ZIOPHARM Reports Second-Quarter 2016 Financial Results and Provides Update on Recent Activities - Company to Host Conference Call at 4:30 PM ET Today - BOSTON, MA

ZIOPHARM Reports Second-Quarter 2016 Financial Results and

Provides Update on Recent Activities

- Company to Host Conference Call at 4:30 PM ET Today -

BOSTON, MA August 9, 2016 ZIOPHARM Oncology, Inc. (Nasdaq: ZIOP) today announced financial results for the second

quarter ended June 30, 2016, and provided an update on the Company s recent activities.

ZIOPHARM had a very productive first

half, with the achievement of pipeline and corporate milestones across the breath of our portfolio and the advancement of our goal to position the company at the forefront of those harnessing the immune system to target cancer, said Laurence

Cooper, M.D., Ph.D., Chief Executive Officer of ZIOPHARM Oncology. Central to this effort, we were pleased to have amended the terms of our collaboration with Intrexon to facilitate the commercialization of our immunotherapy assets. The

benefit of this new structure is expected to be first realized with our gene therapy Ad-RTS-hIL-12 + veledimex program, which remains on track to move into a registrational trial in advanced glioblastoma in 2017.

Dr. Cooper added: As we progress through the remainder of 2016, we will continue to work with our collaborators, including Intrexon Corporation and

the MD Anderson Cancer Center, to advance new therapies into the clinic. We look forward in 2016 to seeing six clinical trials exploring immuno-oncology approaches and combinations, in addition to preclinical projects advancing towards the clinic.

As these programs mature, we expect to see proof-of-concept clinical data that will drive value for all of our stakeholders.

Exclusive Channel Collaborations with Intrexon to Improve Alignment as Programs Advance through Development. In June, ZIOPHARM and Intrexon Corporation (NYSE:XON) announced amendments to their Exclusive Channel Collaborations (ECCs) in the

fields of oncology and graft-versus-host-disease (GvHD) to improve alignment between both companies as ZIOPHARM broadens its pipeline and advances multiple therapeutic programs in the clinic.

Under the terms of the amendments:

In consideration of the amendments, ZIOPHARM has issued shares of a new class of preferred stock that carries an initial stated value of $120 million and a

monthly dividend of 1%, payable in additional preferred shares. Only upon the first approval of a product in the United States or upon certain fundamental transactions, such as a change of control of ZIOPHARM, the preferred shares issued to Intrexon

will be converted into ZIOPHARM common stock equal to the aggregate stated value divided by the volume weighted average closing price of ZIOPHARM s common stock over the 20 trading days ending on the date that the product approval or such

transaction is announced.

Ad-RTS-hIL-12 + veledimex is a gene therapy candidate for the controlled expression of interleukin 12 (IL-12), a critical protein for stimulating an

anti-cancer immune response, using the RheoSwitch Therapeutic System (RTS ) gene switch. ZIOPHARM is currently enrolling patients in

two studies of Ad-RTS-hIL-12 + veledimex: a multi-center Phase 1 study in patients with recurrent or progressive glioblastoma multiforme (GBM), an aggressive form of brain cancer, and a Phase 1b/2 study for the treatment of patients with locally

advanced or metastatic breast cancer following standard chemotherapy.

Adoptive Cell Therapies

ZIOPHARM is developing

various immuno-oncology programs, including chimeric antigen receptor T-cell (CAR-T), T-cell receptor (TCR), and natural killer (NK) adoptive cell-based therapies. These programs are being advanced in collaboration with Intrexon, MD Anderson Cancer

Center, and Merck Serono (CAR-T only).

The paper describes results for 26 patients with multiply relapsed B-lineage acute lymphoblastic leukemia (ALL, n=17) or B-cell non-Hodgkin

lymphoma, (NHL, n=9) who were enrolled in two investigator-initiated clinical trials at the University of Texas MD Anderson Cancer Center infused with SB-modified T cells after autologous (n=7) or allogeneic (n=19) hematopoietic stem-cell

transplantation (HSCT). Although the primary objective of these trials was not to establish efficacy, the recipients outcomes are encouraging, with apparent doubling of survivals compared to historical controls which is attributed to the

persistence of the infused T cells. Additionally, by infusing a CD19-specific CAR T cells to target minimal residual disease after autologous and allogeneic HSCT, the approach may improve tolerability by avoiding cytokine storm.

ZIOPHARM achieved and expects the following milestones to occur in 2016:

The Company is also evaluating additional potential preclinical candidates and continuing discovery efforts aimed at identifying other potential product

candidates under its Exclusive Channel Agreement with Intrexon. In addition, the Company may seek to enhance its pipeline in immuno-oncology through focused strategic transactions, which may include acquisitions, partnerships and in-licensing

ZIOPHARM will host a

conference call and webcast slide presentation today, August 9, 2016, at 4:30 pm ET. The call can be accessed by dialing 1-844-309-0618 (U.S. and Canada) or 661-378-9465 (international). The passcode for the conference call is 58685274. To

access the slide and live audio webcast, or the subsequent archived recording, visit the Investors & Media section of the ZIOPHARM website at www.ziopharm.com. The webcast will be recorded and available for replay on the

Company s website for two (2) weeks.

Second-Quarter 2016 Financial Results

About ZIOPHARM Oncology, Inc.:

ZIOPHARM Oncology is a Boston, Massachusetts-based biotechnology company employing novel gene expression, control and cell technologies to deliver safe,

effective and scalable cell- and viral-based therapies for the treatment of cancer. The Company s immuno-oncology programs, in collaboration with Intrexon Corporation (NYSE:XON) and the MD Anderson Cancer Center, include chimeric antigen

receptor T cell (CAR-T) and other adoptive cell-based approaches that use non-viral gene transfer methods for broad scalability. The Company is advancing programs in multiple stages of development together with Intrexon Corporation s RheoSwitch

Therapeutic System technology, a switch to turn on and off, and precisely modulate, gene expression in order to improve therapeutic index. The Company s pipeline includes a number of

cell-based therapeutics in both clinical and preclinical testing which are focused on hematologic and solid tumor malignancies.

Safe-Harbor Statement:

This press release contains certain forward-looking information about ZIOPHARM Oncology, Inc. 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, and in some cases can be identified by

terms such as may, will, could, expects, plans, anticipates, and believes. These statements include, but are not limited to, statements regarding the Company s

plans and expectations regarding its securities offerings, fundraising activities and financial strategy, the progress, timing and results of preclinical and clinical trials involving the Company s drug candidates, and the progress

of the Company s research and development programs. 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 by, the forward-looking statements. These risks and uncertainties include, but are not limited to: our ability to finance our operations

and business initiatives and obtain funding for such activities, whether chimeric antigen receptor T cell (CAR T) approaches, Ad-RTS-hIL-12, TCR and NK cell-based therapies, or any of our other therapeutic candidates will advance further in the

pre-clinical or 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 chimeric antigen

receptor T cell (CAR T) approaches, Ad-RTS-hIL-12, TCR and NK cell-based therapies, and our other therapeutic products will be successfully marketed if approved; the strength and enforceability of our intellectual property rights; competition from

other pharmaceutical and biotechnology companies; 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, 2015, and our Quarterly Report for the quarter ended June 30, 2016. 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.

RheoSwitch Therapeutic System and RTS technology are registered trademarks of Intrexon Corporation.

ZIOPHARM Oncology, Inc.

Condensed Statements of Operations

(in thousands except share and per share data)

ZIOPHARM Oncology, Inc.

Lori Ann Occhiogrosso

ZIOPHARM Oncology, Inc.