166Ho and 90Y labeled 6D2 monoclonal antibody for targeted radiotherapy of melanoma: Comparison with 188Re radiolabel

166Ho-labeled mAb to melanin produced some therapeutic effect on the tumor without any toxic effects while the administration of the 90Y-labeled radioconjugate was toxic to mice with no appreciable anti-tumor effect. We concluded that the serum half-life of the 6D2 carrier antibody matched well the physical half-life of 166Ho to deliver the tumoricidal absorbed dose to the tumor. Further investigation of this radionuclide for RIT of melanoma is warranted.