CLINICAL TRIALS AND OBSERVATIONS Pharmacokinetics, pharmacodynamics, efficacy, and safety of a new recombinant asparaginase preparation in children with previously untreated acute lymphoblastic leukemia: a randomized phase 2 clinical trial

The pharmacokinetics, pharmacodynamics, efficacy, and safety of a new recombinant Escherichia coli–asparaginase preparation was compared with Asparaginase medac. Thirty-two children with acute lymphoblastic leukemia were randomized to receive one of both agents at a dose of 5000 U/m2 every 3 days, for a total of 8 doses during induction treatment. The serum activity-time profile after the first dose of recombinant asparaginase was similar to that of Asparaginase medac. The trough serum activities were greater than the desired threshold of 100 U/L in both treatment groups. Asparagine was completely depleted in serum and in cerebrospinal fluid, whereas glutamine levels were only moderately influenced. No significant difference between the 2 treatments regarding the degree of asparagine depletion, duration of depletion, complete remission rate, and minimal residual disease status at the end of induction, overall frequency or intensity of adverse events was seen. Observed adverse reactions are known as possible and labeled side effects of asparaginase treatment and chemotherapy. We conclude that the new recombinant asparaginase and other native Asparaginase medac are bioequivalent and have the same pharmacodynamic effects and the same direct toxicity profile in children with acute lymphoblastic leukemia. This trial was registered at http://www.controlled-trials.com as no. ISRCTN 75734403. (Blood. 2008; 112:4832-4838)