[Preliminary study on the safety and pharmacodynamic action of low dose L-asparaginase].

Objective To investigate the safety and therapeutic effect of low dose (1000 U/m2) Lasparaginase( L-Asp) in the treatment of children with acute lymphoblastic leukemia (ALL). Methods Six patients were treated with low dose L-Asp after previously suffered severe side effects from standard dose L-Asp (5000-10 000 U/m2) . Twenty-eight blood samples were obtained randomly from 5 of them. Plasma as-paragine concentration was detected by reverse phase-high performance liquid chromatography ( RP-HPLC ). Results All the patients treated with low dose L-Asp showed no any toxic symptoms. The plasma asparagine levels in the patients were all above 5 μmol/L except case 4 (4. 91 μmol/L) before receiving L-Asp, and were all decreased below 0. 5 μmol/L five days after receiving low dose L-Asp, except case 3 (3. 70 μmol/ L) , the results being like that of receiving standard dose L-Asp. Conclusion Low dose L-Asp has definite efficacy for childhood ALL, while avoids serious side effects from standard dose L-Asp.