UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): March 5, 2019

ZIOPHARM Oncology, Inc.

(Exact Name of Registrant as Specified in Charter)

(617) 259-1970

(Registrant’s telephone number, including area code)

Not applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act (17 CFR 230.405) or Rule 12b-2 of the Exchange Act (17 CFR 240.12b-2).

Emerging growth company  ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

On March 5, 2019, Ziopharm Oncology, Inc., or the Company, issued a press release announcing its financial condition and results of operations for the three months and year ended December 31, 2018. A copy of the press release is furnished as Exhibit 99.1 and is incorporated herein by reference.

This information, including the information contained in the press release furnished as Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, and is not incorporated by reference into any of the Company’s filings, whether made before or after the date hereof, regardless of any general incorporation language in any such filing.

2

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

3

Exhibit 99.1

Ziopharm Oncology Reports Fourth Quarter and Full Year 2018 Financial Results and Provides Corporate Update

- Phase 1 Trial of Sleeping Beauty-TCR-T cell therapy for patients with solid tumors to begin at National Cancer Institute in mid-2019 –

- Third-generation Sleeping Beauty CD19-specific CAR-T U.S. trial to begin in 2H2019 –

- Eden BioCell to advance third-generation Sleeping Beauty CAR-T for Greater China –

- Third cohort enrolling patients in Controlled IL-12 combination trial with OPDIVO^® for recurrent glioblastoma (rGBM) –

- Phase 2 trial of Controlled IL-12 in combination with Regeneron’s Libtayo^® for patients with rGBM expected to open 2Q2019 –

- Company to host conference call today at 4:30 p.m. ET –

BOSTON, MA, March 5, 2019 (GLOBE NEWSWIRE) — Ziopharm Oncology, Inc. (Nasdaq:ZIOP) today announced its financial results for the fourth quarter and year ended December 31, 2018, and provided an update on the Company’s recent activities.

“We are executing on our strategy to focus on solid tumors with our Sleeping Beauty TCR-T program and our Controlled IL-12 platform and advancing a solution that addresses the cost and complexity of CAR-T therapies,” said Laurence Cooper, M.D., Ph.D., CEO of Ziopharm. “Under our collaboration at the National Cancer Institute (NCI), we expect to begin treating patients with solid tumors mid-year with the first non-viral, neoantigen-specific TCR-T cell therapy designed to attack the very mutations that cause cancer. In addition, we are advancing - in both the United States and greater China - our non-viral CAR-T therapy to solve the issues standing in the way of commercial success for approved CD19-specific CAR-T therapies. And, with maturing data showing a positive effect on overall survival for patients with recurrent glioblastoma, there is growing excitement for our Controlled IL-12 platform among treating physicians.”

David Mauney, M.D., President of Ziopharm, added, “We have significant momentum following our transformational fourth quarter 2018 when we established a new license agreement that provides us with clinical development autonomy. We secured two new business development deals and strengthened our balance sheet by eliminating $157 million in preferred stock and raising $50 million in a private placement. Thus, we are now well positioned to achieve multiple milestones and to be in the clinic in 2019 with each of our pillar programs: TCR-T, CAR-T and Controlled IL-12.”

Program Updates

Sleeping Beauty TCR-T Therapies

The Company is using its Sleeping Beauty platform to develop a personalized T-cell therapy targeting solid tumors with T-cell receptors or TCRs. Under a Cooperative Research and Development Agreement (CRADA), the NCI is expected to initiate a Phase 1 clinical trial to treat patients who may have one of a variety of solid tumors using the Sleeping Beauty platform to genetically modify T-cells to target patient-specific neoantigens.

Sleeping Beauty CAR-T Therapies

Ziopharm is advancing the Sleeping Beauty platform towards the very rapid manufacturing of genetically modified CAR⁺ T cells, co-expressing membrane-bound interleukin-15, or mbIL15, with a safety switch, within two days after genetically modifying T cells from the patient. This work is being done in collaboration with the University of Texas MD Anderson Cancer Center in the United States and will be done in Greater China through a joint venture, Eden BioCell.

