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)

November 1, 2020

MATEON THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

29397 Agoura Road Suite 107

Agoura Hills, CA 91301

(Address of principal executive offices and Zip Code)

Registrant’s telephone number, including area code

(650) 635-7000

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

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 of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

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. [  ]

Item 4.01. Change in Registrant’s Certifying Accountant

On November 1, 2020, Mateon Therapeutics, Inc., a Delaware corporation (the “Company”) was notified that Squar Milner LLP (“Squar Milner”) an independent registered public accounting firm, was combined with Baker Tilly US, LLP (“Baker Tilly”) in a transaction pursuant to which Squar Milner combined its operations with Baker Tilly and certain of the professional staff and partners of Squar Milner joined Baker Tilly either as employees or partners of Baker Tilly. On November 1, 2020, Squar Milner resigned as the auditors of the Company and with the approval of the Audit Committee of the Company’s Board of Directors, Baker Tilly was engaged as its independent registered public accounting firm.

Prior to engaging Baker Tilly, the Company did not consult with Baker Tilly regarding the application of accounting principles to a specific completed or contemplated transaction or regarding the type of audit opinions that might be rendered by Baker Tilly on the Company’s financial statements, and Baker Tilly did not provide any written or oral advice that was an important factor considered by the Company in reaching a decision as to any such accounting, auditing or financial reporting issue.

The report of independent registered public accounting firm of Squar Milner regarding the Company’s financial statements for the fiscal years ended December 31, 2019 and 2018 did not contain any adverse opinion or disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope or accounting principles, except that the audit reports for the years ended December 31, 2019 and December 31, 2018 contained an explanatory paragraph disclosing the uncertainty regarding the Company’s ability to continue as a going concern.

During the years ended December 31, 2019 and 2018, and during the interim period from the end of the most recently completed fiscal year through November 1, 2020, the date of resignation, there were no disagreements with Squar Milner on any matter of accounting principles or practices, financial statement disclosure or auditing scope or procedures, which disagreements, if not resolved to the satisfaction of Squar Milner would have caused it to make reference to such disagreement in its reports.

The Company provided Squar Milner with a copy of this Current Report on Form 8-K prior to its filing with the Securities and Exchange Commission and requested that Squar Milner furnish the Company with a letter addressed to the Securities and Exchange Commission stating whether it agrees with above statements and, if it does not agree, the respects in which it does not agree. A copy of the letter, dated November 1, 2020, is filed as Exhibit 16.1 (which is incorporated by reference herein) to this Current Report on Form 8-K.

Item 9.01 Financial Statements and Exhibits

See Exhibit Index.

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.

Exhibit Index