Safety and efficacy of direct oral anticoagulants in pediatric oncology patients: real-world data from two quaternary care pediatric centers

Background: Pivotal, phase 3 randomized controlled trials have led to the approval of direct oral anticoagulants (DOACs) for both the management of venous thromboembolism (VTE) and thromboprophylaxis in children. However, few children with cancer-associated thrombosis were enrolled in these trials. There is consequently a need for well-designed observational studies to address current gaps in the pediatric literature. Objectives: The principal objective of this retrospective cohort study was to investigate the safety and efficacy of DOACs for both treatment and prophylaxis of cancer-associated VTE in children. Methods: Prospectively maintained databases at 2 quaternary care children's hospitals were queried for children diagnosed with cancer who received a DOAC for either treatment of VTE or thromboprophylaxis. Medical records of eligible subjects were reviewed for clinical and radiological characteristics. Results: Fifty-one patients (53% female) met eligibility. Forty-seven (92%) patients received DOACs in the setting of a VTE diagnosis (treatment and secondary thromboprophylaxis), while 4 (8%) patients received DOACs for primary thromboprophylaxis. The median age at VTE diagnosis was 14.4 years. Rivaroxaban and apixaban were used in 55% and 45% of patients, respectively. Therapeutic and prophylactic-intensity DOACs were administered in 86% and 78% of patients, respectively, with many patients receiving both. Recurrent/progressive thrombosis occurred in 4 patients (8%). Major and clinically relevant nonmajor bleeding were reported in 6% and 20% of patients, respectively. No deaths were attributed to thrombosis or anticoagulant-related bleeding. Conclusion: Rates of recurrent/progressive thrombosis and clinically relevant bleeding in our cohort of children with cancer-associated thrombosis are higher than those reported in previous studies, highlighting the importance of real-world data.