Synthesis and evaluation of antiproliferative activity of a geldanamycin–Herceptin™ immunoconjugate

Geldanamycin was modified with 1,4-diaminobutane to introduce a primary amine that was subsequently employed to provide a maleimide for protein linkage. Monoclonal antibody Herceptin™ was then derivatized to generate thiol groups that reacted with the maleimide derivative to produce the immunoconjugate. The product showed antiproliferative activity greater than native Herceptin™.