ZIOPHARM Reports Fourth Quarter and Full Year 2010 Financial Results NEW YORK, NY (

ZIOPHARM Reports Fourth Quarter and Full Year 2010 Financial Results

NEW YORK, NY (March 1, 2011) - ZIOPHARM Oncology, Inc. (Nasdaq: ZIOP), announced today its financial results for the fourth quarter and full year 2010, and the filing of its Annual Report on Form 10-K with the Securities and Exchange Commission. Summary financials for the fourth quarter and for the year are attached.

For the fourth quarter of 2010, the Company reported net loss of $11.9 million, or $(0.25) per share, compared to a net income of $1.0 million, or $0.03 per share, in the fourth quarter of 2009. Excluding recognition of a non-cash gain of $5.0 million attributable to the change in liability-classified warrants, there was a net loss of $4.0 million, or $(0.14) per share, for the fourth quarter ended December 31, 2009. Net loss for the year was $32.7 million, or $(0.71) per share, compared to a net loss of $7.6 million, or $(0.33) per share, for the full year 2009. Total operating expenses for the year were $24.5 million, compared to $12.1 million for 2009, or an increase of $12.4 million. The increase in operating

expenses is attributable to initiation of the Phase III palifosfamide pivotal trial during 2010 as well as related support activity. The difference between 2010 full year operating expenses and net loss is primarily attributable to a non-cash charge of $8.9 million related to the change in fair value of liability-classified warrants. The Company ended the December 2010 quarter with cash of approximately $60.4 million which, along with net proceeds of approximately $71 million from financing transactions completed in January and February 2011, and under current assumptions which are subject to change, is expected to support operations into late 2012.

"ZIOPHARM achieved a number of significant milestones in 2010 with regard to our clinical and financial goals, including the launch of PICASSO 3, our pivotal, Phase III study of palifosfamide in metastatic soft-tissue sarcoma," stated Jonathan Lewis, MD, PhD, Chief Executive Officer and Chief Medical Officer of ZIOPHARM. "With the addition in early 2011 of Intrexon's products and revolutionary platform technologies to our research and development efforts, ZIOPHARM is well positioned to deliver a range of important cancer medicines to areas of unmet medical need. As always, we will continue pursuing this important goal while operating under rigorous financial

Full Year 2010 and Recent Highlights

The presented data demonstrated that palifosfamide in combination with doxorubicin is well tolerated, easy to administer, can be given in the outpatient setting, and is active in soft tissue sarcoma. Further, the study reported a hazard ratio of 0.39 (p= 0.023) for patients receiving either doxorubicin or doxorubicin in combination with palifosfamide for 6 cycles or less (the standard treatment period for doxorubicin). Updated safety data showed there was similarity between the arms of the study. The most common grade 3+ events were neutropenia and elevated creatinine. There was no encephalopathy, hemorrhagic cystitis or Fanconi's Syndrome.

Financing Highlights:

About ZIOPHARM Oncology, Inc.:

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

Palifosfamide (Zymafos 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 the standard of care addressing small cell lung cancer and an oral form of the drug for treatment of solid tumors is currently in the advanced preclinical stage of development.

Darinaparsin (Zinapar 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 or ZIO-301) is a novel, oral tubulin binding agent that that is expected to have several 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 is also pursuing the development of novel DNA-based biotherapeutics in the field of cancer pursuant to a partnering arrangement with Intrexon Corporation. The partnership includes two existing clinical-stage product candidates, the first of which is in a Phase Ib study and the second of which is the basis of an Investigational New Drug application that ZIOPHARM expects to submit during the first half of 2011.

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.

Forward-Looking Safe Harbor Statement:

This press release contains forward-looking statements for ZIOPHARM Oncology, Inc. that involve risks and uncertainties that could cause ZIOPHARM Oncology'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 ZIOPHARM Oncology'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 ZIOPHARM Oncology's product candidates, the risk that the results of clinical trials may not support ZIOPHARM Oncology's claims, the risk that pre-clinical or clinical trials may not proceed on schedules that are consistent with ZIOPHARM Oncology's current expectations or at all, risks related to ZIOPHARM Oncology'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 ZIOPHARM Oncology's ability to obtain additional financing to support its operations thereafter, as well as other risks regarding ZIOPHARM

Oncology's that are discussed under the heading "Risk Factors" in ZIOPHARM Oncology'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. ZIOPHARM Oncology assumes no obligation to update these forward-looking statements, except as required by law.

ZIOPHARM Oncology, Inc.

Condensed Statements of Operations

(in thousands except share and per share data)

ZIOPHARM Oncology, Inc.

ZIOPHARM Oncology, Inc.