Compositions, methods, and kits are provided for treating or preventing prostate cancer. In certain aspects, the compositions, methods, and kits are designed to kill prostate cancer cells. The compositions, methods, and kits can be useful to prevent or treat metastatic prostate cancer. The present invention provides a bispecific binding reagent comprising at least a first domain and a second domain, wherein the first domain specifically binds to a prostate cancer cell surface antigen, and wherein the second domain specifically binds to a T cell surface antigen. The bispecific binding reagent can be used to stimulate immune cell activity against the prostate cancer cell. In certain aspects, the present invention provides a plurality of bispecific binding reagents for co-stimulation of immune cells. Methods for preventing and/or treating metastatic prostate cancer in a subject in need thereof using one or more bispecific binding reagents of the present invention are also provided. In other aspects, the present invention provides isolated nucleic acids, vectors, processes of production, pharmaceutical compositions, and kits related to the bispecific binding reagents described herein. Exemplified are TCTOOl against STEAP1 and CD3E and TCT002 against EpCam and CD28, as well as the combination of the two.Linvention concerne des compositions, des méthodes et des kits de traitement ou de prévention du cancer de la prostate. Dans certains aspects, les compositions, les méthodes et les kits sont conçus pour éliminer les cellules du cancer de la prostate. Les compositions, les méthodes et les kits peuvent être utilisés pour prévenir et traiter le cancer de la prostate métastatique. Linvention concerne un réactif de liaison bispécifique comprenant au moins un premier domaine et un second domaine, ledit premier domaine se liant spécifiquement à lantigène de surface des cellules du cancer de la prostate, ledit second domaine se liant spécifiquement à lantigène de surface des lymp
