NEW YORK--(BUSINESS WIRE)--Oct. 21, 2003--Callisto Pharmaceuticals, Inc. (OTCBB: CLSP - News) announced today that it will participate in the Rodman & Renshaw Techvest Healthcare Conference, to be held October 21 - 23, 2003 at the Boston Marriott Long Wharf Hotel in Boston, MA. Gary S. Jacob, Ph.D., CEO of Callisto, is scheduled to speak at 6:00 PM EDT on October 22, 2003 and is expected to discuss Callisto's drug development programs directed towards multiple myeloma, osteolytic bone disease and other cancers.

About Callisto Pharmaceuticals, Inc.
Callisto is a biopharmaceutical company primarily focused on the development of drugs to treat multiple myeloma, osteolytic bone disease and other cancers. 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 filed an IND on September 23, 2003 with the U.S. Food and Drug Administration on Atiprimod to enter a Phase I/IIa 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, as a protection against the devastating effects of toxic shock syndrome. Callisto has two operating subsidiaries, Callisto Research Labs, LLC and Synergy Pharmaceuticals Inc.

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 have been correct. Callisto's actual results could differ materially from those anticipated in the forward-looking statements as a result of various factors.