Ziopharm Oncology Reports First Quarter 2021 Financial Results and Provides Corporate Updates Annual shareholder meeting planned for

Ziopharm Oncology Reports First Quarter 2021 Financial Results and Provides Corporate Updates

Annual shareholder meeting planned for May 19, 2021

Company to host conference call today at 4:30 pm ET

Boston, May 6, 2021 Ziopharm Oncology, Inc. ( Ziopharm or the Company ) (Nasdaq: ZIOP), today

announced its financial results for the first quarter ended March 31, 2021 and provided additional corporate updates. The Company will host a conference call and webcast today at 4:30 pm ET.

Recent Corporate Highlights and Updates

Our first quarter was highlighted by execution and important strategic decisions that focus our

capital on our prioritized development programs, said Heidi Hagen, Chief Executive Officer of Ziopharm. In the coming months, we are focused on delivering important milestones on our clinical trials, including our first TCR-T trial, where we plan to treat patients beginning in the second half of the year, and continued progress on the Eden BioCell CD19-specific RPM CAR-T Trial in

First Quarter 2021 Financial Results

Earnings Conference Call and Webcast

Ziopharm will host a conference call and webcast for the investment community today, May 6, 2021, at 4:30 p.m. EDT. The conference call can be accessed by

dialing 855-327-6837 (U.S. and Canada) or 631-891-4304 (International). The

passcode for the conference call is 10013973. The live webcast may be accessed using the link here, or by visiting the Investors section of the Ziopharm website at www.ziopharm.com. The call will be recorded and available for

replay on the Company s website for approximately 90 days after the call.

Annual Meeting of Stockholders

Ziopharm will host its annual meeting virtually on May 19, 2021 at 9:00 am. Shareholders and interested stakeholders may attend the meeting, submit

questions, and vote their shares electronically during the meeting by visiting www.virtualshareholdermeeting.com/ZIOP2021.

Ziopharm is developing non-viral and cytokine-driven cell and gene therapies that

weaponize the body s immune system to treat the millions of people globally diagnosed with cancer each year. With its

multiplatform approach, Ziopharm is at the forefront of immuno-oncology. Ziopharm s pipeline is built for commercially scalable, cost effective T-cell

receptor T-cell therapies based on its non-viral Sleeping Beauty gene transfer platform, a rapidly manufactured Sleeping Beauty-enabled CD19-specific CAR-T program and a precisely controlled IL-12 gene therapy. The Company has clinical and strategic collaborations with the National Cancer Institute, The University of Texas

MD Anderson Cancer Center and Regeneron Pharmaceuticals. For more information, please visit www.ziopharm.com.

Forward-Looking Statements

Disclaimer This press release contains forward-looking statements as defined in 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 business and strategic plans, the wind down of the Company s Controlled IL-12 clinical program, the anticipated closure of the CD19 RPM CAR-T

Allogeneic Phase I Trial at MD Anderson Cancer Center, the timing of activities relating to the Company s GMP facility, and the timing of the Company s research and development programs, including the anticipated dates for enrolling

patients in the Company s TCR-T clinical trial. Although Ziopharm s management team believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned

that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of Ziopharm, that could cause actual results and developments to differ

materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties include, among other things, changes in the Company s operating plans that may impact its cash

expenditures, the uncertainties inherent in research and development, future clinical data and analysis, including whether any of Ziopharm s product candidates will advance further in the preclinical research or clinical trial process,

including receiving clearance from the U.S. Food and Drug Administration or equivalent foreign regulatory agencies to conduct clinical trials and whether and when, if at all, they will receive final approval from the U.S. FDA or equivalent foreign

regulatory agencies and for which indication; the strength and enforceability of Ziopharm s intellectual property rights; competition from other pharmaceutical and biotechnology companies as well as risk factors discussed or identified in the

public filings with the Securities and Exchange Commission made by Ziopharm, including those risks and uncertainties listed in Ziopharm s Quarterly Report on Form 10-Q filed by Ziopharm with the

Securities and Exchange Commission. We are providing this information as of the date of this press release, and Ziopharm does not undertake any obligation to update or revise the information contained in this press release whether as a result of new

information, future events or any other reason.

Investor Relations Contacts:

Adam D. Levy, Ph.D., MBA

EVP, Investor Relations and Corporate

E: alevy@ziopharm.com

Media Relations Contact:

LifeSci Communications:

E: pbursey@lifescicomms.com

ZIOPHARM Oncology, Inc

Statement of Operations

thousands except per share data)

ZIOPHARM Oncology, Inc

Selected Balance Sheet Data