NEW YORK, August 29 /PRNewswire/ --

Callisto Pharmaceuticals, Inc. (Amex: KAL; FWB: CA4), a developer of new 
drug treatments in the fight against cancer and gastrointestinal disorders 
and diseases, today announced that the staff of the American Stock Exchange 
("AMEX") has reviewed the Company's plan of compliance to meet the AMEX's 
continued listing standards and will continue the Company's listing while the 
Company seeks to regain compliance with Sections 1003 (a)(i) and 1003 (a)(ii) 
during the period ending April 3, 2008. As previously announced, on October 
3, 2006 the Company received notice from the AMEX staff indicating that the 
Company was below certain of the Exchange's continued listing standards due 
to guidelines set forth in sections 1003(a)(iv) and Section 1003(a)(i) of the 
AMEX Company Guide. The Company was further advised on June 18, 2007 that it 
was not in compliance with Section 1003 (a)(ii). Based upon a review of 
publicly available information, the AMEX staff has determined that the 
Company has resolved the continued listing deficiency with respect to Section 
1003 (a)(iv). The Company will be subject to periodic review by the AMEX 
Staff during the plan period. Failure to make progress consistent with the 
plan or to regain compliance with the continued listing standards by the end 
of the extension periods could result in the Company being delisted from the 
AMEX.

About Callisto Pharmaceuticals, Inc.

Callisto is a biopharmaceutical company focused on the development of new
drugs to treat various forms of cancer and gastrointestinal diseases.
Callisto's drug candidates in development currently include anti-cancer
agents in clinical development, in addition to drugs in pre-clinical
development for other significant health care markets, including
gastrointestinal disorders. One of the Company's lead drug candidates,
Atiprimod is presently in a Phase II clinical trial in advanced carcinoid
cancer patients, and in a Phase I/IIa human clinical trial in relapsed or
refractory multiple myeloma patients. Another anti-cancer drug, L-Annamycin,
is being developed as a treatment for forms of relapsed or refractory acute
leukemia, a currently incurable blood cancer. L-Annamycin is currently in a
Phase I clinical trial in adult relapsed or refractory acute lymphocytic
leukemia, and in a Phase I clinical trial in children and young adults with
refractory or relapsed acute lymphocytic leukemia or acute myelogenous
leukemia. L- Annamycin, a member of the anthracycline family of proven
anti-cancer drugs, has a novel therapeutic profile, including potential
activity against multi- drug resistant tumors and significantly reduced
cardiotoxicity, or damage to the heart, compared to currently available drug
alternatives. Callisto also has a proprietary drug Guanilib in preclinical
development for gastro- intestinal disorders. Callisto has exclusive
worldwide licenses from AnorMED Inc. and M.D. Anderson Cancer Center to
develop, manufacture, use and sell Atiprimod and L-Annamycin, respectively.
Callisto is also listed on the Frankfurt Stock Exchange under the ticker
symbol CA4. More information is available at http://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 for the
year ended December 31, 2006, 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.

CONTACT: Gary S. Jacob of Callisto Pharmaceuticals, Inc.,
             +1-212-297-0010, jacob@callistopharma.com
             Web site: http://www.callistopharma.com/



Web site: http://www.callistopharma.com