Callisto Pharmaceuticals Opens Additional Sites for Phase II Clinical Trial of Atiprimod in Advanced Carcinoid Cancer Patients

New York (ots/PRNewswire) -

Callisto Pharmaceuticals, Inc. (Amex: KAL; FWB: CA4), a developer
of new drug treatments in the fight against cancer and inflammatory
diseases, announced today the addition of two sites to its Phase II
clinical trial of Atiprimod to treat low to intermediate grade
neuroendocrine carcinoma (advanced carcinoid cancer). With the
addition of the Robert H. Lurie Comprehensive Cancer Center of
Northwestern University, 676 N. St. Clair Street, Suite 850, Chicago,
IL and the H. Lee Moffitt Cancer Center & Research Institute, 12902
Magnolia Drive, Tampa, FL 33612, the Phase II clinical trial is
presently being conducted in seven sites. The principal investigator
for Northwestern is Mary Mulcahy, MD, and the principal investigator
for Lee Moffitt is Larry K. Kvols, M.D.

"The addition of these two major cancer centers to the Phase II
trial of Atiprimod in advanced carcinoid patients signifies our
continuing commitment to facilitate rapid enrollment of this trial,"
said Dr. Gary S. Jacob, Chief Executive Officer of Callisto. "Both
sites are active in the treatment of neuroendocrine cancers, and have
built significant reputations within the carcinoid community, which
should substantially enhance the pace of enrollment and increased
accessibility to prospective patients interested in participating in
this trial." Currently Callisto has enrolled 31 patients of the 40
subjects planned for this Phase II clinical trial.

The primary objective of the Phase II clinical trial is to
evaluate efficacy of Atiprimod in patients with low to intermediate
grade neuroendocrine carcinoma who have metastatic or unresectable
cancer and who have progression of their disease despite standard
therapy (octreotide). Patients, after signing an informed consent,
are required to complete two weeks of a symptoms diary to establish
their symptoms baseline before commencing Atiprimod dosing. A maximum
of 40 evaluable patients will be enrolled in this trial. Efficacy
evaluations will include the measure of target lesions (per RECIST),
and the quantization of symptom relief. Further details of this trial
can be found at http://www.clinicaltrials.gov.

The other five sites currently participating in this Phase II
trial are: 1) the Hematology Oncology Services of Arkansas in Little
Rock, Arkansas, 2) the Dana-Farber Cancer Institute in Boston, MA. 3)
Mount Sinai in New York City, 4) Lahey Clinic in Burlington, MA. and
5) Scott & White Memorial Hospital in Temple TX.

About Atiprimod

Atiprimod is an orally bio-available small molecule drug that
displays multiple mechanisms of action. The drug has been shown to be
antiangiogenic, inhibit secretion of VEGF and IL-6, elicit an
apoptotic response (programmed cellular death), and inhibit
phosphorylation of key kinases involved in tumor progression and
survival including Akt and STAT3. The drug is presently in two
clinical trials: a Phase II trial in advanced carcinoid cancer
patients, and a Phase I/IIa human clinical trial in relapsed or
refractory multiple myeloma patients. Callisto earlier announced in
June, 2006 interim data from a Phase I trial of Atiprimod in advanced
cancer patients. The patients who were entered into this trial had
growing tumors and symptoms that were no longer controlled by the
standard therapies utilized. During treatment, three of the five
advanced carcinoid patients had measurable tumor regressions and loss
of many of the debilitating symptoms of this disease.

About Carcinoid Cancer

Carcinoid tumors, or carcinoids, originate in hormone-producing
cells of the gastrointestinal (GI) tract, the respiratory tract, the
hepatobiliary (liver) system and the reproductive glands. The most
common site of origin is the GI tract, with tumors often developing
in the rectum, and other sections of the small intestine.
Approximately 7,000 cases of carcinoid cancer are diagnosed in the
U.S. annually, with the number increasing over the past 20-30 years.
Carcinoid tumors that metastasize to the liver have a poor prognosis.
Traditionally, chemotherapy relieves symptoms in less than 30% of
cases of metastatic carcinoid tumors, usually for less than 1 year.
Carcinoid tumors typically produce a condition called "carcinoid
syndrome" which is caused by the release of hormones by the tumors
into the blood stream. The symptoms vary depending on which hormones
are released by the tumors, but typically include diarrhea, facial
flushing, wheezing, abdominal pain and valvular heart disease.

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, a neuroendocrine tumor, 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 Genzyme 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 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 Jacob of Callisto Pharmaceuticals, Inc., +1-212-297-0010
Web site: http://www.callistopharma.com
Barretto Pacific Corporation
John Baldissera
+1-800-368-1217
Web site: http://www.callistopharma.com
http://www.clinicaltrials.gov

ots Originaltext: Callisto Pharmaceuticals. Inc.
Im Internet recherchierbar: http://www.presseportal.de

Contact:
Gary Jacob of Callisto Pharmaceuticals, Inc., +1-212-297-0010, or
jacob@callistopharma.com, or John Baldissera of Barretto Pacific
Corporation, +1-800-368-1217, for Callisto Pharmaceuticals, Inc.