A pharmaceutical composition useful in the treatment or prevention of transgenic xenograft rejection comprising immunosuppressant compounds selected from the group consisting of an IL-2 transcription inhibitor and immunosuppressant compounds that immunosuppress for B-cell-mediated or antibody-mediated rejection of xenografts, and pharmaceutically acceptable diluents or carriers, and a method of preventing hyperacute rejection, reducing early graft damage, improving early xenograft function and promoting long term survival of said transgenic xenografts comprising the steps of i) contacting the body fluid removed from a human recipient with a xenoantigenic material which is bound to a biocompatible solid support, ii) reintroducing the treated body fluid into the recipient, and iii) treating the recipient with said pharmaceutical composition.