Callisto is a biopharmaceutical company focused on the development of new drugs to treat various forms of cancer and other serious afflictions. Callisto's drug candidates in development currently include anti-cancer agents in clinical development, in addition to drugs for a range of other significant health care market segments, including biodefense. One of the Company's lead drug candidates, L-Annamycin, is being developed as a treatment for forms of relapsed leukemia, a currently incurable blood cancer. Callisto initiated a clinical trial of L-Annamycin in adult relapsed acute lymphocytic leukemia patients in 4Q 2005. L-Annamycin, a new compound from the anthracycline family of proven anti-cancer drugs, has a novel therapeutic profile, including activity against resistant diseases and significantly reduced cardiotoxicity, or damage to the heart, compared to currently available drug alternatives. Another anti-cancer drug, Atiprimod, is in development to treat relapsed multiple myeloma, a blood cancer.