in which cytotoxic drugs, for example kinesin spindle protein inhibitors, are masked with legumain-cleavable groups and hence release the drug, and to the use of these prodrugs or conjugates for treatment and/or prevention of diseases, and to the use of these prodrugs or conjugates for production of medicaments for treatment and/or prevention of diseases, especially of hyperproliferative and/or angiogenic disorders, for example cancers.