The drugmaker submitted data on how well the injectable drug, called Omapro, worked in just 66 patients although plans for the study had called for 100 enrollees, U.S. Food and Drug Administration staff also said.
FDA officials released the documents ahead of a public meeting of outside advisers on Wednesday to discuss whether to recommend approval of the drug.
Omapro, or omacetaxine mepesuccinate, is secondary treatment aimed at those with chronic myeloid leukemia who do not improve with Novartis AG's Gleevec.
While Bristol-Myers Squibb Co's Sprycel and Novartis's Tasigna also aim to treat patients after unsuccessful Gleevec treatment, Omapro targets those who test positive for a specific genetic mutation known as the Bcr-Abl T315I mutation.
'However, there is no commercially available assay for the detection of this mutation,' FDA staff wrote.
In a separate document, ChemGenex said its drug showed acceptable risks and benefits with manageable side effects. Omapro 'offers the only therapeutic treatment alternative for a patient population with a poor prognosis and no proven treatment options,' it wrote.
(Reporting by Susan Heavey, editing by Gerald E. McCormick) Keywords: CHEMGENEX OMAPRO/ (sheavey@thomsonreuters.com; +1 202-354-5848; www.twitter.com/ReutersDChealth) COPYRIGHT Copyright Thomson Reuters 2010. All rights reserved. The copying, republication or redistribution of Reuters News Content, including by framing or similar means, is expressly prohibited without the prior written consent of Thomson Reuters.
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