Wypij JM and Pondenis HC. E. coli-Derived L-Asparaginase Retains Enzymatic and Cytotoxic Activity In Vitro for Canine and Feline Lymphoma after Cold Storage. Vet Med Int. 2013; 2013: 786162. [free, full text]
The most common hematopoietic cancer in cats and dogs is lymphoma. L-asparaginase is a chemotherapeutic agent used in the effective treatment of lymphoma in both species. Pet owners often find chemotherapy poses a significant financial cost, limiting the options of treating their pet. L-asparaginase is available in single dose vials that often result in significant drug wastage, and intermittent drug shortages limit consistent availability for use. One possible option to overcome added drug costs and availability issues is the long-term cold storage of a reconstituted drug. The researchers in this study wanted to test the hypothesis that E. coli-derived L-asparaginase would retain enzymatic and anti-neoplastic activity in canine and feline lymphoma cells after cold storage.
In this situation, the L-asparaginase was cold stored with refrigeration (7-14 days) and freezing (14 days to 6 months, one to three freeze/thaw cycles). Enzymatic activity of asparaginase was then measured, and the effects on cell proliferation and cytoxicity were evaluated on feline and canine lymphoma cells. The results of the study suggest that E.coli-derived L-asparaginase does not lose efficacy in vitro following cold storage under the above conditions. Tests demonstrated no significant differences as one to three freeze/thaw cycles were statistically similar to freshly reconstituted drug. The study did not look at the issues of extralabel use of a drug packaged for single use or concerns of sterility and patient safety when using single-dose, preservative-free solution for multiple doses in treating patients with lymphoma. [VT]
Funding: this project was partially funded by Winn Feline Foundation grant W10-049.