L-Asparaginase: human toxicology and single agent activity in nonleukemic neoplasms

The early hope that L-asparaginase would be a breakthrough in medical treatment, with selective toxic effects based on the qualitative presence or absence of a specific enzyme (asparagine synthetase), has not been realized. Despite its failure to live up to early hopes, L-asparaginase is now commercially available because of its usefulness in treating selected forms of acute leukemia and T-cell lymphoid neoplasms. By and large, hints of useful activity in other tumors have not been confirmed, and L-asparaginase remains experimental for all other indications. It is variably toxic in man, and severe toxic effects are not unusual. Toxic reactions are generally hypersensitivity reactions or depression of protein synthesis.