Antitumor effects of liposomes containing adriamycin on chemically-induced rat malignant fibrous histiocytoma

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma. No effective chemotherapeutic agents, however, have been reported. Here we report our evaluation of the antitumor effects of liposomes containing adriamycin (LADM) against chemically-induced rat MFH. Either free adriamycin (ADM) or LADM was administered at dosages of 4.0, 8.0 or 12.0 mg/kg by intravenous injection. The tumor responded to LADM with prolonged growth delay, but equivalent doses of free ADM were less effective. Additionally, LADM prolonged the life span of rats longer than did free ADM. Also, the body weight loss was less with LADM than with equivalent doses of free ADM. In tissue distribution studies, we observed that the ADM level in the blood and in the tumor with LADM remained higher than with free ADM. These results indicate that liposomes alter in vivo ADM tissue distribution and increase antitumor activity against rat MFH with reduced toxic side effects.