Phase 3 Trial of ZIOPHARM'S Palifosfamide in First-Line Metastatic Soft Tissue Sarcoma Reaches Target Number of Progression-Free

Phase 3 Trial of ZIOPHARM'S Palifosfamide in First-Line Metastatic Soft Tissue
Sarcoma Reaches Target Number of Progression-Free Survival Events

Results Will be Announced Last Week of March

NEW YORK, Feb. 12, 2013 (GLOBE NEWSWIRE) -- ZIOPHARM Oncology, Inc.
(Nasdaq:ZIOP) announced today that the Phase 3 (PICASSO 3) trial of
palifosfamide (ZIO-201) in first-line metastatic soft tissue sarcoma has
reached its target number of progression-free survival (PFS) events. PICASSO 3
is an international, randomized, double-blind, placebo-controlled trial whose
primary endpoint is PFS. According to the protocol and statistical plan,
reaching the target number of PFS events leads to completion of the blinded
data collection process and then formal efficacy analysis by the IDMC
(Independent Data Monitoring Committee).The Company will announce topline
results from this trial during the last week of March 2013.

"Reaching the target number of progression events for PICASSO 3 positions us
one step closer to understanding palifosfamide's full potential for this
significant unmet medical need," said Jonathan Lewis, M.D., Ph.D., Chief
Executive Officer of ZIOPHARM."With a positive study outcome, palifosfamide
has the potential to become the first new treatment option in nearly 30 years
for patients with first-line metastatic soft tissue sarcoma."

About ZIOPHARM Oncology, Inc.:

ZIOPHARM Oncology is a biopharmaceutical company focused on the development
and commercialization of new cancer therapies. The Company's clinical programs

Palifosfamide (ZIO-201) is a potent bi-functional DNA alkylating agent that
has activity in multiple tumors by evading typical resistance pathways.
Palifosfamide is in the same class as bendamustine, cyclophosphamide, and
ifosfamide. Intravenous palifosfamide is currently being studied in a
randomized, double-blinded, placebo-controlled Phase 3 trial (PICASSO 3) for
the treatment of first-line metastatic soft tissue sarcoma and is also in a
pivotal Phase 3 trial (MATISSE) for first-line metastatic small cell lung
cancer. Additionally, the Company is developing an oral capsule form of

Ad-RTS IL-12 is currently being tested in a Phase 2 study. Ad-RTS IL-12 uses
synthetic biology to enable controlled, local delivery of therapeutic
interleukin-12 (IL-12), a protein important for an immune response to cancer.
ZIOPHARM's DNA synthetic biology platform is being developed in partnership
with Intrexon Corporation and employs an inducible gene-delivery system that
enables controlled, local delivery of genes that produce therapeutic proteins
to treat cancer. This is achieved by placing IL-12 under the control of a
proprietary biological "switch" (the RheoSwitch Therapeutic System^®, RTS^®)
to turn on/off the therapeutic protein expression at the tumor site.

Indibulin (ZIO-301) is a novel, tubulin binding agent that is expected to have
several potential benefits, including oral dosing, application in multi-drug
resistant tumors, no neuropathy and a tolerable toxicity profile. It is
currently being studied in a Phase 1/2 trial in metastatic breast cancer.

Darinaparsin (ZIO-101) is a novel mitochondrial-and hedgehog-targeted agent
(organic arsenic) currently in ongoing studies with Solasia Pharma K.K.

ZIOPHARM's operations are located in Boston, MA, and New York City. Further
information about ZIOPHARM may be found at

Forward-Looking Safe Harbor Statement:

This press release contains certain forward-looking information about ZIOPHARM
Oncology that is intended to be covered by the safe harbor for
"forward-looking statements" provided by the Private Securities Litigation
Reform Act of 1995, as amended.Forward-looking statements are statements that
are not historical facts. Words such as "expect(s)," "feel(s)," "believe(s),"
"will," "may," "anticipate(s)" and similar expressions are intended to
identify forward-looking statements. These statements include, but are not
limited to, statements regarding our ability to successfully develop and
commercialize our therapeutic products; our ability to expand our long-term
business opportunities; financial projections and estimates and their
underlying assumptions; and future performance. All of such statements are
subject to certain risks and uncertainties, many of which are difficult to
predict and generally beyond the control of the Company, that could cause
actual results to differ materially from those expressed in, or implied or
projected by, the forward-looking information and statements. These risks and
uncertainties include, but are not limited to: whether Palifosfamide, Ad-RTS
IL-12, Darinaparsin, Indibulin, or any of our other therapeutic products will
advance further in the clinical trials process and whether and when, if at
all, they will receive final approval from the U.S. Food and Drug
Administration or equivalent foreign regulatory agencies and for which
indications; whether Palifosfamide, Ad-RTS IL-12, Darinaparsin, Indibulin, and
our other therapeutic products will be successfully marketed if approved;
whether any of our other DNA-based biotherapeutics discovery and development
efforts will be successful; our ability to achieve the results contemplated by
our collaboration agreements; the strength and enforceability of our
intellectual property rights; competition from pharmaceutical and
biotechnology companies; the development of and our ability to take advantage
of the market for DNA-based biotherapeutics; our ability to raise additional
capital to fund our operations on terms acceptable to us; general economic
conditions; and the other risk factors contained in our periodic and interim
SEC reports filed from time to time with the Securities and Exchange
Commission, including but not limited to our Annual Report on Form 10-K for
the fiscal year ended December 31, 2011, and our Quarterly Report on Form 10-Q
for the fiscal quarter ended September 30, 2012. Readers are cautioned not to
place undue reliance on these forward-looking statements that speak only as of
the date hereof, and we do not undertake any obligation to revise and
disseminate forward-looking statements to reflect events or circumstances
after the date hereof, or to reflect the occurrence of or non-occurrence of
any events.

         Nicole Jones
         ZIOPHARM Oncology, Inc.
         Media Contacts:
         David Schull or Lena Evans
         Russo Partners, LLC

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