The frequency and management of asparaginase‐related thrombosis in paediatric and adult patients with acute lymphoblastic leukaemia treated on Dana‐Farber Cancer Institute consortium protocols

The optimal management of asparaginase-associated thrombotic complications is not well-defined. We report the features, management and outcome of paediatric (ages 0-18years) and adult (18-50years) patients with acute lymphoblastic leukaemia (ALL) with asparaginase-related venous thromboembolic events (VTE) treated at Dana-Farber Cancer Institute on clinical trials for newly diagnosed ALL between 1991-2008. Of 548 patients, 43 (8%) had VTE, including 27/501 (5%) paediatric and 16/47 (34%) adult patients. Sinus venous thrombosis occurred in 1·6% of patients. Age was the only significant predictor of VTE, with those aged >30years at very high risk (VTE rate 42%). 74% of patients received low molecular weight heparin after VTE. Complications of anticoagulation included epistaxis (9%), bruising (2%) and, in two adult patients, major bleeding. Thirty patients (70%) ultimately received at least 85% of the intended doses of asparaginase. 33% of patients experienced recurrent VTE (paediatric 17% vs. adults 47%, P=0·07). The 48-month event-free survival for patients with VTE was 85±6% compared with 88±2% for those without VTE (P=0·36). This study confirms that, after VTE, asparaginase can be restarted with closely monitored anticoagulation after imaging demonstrates clot stabilization or improvement. With this management strategy, a history of VTE does not appear to adversely impact prognosis.