Monitoring asparaginase activity in middle-income countries

Serum asparagine (Asn) deamination selectively eliminates leukaemia cells preserving normal cells, since normal cells have the ability to synthesise Asn intracellularly.2,3 In order to ensure therapeutic benefit, it is necessary to measure ASNase activity, since different formulations and silent inactivation might exist (values below 0·1 IU/mL).4 In 1996, Boos and colleagues5 described that different ASNase preparations could have different half-lives and different initial concentrations, probably because of distinct Escherichia coli strains. Several reports2,4 from European groups have indicated that monitoring ASNase activity is part of an adequate treatment, because different methods of administration, formulation, dose, and immune responses could generate a substantial variability in ASNase activity, as well as in interpatient response. Since the monitoring of the biological activity of ASNase is not performed in Brazil, our study emphasises the relevance of following the international expert recommendations. Since many low-income and middle-income countries do not regularly monitor the quality and efficiency of antineoplastic drugs we wonder what is the expected impact on health.