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ChemGenex's Omacetaxine Kills Leukemic Stem Cells in Human CML Models

Update: Synribo (omacetaxine) Now FDA Approved - October 26, 2012

New In Vitro Research with Omacetaxine in Human Cancer Stem Cells May Point to a Future Approach to Treating CML

MELBOURNE, Australia & MENLO PARK, Calif.--(BUSINESS WIRE)--Jun 8, 2009 - ChemGenex Pharmaceuticals Limited (ASX:CXS), announced today that the results of pre-clinical research that demonstrated that omacetaxine kills model human leukemic stem cells were presented at the 14th Congress of the European Hematology Association (EHA) in Berlin, Germany on Sunday. Human leukemic stem cells are known to be insensitive to tyrosine kinase inhibitors (TKIs), the drug family currently approved to treat Chronic Myeloid Leukemia (CML). The work was carried out in collaboration with Professor Tessa Holyoake at the University of Glasgow, Scotland, UK.

Ms. Elaine Allan, Clinical Scientist of the Scottish National Blood Transfusion Service working at the Paul O'Gorman Leukaemia Research Centre, University of Glasgow in Scotland, UK delivered the oral presentation. Ms Allan said, “Currently licensed drugs target and disable the diseased cells in the blood stream and bone marrow, but they have little, if any, effect on the primitive leukemic stem cells that are at the “root” of this blood cancer. In contrast, we have shown omacetaxine to be not only anti-proliferative, but also to induce apoptosis in human CML stem cells.”

Hagop M. Kantarjian, M.D., Chairman and Professor, Department of Leukemia, at the University of Texas M. D. Anderson Cancer Center, described the study results as exciting. Dr. Kantarjian added, “These results raise the possibility of eradicating the dormant malignant stem cells that are thought to be responsible for relapse in CML patients who discontinue TKIs. I look forward to working with ChemGenex in future trials to evaluate the clinical application of this research."

Dr. Greg Collier, Chief Executive Officer and Managing Director of ChemGenex, said, “The data presented today is entirely consistent with our strategic plans to investigate omacetaxine in combination with selected TKIs in an attempt to eradicate this form of leukemia. In the meantime ChemGenex remains focused on our primary objective of developing omacetaxine as a therapeutic option for CML patients who have developed the T315I mutation. This is one of the most pressing unmet medical needs in the field of CML management.”

Omacetaxine Overview

Omacetaxine mepesuccinate is a first-in-class cetaxine with demonstrated clinical activity as a single agent in a range of hematological malignancies. Omacetaxine has a novel mechanism of action, specifically binding to the ribosomal A-site cleft and inhibiting protein translation of short-lived oncoproteins that are upregulated in leukemic cells (particularly Cyclin-D1, Mcl-1 and c-Myc). As omacetaxine acts independently of tyrosine kinase inhibitors, it may have a therapeutic advantage for patients who have developed resistance to TKIs. Omacetaxine is administered subcutaneously.

About ChemGenex Pharmaceuticals Limited (

ChemGenex Pharmaceuticals is a pharmaceutical development company dedicated to improving the lives of patients by developing personalized oncology medicines. ChemGenex harnesses the power of genomics both to discover novel targets and drug compounds, and in clinical trials to develop more individualized treatment outcomes. ChemGenex's lead compound, omacetaxine mepesuccinate, is currently in phase 2/3 clinical trials for chronic myeloid leukemia (CML). ChemGenex has a second anticancer compound, amonafide dihydrochloride (Quinamed®), which is in phase 2 clinical development for various solid cancers, and a portfolio of assets in pre-clinical development. ChemGenex currently trades on the Australian Stock Exchange under the symbol "CXS" and on NASDAQ under the symbol "CXSP". For additional information on ChemGenex Pharmaceuticals, please visit our web site at

Details on the clinical trials can be accessed from the following websites; and

Safe Harbor Statement

Certain statements made herein (including for this purpose sites to which a hyperlink has been provided) that use the words “estimate”, “project”, “intend”, “expect”, “believe” and similar expressions are intended to identify forward-looking statements within the meaning of the US Private Securities Litigation Reform Act of 1995. These forward-looking statements involve known and unknown risks and uncertainties which could cause the actual results, performance or achievements of the company to be materially different from those which may be expressed or implied by such statements, including, among others, risks or uncertainties associated with the development of the company's technology, the ability to successfully market products in the clinical pipeline, the ability to advance promising therapeutics through clinical trials, the ability to establish our fully integrated technologies, the ability to enter into additional collaborations and strategic alliances and expand current collaborations and obtain milestone payments, the suitability of internally discovered genes for drug development, the ability of the company to meet its financial requirements, the ability of the company to protect its proprietary technology, potential limitations on the company's technology, the market for the company's products, government regulation in Australia and the United States, changes in tax and other laws, changes in competition and the loss of key personnel. These statements are based on our management's current expectations and are subject to a number of uncertainties that could change the results described in the forward-looking statements. Investors should be aware that there are no assurances that results will not differ from those projected.

Contact: ChemGenex
Dr. Greg Collier
CEO and Managing Director
Cell (Australia): +61 419 897501
Cell (USA): +1 650 200 8145
Buchan Consulting
Media Relations – Australia
Rebecca Wilson
Tel: +61 (0)3 9866 4722
Cell: + 61 (0)417 382 391
Kureczka/Martin Associates
Media Relations – USA
Joan Kureczka
Tel: +1 415 821 2413
Cell: +1 415 690 0210

Posted: June 2009