NEW YORK--(BUSINESS WIRE)--Dec. 22, 2005--Callisto Pharmaceuticals, Inc. (AMEX:KAL) (FWB:CA4), a developer of new drug treatments in the fight against cancer and other major health threats, has established Guanilib as the developmental name for its proprietary drug candidate previously identified as SP304. Callisto scientists developed this first-in-class compound as a treatment for serious inflammatory gastro-intestinal diseases. Guanilib is designed to mimic a naturally-occurring hormone called uroguanylin normally produced in the body’s intestinal tract, but with the added advantage of providing greater anti-inflammatory potency and therapeutic effect. Research also suggests that the drug may also act as a preventative against the formation of polyps that are a major risk factor in the development of colon cancer.