· Company will submit new NDA in CML patients who have failed multiple TKIs

· Investor Teleconference to be held today - Wednesday 14^th July 10.30am AEST / Tuesday 13^th July 5.30pm PDT

MELBOURNE, Australia, and MENLO PARK, California U.S.A. (14 July 2010) – ChemGenex Pharmaceuticals Limited (ASX: CXS) announced today it has agreed with the U.S. Food and Drug Administration (FDA) a potential regulatory path to progress OMAPRO™ (omacetaxine mepesuccinate) for the treatment of patients with Chronic Myeloid Leukemia (CML).

The recent Type A Meeting, which included discussion of a regulatory path forward, addressed outstanding issues regarding the previously received Complete Response letter dated 8 April 2010.

Based on the discussion with the FDA, ChemGenex intends to combine data from its two pivotal studies, Study 202 and Study 203, and submit a New Drug Application (NDA) for OMAPRO for those patients with CML who have failed prior treatment with two or more currently approved tyrosine kinase inhibitors (TKIs). The proposed indication of this new NDA will be for the treatment of CML patients who have failed two or more TKIs, regardless of their mutation status.

“The FDA’s agreement that a combined data set could serve as the basis of an NDA in a third-line setting provides us with a pathway to an expanded indication for OMAPRO to treat CML patients who are resistant to at least two TKIs,” said Adam Craig, MD, Chief Medical Officer of ChemGenex.

“We also appreciate FDA’s invitation to discuss this approach further in a pre-NDA meeting,” he added. “We welcome the opportunity granted by the agency to submit combined data from our two completed pivotal studies and to potentially provide a new therapeutic choice for this significant group of patients who currently have very limited treatment options.”

Greg Collier Ph.D., Managing Director and Chief Executive Officer of ChemGenex added: “We are pleased with the outcome of this Type A meeting as it provides another option for advancing the development timeline for OMAPRO. By pursuing this new indication for multi TKI-resistant patients, OMAPRO can potentially treat a significantly larger patient population in the United States, and we plan to submit our new NDA to the FDA by the end of the year.”

ChemGenex is continuing its discussions with the FDA’s Center for Devices and Radiological Health towards approval of a diagnostic test for the T315I mutation, and the existing NDA for T315I positive CML patients who have failed imatinib remains open.

The Company also has a Marketing Authorisation Application under review with the European Medicines Agency for CML patients who have failed imatinib and have the T315I mutation. This review is on track, with a potential approval in Europe in the first quarter of 2011.

The updated corporate overview for ChemGenex is appended to this announcement.

Investor teleconference

ChemGenex will host an investor teleconference today: Wednesday 14^th July 10.30am Australian Eastern Standard Time / Tuesday 13^th July 5.30pm Pacific Daylight Time

To join the call please dial the access number below for your location. A participant pin number is not required.

Dial-In numbers: 1800 131 617 Australia Free Call

866 746 2596 USA/Canada Free Call

+61 7 3107 0222 begin_of_the_skype_highlighting              +61 7 3107 0222      end_of_the_skype_highlighting begin_of_the_skype_highlighting              +61 7 3107 0222      end_of_the_skype_highlighting International / Metered Number

0800 446 958 New Zealand Free Call

800 120 4406 Singapore Free Call

800 962 283 Hong Kong Free Call

001 803 011 4106 Indonesia Free Call

0044 22 132 558 Japan Free Call

0800 376 8339 UK Free Call

0800 330 2094 Germany Free Call

0805 111 476 France Free Call

0800 001 230 Switzerland Free Call

A recording of the call will be made available on the ChemGenex website.

About OMAPRO™ (omacetaxine mepesuccinate)

Omacetaxine 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 up-regulated in leukemic cells (particularly Cyclin-D1, Mcl-1 and c-Myc).

Omacetaxine mepesuccinate is administered subcutaneously and acts differently from TKIs. It may have a therapeutic advantage for patients who have failed TKIs. Omacetaxine has been granted Orphan Drug designations by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) as well as Fast Track status by the FDA.

About Chronic Myeloid Leukemia (CML)

Chronic myeloid leukemia (CML) is a cancer of the bone marrow with a worldwide prevalence of greater than 100,000 patients. The bone marrow is responsible for the production of specialized cells that constitute blood; these cells include red blood cells (to carry oxygen around the body), thrombocytes (to help stop bleeding) and certain white cells (part of the body’s defense system against infection). In patients with CML the cell production system is diseased and defective. Cells multiply uncontrollably and do not fully develop (differentiate) into functional blood cells.

