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                              May 3, 2020

       Vuong Trieu, Ph.D.
       Chief Executive Officer
       Mateon Therapeutics, Inc.
       23937 Agoura Road, Suite 107
       Agoura Hills, CA 91301

                                                        Re: Mateon
Therapeutics, Inc.
                                                            Amendment No. 2 to
Preliminary Proxy Statement on Schedule 14A
                                                            Filed April 17,
2020
                                                            File No. 000-21990

       Dear Dr. Trieu:

              We have reviewed your filing and have the following comments. In
some of our
       comments, we may ask you to provide us with information so we may better
understand your
       disclosure.

              Please respond to these comments within ten business days by
providing the requested
       information or advise us as soon as possible when you will respond. If
you do not believe our
       comments apply to your facts and circumstances, please tell us why in
your response.

                                                        After reviewing your
response to these comments, we may have additional comments.

       Amendment No. 2 to Preliminary Proxy Statement on Schedule 14A filed
April 17, 2020

       Background of the Corporate Actions

   1.                                                   We note that in your
response dated November 18, 2019 to our prior comment 6, you
                                                        stated that you intend
to file a further amendment with financial statements for Oncotelic,
                                                        Inc. and PointR Data
once available. Please revise the proxy statement to provide the
                                                        disclosures required by
Item 13(a) of Schedule 14A, including financial statements for
                                                        Oncotelic, Inc. and
PointR Data pursuant to rules 8-04 and 8-05 of Regulation S-X. For
                                                        additional guidance,
refer to Note A of Schedule 14A.
 Vuong Trieu, Ph.D.
FirstName LastNameVuong Trieu, Ph.D.
Mateon Therapeutics, Inc.
Comapany NameMateon Therapeutics, Inc.
May 3, 2020
Page 2
May 3, 2020 Page 2
FirstName LastName
Corporate Action No. 4: Approval to Increase the Number of Shares of Authorized
Common
Stock
Effects of the Capital Increase

2.       We note your revisions in response to our prior comment 1 from our
letter dated
         November 22, 2019. Please revise the capitalization table to clarify
that the column
         labelled "Issued and Outstanding Prior to Corporate Action No. 4" does
not reflect the
         number of shares of Common Stock issued and outstanding prior to
Corporate Action No.
         4, given that the 278,187 shares of Series A Convertible Preferred
Stock are not
         convertible into 278,187 shares of Common Stock. In addition, we note
your statement
         that in the event stockholders approve the Capital Increase and the
Reverse Split,
         36,209,113 shares of Common Stock will be authorized for issuance.
Please provide us
         support for this total or revise, as appropriate.
General

3.       Please revise your proxy statement to include the information required
by Items 6(d) and
         8(b) of Schedule 14A.
        We remind you that the company and its management are responsible for
the accuracy
and adequacy of their disclosures, notwithstanding any review, comments, action
or absence of
action by the staff.

       Please contact Irene Paik at (202) 551-6553 or Joe McCann at (202)
551-6262 with any
questions.



                                                             Sincerely,

                                                             Division of
Corporation Finance
                                                             Office of Life
Sciences
cc:      James A. Mercer III, Esq.