Callisto Pharmaceuticals, Inc. described its preclinical findings regarding the anticancer activities of its lead drug candidate, Atiprimod, in a poster at the Conference on Molecular Targets and Cancer Therapeutics, sponsored by the American Association for Cancer Research, the National Cancer Institute and the European Organization for Research and Treatment of Cancer which was held in Boston, Massachusetts.

Atiprimod is Callisto's lead drug candidate for multiple myeloma. Callisto recently filed an investigational new drug application (IND) on Atiprimod, and a Phase I/IIa clinical trial in multiple myeloma patients is expected to begin shortly. According to Dr. Kunwar Shailubhai, Executive Vice President and the poster presenter, Atiprimod has unique properties, centering on its ability to inhibit angiogenesis and proliferation of cancer cells, as well as 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. In collaboration with scientists at the National Cancer Institute, Atiprimod has been found to inhibit the proliferation of a panel of human cancer cells and to induce apoptosis -- programmed cell death. Further, the compound has been shown to inhibit both cancer cell migration and angiogenesis -- the process that grows blood vessels to supply oxygen and nutrients to tumor cells.

" In essence, we've shown in these early studies that Atiprimod has the potential to intervene with cancer cells and tumors in three ways -- by inhibiting their formation, by programming their death and by limiting their ability to grow blood vessels necessary for their survival. Taken together, these findings suggest that Atiprimod could potentially represent a novel class of compounds for development for therapeutic intervention in human cancers," says Dr. Shailubhai.

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. Callisto's lead drug candidate, Atiprimod, is a small-molecule, orally available drug with antiproliferative and antiangiogenic activity. Atiprimod successfully completed Phase I clinical trials in rheumatoid arthritis patients and Callisto plans to enter Atiprimod in a safety and proof-of-principle clinical trial in multiple myeloma patients. The drug is also being explored as an agent to treat osteolytic bone disease. In addition, Callisto 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. For additional information, visit www.callistopharma.com.
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.