ChemGenex's omacetaxine may provide first viable treatment option for highly resistant f...( MELBOURNE Australia and MENLO PARK C...),Health

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
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