The present invention relates compounds of the formula: oligosaccharide-spacer-(GpIIb/IIIa antagonist), wherein the oligosaccharide is a negatively charged oligosaccharide residue comprising four to twenty five monosaccharide units, the charge being compensated by positively charged counterions, and wherein the oligosaccharide residue is derived from an oligosaccharide which has (AT-III mediated) anti-Xa activity per se the spacer is a bond or an essentially pharmacologically inactive linking residue the GpIIb/IIIa antagonist is a residue mimicking the RGD and/or K(QA)GD fragment of fibrinogen, comprising a carboxylate moiety and a basic moiety located within the residue at a distance of 10-20 Å from each other or a pharmaceutically acceptable salt thereof or a prodrug or a solvate thereof wherein the compound of formula I further comprises at least one covalent bond with a biotin label or an analogue thereof. The compounds of the invention have antithrombotic activity and can be used in treating or preventing thrombotic diseases. The antithrombotic activity of the compound of this invention can be neutralized in case of emergency upon adminstration of avidin, streptavidin and analogues thereof having high biotin affinity.
