The present invention is for novel compositions and methods for treating diseases caused by cellular proliferation, particularly, for treating cancer in mammals and more particularly in humans. The therapeutic compositions of the present invention include SN-38 lipid complexes in which the complexes can contain any of a variety of neutral or charged lipids and, desirably, cardiolipin. The compositions are capable of efficiently incorporating SN-38 into complexes and are capable of solubilizing relatively high concentrations of SN-38.