THE
      SECURITIES REPRESENTED BY THIS OPTION ARE NOT TRANSFERABLE WITHOUT THE EXPRESS
      WRITTEN CONSENT OF ZIOPHARM, INC. (THE "COMPANY") AND HAVE NOT BEEN REGISTERED
      UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE SECURITIES
      LAWS, AND MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED OR
      OTHERWISE TRANSFERRED IN THE ABSENCE OF A REGISTRATION STATEMENT IN EFFECT
      WITH
      RESPECT TO THE SECURITIES UNDER SUCH ACT OR AN EXEMPTION FROM SUCH ACT. ANY
      SUCH
      TRANSFER MAY ALSO BE SUBJECT TO APPLICABLE STATE SECURITIES
      LAWS.

    


    ZIOPHARM,
      INC.

    


    Option
      for the Purchase of Shares of 

    Common
      Stock

    
      
        	
                No.
                  MDACC-_

              	
                _______ Shares

              


      

    

    


    FOR
      VALUE
      RECEIVED, ZIOPHARM, INC., a Delaware corporation (the "Company"), hereby
      certifies that THE UNIVERSITY OF TEXAS M.D. ANDERSON CANCER CENTER or
      its registered assigns (the "Holder") is entitled to purchase from the Company,
      subject to the provisions of this Option, at any time following the Vesting
      Date
      (as defined below) and prior to 5:00 P.M. Eastern Standard Time on the date
      that
      is five years from the Vesting Date (the "Termination Date"), fully paid and
      non-assessable shares of the Common Stock, $.001 par value, of the Company
      ("Common Stock") at an initial per share exercise price equal to
$0.001(the
      "Per
      Share Exercise Price"), or an aggregate exercise price of (the
      "Aggregate Exercise Price"). The shares of Common Stock deliverable upon such
      exercise are sometimes referred to in this Option as the "Option Shares."


    


    1)    Exercise
      of Option.


    (a)    Following
      the Vesting Date and prior to the Termination Date, this Option may be exercised
      in whole or in part, from time to time, by the Holder by presentation and
      surrender of this Option (with the subscription form attached to this Option
      duly executed) at the address set forth in Section 8 of this Option, together
      with payment, by certified or official bank check or wire transfer payable
      to
      the order of the Company, of the Aggregate Exercise Price or the proportionate
      part of such Aggregate Exercise Price if exercised in part.

    


    (b)    If
      this
      Option is exercised only in part, the Company shall, upon presentation of this
      Option upon such exercise, execute and deliver (with the certificate for the
      Option Shares purchased) a new Option evidencing the rights of the Holder of
      this Option to purchase the balance of the Option Shares purchasable under
      this
      Option upon the same terms and conditions as set forth in this Option. Upon
      proper exercise of this Option, the Company promptly shall deliver certificates
      for the Option Shares to the Holder duly legended as authorized by the
      subscription form. No fractional shares shall be issued upon exercise of this
      Option. Any fractional number of shares called for upon exercise of this Option
      shall be rounded down to the nearest whole share.

    


    
      
        
        

      

      
        1

        
          

        

      

      
        
        

      

    

     

    2)    Vesting
      of
      Options.
      


    3)    Protection
      Against Dilution.

     

