EFFECTS OF ERWINIA-ASPARAGINASE ON THE COAGULATION SYSTEM

L-Asparaginase treatment during induction therapy in acute lymphoblast ic leukaemia (ALL) is known to be frequently complicated by thromboemb olic events. It was recently suggested that L-asparaginase derived fro m Erwinia chrysanthemi alters the coagulation system less severely tha n does Escherichia coli asparaginase. In a series of 11 adult patients with ALL, we investigated some parameters of the coagulation system d uring treatment with Erwinia asparaginase. The doses employed were rat her high; all patients below the age of 60 years received 15 000 U/m(2 ) daily over 14 days. In accordance with what is known from treatment with E. coli asparaginase, we observed significant lowering of antithr ombin as well as of fibrinogen. However, as to fibrinogen indeed a sig nificant decrease had occurred prior to the institution of Erwinia asp araginase treatment. The most striking observation in the present stud y was that the levels of prothrombin complex, reflecting the function of K-vitamin dependent coagulation factors II, VII and X, remained wit hin normal ranges during treatment. This indicates that these coagulat ion factors were not affected by Erwinia asparaginase, an observation at variance with several reports where E. coli asparaginase was invest igated. This latter observation was the only finding which could lend support to the view that Erwinia asparaginase affects the coagulation system less than E. coli asparaginase. Finally, one of our patients de veloped a sinus thrombosis, a severe thrombotic complication.