UNITED
STATES

SECURITIES
AND EXCHANGE COMMISSION

Washington,
D.C. 20549



FORM
10-K/A

(Amendment
No. 1)



(Mark
One)



[X] ANNUAL
REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934



For
the fiscal year ended December 31, 2019



OR



[  ] TRANSITION
REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934



For
the transition period from                to



Commission
File Number: 0-21990



Mateon
Therapeutics, Inc.

(Exact
name of registrant as specified in its charter)



|Delaware                                                                               |  | 13-3679168                                                  
|-------------------------------------------------------------------------------------- |  | ------------------------------------------------------------
|(State
        or other jurisdiction of
        incorporation
        or organization) |  | (I.R.S.
        Employer
        Identification
        No.)
|                                                                                       | 
|29397
        Agoura Road, Suite 107
        Agoura
        Hills, CA                  |  | 91301                                                       
|(Address
    of principal executive offices)                                           |  | (Zip
    Code)                                              



Registrant’s
telephone number, including area code: (650) 635-7000



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



|Title
    of Each Class |  | Name
    of Each Exchange on Which Registered
|----------------------- |  | ---------------------------------------------
|None                    |  |                                              



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

Common
stock, par value $0.01 per share










Indicate
by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes [  ]
No [X]



Indicate
by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act. Yes
[  ] No [X]



Indicate
by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange
Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports),
and (2) has been subject to such filing requirements for the past 90 days. Yes [X] No [  ]



Indicate
by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant
to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that
the registrant was required to submit such files). Yes [X] No [  ]



Indicate
by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405 of this chapter) is not
contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K, or any amendment to this Form 10-K. [X]



Indicate
by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting
company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,”
“smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):



|Large
    accelerated filer | [  ] | Accelerated
    filer         | [  ]
|--------------------------- | ---- | ----------------------------- | ----
|                            |      |                               |     
|Non-accelerated
    filer   | [  ] | Smaller
    reporting company | [X] 
|                            |      |                               |     
|                            |      | 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. [  ]



Indicate
by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness
of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered
public accounting firm that prepared or issued its audit report. [  ]



Indicate
by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes [  ] No
[X]



The
aggregate market value of the registrant’s voting and non-voting common stock held by non-affiliates of the registrant (without
admitting that any person whose shares are not included in such calculation is an affiliate) computed by reference to the price
at which the common stock was last sold, as of June 28, 2019 was approximately $11,546,000.



As
of May 8, 2020 the aggregate number of outstanding shares of common stock of the registrant was 87,012,809



DOCUMENTS
INCORPORATED BY REFERENCE



None.


















EXPLANATORY
NOTE



Mateon
Therapeutics, Inc. (the “Company”) is filing this Amendment No. 1 on Form 10-K/A (this “Amendment
No. 1”) to its Annual Report on Form 10-K for the year ended December 31, 2019, originally filed with the Securities
and Exchange Commission (the “SEC”) on May 14, 2020 (the “Original Form 10-K”), solely to
disclose that the Company had filed the Original Form 10-K after the March 30, 2020 deadline applicable to the Company for the
filing of a Form 10-K in reliance on the 45-day extension provided by an order issued by the U.S. Securities and Exchange Commission
(the “SEC”) under Section 36 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”),
dated March 4, 2020 (Release No. 34-88318), as modified and superseded by a new SEC order issued on March 25, 2020 (Release No.
34-88465) (collectively, the “Order”).



On
March 25, 2020, the Company filed a Current Report on Form 8-K (the “Form 8-K”) to indicate its intention to
rely on the Order for such extension. The Company is currently in the planning and researching stages for the development of its
lead product OT-101 as an antiviral for the current Coronavirus (“COVID-19”) pandemic, which is consuming the
majority of its staffing and financial resources. Additionally, the Company’s key internal accounting personnel responsible
for assisting the Company in the preparation of its financial statements are being required to work remotely because of the COVID-19
pandemic. Due to these circumstances, the Company was unable to timely provide to its auditors and accountants the financial records
to provide consent, which resulted in the Company being unable to timely file an accurate Annual Report on Form 10-K for its year
ended December 31, 2019 by the prescribed date without undue hardship and expense to the Company. Consistent with the Company’s
statements made in the Form 8-K, the Company was unable to file the Original Form 10-K until May 14, 2020, and therefore relied
on the Order due to circumstances related to COVID-19.



In
accordance with Rule 12b-15 under the Exchange Act, the Company is including in this Amendment No. 1 an amended Part IV, Item
15 to include currently dated certifications pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 from the Company’s
principal executive officer and principal financial officer. Because no financial statements have been included in this Amendment
and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3,
4 and 5 of the certifications have been omitted. Similarly, we are not including the certifications under Section 906 of the Sarbanes-Oxley
Act of 2002 as no financial statements are being filed with this Amendment.



Except
as described above, this Amendment does not amend, modify or update the information in, or exhibits to, the Original 10-K. Furthermore,
this Amendment does not change any previously reported financial results nor does it reflect events occurring after the filing
of the Original 10-K. This Amendment should be read in conjunction with the Original 10-K and with the Company’s other filings
made with the SEC subsequent to the filing of the Original 10-K.











PART
IV



|ITEM
    15. | EXHIBITS
    AND FINANCIAL STATEMENT SCHEDULES
|------------ | ----------------------------------------------



|(a) | The
    following documents are filed as part of this Annual Report:
|--- | --------------------------------------------------------------------



|Exhibit
                                                                                Number |  | Description                                                                       
|---------------------------------------------------------------------------------------------- |  | ----------------------------------------------------------------------------------
|31.1                                                                                           |  | Certification of Chief Executive Officer pursuant to Rule 13a-14(a) and 15d-14(a).
|31.2                                                                                           |  | Certification of Chief Financial Officer pursuant to Rule 13a-14(a) and 15d-14(a).











SIGNATURES



Pursuant
to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report
to be signed on its behalf by the undersigned, thereunto duly authorized.



|                       | Mateon
    Therapeutics, Inc.
|---------------------- | -----------------------------
|                       |                              
|Date:
    May 20, 2020 | By:                          
|                       |                              
|                       |