Controlled IL-12

Ziopharm is developing its Controlled IL-12 platform, or Ad-RTS-hIL-12 plus veledimex, as a drug to control the production of human interleukin 12 (hIL-12) which activates the immune system to recruit cancer-fighting T cells into tumors. In the setting for the treatment of recurrent glioblastoma (rGBM), Ziopharm is advancing Ad-RTS-hIL-12 plus veledimex as a monotherapy and in combination with immune checkpoint inhibitors.

Corporate Update

In addition to the clinical collaboration with Regeneron and the execution of an agreement to launch Eden BioCell during the fourth quarter of last year, Ziopharm on October 9, 2018, announced that it entered into a new licensing agreement that replaced all existing agreements with Intrexon Corp. and its subsidiary Precigen, Inc. Under the new license agreement, Ziopharm has full developmental control and exclusivity utilizing Sleeping Beauty for TCRs for the treatment of cancer. The CRADA with the NCI related to Sleeping Beauty-generated T cells expressing TCRs to target neoantigens within solid tumors was transferred to Ziopharm and the Company will maintain this program. Ziopharm will build on its Controlled IL-12 platform with exclusive access to Precigen’s RheoSwitch Therapeutic System^® gene switch with adenovirus for the treatment of cancer. Using the Sleeping Beauty system, Ziopharm will continue to exclusively advance its CD19-specific chimeric antigen receptor (CAR) program leveraging membrane-bound interleukin 15, while retaining rights to a second, unnamed CAR target. Ziopharm has sole oversight for the relationship with MD Anderson Cancer Center, the Company’s initial development partner for the Sleeping Beauty platform.

As part of the new licensing agreement, Ziopharm successfully negotiated the complete elimination of preferred stock that had been issued to Intrexon that was valued at approximately $157 million at that time.

In December, David Mauney, M.D., was promoted to President. Dr. Mauney had joined the Company in September 2017 as Executive Vice President and Chief Business Officer.

Fourth-Quarter 2018 Financial Results

Full Year 2018 Financial Results

The Company ended the year with unrestricted cash resources of approximately $61.7 million.

In addition, a prepayment of approximately $27.8 million remains for programs to be conducted by the Company at MD Anderson Cancer Center under the current Research and Development Agreement.

The Company believes its current resources will be sufficient to fund its currently planned operations into the second quarter of 2020.

ZIOPHARM Oncology, Inc.

Statements of Operations

(in thousands except share and per share data)

(unaudited)

ZIOPHARM Oncology, Inc.

Balance Sheet Data

(in thousands)

(unaudited)

Conference Call and Slide Webcast

The call can be accessed by dialing 1-844-309-0618 (U.S. and Canada) or 1-661-378-9465 (international). The passcode for the conference call is 3091306. To access the slides and live 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 weeks.

About Ziopharm Oncology, Inc.

Ziopharm Oncology is an immuno-oncology company focused on developing end-to-end cost-effective solutions using its non-viral Sleeping Beauty platform for TCR and CAR T-cell therapies and immune-stimulating gene therapy with Controlled interleukin 12 (IL-12). The Sleeping Beauty platform genetically modifies T cells with DNA plasmids to express T-cell receptors (TCRs) to target specific antigens in solid tumors and chimeric antigen receptors (CARs) to target CD19 in blood cancers with the Company’s very rapid (3^rd generation) T-cell manufacturing process. The Sleeping Beauty platform is being advanced in collaboration with the National Cancer Institute, The University of Texas MD Anderson Cancer Center and Eden BioCell. The Company also is developing its Controlled IL-12 platform or Ad-RTS-hIL-12 plus veledimex as monotherapy and in combination with immune checkpoint inhibitors to treat brain cancer, including in collaboration with Regeneron Pharmaceuticals.

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 availability of cash resources, the progress and timing of the Company’s research and development programs, including the anticipated dates for the initiation, completion and readouts of its clinical trials, the expected timing and closing of the joint venture with TriArm and the future funding of Eden BioCell by TriArm. 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 our operating plans that may impact our 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 Annual Report on Form 10-K 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.

Company contacts: