Novel cytostatic conjugates with integrin ligands

The present invention relates to cytostatics which have a tumour-specific action as a result of linkage to alphavbeta3 integrin antagonists via preferred linking units which can be selectively cleaved by elastase, i.e. by an enzyme which can especially be found in tumour tissue. The preferred linking units provide sufficient stability of the conjugate of cytostatic and alphavbeta3 integrin antagonist in biological fluids and, at the same time, the desired intracellular action within tumour cells as a result of its specific enzymatic or hydrolytic cleavability with release of the cytostatic.