    (a)    In
      case
      the Company shall (i) pay a dividend or make a distribution on its capital
      stock
      in shares of Common Stock or any other capital stock, (ii) subdivide its
      outstanding shares of Common Stock into a greater number of shares, (iii)
      combine its outstanding shares of Common Stock into a smaller number of shares
      or (iv) reclassify its Common Stock or effect a capital reorganization of the
      Company,
      or
      in
      case of the consolidation of the Company with or the merger of the Company
      with
      or into any other company or of the sale of the properties and assets of the
      Company as, or substantially as, an entirety to any other company,
      then the
      number and type of unexercised Option Shares subject to this Option shall be
      proportionately adjusted so that the Holder shall be entitled to receive the
      aggregate number and type of shares or other property that, if the unexercised
      Option Shares had been exercised in full immediately prior to such time, the
      Holder would have owned upon such exercise and been entitled to receive upon
      such dividend, subdivision, combination, reclassification or recapitalization.
      Whenever the number of shares issuable upon exercise of this Option is adjusted
      pursuant to this Section 3(a), the Per Share Exercise Price shall simultaneously
      be adjusted by multiplying the number of unexercised Option Shares issuable
      upon
      exercise of this Option by the Per Share Exercise Price in effect on the date
      thereof and dividing the product so obtained by the number of Option Shares
      issuable upon exercise of the Option immediately following the adjustments
      made
      in 3(a) above. Such adjustment shall be made successively whenever any event
      listed in this paragraph 3(a) shall occur. An adjustment made pursuant to this
      Subsection 3(a) shall become effective immediately after the record date in
      the
      case of a dividend or distribution and shall become effective immediately after
      the effective date in the case of a subdivision, combination or
      reclassification.

    


    
      
        
        

      

      
        2

        
          

        

      

      
        
        

      

    

    (b)    If,
      as a
      result of an adjustment made pursuant to this Section 3, the Holder shall become
      entitled to receive shares of two or more classes of capital stock or shares
      of
      Common Stock and other capital stock of the Company upon surrender of this
      Option , the Board of Directors (whose determination shall be conclusive and
      shall be described in a written notice to the Holder promptly after such
      adjustment) shall determine the allocation of the adjusted Per Share Exercise
      Price between or among shares or such classes of capital stock or shares of
      Common Stock and other capital stock.

    


    (c)    When
      any
      adjustment is required to be made in the number or kind of shares purchasable
      upon exercise of the Option, the Company shall promptly notify the Holder of
      such event and of the number of shares of securities or property thereafter
      purchasable upon exercise of the Option. Whenever the Company intends to declare
      a dividend or other distribution on its Common Stock, it shall provide Company
      notice at least thirty (30) days prior to the record date for such dividend
      or
      distribution.

    


    4)    Reservation
      of Option Shares; Fully Paid Shares; Taxes.
      The
      Company hereby undertakes until expiration of this Option to reserve for
      issuance or delivery upon exercise of this Option, such number of shares of
      the
      Common Stock as shall be required for issuance and/or delivery upon exercise
      of
      this Option in full, and agrees that all Option Shares so issued and/or
      delivered will be validly issued, fully-paid and non-assessable, and further
      agrees to pay all taxes and charges that may be imposed upon such issuance
      and/or delivery.

    


    5)    Limited
      Transferability.
      This
      Option may not be sold, transferred, assigned or hypothecated by the Holder
      except in compliance with the provisions of the Securities Act of 1933, as
      amended (the "Act"), and the applicable state securities or "blue sky" laws,
      and
      is so transferable only upon the books of the Company which the Company shall
      cause to be maintained for such purpose. The Company may treat the registered
      holder of this Option as such holder appears on the Company's books at any
      time
      as the holder for all purposes. All Options issued upon the transfer or
      assignment of this Option will be dated the same date as this Option, and all
      rights of the holder of such Option shall be identical to those of the Holder
      and upon such transfer or assignment, the Holder shall have no further rights
      under this Option.

    


    6)    Loss,
      etc., of Option.
      Upon
      receipt of evidence satisfactory to the Company of the loss, theft, destruction
      or mutilation of this Option, and of indemnity satisfactory to the Company,
      if
      lost, stolen or destroyed, and upon surrender and cancellation of this Option,
      if mutilated, the Company shall execute and deliver to the Holder a new Option
      of like date, tenor and denomination.

