Solid tumor treatment method and composition

A liposome composition for use in localizing an anthracycline anti-tumor drug in a solid tumor via the bloodstream by liposome extravasation into the tumor, comprising,

• liposomes (i) composed of vesicle-forming lipids and between 1-20 mole percent of an amphipathic vesicle-forming lipid derivatized with polyethyleneglycol, and (ii) having an average size in a selected size range between about 0.07 to 0.12 microns, and
• the drug, at least about 80% in liposome-entrapped form, and having a concentration in the liposomes greater than 50 .mu.g agent/.mu.mole liposome lipid,
• and characterized by a liposome blood lifetime, 24 hours after intravenous injection, that is several times greater than the blood lifetime of liposomes in the absence of the derivatized lipid.

A method of localizing a compound in a solid tumor in a subject by extravasation of liposomes containing the agent into the solid tumor comprising,

• preparing a composition of liposomes (i) composed of vesicle-forming lipids and between 1-20 mole percent of an amphipathic vesicle-forming lipid derivatized with a hydrophilic polymer selected from the group consisting of polyethyleneglycol, polylactic acid, polyglycolic acid and polylactic acid/polyglycolic acid copolymers, said liposomes having a blood lifetime, as measured by the percent of a liposome marker present in the blood 24 hours after intravenous administration, which is several times greater than that of liposomes in absence of the derivatized lipids, (ii) having an average size in a selected size range between about 0.07-0.12 microns, and (iii) containing the compound in liposome-entrapped form,
• injecting the composition intravenously in the subject in an amount effective to localize a therapeutically effective quantity of the agent in the solid tumor, and
• by said injecting, achieving a localization of the liposomes in the solid tumor, 48 hours after intravenous administration, that is substantially greater than that of liposomes in the absence of the derivatized lipid.

A method of treating breast or colon carcinoma in a subject with an anthracycline antibiotic drug, comprising

• entrapping the drug in liposomes (i) composed of vesicle-forming lipids and between 1-20 mole percent of an amphipathic vesicle-forming lipid derivatized with a hydrophilic polymer selected from the group consisting of polyethyleneglycol, polylactic acid, polyglycolic acid and polylactic acid/polyglycolic acid copolymers, said liposomes having a blood lifetime, as measured by the percent of a liposome marker present in the blood 24 hours after intravenous administration, which is several times greater than that of liposomes in absence of the derivatized lipids, and (ii) having an average size in a selected size range between about 0.07-0.12 microns at a concentration of entrapped drug of greater than about 50 .mu.g drug/.mu.mole liposome lipid, with at least about 80% of the drug entrapped in the liposomes, and
• injecting the composition intravenously in the subject in an amount effective to localize a therapeutically effective quantity of the agent in the carcinoma.