Thrombotic complications during L-asparaginase treatment for acute lymphocytic leukemia

We report 2 new cases of thrombosis occurring in a cohort of 21 consecutive patients with acute lymphocytic leukemia treated with L-asparaginase (L-ase), 6,000 U/die s.c. or i.m. days 15-21 from start of chemotherapy, according to the GIMEMA LAL 0288 protocol. The first patient died of massive diffuse thromboembolism (thrombosis of sagittal sinus and of suprahepatic veins and pulmonary arteries; multiple hepatic and splenic infarctions) associated with markedly reduced levels of protein C, antithrombin III and plasminogen. In the second patient, portal vein thrombosis developed soon after the completion of L-ase. Antithrombin III was reduced, whereas protein C level was normal. Therapy with fresh frozen plasma and subcutaneous calcium heparin (12,500 U twice daily) proved successful, and 8 days later abdominal echotomography revealed the complete disappearance of the thrombus. The incidence of thrombosis is similar to that previously found in a cohort of consecutive patients treated at our Department with a different schedule and dosage of L-ase administration, and similar to that reported in previous series.