Callisto Announces Availability of Presentation Outlining Drug Development Pipeline and Market Opportunities; Development Programs Include New Drugs to Treat Leukemia and Multiple Myeloma Cancers, and to Fight Biowarfare Threats.

NEW YORK -- Callisto Pharmaceuticals, Inc. (AMEX:KAL)(FWB:CA4), a developer of new drug treatments in the fight against hematological cancers and related diseases, has announced the online availability of an electronic presentation that provides an informative overview of the Company's development pipeline of needed drugs to treat diseases including blood cancers and serious gastrointestinal inflammation, as well as its program to develop drugs to protect against biowarfare agents for use in homeland security applications.

The presentation, available to all interested investors, provides an overview of the multi-million-dollar markets for the Company's drug candidates. These drugs include Atiprimod, which the Company is developing as a treatment for multiple myeloma, a currently incurable blood cancer, and Annamycin, a drug to treat forms of leukemia. "Callisto is developing drugs such as Atiprimod and Annamycin to give new hope to patients with relapsed multiple myeloma and relapsed leukemia," said Dr. Gary S. Jacob, CEO of Callisto. "There are significant numbers of desperately ill patients with these cancers who are not receiving any benefit from the existing drug therapies, creating a very important need for new treatment options that Callisto is working to fill."

Advanced animal-model research on Atiprimod has indicated that it inhibits the growth of multiple myeloma tumors in animals. A report on Atiprimod was published in the July issue of the American Society of Hematology's journal, "Blood," in Volume 106, Number 2, pp. 713-716 (2005.) The article entitled, "A clinically relevant SCID-hu in vivo model of human multiple myeloma," was authored by a team of scientists at Dana-Farber Cancer Institute (Boston, MA) and at Callisto Pharmaceuticals, Inc.

Callisto's anti-cancer drug Annamycin is also highlighted in the presentation. It is being developed as a treatment for patients diagnosed with the blood cancers acute lymphocytic leukemia (ALL) and acute myelogenous leukemia (AML.) Annamycin, which has a novel therapeutic profile and the expectation of reduced cardiotoxicity, is also being developed as a new treatment for relapsed patients who fail to respond to currently available drug therapies.

The presentation also provides background on the Company's project to develop a superantigen drug platform to create drugs for defense against biowarfare toxins, as well as research and development of a new drug to treat ulcerative colitis, a gastrointestinal inflammation disease.

The presentation is available for viewing at http://www.trilogy-capital.com/tcp/callisto/powerpoint.html.

About Callisto Pharmaceuticals, Inc.

Callisto is a biopharmaceutical company focused on the development of drugs to treat cancer and osteolytic bone disease. Callisto has two lead drugs in clinical development, Annamycin to treat relapsed leukemia, and Atiprimod to treat relapsed multiple myeloma. Callisto intends to initiate a clinical trial of Annamycin in relapsed acute lymphoblastic leukemia patients in 4Q 2005. Annamycin, a drug from the anthracycline family, has a novel therapeutic profile, including activity against resistant diseases and significantly reduced cardiotoxicity. Callisto's second drug, Atiprimod, is in a Phase I/IIa clinical trial in relapsed multiple myeloma patients, and is a small-molecule, orally-available drug with antiproliferative and antiangiogenic activity. Callisto also has drugs in preclinical development for gastrointestinal inflammation, and a program focused on the development of a drug to protect against staphylococcus and streptococcus biowarfare agents. Callisto has exclusive worldwide licenses from AnorMED Inc. and M.D. Anderson Cancer Center to develop, manufacture, use and sell Atiprimod and Annamycin, respectively. For investor-specific information about Callisto, including recent news and stock price data, please visit http://www.trilogy-capital.com/tcp/callisto/. For an Investor Fact Sheet about Callisto, please visit http://www.trilogy-capital.com/tcp/callisto/factsheet.html. Callisto is also listed on the Frankfurt Stock Exchange under the ticker symbol CA4. For additional information, visit www.callistopharma.com.

Forward-Looking Statements

Certain statements made in this press release are forward-looking. 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. As discussed in the Callisto Pharmaceuticals Annual Report on Form 10-K/A for the year ended December 31, 2004, and other periodic reports, as filed with the Securities and Exchange Commission, actual results could differ materially from those projected in the forward-looking statements as a result of the following factors, among others: uncertainties associated with product development, the risk that products that appeared promising in early clinical trials do not demonstrate efficacy in larger-scale clinical trials, the risk that Callisto will not obtain approval to market its products, the risks associated with dependence upon key personnel and the need for additional financing.