**AMENDMENT**




This
      Amendment (the “Amendment”) is made as of January 29, 2008 between Lixte
      Biotechnology Holdings, Inc., a Delaware corporation (“Lixte”), and Chem-Master
      International, Inc., a New York corporation (“Chem-Master”), with reference to
      the following:




A.  Pursuant
      to that certain Agreement dated as of February 5, 2007 (the “Agreement”)
      between Lixte and Chem-Master, Lixte engaged Chem-Master to synthesize certain
      organic compounds. Defined Terms not defined herein shall have the meaning
      ascribed to them in the Agreement.




B.  Lixte
      is
      desirous of extending the term of the Agreement and to expressly provide for
      the
      synthesis of the compound LB-3 as well as additional compounds not yet
      determined.




NOW
      THEREFORE, in consideration of the premises and the mutual covenants set forth
      hereinafter, Chem-Master and Lixte agree to amend the Agreement as
      follows:




**ARTICLE
      I**




**AMENDMENT**




1.1  Section
      1.2 is hereby amended by adding “and LB-3” after “LB-1” on the first line
      thereof.




1.2  Article I
      is further amended by adding a new Section 1.6 as follows:




“1.6  ‘LB-3’
      shall mean the compound having the physical properties set forth in Appendix
      B.”




1.3  Article III
      is hereby amended by adding a new Section 3.3 and Section 3.4 as
      follows:




“3.3  Within
      thirty days of the date hereof, Lixte shall issue to Chem-Master 100,000
      restricted shares (the “New Shares”) of the Common Stock of Lixte.




“3.4  Lixte
      hereby grants to Chem-Master an option to purchase 200,000 shares of Common
      Stock of Lixte (the “New Options”) at an exercise price of $1.65 per share in
      two tranches. Provided that the Agreement is in force and effect at the time
      of
      the applicable vesting date, options to purchase 100,000 shares shall vest
      on
      August 1, 2009, and options to purchase the remaining 100,000 shares shall
      vest on February 1, 2011. Each tranche of the New Options may be
      exercisable for a period of two years from the date such tranche
      vests.”




1.4  Section
      6.1 is hereby amended by substituting February 15, 2014 for ‘the second
      anniversary of the Effective Date’ on the second line thereof.”







**ARTICLE
      II**




**REPRESENTATIONS
      OF CHEM-MASTER**




Chem-Master
      represents that the New Shares and New Warrants are being acquired by
      Chem-Master for investment purposes only and not with a view to distribution.
      Chem-Master acknowledges that the New Shares and New Warrants are restricted,
      the certificates for which will bear a customary legend, and may not be resold
      absent an applicable exemption under the securities laws.







**ARTICLE
      III**




**EFFECT
      OF AMENDMENT**




Except
      as
      expressly provided in this Amendment, the Agreement remains in full force and
      effect:




IN
      WITNESS WHEREOF, the parties have caused this Amendment to be executed as of
      the
      date set forth above.




LIXTE
              BIOTECHNOLOGY HOLDINGS, INC.
            
            
            CHEM-MASTER
              INTERNATIONAL, INC.By:
              /s/ JOHN
              S. KOVACH
            
            
            By:
              /s/ FRANCIS JOHNSONName:John
                S. Kovach
              Title:President
            
            
            Name:Francis
                Johnson, Ph.D.
              Title:President




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