The aim of the present invention is to provide substances which show an apoptotic effect after administration in a relatively low concentration and can thus be useful for cancer therapy. To achieve this aim, the invention provides conjugates of an aglycosylated or aglycosyl anti-TWEAKR antibody with KSP inhibitors of formula (I), wherein one or more of the compounds of formula (I) is or are connected to the antibody via a linker L. Aglycosylated antibodies are antibodies which have no glycans at the preserved N-binding site in the CH2 domain of the Fc region. The antibody is preferably a human, humanised or chimeric monoclonal antibody. More preferably, the antibody is an anti-TWEAKR antibody, which specifically binds to the amino acid D in position 47 (D47) of TWEAKR (SEQ ID NO:169), in particular the anti-TWEAKR antibody TPP-2658.
