ZIOPHARM Oncology Appoints Mark Thornton, M.D., Ph.D., as Executive Vice President and Chief Development Officer

ZIOPHARM Oncology, Inc. (Nasdaq: ZIOP) announced today that it has appointed Mark O. Thornton, M.D., Ph.D., Executive Vice President and Chief Development Officer. In this position, Dr. Thornton will be responsible for the oversight of all disciplines involved in the product development process and will report to the Chief Executive Officer and Chief Medical Officer, Jonathan Lewis, M.D., Ph.D. Dr. Thornton is rejoining ZIOPHARM Oncology, having previously served as the Company’s Chief Medical Officer & Head of Product Development and after having served as Medical Officer at the Food and Drug Administration’s Center for Biologics Evaluation and Research (CBER).

"We are delighted to welcome Dr. Thornton back to ZIOPHARM’s senior management team,” stated Dr. Lewis. "Mark’s passion for regulatory reform, his advocacy work, and his distinguished career both at FDA and within industry will prove invaluable as we work to bring our portfolio of oncology products to market and as we look to new opportunities for the future.”

"It is with great pleasure that I rejoin ZIOPHARM and their effort to bring new and novel therapies to areas of unmet need in oncology,” stated Dr. Thornton. "The Company has a robust and dynamic portfolio of product candidates maturing in a number of directions. I look forward to applying my experience from the many facets of biopharmaceutical drug development to ZIOPHARM’s current and future pursuits.”

Dr. Thornton, a clinical pharmacologist and trialist, has divided his 20 year career at FDA and in the biopharmaceutical industry between oncology and infectious disease drugs and biologics, serving most recently as Chief Medical Officer at Novavax, Inc. He is a leading advocate for reform in cancer drug policy, having published several op-ed’s in the Wall Street Journal on policy issues stimulating innovation in cancer drug development. He recently led efforts to have specific guidance developed at the U.S. Food and Drug Administration that would streamline regulatory approvals for drugs targeting rare cancers. His advocacy work originates from his leadership of the Sarcoma Foundation of America, which he co-founded with his wife Patricia in 2001, and the National Organization Against Rare Cancers. Dr. Thornton received his M.D. and his Ph.D. in Pharmacology from West Virginia University, and his M.P.H. from the Johns Hopkins University School of Public Health. Following medical school, Dr. Thornton served as a Medical Officer in the U.S. Navy.

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 is also currently conducting a Phase I intravenous study of palifosfamide in combination with standard of care addressing small cell lung cancer and expects to initiate an additional study with drug in the oral form treating solid tumors.

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.

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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.