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): February 5, 2020

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:

Securities registered pursuant to Section 12(b) of the Act:

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 February 5, 2020, Ziopharm Oncology, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Jefferies LLC, as representative of the several underwriters listed on Schedule A thereto (the “Underwriters”), to issue and sell 27,826,086 shares of common stock of the Company, par value $0.001 per share (“Common Stock”), in connection with an underwritten public offering pursuant to an effective registration statement on Form S-3ASR (File No. 333-232283) and a related prospectus and prospectus supplement, in each case filed with the Securities and Exchange Commission (the “Offering”). The offering price to the public is $3.25 per share. In addition, the Company granted the Underwriters an option to purchase, for a period of 30 days, up to an additional 4,173,912 shares of Common Stock. The Company estimates that the net proceeds from the Offering will be approximately $84.3 million, or approximately $97.0 million if the Underwriters exercise in full their option to purchase additional shares of Common Stock, in each case after deducting underwriting discounts and commissions and estimated offering expenses. The closing of the Offering is expected to occur on or about February 7, 2020, subject to customary closing conditions.

The Underwriting Agreement contains customary representations, warranties, covenants and agreements by the Company, customary conditions to closing, indemnification obligations of the Company and the Underwriters, including for liabilities under the Securities Act of 1933, as amended (the “Securities Act”), other obligations of the parties and termination provisions. The representations, warranties and covenants contained in the Underwriting Agreement were made only for purposes of such agreement and as of specific dates, were solely for the benefit of the parties to such agreement, and may be subject to limitations agreed upon by the contracting parties.

A copy of the Underwriting Agreement is filed as Exhibit 1.1 to this Current Report on Form 8-K and is incorporated herein by reference. The foregoing description of the Underwriting Agreement is qualified in its entirety by reference to the full text of the Underwriting Agreement, which is attached as Exhibit 1.1 to this Current Report on Form 8-K and incorporated in this Item 1.01 by reference. A copy of the opinion of Cooley LLP as to the legality of the shares of Common Stock to be issued and sold in the Offering is filed as Exhibit 5.1 to this Current Report on Form 8-K.

On February 5, 2020, the Company issued a press release announcing that it had priced the Offering. A copy of the press release is filed herewith as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Caution Concerning Forward-Looking Statements

This Current Report on Form 8-K may contain forward-looking statements made in reliance upon the safe harbor provisions of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements include all statements that do not relate solely to historical or current facts, and can be identified by the use of words such as “may,” “will,” “expect,” “project,” “estimate,” “anticipate,” “plan,” “believe,” “potential,” “should,” “continue” or the negative versions of those words or other comparable words. These forward-looking statements include statements about the Company’s anticipated public offering and the anticipated use of proceeds of the offering. These forward-looking statements are based on information currently available to the Company and its current plans or expectations, and are subject to a number of uncertainties and risks that could significantly affect current plans. Actual results and performance could differ materially from those projected in the forward-looking statements as a result of many factors, including the uncertainties related to market conditions and the completion of the public offering on the anticipated terms or at all. The Company’s forward-looking statements also involve assumptions that, if they prove incorrect, would cause its results to differ materially from those expressed or implied by such forward-looking statements. These and other risks concerning the Company’s business are described in additional detail in the Company’s Quarterly Report on Form 10-Q for the period ended September 30, 2019 and in the Company’s other reports filed with the Securities and Exchange Commission. The Company is under no obligation to, and expressly disclaims any such obligation to, update or alter its forward-looking statements, whether as a result of new information, future events or otherwise.

(d) Exhibits

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.