FDA has issued ChemGenex Pharmaceuticals a complete response letter regarding its NDA for Omapro™ for the treatment of adults with chronic myeloid leukemia (CML) who have failed prior therapy with imatinib and have the Bcr-Abl T315I mutation. The complete response letter asks for the development of a molecular diagnostic but does not request a new study nor the enrollment of additional patients into the pivotal study on Omapro, ChemGenex states.
The agency reportedly brought up similar concerns as the Oncology Drug Advisory Committee (ODAC), which on March 22 recommended that a test to identify the T315I mutation be reviewed by the FDA prior to approving Omapro. FDA specifically asked ODAC to evaluate whether a well-characterized in vitro diagnostic to identify patients with the T315I mutation should be required and reviewed by the FDA and correlated to clinical trial results prior to approval of the drug for the proposed indication. ODAC members voted 7-1 that such a diagnostic tool be developed, validated, and then presented to the FDA.
Subsequently, ChemGenex met with the FDA’s Center for Devices and Radiological Health on April 9 to discuss a path forward for the development of a well-defined T315I mutation diagnostic test.
“Because the principal issues raised by the FDA were similar to those discussed during the 22 March meeting of the Oncology Drug Advisory Committee, 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,” comments Greg Collier, Ph.D., CEO.
ChemGenex’ application for Omapro is currently under review at the EMEA for CML patients who have failed imatinib therapy and have the Bcr-Abl T315I mutation. The company has an alliance with Hospira to develop and commercialize the drug in Europe, the Middle East, and parts of Africa. ChemGenex plans to commercialize Omapro itself in North America but is seeking to establish commercial partnerships in the rest of the world.