Xanthus Pharmaceuticals, Inc.' Xanafide Bypasses Multi-Drug Resistance Proteins in Acute Myeloid Leukemia

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Xanthus Pharmaceuticals, Inc. today announced results from an independent study of Xanafide® (amonafide malate) in multi-drug resistant (MDR) leukemia and myeloma cell lines and in pre-treatment marrow samples from patients with secondary acute myeloid leukemia (s-AML). The study, presented on December 9th at the 2007 American Society of Hematology Annual Meeting in Atlanta, GA, demonstrated that the uptake, efflux and cytotoxicity of Xanafide in this study were unaffected by MDR proteins expressed in AML cells, and s-AML cells in particular, while other topoisomerase II inhibitors evaluated in this study were affected by the expression of these proteins. Increased levels of these proteins are a common cause of multi-drug resistance of AML cells to currently used treatments, so this study indicates that Xanafide may not be subject to this mode of drug resistance. Xanafide’s ability to overcome resistance in s-AML cells may explain the encouraging complete remission rates previously observed in Phase 1 and Phase 2 trials of Xanafide in AML.