimen will be an initial 12g bolus infusion over 10 minutes, followed immediately by a loading infusion of 12g over 6 hours which will then be followed by a maintenance regimen of 12g infused over 18 hours for a total infusion of 24 hours and 10 minutes).

All subjects may be discharged from the clinical site between Days 3 and 7 inclusive and will return for a Follow-up visit on Day 7, if already discharged, and on Day 35 ( 3 days).