Exhibit 23.1
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We hereby consent to the incorporation by reference, in the Prospectus constituting a part of this Amendment No. 2 to the Registration Statement on FormS-1 (No. 333-217904), of our report dated March 30, 2017 (which report expresses an unqualified opinion and includes an explanatory paragraph expressing substantial doubt about the Company’s ability to continue as a going concern), relating to the financial statements of Mateon Therapeutics, Inc. included in the Annual Report on Form10-K for the year ended December 31, 2016.
We also consent to the reference to us under the caption “Experts” in the Prospectus.
/s/ OUM & CO. LLP
San Francisco, California
August 2, 2017