Antitumor activities of L-MTP-PE (
Liposome entrapped myuramyl tripeptide
phosphatidylethanolamine) in the combination treatment with chemo- or immune-therapeutic
antitumor agents against various syngeneic
tumors were tested.Against Meth A
fibrosarcoma solid
tumor system, L-MTP-PE showed slight but statistically significant elongation of survival days against
5-FU monotherapy in spite of its non-effect on
tumor growth, when combined with
5-FU. Against liver
metastasis model of M5076
carcinoma, L-MTP-PE showed a tendency of elongation of survival days by its single
drug treatment, however, elongation with statistical significance was observed in the combination treatment with
5-FU in comparison with control group.These data suggest that L-MTP-PE seems to elongate the survival days of the solid
tumor bearing mice and the liver
metastasis model basically due to its saving effect on chemotherapeutic
drug-induced immunosuppression. In the combination with an immunotherapeutic agent in mice, TNF production induced by another
biological response modifier OK-432 was potentiated when primed with L-MTP-PE. L-MTP-PE also potentiate the antitumor effect of
OK-432 possibly through the enhanced production of TNF-α. Combination of L-MTP-PE and
OK-432 is considered to be a candidate for a new treatment model for
cancer.