Liposomes are closed lipid vesicles used for a variety of therapeutic purposes, and in particular, for carrying therapeutic agents to a target region or cell by systemic administration. Specially modified liposomes with a surface coating of water-soluble, biocompatible polymers (Pegylated Liposomes) have become important drug carries (e.g. Doxil/Caelyx). Pegylated liposomes have an extended blood circulation lifetime over the traditional liposomes lacking the polymer coating, allowing liposomal drugs to reach and accumulate in target cancer sites. This selectivity for cancer sites is due to the enhanced vascular permeability characteristic of tumors.
Mitomycin-C (MMC) is a well-known chemotherapeutic agent administered for various types of cancers, including breast, stomach, colon, anal, and bladder cancers. When given intravenously to patients, MMC has problematic side effects, mainly due to its toxicity to bone marrow and kidneys, and as a result the dose of MMC administered to patients is very low.
Efficient delivery of MMC directly to a target organ could overcome the problems associated with MMC and turn it into a safer anticancer drug that will serve as a therapeutic choice in a variety of cancers, particularly those of gastrointestinal origin.
Lipomedix has developed a pegylated liposome delivery system platform based on the encapsulation of a new chemical entity known as MLP, a proprietary prodrug form of the anticancer agent MMC. This novel formulation, known as Promitil®, enables efficient and selective tumor delivery of MLP in vivo with rapid activation in tissues to a powerful MMC metabolite, yet with improved safety profile. In tumor models in which free MMC was unable to achieve therapeutic efficacy against multi-drug resistant tumors, Promitil® demonstrated significant therapeutic efficacy.