ZIOPHARM Receives Positive Opinion for Orphan Drug Designation for Darinaparsin from European Medicines Agency NEW YORK, NY (

Receives Positive Opinion for Orphan Drug Designation for Darinaparsin from

European Medicines Agency

NEW YORK, NY (January 20,

2011) - ZIOPHARM Oncology, Inc. (Nasdaq: ZIOP), announced today that The

Committee for Orphan Medicinal Products (COMP) within the European Medicines

Agency (EMA) adopted a positive opinion for darinaparsin (Zinapar or ZIO-101)

designation as an orphan medicinal product for the treatment of

peripheral T-cell lymphoma (PTCL). A positive opinion by the COMP immediately

precedes official designation of darinaparsin as an orphan drug by the European

Commission (EC). Intravenous darinaparsin has demonstrated evidence of activity

in lymphoma, in particular PTCL. ZIOPHARM expects to initiate a

registration-directed study of darinaparsin in patients with PTCL by the end of

designation recognizes the acute need for new therapies for unmet medical needs,

in this case addressing PTCL, an aggressive form of lymphoma for which there

remains such a need," said Jonathan Lewis, M.D., Ph.D., Chief Executive Officer

and Chief Medical Officer of ZIOPHARM.

Drug Designation by the EC provides regulatory and financial incentives for

companies to develop and market therapies that treat a life-threatening or

chronically debilitating condition affecting no more than five in 10,000 persons

in the European Union (EU). In addition to a 10-year period of marketing

exclusivity in the EU after product approval, Orphan Drug Designation provides

companies with scientific advice and regulatory assistance from the EMA during

the product development phase, direct access to centralized marketing

authorization, as well as reductions in certain fees associated with the

application and approval process.

September, ZIOPHARM announced that darinaparsin was granted Orphan Drug

Designation by the U.S. Food and Drug Administration (FDA) for the treatment of

T-cell Lymphoma represents a subgroup of aggressive lymphomas that develop from

T-cells in different stages of maturity. According to the Lymphoma Research

Foundation, PTCL accounts for approximately 10-15% of the estimated 66,000 new

cases of non-Hodgkin's lymphoma diagnosed each year in the United States (53,000

in the EU, according to the European Cancer Observatory). PTCL generally affects

people of the age of 60 and is diagnosed in more men than women.

ZIOPHARM Oncology, Inc.:

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.

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.

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

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.

is also pursuing the development of novel DNA-based therapeutics 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

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.

Safe Harbor Statement:

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 will 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