AVE5026: A new hemisynthetic ultra low molecular weight heparin (ULMWH) with enriched anti-Xa activity and enhanced antithrombotic activity for management of cancer associated thrombosis

Abstract

14653 Background: AVE5026 is an ULMWH with a high anti-Xa activity associated with residual anti-IIa activity (ratio anti-Xa/IIa>30). This ratio may be favorable for use in cancer patients as it may have a higher therapeutic window. This agent is a polydisperse mixture of oligomeric heparin fragments (molecular weight 2000–3000 daltons) prepared by partial and controlled depolymerization of porcine mucosal heparin (UFH). The anticoagulant profile of AVE5026 has been previously reported (Hoppensteadt, et al. Blood 2007). Methods: To validate the hypothesis that AVE5026 is an appropriate antithrombotic in cancer, studies were carried out to determine its antithrombotic, bleeding, tumor growth, angiogenesis and apoptosis effects in animal models. Results: AVE5026 produced a dose-dependent antithrombotic response in the rat laser model of microvascular thrombosis (2.5 mg/kg IV, 9±1.7 laser shots; 5.0 mg/kg SC, 8±1.6 laser shots; control 3+0.8 laser shots). The relative bleeding effects of AVE5026 in a rat tail bleeding model were negligible in comparison to enoxaparin (E) and UFH (all 5 mg/kg IV; UFH >1000 sec; E 360±57 sec; AVE5026 209±29 sec; Control 215±32 seconds). Repeated administration of AVE5026 in dose ranges of 1–5 mg/kg od, SC for 14 days did not result in accumulation of the anti-Xa activity. Furthermore, in contrast to E, there was no enhancement of the hemorrhagic profile. Both E and AVE5026 inhibited tumor growth by regulating angiogenesis and apoptosis in a Lewis lung carcinoma (14% vs. 22% decrease) rat model and in a Walker 256 carcinosarcoma model (21% vs. 30% decrease) Conclusions: Although comparable results to E were demonstrated in animal models of arterial thrombosis, the bleeding effect of AVE5026 were disproportionately lower. This superior safety-efficacy ratio may translate into improved antithrombotic efficacy with decreased bleeding risk, suggesting that AVE5026 may provide the optimal treatment strategy for the management of cancer associated thrombosis. No significant financial relationships to disclose.