NEW YORK--(BUSINESS WIRE)--January 6, 2004 --Callisto Pharmaceuticals, Inc. (OTCBB: CLSP - News) announced today that the Office of Orphan Products Development of the United States Food and Drug Administration (FDA) has granted orphan drug designation to the company’s lead drug candidate, Atiprimod, for the treatment of multiple myeloma, a blood cancer that proliferates in bone marrow. Callisto filed an investigational new drug application (IND) on Atiprimod in September 2003 and a Phase I/IIa clinical trial in multiple myeloma patients is expected to begin in January 2004.

Atiprimod has unique properties, centering on its ability to inhibit angiogenesis and proliferation of cancer cells through its ability to inhibit production of vascular endothelial growth factor (VEGF) and Interleukin-6 (IL-6), two essential factors for tumor growth and metastasis in multiple myeloma and other solid tumors. Patients will also be evaluated for the effect of Atiprimod on bone resorption, a debilitating side effect of multiple myeloma. Other anti-cancer uses for Atiprimod are presently being evaluated pre-clinically in collaboration with the National Cancer Institute.

The FDA grants orphan drug status for drug candidates that are intended to treat rare life-threatening diseases that, at the time of application, affect no more than 200,000 patients in the United States. The drug must have the ability to provide significant patient benefit over currently available treatment or fill an unmet medical need. Orphan drug designation entitles Callisto to seven years of market exclusivity in the United States upon FDA approval, provided that Callisto continues to meet certain conditions established by the FDA.

Once the FDA grants marketing approval of a new drug, the FDA will not accept or approve other applications to market the same medicinal product for the same therapeutic indication. Other incentives provided by orphan status include certain tax benefits, eligibility for research grants and protocol assistance. Protocol assistance includes regulatory assistance and possible exemptions

About Callisto Pharmaceuticals, Inc.
Callisto is a biopharmaceutical company primarily focused on the development of drugs to treat multiple myeloma, other cancers and osteolytic bone disease. In addition to its program to evaluate Atiprimod and the class of azaspiranes as agents to treat cancer, Callisto also has programs focused on the development of an analog of the human intestinal hormone, uroguanylin, to treat colon cancer, and drugs to protect against staphylococcal and streptococcal bioweapons, protecting against the devastating effects of toxic shock syndrome. Callisto has two operating subsidiaries, Callisto Research Labs, LLC and Synergy Pharmaceuticals Inc. Callisto has an exclusive worldwide license from AnorMED Inc. to develop, manufacture, use and sell Atiprimod.

Included in this release are “forward-looking” statements. Such statements are indicated by words such as “expect,” “should,” “anticipate” and similar words indicating uncertainty in facts and figures. Although Callisto believes that the expectations reflected in such forward-looking statements are reasonable, it can give no assurance that such expectations reflected in such forward-looking statements will prove to be correct. Callisto’s actual results could differ materially from those anticipated in the forward-looking statements as a result of various factors.