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ChemGenex Announces Second Publication Demonstrating Activity of Ceflatonin in T315I-Positive Chronic Myeloid Leukemia (CML)

MELBOURNE, Australia & MENLO PARK, Calif.--(BUSINESS WIRE)--Sep 24, 2007 - ChemGenex Pharmaceuticals Limited (ASX:CXS and NASDAQ:CXSP) announced today the publication of a clinical communication in Blood (the journal of the American Society of Hematology) demonstrating clinical activity of the company's lead compound, Ceflatonin(R) (Homoharringtonine, HHT(1)) against Gleevec(R) (imatinib mesylate)-resistant, accelerated phase chronic myeloid leukemia (CML) associated with the T315I BCR-ABL kinase domain mutation.

The publication describes positive clinical outcomes for two CML patients with the T315I BCR-ABL kinase domain mutation, one of whom was treated with Ceflatonin, the other was treated with interferon-alpha. The T315I BCR-ABL mutation results in resistance to tyrosine kinase inhibitor (TKI) drugs, including Gleevec, Sprycel(R) (dasatinib), and Tasigna(R) (nilotinib) that are currently used to treat CML patients. As a result, therapeutic options for CML patients with this mutation are very limited, and there is a significant unmet medical need for novel therapies to treat these patients.

The patient treated with Ceflatonin was resistant to Gleevec and Sprycel and had progressed to accelerated-phase CML with 100% of BCR-ABL positive cells showing the T315I mutation. The authors, Dr. Hugues de Lavallade and his associates, including Professor John M. Goldman and Dr. David Marin of the Hammersmith Hospital and Imperial College, London, UK, reported that the patient experienced a 30% reduction of T315I BCR-ABL levels within one month of the initiation of Ceflatonin treatment and a complete hematological response after five months.

The Blood publication follows a clinical report in Leukemia in May, 2007, describing clinical activity for Ceflatonin in another CML patient harboring the T315I BCR-ABL kinase domain mutation. Together, these two reports strongly support ChemGenex's clinical and regulatory approval program. ChemGenex is currently undertaking two phase 2/3 clinical trials in CML - the first trial includes Gleevec-resistant patients with the T315I BCR-ABL kinase domain mutation, and the second trial is for CML patients who are resistant to treatment with two or more of the current TKI drugs available. Positive results from the two trials may support the filing of a New Drug Application (NDA) with the US Food and Drug Administration and other regulatory authorities.

"The Blood and Leukemia publications are consistent with the understanding that Ceflatonin works via a different mechanism than the current TKI therapies," said Greg Collier, Chief Executive Officer and Managing Director of ChemGenex.

"Documented activity in both a chronic phase and an accelerated phase CML patient with the T315I BCR-ABL kinase domain mutation strongly supports Ceflatonin as a potential new therapeutic option for the growing number of patients identified with this mutation," Dr Collier added. "Estimates indicate that the global CML market will approach US$4 billion in 2008, and it is clear that therapeutics that overcome limitations with existing TKIs will play an important part in the treatment of CML patients."

For current clinical trial information search "Ceflatonin" at

Ceflatonin(R) is a registered trademark of ChemGenex Pharmaceuticals Limited.

Gleevec(R)/Glivec(R) is a registered trademark of Novartis AG.

Sprycel(R) is a registered trademark of the Bristol-Myers Squibb Company.

Tasigna(R) is a registered trademark of Novartis AG.

(1) ChemGenex recently received United States Adopted Names (USAN) Council approval for its proposed International Non-Proprietary Name (INN) for Ceflatonin. The new non-proprietary name is omacetaxine mepesuccinate, representing the first in the new family of 'cetaxine' drugs. The Company will phase in the use of omacetaxine mepesuccinate in place of the previous non-proprietary name (homoharringtonine, HHT) in its written materials. The Company has also initiated a project for the development of a new trade name for the drug as part of a pre-commercialization strategy.

Publication details

Interferon-a or homoharringtonine as salvage treatment for chronic myeloid leukemia patients who acquire the T315I BCR-ABL mutation. Blood 2007;110:2779-2780.

Hugues de Lavallade(1), Jamshid S. Khorashad(1), Howard P. Davis(2), Dragana Milojkovic(1), Jaspal S. Kaeda(1), John M. Goldman(1), Jane F. Apperley(1) and David Marin(1)

(1) Department of Haematology, Hammersmith Hospitals Trust, Imperial College London, London, UK

(2) Department of Haematology, Queen Elizabeth II Hospital, Welwyn Garden City, Herts, UK

About ChemGenex Pharmaceuticals Limited (

ChemGenex Pharmaceuticals is a pharmaceutical development company dedicated to improving the lives of patients by developing therapeutics in the areas of oncology, diabetes and obesity. ChemGenex harnesses the power of genomics for target discovery and validation, and in clinical trials to develop more individualized therapeutic outcomes. ChemGenex's lead compound, Ceflatonin(R), is currently in phase 2/3 clinical trials for chronic myeloid leukemia (CML) and Quinamed(R) is in phase 2 clinical development for prostate, breast and ovarian cancers. The company has a significant portfolio of anti-cancer, diabetes and obesity programs, several of which have been partnered with international pharmaceutical companies. ChemGenex currently trades on the Australian Stock Exchange under the symbol "CXS" and on NASDAQ under the symbol "CXSP".

Safe Harbor Statement

Certain statements made herein 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.


ChemGenex Information
Dr. Greg Collier, +61 3 5227 2752
Cell: +61 (0) 419 897 501
CEO and Managing Director
Dr. Dennis Brown, +1 650 474 9800 ext 108
Cell: +1 650 269 1984
President and Director
Investor Relations â?? Australia
Buchan Consulting
Rebecca Piercy, +61 2 9237 2800
Investor Relations â?? United States
Trout Group
Brandon Lewis, + 1 646 378 2915

Posted: September 2007