Acute, chronic and terminal toxicity to 4'-demethylepipodophyllotoxin thenylidene glucoside (VM26) in mice.

The development of toxicity to 4'-demethylepipodophyllotoxin-9-(4,6,-O-thenylidene-beta-glucopyranoside) an epipodophyllotoxin with oncolytic activity, was characterized in mice treated three times at 3-day intervals with 10 mg of drug i.p. per kg of body weight. Changes in organ function and general metabolism were determined by measuring 18 constituents of blood for up to 10 weeks after drug administration. The results indicate three distinct phases of toxicity to 4'-demethylepipodophyllotoxin 9-(4,6-O-2-thenylidene-beta-glucopyranoside). Acute toxicity developed within the first 10 days and was expressed by a depressed hematocrit and elevated plasma levels of glutamate-pyruvate transaminase, glutamate-oxaloacetate transaminase, lactic dehydrogenase, amylase, lipase, and uric acid. By 4 weeks, levels ahd returned to normal. The acute phase was followed by a chronic phase, which was characterized by progressive decreases in plasma levels of glucose, cholesterol, albumin, and total protein. Finally, about 7 weeks after treatment, a terminal phase indicated by correlated increases in glutamate-pyruvate transaminase, glutamate-oxaloacetate transaminase, lactic dehydrogenase, and blood urea nitrogen became apparent. Plasma levels of creatine phosphokinase, calcium, inorganic phosphate, total bilirubin, ketones, and alkaline phosphatase did not change. Although the pancreas liver and marrow were all affected during acute toxicity, boserved changes in blood components during the chronic and terminal phases correlate best with continued hepatotoxicity. The present evidence on delayed toxicity to 4'-demethylepipodophyllotoxin 9-(4,6-o-2-thenylidene-beta-D-glucopyranoside) is most compatible with irreversible hepatotoxocity which leads to metabolic deficiencies and terminates in death of mice.