Clinical investigators from cancer centres in the USA, Canada, France and Italy, reported on combined data from ChemGenex’s two phase 2/3 clinical trials in chronic myeloid leukemia (CML) patients who either (a) had failed imatinib and had the T315I mutation, or (b) had failed imatinib and at least one other tyrosine kinase inhibitor (TKI). Data were presented from 170 patients: 93 in chronic phase, 42 in accelerated phase and 35 in blast phase. Conclusions from the analysis were:

· The primary toxicity of omacetaxine is hematologic, with infrequent grade 3/4 non-hematologic events experienced;

· Grade 3/4 hematologic adverse events were manageable and decreased in frequency and severity with dose adjustments; and,

· Injection site reactions were primarily grade 1/2 events, demonstrating that at-home subcutaneous administration of omacetaxine has an acceptable safety profile for CML patients who have failed prior therapies.

“Additional data continue to support that OMAPRO is safe and reinforces our belief that it is a promising candidate for CML patients who fail to respond adequately to tyrosine kinase inhibitors” said Greg Collier, Ph.D., Managing Director and Chief Executive Officer of ChemGenex. “We are in ongoing discussions with the FDA as we respond to the Complete Response letter to our New Drug Application for OMAPRO, and in Europe review of the Marketing Authorization Application by the EMA is proceeding according to schedule.”

About OMAPRO™ (omacetaxine mepesuccinate)

Omacetaxine 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 up-regulated in leukemic cells (particularly Cyclin-D1, Mcl-1 and c-Myc).

Omacetaxine mepesuccinate is administered subcutaneously and acts differently from TKIs. It may have a therapeutic advantage for patients who have failed TKIs. Omacetaxine has completed two phase 2/3 clinical trials for subsequent indications within CML and has been granted Orphan Drug designations by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMEA) as well as Fast Track status by the FDA.

About Chronic Myeloid Leukemia (CML)

Chronic myeloid leukemia (CML) is a cancer of the bone marrow with a worldwide prevalence of approximately 200,000 patients. The bone marrow is responsible for the production of specialized cells that constitute blood; these cells include red blood cells (to carry oxygen around the body), thrombocytes (to help stop bleeding) and certain white cells (part of the body’s defense system against infection). In patients with CML the cell production system is diseased and defective. Cells multiply uncontrollably and do not fully develop (differentiate) into functional blood cells.

As part of an ongoing investor awareness program Greg Collier, Ph.D., Chief Executive Officer and Managing Director, ChemGenex will be presenting an update at the RBS Morgans Life Science conference in Sydney today, Tuesday 4th May 2010.

An updated version of the company’s overview presentation is available here

Investor teleconference details

The teleconference will be held on Thursday 6th May 11am AEST / Wednesday 5th May 6pm PST.

International toll free access numbers:

Participant Pin No:                               480377#

Dial in details for any other locations or further information is available from Kyahn Williamson - kwilliamson@bcg.com.au / +61 40 101 8828.

The complete response letter does not contain a request for a new study, nor is there a request for enrollment of additional patients into the pivotal study on OMAPRO.

Commenting on the correspondence from the FDA, Greg Collier, PhD, CEO for ChemGenex said, “The complete response letter from the FDA provides the initial guidance towards our endeavor to bring a new therapy to CML patients who harbour the T315I mutation and currently have very limited or unsatisfactory treatment options. Because the principal issues raised by the FDA were similar to those discussed during the 22 March meeting of the Oncology Drug Advisory Committee (ODAC), and based upon our interpretation of the scientific requirements underpinning the complete response letter, we are confident that we can work in a positive manner with the FDA to address the outstanding matters. We appreciate the constructive comments made by the agency in the response letter and ChemGenex will seek a meeting with the FDA to discuss and find agreeable solutions for each of the FDA’s requests.”

Minutes from the 22 March ODAC meeting can be accessed from the FDA’s website - here

ChemGenex also met on April 9th with the US FDA’s Center for Devices and Radiological Health (CDRH) to discuss a path forward for the development of a well defined diagnostic test for the T315I mutation. Both parties agreed to work together toward the validation of the T315I assay that meets the FDA’s requirements.

