Published on April 19, 2007
 
                                                         File
      No. 2392-1
    April
      16, 2007
    Mr. Russell
      Mancuso
    Branch
      Chief
    United
      States Securities and Exchange Commission
    Office
      of
      Emerging Growth Companies
    Mail
      Stop
      3561
    100
      F
      Street, N.E.
    Washington,
      D.C. 20549
    | Re: | 
Lixte
                Biotechnology Holdings, Inc. 
                 Amendment
                  No. 3 to Form SB-2 Filed
                  March 13, 2007 File
                  No. 333-137208 | 
Dear
      Mr. Mancuso:
    This
      is
      in response to your letter dated April 3, 2007. We are concurrently filing
      herewith Amendment No. 4.
    General
    | 1. | Please
                ensure that your document is updated throughout and internally consistent.
                For example, we note your disclosure on page 31 regarding the
                January 5, 2007 agreement with the University of Regensburg. However,
                on page 39, you disclose that the agreement is under
                negotiation. | 
Company
      Response
    We
      have
      updated and made the conforming changes.
    Management’s
      Discussion and Analysis of Financial Condition and Results of Operations,
      page 24
    | 2. | It
                appears that you are subject to penalties under the registration
                rights
                agreement if the registration statement is not declared effective
                by a
                specified date. With a view towards disclosure, please quantify the
                penalty and tell us how it affects the proceeds from the transaction,
                and
                your liquidity. File any related
                waivers. | 
Company
      Response
    We
      have
      reflected the registration penalty in the amended financials and the
      Management’s Discussion and Analysis. We have filed as Exhibit 2.4 the waiver of
      monetary penalties with respect to the placement agent warrants.
    
Mr. Russell
          Mancuso
        April
          16,
          2007
        Page 2
      Going
      Concern, page 30
    | 3. | The
                amount of net proceeds from the second closing of your private placement
                completed on July 27, 2006 ($411,302) as indicated here and on page 6
                of “Risk Factors” does not reconcile to the amount disclosed in
                Notes 2 and 3 on pages F-9 and F-13, respectively ($446,433). Please
                make all appropriate revisions. | 
Company
      Response
    We
      have
      made the revision.
    Principal
      Commitments, page 31
    | 4. | 
We
                see you indicate herein that, “Pursuant to the CRADA, Lixte agreed to
                provide total payments of $400,000 over the term of the CRADA, of
                which
                $200,000 had been paid at December 31, 2006 and
                $200,000 is due and payable in April 2007.”
                Please tell us whether the referenced $200,000 represents a liability
                that
                needs to be reflected in your most recent balance sheet. Revise the
                filing
                as necessary based on our concern or tell us why no revisions are
                necessary.
 | 
Company
        Response
      We
        have
        changed the reference from “due and payable” to “scheduled for
        payment.”
    Presented below is a summary of the Company’s analysis as to the accounting for the second $200,000 payment under the CRADA (text denoted in italics represents emphasis added by the Company).
The
        Company has reviewed CON6, and in particular, paragraph 35, which states
        that
“Liabilities are probable future sacrifices of economic benefits arising from
        present
        obligations
        of a particular entity to transfer assets or provide services to other entities
        in the future as a result of past transactions or events.”
      
Paragraph
        36 of CON6 states, in part: “A liability has three essential characteristics:
        (a) it embodies a present duty or responsibility to one or more other entities
        that entails settlement by probable future transfer or use of assets at a
        specified or determinable date, on occurrence of a specified event, or on
        demand, (b) the duty or responsibility obligates a particular entity, leaving
        it
        little or no discretion to avoid the future sacrifice, and
        (c) the transaction or other event obligating the entity has
        already happened.”
      
