The present invention is directed to the use of bcl-2 antisense oligomers to treat and prevent bcl-2 related disorders. These disorders include cancers, tumors, carcinomas and cell-proliferative related disorders. In one embodiment of the invention, a bcl-2 antisense oligomer is administered at high doses. The present invention is also directed to a method of preventing or treating a bcl-2 related disorder, in particular cancer, comprising administering a bcl-2 antisense oligomer for short periods of time. The present invention is further drawn to the use of bcl-2 antisense oligomers to increase the sensitivity of a subject to cancer therapeutics. The present invention also relates to pharmaceutical compositions comprising one or more bcl-2 antisense oligomers, which may comprise one or more cancer therapeutic agents.