Thrombosis Prophylaxis with Apixaban in Patients Treated with Asparaginase

Background: Acute Lymphoblastic Leukemia (ALL) outcomes have significantly improved over time with multi-agent chemotherapy, and the addition of asparaginase (ASP) has demonstrated the ability to prolong overall survival. ASP has multiple toxicities, and it remains a challenge to manage them safely, particularly coagulopathy and thrombosis (30-40% based on historical studies). The best prophylactic anticoagulation strategy in patients with acute leukemias, particularly ALL with asparaginase use, remains unclear due to severe coexisting thrombocytopenia and coagulopathy. Though the current guidelines recommend using Antithrombin (AT) replacement or low molecular weight heparin (LMWH) for thrombosis prophylaxis, the evidence is weak with concerns of thrombosis (Blood (2020) 136 (3): 328-338) with the use of fibrinogen concentrates(cryoprecipitate) and limited efficacy data with AT replacement and unfractionated heparin (UFH) for thrombosis prophylaxis. Due to potential “resistance” to LMWH and UFH from acquired AT deficiency with ASP use, our institution in 2017 has adopted the use of the direct Xa inhibitor, Apixaban for thrombosis prophyalxis. We report the safety and effectiveness of Apixaban for thrombosis prophylaxis with ASP.