News & Events

- Highest Response Rates Yet for T315I + CML Clinical Trial -
- Findings Suggest Omapro Represents a New Potential Therapy for CML Patients with the T315I Resistance Mutation -

ChemGenex Pharmaceuticals Limited (ASX:CXS) announced today updated clinical data showing that Omapro^TM (omacetaxine mepesuccinate) produced durable hematologic and cytogenetic responses in chronic myeloid leukemia (CML) patients who have failed treatment with imatinib and who have developed the Bcr-Abl T315I mutation. New data was presented at a pre-conference press showcase at the 51st Annual American Society of Hematology Annual Meeting in New Orleans, Louisiana.

At the press conference titled "Advances in Diagnosing and Treating Leukemia and Myeloproliferative Disorders" 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 data on behalf of a team including investigators from ChemGenex and leading U.S. and
European clinical research centers. Completing his presentation, Dr Cortes concluded that Omapro represents a new potential therapy for patients with T315I+ CML.

Data were presented from 81 CML patients: 49 in chronic phase, 17 in accelerated phase and 15 in blast phase. Highlights of the data were:

• Complete hematologic responses (CHR) in 86% of chronic phase patients, median response duration 9 months

• Total cytogenetic response rate of 41% in chronic phase patients, with major cytogenetic response (MCyR) rate of 27%

• Overall hematologic responses in 35% of accelerated phase patients (median duration 7 months)

• Overall hematologic responses in 47% of blast phase patients (median duration 2 months)

• Investigators reported that omacetaxine is safe for self-administration, is well tolerated, and that reversible and manageable myelosuppression is the most common side effect

"We are delighted with the positive data presented today that continues to show that Omapro can provide clinical benefit to patients in this very difficult to treat sub-set of CML where there are no other approved treatment options," said Greg Collier, Ph.D., Managing Director and Chief Executive Officer of ChemGenex. "We would like to thank Dr. Cortes and all of our investigators for their efforts to produce this data. These results support our regulatory filings, and we look forward to working with the agencies in the U.S. and Europe over the next several months as we seek approval for Omapro in 2010."

Applications for marketing approval for Omapro are currently under review by the U.S. Food & Drug Administration (priority review), and the European Medicines Evaluation Agency.

The complete oral presentation by Dr. Cortes detailing this study will take place:
Date/Time: Monday, December 7, 2009 at 4:45 p.m., U.S. Central Time
Abstract/Title: #644: Safety and Efficacy of Subcutaneous-Administered Omacetaxine Mepesuccinate in Imatinib-Resistant Chronic Myeloid Leukemia (CML) Patients Who Harbor the Bcr- Abl T315I Mutation - Results of An Ongoing Multicenter Phase 2/3 Study Oral Session: Chronic Myeloid Leukemia - Therapy: Managing Resistance and Residual Disease Location: Conference Auditorium AB (Ernest N. Morial Convention Center)

About the Study
The study was designed to evaluate the safety and efficacy of subcutaneously (SC) administered omacetaxine in patients with imatinib resistant T315I+ Philadelphia chromosome positive CML.  Eligible patients include adult CML Patients in chronic, accelerated, or blast disease phase (CP, AP, BP) with a confirmed Bcr-Abl T315I mutation and resistance to imatinib therapy. Patients were given 1.25 mg/m2 SC omacetaxine twice daily for 14 days every 28 days until hematologic response for induction therapy. For maintenance therapy, patients were dosed 1.25 mg/m2 SC omacetaxine twice daily for 7 days every 28 days. Eighty one patients were described in this presentation (49 CP, 17 AP and 15 BP). The median age was 58 years (19-83) with a median CML disease duration of 54 months (5-286). All patients had failed prior imatinib therapy, and 79% had failed two or more prior TKIs. The presence of baseline T315I mutation was confirmed in all patients.