Background. L-
asparaginase is effective in treating canine and feline
lymphoma, however
chemotherapy poses a significant financial cost to veterinary clients, limiting
therapy for many pets. Single dose vials result in significant
drug wastage, and
drug shortages limit consistent availability for pets. Hypothesis. E. coli-derived
asparaginase retains enzymatic and
antineoplastic activity in canine and feline
lymphoma cells after cold storage. Methods. E. coli-derived
asparaginase was cold-stored: refrigeration (7-14 days) and freezing (14 days-six months, one to three freeze/thaw cycles). Enzymatic activity of
asparaginase was measured via a modified
asparagine assay. Effects of cold-stored
asparaginase on cell proliferation and cytotoxicity were measured in feline (MYA-1, F1B) and canine (17-71, OSW)
lymphoma cells. Results. Cold-stored E. coli-derived
asparaginase retains
antineoplastic activity in all four cell lines tested. Cold-stored E. coli-derived L-
asparaginase depletes
asparagine and retains enzymatic activity. Duration of refrigeration, duration of freezing, and number of freeze-thaw cycles have minimal effect on
asparaginase enzyme activity. Conclusions and Clinical Importance. This study establishes a scientific basis for long-term cold storage of reconstituted E. coli-derived
asparaginase that may result in better utilization of limited
drug resources and improve financial feasibility of E. coli-derived
asparaginase as a therapeutic option for pets with
lymphoma.