The present invention relates to cytostatics which have a tumour-specific action as a result of linkage to alpha v beta 3 integrin antagonists via preferred linking units. The preferred linking units guarantee serum stability of the conjugate of cytostatic and alpha v beta 3 integrin antagonist and at the same time the desired intracellular action in tumour cells as a result of their enzymatic or hydrolytic cleavability with release of the cytostatic.
