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NEW YORK--(BUSINESS WIRE)-- ZIOPHARM Oncology, Inc. (Nasdaq: ZIOP) announced today that new preclinical data on the novel mechanism of its organic arsenic darinaparsin (ZIO-101) in various lymphoma models were presented at the 52nd Annual Meeting and Exposition of the American Society of Hematology (ASH) in Orlando Florida. Andrew M Evens, DO, MSc, Associate Professor of Medicine, Feinberg School of Medicine of Northwestern University and Director, Translational Therapeutics Division of Hematology/Oncology, Robert H. Lurie Comprehensive Cancer Center of Northwestern University, presented the abstract (# 2840) titled "the Novel Organic Arsenical, Darinaparsin (ZIO-101), Induces Apoptosis through AKT and MEK/ERK Pathways in Hodgkin's Lymphoma and T-Cell Lymphoma Cell Lines."

The preclinical work was designed to study the effects of increasing concentrations of darinaparsin in T Cell Lymphoma and resistant Hodgkin's Lymphoma. Results demonstrated that darinaparsin inhibited cell growth and induced apoptosis through the AKT and MEK/ERK pathways and all cell lines at 1-3µM. AKT and MEK/ERK-based pathways are known to play a key role in multiple cellular processes, including cell proliferation, apoptosis, transcription and cell migration. At 2µM (48 hours), darinaparsin induced approximately 80% apoptosis in each of the four TCL lines, while 3µM resulted in 65% apoptosis in L428 cells. By comparison, >10µM of arsenic trioxide or inorganic arsenic (ATO) for 48 hours was required to induce 40% apoptosis in TCL and 25% apoptosis in L428 cells. L428 cells were also treated with the MEK inhibitor U0126 or ERK2 siRNA, both combined with darinaparsin. Preincubation with U0126 or siRNA knock down of ERK2, followed by treatment with darinaparsin, significantly enhanced darinaparsin-induced apoptosis (p<0.05). Finally, markedly higher intracellular darinaparsin levels were achieved in lymphoma cells compared with equivalent concentrations of ATO.

"These data demonstrate darinaparsin's potent and targeted effects on two signaling pathways important to proliferation in hematologic malignancies, AKT and MEK/ERK, an effect which can be enhanced in combination with MEK/ERK-targeted inhibitors," said Dr. Evens. "The results lend further support to the encouraging clinical data seen to date in lymphomas and warrant continued preclinical and clinical trial investigation of darinaparsin in Hodgkin's and T Cell Lymphoma."

In September, ZIOPHARM announced that darinaparsin was granted Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) for the treatment of peripheral T-cell Lymphoma (PTCL). Intravenous darinaparsin has demonstrated favorable results in a Phase II trial in lymphoma and particularly for PTCL. Clinical development is expected to proceed in both PTCL and solid tumors.

About ZIOPHARM Oncology, Inc.:

ZIOPHARM Oncology is a biopharmaceutical company engaged in the development and commercialization of a diverse portfolio of cancer drugs. The Company is currently focused on three clinical programs.

Palifosfamide (Zymafos^TM or ZIO-201) is a novel DNA cross-linker in class with bendamustine, ifosfamide, and cyclophosphamide. ZIOPHARM is currently enrolling patients in a randomized, double-blinded, placebo-controlled Phase III trial with palifosfamide administered intravenously for the treatment of metastatic soft tissue sarcoma in the front-line setting. The Company expects to initiate additional studies in the near-term, including a Phase I intravenous study of palifosfamide in combination with standard of care addressing small cell lung cancer and a Phase I study of oral palifosfamide.

Darinaparsin (Zinapar^TM or ZIO-101) is a novel mitochondrial-targeted agent (organic arsenic) being developed intravenously for the treatment of peripheral T-cell lymphoma with a pivotal study expected to begin in late 2011. An oral form is in a Phase I trial in solid tumors.

Indibulin (Zybulin^TM or ZIO-301) is a novel, oral tubulin binding agent that is expected to have several potential benefits including oral dosing, application in multi-drug resistant tumors, no neuropathy and minimal overall toxicity. It is currently being studied in Phase I/II in metastatic breast cancer.

ZIOPHARM's operations are located in Boston, MA with an executive office in New York City. Further information about ZIOPHARM may be found at www.ziopharm.com.

ZIOP-G

Forward-Looking Safe Harbor Statement:

This press release contains forward-looking statements for ZIOPHARM Oncology, Inc. that involve risks and uncertainties that could cause the Company's actual results to differ materially from the anticipated results and expectations expressed in these forward-looking statements. These statements are based on current expectations, forecasts and assumptions that are subject to risks and uncertainties, which could cause actual outcomes and results to differ materially from these statements. Among other things, there can be no assurance that any of the Company's development efforts relating to its product candidates will be successful, or such product candidates will be successfully commercialized. Other risks that affect forward-looking information contained in this press release include the possibility of being unable to obtain regulatory approval of the Company's product candidates, the risk that the results of clinical trials may not support the Company's claims, the risk that pre-clinical or clinical trials will proceed on schedules that are consistent with the Company's current expectations or at all, risks related to the Company's ability to protect its intellectual property and its reliance on third parties to develop its product candidates, risks related to the sufficiency of existing capital reserves to fund continued operations for a particular amount of time and uncertainties regarding the Company's ability to obtain additional financing to support its operations thereafter, as well as other risks regarding the Company that are discussed under the heading "Risk Factors" in the Company's filings with the United States Securities and Exchange Commission. Forward-looking statements can be identified by the use of words such as "may," "will," "intend," " should," "could," "can," "would," "expect," "believe," "estimate," " predict," "potential," "plan," "is designed to," "target" and similar expressions. The Company assumes no obligation to update these forward-looking statements, except as required by law.

ZIOPHARM Oncology, Inc.
Tyler Cook, 617-259-1982
tcook@ziopharm.com
or
Media:
Argot Partners
David Pitts, 212-600-1902
david@argotpartners.com

Source: ZIOPHARM Oncology

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