ZIOPHARM Presents Positive Data From Phase II Study Of Darinaparsin In Advanced Hematological Malignancies At AACR 2008 Annual Meeting

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ZIOPHARM Presents Positive Data From Phase II Study Of Darinaparsin In Advanced

Hematological Malignancies At AACR 2008 Annual Meeting

18 Apr 2008

ZIOPHARM Oncology, Inc. (NASDAQ:ZIOP) announced that it presented positive data

from a phase II study of darinaparsin, the Company's novel organic arsenic

compound, in advanced hematological malignancies at the American Association for

Cancer Research (AACR) Annual Meeting, in San Diego, CA.

A total of 40 patients with a variety of hematological malignancies, including

leukemias and lymphomas, have been enrolled in the study, with 40 patients

evaluable for safety and 21 evaluable for efficacy. In 3 of 7 lymphoma patients

evaluable for efficacy, 1 patient (peripheral T-cell lymphoma) achieved a

complete response, one patient (nodular sclerosis) is ongoing in cycle 3 with a

PET scan interval response, and one patient (B-cell lymphoma) is ongoing with

stable disease after 5 cycles of therapy. Of 14 leukemia patients evaluable for

efficacy, 6 patients achieved stable disease (3 MDS and 3 CML) and 1 patient

withdrew consent prior to efficacy evaluation. The study is ongoing and patient

accrual continues. In these patients, therapy with darinaparsin was well

tolerated with the most common serious adverse events being constitutional

(pyrexia), pulmonary (dyspnea), cardiovascular (hypotension), and infection

(sepsis) related.

" Administration of darinaparsin to patients diagnosed with advanced

hematological malignancies has been well-tolerated, and tumor response,

including a complete response in a highly refractory T-cell lymphoma patient, is

very encouraging, " commented Craig, M.D., Assistant Professor and

Interim Director of Blood and Marrow Transplantation of West Virginia University

and a lead investigator of the study. " Because cure rates are low in advanced

disease but progression can be slow, achieving stable disease or better could

have a meaningful impact on patient outcome. Further study of darinaparsin in

hematological malignancies, particularly in lymphomas, is highly warranted. "

For more details on these trials please see http://www.clinicaltrials.gov.

About Darinaparsin

Darinaparsin is a proprietary small molecule organic arsenic licensed from The

University of Texas M. D. Cancer Center and Texas A & M University.

Darinaparsin induces cell cycle arrest and cell death by targeting several

cellular pathways essential for cell survival. Exposure to darinaparsin has a

direct as well as indirect effect on mitochondrial functions, resulting in

depletion of energy supply to the cell and induction of apoptosis (programmed

cell death). Increase in intra-cellular Reactive Oxygen Species enhances this

effect on mitochondrial functions and consequently the activation of the signal

transduction pathway leading to apoptosis. In addition, darinaparsin interrupts

the cell cycle at the G2/M phase of tumor cells inducing cell death through this

pathway.