Liposomal methotrexate in the treatment of murine L1210 leukemia.

To assess the therapeutic effectiveness of methotrexate (MTX) when administered in a liposome carrier, mice bearing intracranial L1210 leukemia were tested with liposomal MTX, free MTX, or saline. Single i.p. injections of liposomal MTX at doses of 5 mg/kg and 2.5 mg/kg prolonged survival of mice bearing intracranial L1210 leukemia. The same doses of the free drug did not prolong survival of the tumor-bearing mice. This system may have clinical application not only for MTX, but also other polar anticancer agents in the treatment for central nervous system malignancy.