One study found no cardiotoxicity in 40 patients receiving cumulative doses of 500-1500 mg/m 2 of doxorubicin [62] . Free doxorubicin, on the other hand, is limited to a maximum recommended cumulative dose of 450-550 mg/m 2 . Colbern et al. found that the activity of PEGylated liposomal doxorubicin 1-2 mg/kg was almost equivalent to that of free doxorubicin 9 mg/kg in mouse Lewis lung carcinoma [59] .