Myelosuppressive effect of colaspase (L-asparaginase) in initial treatment of acute lymphoblastic leukaemia.

Analysis of the remission induction phase in three Medical Research Council trials of treatment of acute lymphoblastic leukaemia has provided evidence of the adverse effect of the combination of colaspase (L-asparaginase) with vincristine and prednisolone. Significant myelosuppression, particularly of the granulocytic series, resulted in an increase in Gram-negative sepsis and death during the neutropenic phase induced by colaspase. The rate of blast-cell regression was increased by colaspase. It is suggested that the introduction of colaspase should be delayed until there is evidence of bone marrow regeneration in order to procure this benefit without the attendant toxicity.