Callisto Pharmaceuticals, Inc., a biopharmaceutical company primarily focused on the development of drugs to treat cancer, has received notification from the Office of Orphan Products Development of the United States Food and Drug Administration (FDA) of orphan drug designation for the company's drug candidate Annamycin for use in the treatment of acute myeloid leukaemia (AML).

Initially developed at M.D. Anderson Cancer Centre, Annamycin, a second-generation anthracycline, is currently being developed by Callisto to treat both acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML) patients. A single-agent clinical trial of Annamycin in adult relapsed ALL patients is expected to proceed shortly. Callisto also plans to initiate a clinical trial of Annamycin in combination with Ara-C in adult relapsed AML patients in 2005.

Callisto CEO, Dr. Gary S. Jacob states, "This is very timely for Callisto, as we are about to embark on an ambitious clinical development program on Annamycin in relapsed leukaemia patients. Orphan drug designation for Annamycin to treat AML, in addition to the earlier granting of orphan drug designation for Annamycin to treat ALL, provides additional assurance to the company and its investors that Callisto is well protected against potential competition."

Annamycin, a drug from the anthracycline family, earlier completed a Phase I/IIa trial in refractory leukemia patients. The drug was developed at M.D. Anderson Cancer Centre to address limitations associated with other anthracyclines. Annamycin circumvents multiple drug resistance, shows decreased cardiotoxicity, and achieves greater than 95 per cent incorporation into liposomes, providing a favourable means of drug administration, the release says.