The effect of L‐asparaginase on plasma coagulation factors in acute lymphoblastic leukemia

Serial coagulation studies were performed in 26 pediatric patients with acute lymphoblastic leukemia during initial induction therapy with vincristine, prednisone, and L‐asparaginase. Prolongation of screening coagulation tests was frequent: prothrombin time (in 16 of 26 patients), partial thromboplastin time (23/26) and thrombin time (21/26). In all 26 patients fibrinogen levels fell below .20 g/100 ml and 16 had levels below .10 g/100 ml. Sixteen patients had plasma coagulation factor assays performed. In these 16 patients, Factor XI was less than 70% in 14 and Factor IX was less than 70% in 9, with only a few scattered low levels of other factors. There were no clinical bleeding episodes. Coagulation abnormalities returned to normal at the completion of L‐asparaginase therapy while the patients remained on vincristine and prednisone.