Paragraph
        38 of CON6 states, in part: “Entities routinely incur most liabilities to
        acquire the funds, goods, and services they need to operate and just as
        routinely settle the liabilities they incur. Most liabilities are incurred
        in
        exchange transactions to obtain needed resources or their use, and most
        liabilities incurred in exchange transactions are contractual in nature -
        based
        on written or oral agreements to pay cash or to provide goods or services
        to
        specified, or determinable entities on demand, at
        specified or determinable dates, or on occurrence of specified events.”
      The
        Company believes that the payment obligations under the CRADA are analogous
        to a
        purchase order commitment that becomes a binding obligation at a mutually
        agreeable date in the future when services are provided or assets are
        transferred. Until the Company is receiving the services that it has contracted
        for, it believes that no liability is recordable; it is a commitment until
        such
        time. This agreement was designed so that funds would be paid early in the
        second half of the two-year agreement to fund in advance a full year of research
        and development services. If, for some reason, the Company did not fund the
        second $200,000 payment, no services would be provided under the agreement.
        
      At
        December 31, 2006, the CRADA represents an agreement for the Company to provide
        $200,000 of consideration in the future for research and development services
        to
        be rendered in the future by the National Institute of Neurological Disorders
        and Stroke. At December 31, 2006, no costs have been incurred or benefits
        received with respect to the second half of the two-year agreement to indicate
        that a transaction triggering a recordable liability has occurred.
      In
        addition, consistent with the tentative conclusion reached in EITF Issue
        07-3,
“Accounting for Nonrefundable Advance Payments for Goods and Services to Be
        Used
        in Future Research and Development Activities”, on March 15, 2007, the Company
        believes that the funds paid under the CRADA represent an advance on research
        and development costs that have future economic benefit. As such, the Company
        believes that such costs should be charged to expense when they are actually
        expended by the service provider, which is, effectively, as the service provider
        performs the research activities that they are contractually committed to
        provide. Absent information that would indicate that a different expensing
        schedule is more appropriate, the Company believes that such advances should
        be
        expensed over the contractual service term on a straight-line basis, which
        reflects a reasonable estimate of when the underlying research and development
        costs are being incurred. 
      Accordingly,
        for the reasons enumerated above, the Company believes that its accounting
        for
        the CRADA is correct and appropriate at December 31, 2006.
    
Mr. Russell
            Mancuso
          April
            16,
            2007
          Page 3
        Intellectual
            Property, page 34
          | 5. | We
                      reissue prior comment 4 which sought disclosure regarding your
                      agreement
                      to obtain exclusive commercial rights to the inventions covered
                      by the
                      patent applications. In response 19 in your letter dated
                      December 1, 2006, you stated that the agreement would be executed in
                      December 2006. Your current disclosure implies that the agreement is
                      not yet executed. Therefore, we reissue comment 19 in our letter
                      dated
                      October 4, 2006 which sought that you disclose when the negotiations
                      regarding the agreement began, the status of the negotiations,
                      the
                      principal hurdles than remain before an agreement can be reached,
                      and the
                      scope of your rights to the intellectual property if no agreement
                      can be
                      reached. | 
Company
            Response
          We
            have
            clarified the disclosure.
          Government
      Regulation, page 39
    | 6. | From
                your current disclosure in response to prior comment 5, it appears
                that
                FDA regulation extends only through the “4 to 9 month” period of a
                phase I trial. If this is not correct, we reissue comment
                5. | 
Company
      Response
    We
      have
      made additional disclosure.
    Scientific
      Advisory Committee, page 42
    | 7. | We
                reissue prior comment 6. From the table of contents of your prospectus
                this disclosure continues to appear in the “Management” portion of your
                document and you discuss compensation of the committee as part of
                your
                executive compensation disclosure. Also, the advisory committee disclosure
                is surrounded by management disclosure, with the biographies of your
                board
                preceding your disclosure regarding the advisory committee, and audit
                committee and executive compensation disclosure
                following. | 
Company
      Response
    We
      have
      changed the Table of Contents and placed the Advisory Committee disclosure
      after
      the Compensation disclosure.
    Rule
      144, page 46
    | 8. | 
We
                note your reference to the weekly trading volume. Please revise your
                disclosure to be consistent with question and answer 113.02 in the
                April 2, 2007 interpretations regarding rule 144 available on our web
                site at .
                
 | 
Company
      Response
    We
      have
      made the change in response to your comments.
    
* * *
    
Mr. Russell
        Mancuso
      April
        16,
        2007
      Page 4
    All
      questions and comments regarding the foregoing should be addressed to me at
      (310) 789-1290.
    Very
      truly yours,
    /s/
      David
      L. Ficksman
    DLF/wp