MELBOURNE, Australia, and MENLO PARK, California U.S.A. (23 March 2010) – ChemGenex Pharmaceuticals Limited (ASX: CXS) announced today that the U.S. Food and Drug Administration’s (FDA) Oncologic Drugs Advisory Committee (ODAC) voted 7-1 that a validated test to identify the T315I mutation should be reviewed by the FDA prior to approval of OMAPRO™ (omacetaxine mepesuccinate).

ChemGenex has been working with the FDA on the T315I diagnostic matter and the FDA has confirmed that it will meet with ChemGenex to review the diagnostic strategy on 9 April 2010.

The question posed to the ODAC panel by the FDA was not regarding the safety and efficacy of OMAPRO, but was stated as the following:

“Should a well characterized in vitro diagnostic to identify patients with the T315I mutation be required and reviewed by the FDA and correlated to clinical trial results prior to approval of omacetaxine for the proposed indication?”

“We are encouraged by the positive comments from some members of the ODAC panel about the benefits of OMAPRO and the unmet medical need for CML patients with the T315I mutation,” said Adam R. Craig, M.D., Ph.D., Senior Vice President and Chief Medical Officer, ChemGenex. “We have a meeting scheduled next month with members of the FDA’s drug and diagnostic teams and will continue to work with the agency as it considers our new drug application for OMAPRO.”

“Over the past several months, ChemGenex has been working closely with the FDA on a diagnostic strategy to allow for approval of OMAPRO. We are committed to making OMAPRO available to patients as soon as possible,” added Greg Collier, Ph.D., Chief Executive Officer and Managing Director, ChemGenex.

ChemGenex is seeking FDA approval for OMAPRO™ (omacetaxine mepesuccinate) for the treatment of adults with chronic myeloid leukemia (CML) who have failed prior therapy with imatinib and have the Bcr-Abl T315I mutation.  T315I is a common mutation that renders CML resistant to all currently approved tyrosine kinase inhibitors (TKIs).

ChemGenex will host a webcast conference call today with the following access information:

Date/Time Australia: Tuesday, 23 March - 11:00am AEDST

Dial-in Australia: +1-800-288-277, Passcode: 5527539

Date/Time USA/Canada: Monday, 22 March - 8:00pm EDT / 5:00pm PDT

Dial-in USA/Canada: (800) 882-3610, Passcode: 5527539

All other International callers, dial +1-412-380-2000 Passcode: 5527539.

Webcast: To access the archived recording, visit the ChemGenex website at www.chemgenex.com.

A replay of this call will be available until 30 March 2010 by dialing (877) 344-7529 U.S./Canada and +1-412-317-0088 for International participants. When prompted, enter Conference Number 438881.

The ODAC meeting will consider ChemGenex’s application for OMAPRO™ (omacetaxine mepesuccinate) for the treatment of adults with chronic myeloid leukemia (CML) who have failed prior therapy with imatinib and who have developed the Bcr-Abl T315I mutation.

As an independent panel of experts the role of the ODAC committee is to review safety and efficacy data and make recommendations to the FDA concerning approval.

“The ODAC meeting is a significant milestone in the review process for OMAPRO, our team is well-prepared and we are looking forward to presenting to the ODAC panel” said Greg Collier, PhD, CEO and Managing Director of ChemGenex.

The ODAC meeting was scheduled to review two New Drug Applications, one of which was the application submitted by ChemGenex for OMAPRO™ (omacetaxine mepesuccinate) for the treatment of adults with chronic myeloid leukemia (CML) who have failed prior therapy with imatinib and who have developed the Bcr-Abl T315I mutation. ChemGenex submitted the NDA on 9 September 2009. The NDA was accepted by the FDA on 10 November 2009 and granted Priority Review.

The FDA will notify the company of a new date for the meeting as soon as possible.

ChemGenex believes in the safety and efficacy of OMAPRO™ for the treatment of patients with chronic myeloid leukemia (CML) who are resistant to imatinib and have the Bcr-Abl T315I mutation. The company is aware of the questions posed by the FDA and we are confident in our ability to answer these questions during the ODAC meeting. OMAPRO addresses a significant unmet need for patients with the T315I mutation, a marker for resistance to tyrosine kinase inhibitors, who currently have no effective treatment option and often have a poor prognosis.

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December 17, 2009