News Release

ChemGenex's omacetaxine may provide first viable treatment option for highly resistant form of CML

Data intended for NDA submission presented at ASCO

Peer-Reviewed Publication

Kureczka/Martin Associates

MELBOURNE, Australia, and MENLO PARK, California U.S.A. (June 1st, 2009) – ChemGenex Pharmaceuticals Limited (ChemGenex) (ASX:CXS) announced that the latest data from its pivotal study of omacetaxine in patients with T315I-positive chronic myeloid leukemia (CML) was the subject of an oral presentation and discussion today at the 2009 American Society of Clinical Oncology (ASCO) Annual Meeting in Orlando, Florida. The open label Phase 2/3 study (CGX-635-CML-202) investigated the use of omacetaxine, administered subcutaneously in CML patients who had failed imatinib and who have the highly drug resistant T315I kinase domain mutation.

Dr. Jorge Cortes, MD, Professor of Medicine and Deputy Chair in the Department of Leukemia at The University of Texas, MD Anderson Cancer Center, a lead investigator in the study, presented the data. Dr. Cortes said, "It appears that omacetaxine was well tolerated in this study and durable hematological and cytogenetic responses were observed in some CML patients with the T315I mutation." He added that "Several novel drugs have already been investigated in this difficult-to-treat population, but they have not had a reasonable risk:benefit ratio. These results suggest that omacetaxine may represent the first viable treatment option for this population of patients who currently have no established treatment options."

Data were presented from 66 patients: 40 in chronic phase, 16 in accelerated phase and 10 in blast phase. Highlights of the data were:

Chronic phase patients

  • Complete hematologic response (CHR) rate of 85% with a median response duration 8.9 months
  • Major cytogenetic response (MCyR) rate of 15% with a median response duration 6.1 months

Accelerated phase patients

  • CHR rate of 31% with a median duration 4.1 months
  • MCyR rate of 6% with a median response duration 1.8 months

Blast phase patients

  • CHR rate of 20% with a median duration 3.3 months

Tolerability

Investigators reported that omacetaxine is generally well tolerated, and that the most common side effect is reversible and transient myelosuppression.

Commenting on the presentation, Dr. Greg Collier, Chief Executive Officer and Managing Director of ChemGenex, said, "This is a very important milestone in the development of omacetaxine and in the evolution of ChemGenex. The data presented today will be provided to the FDA in the final part of our rolling NDA submission; this project remains on target for completion in Q3 this year." Dr. Collier finished by expressing his deep appreciation for patients and investigators who participated in this important trial.

Dr. Collier and ChemGenex's Chief Medical Officer Dr. Adam Craig will host an investor conference call and webcast to discuss the clinical results from both ASCO and the EHA Congress on Thursday 11th of June at 10 am AEST. Details of this event will be advised in coming days.

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 (http://www.chemgenex.com)

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 http://www.chemgenex.com.

Details on the clinical trials can be accessed from the following websites;
http://clinicaltrials.gov/ct2/show/NCT00375219?term=homoharringtonine&rank=9 and http://www.tkiresistantcmltrials.com

Contacts

ChemGenex Information
Dr. Greg Collier
CEO and Managing Director
Cell (Australia): +61 419 897501
Cell (USA): +1 650 200 8145
Email: collier@chemgenex.com

Media Relations/Australia
Rebecca Wilson
Buchan Consulting
Tel: +61 (0)3 9866 4722
Cell: + 61 (0)417 382 391
Email: rwilson@bcg.com.au

Media Releases/USA and elsewhere
Joan Kureczka
Kureczka/Martin Associates
Tel: +1 415 821 2413
Cell: +1 415 690 0210
Email: Jkureczka@comcast.net

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.


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.