Thromboembolism is a serious complication in children with acute lymphoblastic leukaemia, resulting in morbidity, mortality, and adverse leukaemia outcomes.1–3 Although thromboembolism is largely preventable, use of anticoagulants in children with acute lymphoblastic leukaemia is challenging since both the disease and myelosuppressive chemotherapy increase bleeding risk. Further, low molecular weight heparin (LMWH)—the preferred anticoagulant for children with cancer—is problematic for paediatric patients because it requires daily injections.