The present invention relates to methods and compositions for pretargeting delivery of alpha-emitting radionuclides, such as 213Bi or 225AC to a target cell or tissue, such as a cancer cell or a tumor. In preferred embodiments, the pretargeting method comprises: a) administering a bispecific antibody comprising at least one binding site for a tumor-associated antigen (TAA) and at least one binding site for a hapten and b) administering a hapten-conjugated targetable construct that is labeled with an alpha-emitting radionuclide. More preferably, the bispecific antibody is rapidly internalized into the target cell, along with the radionuclide. In most preferred embodiments, the bispecific antibody is made as a dock-and-lock (DNL) complex.
