Clinical usefulness of liposomal formulations in cancer therapy: lessons from the experiences of doxorubicin

Liposomes have been long used in cancer therapy with great expectations that they can improve efficacy mainly through enhanced permeation and retention (EPR) effect and reduce toxicity related to un-encapsulated anticancer agents. However, the advantage of liposomal formulations has not been prominent as anticipated in clinical cancer treatment in contrast to preclinical results and this has led nanomedicine field to review the experiences of liposomal anticancer products so far to pursue better strategies. The aim of this review is to look for answers to the questions whether liposomes really increase efficacy and reduce toxicity of encapsulated drugs in humans by consulting recent several meta-analyses. Based on the meta-analyses, liposomal formulations have shown comparable or modestly superior clinical efficacy compared to non-liposomal conventional formulations. Besides, drug-related toxicity, for example, cardiotoxicity of doxorubicin, has been clearly reduced by encapsulation of cytotoxic agents into liposomes despite carrier-related adverse events are newly occurred. In conclusion, liposomes are clinically useful in cancer therapy and their value can be raised by applying more advanced and elaborate strategies through understanding tumor microenvironment.