Failure of actinomycin D entrapped in liposomes to prolong survival in renal cell adenocarcinoma-bearing mice.

The potential prolongation of survival of actinomycin D entrapped in liposomes was examined in Balb C/Cr mice inoculated intrarenally with renal cell adenocarcinoma. There were five groups of animals: group A, a control group, received phosphate-buffered saline 0.3 cm3 i.p.; group B received free actinomycin D 300 micrograms/kg i.p.; group C received liposomes containing actinomycin D 300 micrograms/kg i.p.; group D received a mixture of free actinomycin D 300 micrograms/kg and empty liposomes i.p.; group E received empty liposomes i.p. The best median survival was of group D (free drug) - 54 days followed by group C (liposome entrapped actinomycin D) 45.2 days and group E (a mixture of free and entrapped actinomycin D) - 42 days. In vitro studies utilizing cell lines obtained from the tumor showed no statistical difference in ID50 or in cytotoxicity between the cells treated with free actinomycin D and those treated with liposomes containing drug.