Methods for measurement of platelet function in the assessment of nonclinical drug safety and implications for translatability

Platelets play a pivotal role in normal hemostasis. Drug-induced derangement of platelet function can lead to either an increased bleeding risk when platelet function is inhibited or a proaggregant state that can manifest as thrombosis when it is exacerbated. In both cases, drug-induced platelet dysfunction can lead to serious adverse events in patients that can limit drug prescription or ultimately lead to the withdrawal of the drug from the market. Despite those risks, drug-induced platelet function defects do not appear to be highlighted during drug development; rather they are reported at the postapproval stage indicating that current preclinical assays and clinical development studies are failing to capture these liabilities. However, significant progresses have been made in platelet function testing and clinically useful methods now exist for the measurement of platelet function. This review article discusses these methods and describes their advantages and disadvantages in the setting of nonclinical drug safety to assess drug-induced platelet dysfunction and on the translatability of these tests to predict thrombosis and bleeding in patients.