    


    7)    Status
      of Holder.
      This
      Option does not confer upon the Holder any right to vote or to consent to or
      receive notice as a stockholder of the Company, as such, in respect of any
      matters whatsoever, or any other rights or liabilities as a stockholder, prior
      to the exercise of this Option. If this Option is exercised only in part, the
      Holder shall have no such rights or liabilities with respect to any unexercised
      portion of this Option.

     

    
      
        
        

      

      
        3

        
          

        

      

      
        
        

      

    


    8)    Notices.
      No
      notice or other communication under this Option shall be effective unless,
      but
      any notice or other communication shall be effective and shall be deemed to
      have
      been given if, the same is in writing and is mailed by first-class mail, postage
      prepaid, addressed to:

    


    If
      to the
      Holder:

     

    If
      to the
      Company:   Ziopharm,
      Inc.

    787
      Seventh Avenue, 48th
      Floor

    New
      York,
      NY 10019

    Attn:
      Secretary

     

    9)    Investment
      Intent.

    


    (a)    The
      Holder represents by accepting this Option that it understands that this Option
      and any securities obtainable upon exercise of this Option have not been
      registered for sale under Federal or state securities laws and are being offered
      and sold to the Holder pursuant to one or more exemptions from the registration
      requirements of such securities laws. The Holder is an "accredited investor"
      within the meaning of Regulation D under the Act. In the absence of an effective
      registration of such securities or an exemption from such registration any
      certificates for such securities shall bear the legend set forth on the first
      page of this Option. The Holder understands that it must bear the economic
      risk
      of its investment in this Option and any securities obtainable upon exercise
      of
      this Option for an indefinite period of time, as this Option and such securities
      have not been registered under Federal or state securities laws and therefore
      cannot be sold unless subsequently registered under such laws, unless as
      exemption from such registration is available.

    


    (b)    The
      Holder, by its acceptance of this Option, represents to the Company that it
      is
      acquiring this Option and will acquire any securities obtainable upon exercise
      of this Option for its own account for investment and not with a view to, or
      for
      sale in connection with, any distribution of such securities in violation of
      the
      Act. The Holder agrees that this Option and any such securities will not be
      sold
      or otherwise transferred unless (i) a registration statement with respect to
      such transfer is effective under the Act and any applicable state securities
      laws or (ii) such sale or transfer is made pursuant to one or more exemptions
      from the Act.

    


    10)    Headings.
      The
      headings of this Option have been inserted as a matter of convenience and shall
      not affect the construction of this Option.

     

    
      
        
        

      

      
        4

        
          

        

      

      
        
        

      

    

    
       

    

    11)    Applicable
      Law.
      This
      Option shall be governed by and construed in accordance with the laws of the
      State of New York, without regard to principles of conflicts of law. The parties
      agree to settle any disputes through binding arbitration in the city, county
      and
      State of New York.

    


    The
      Company has caused this Option to be signed by its President and attested by
      its
      Secretary on August 30, 2004.

    


    
      
        	 	 	 
	 	ZIOPHARM INC.
	 
 	 
 	 
 
	Date: 	By:  	 
	 	
                
Name:
                Jonathan Lewis, M.D.
	 	Title: Chief
                Executive Officer
	 	 
	ATTEST:	 
	
              	 
	
                

                David
                  M. Tanen

                Secretary

              	 


      



     

    
      
        
        

      

      
        5

        
          

        

      

      
        
        

      

    


    SUBSCRIPTION

     

    The
      undersigned, ___________________, pursuant to the provisions of the foregoing
      Option, hereby elects to exercise the foregoing Option to the extent of
      purchasing ____________________ shares of Common Stock under such Option and
      hereby makes payment of $___________ by certified or official bank check in
      payment of the exercise price for such Option .

    


    The
      undersigned hereby represents and warrants to the Company that the undersigned
      is acquiring the shares of the Company's Common Stock pursuant to exercise
      of
      the foregoing Option for investment purposes only. The undersigned hereby
      further acknowledges that the undersigned understands that such shares (a)
      have
      not been registered under the Securities Act of 1933, as amended (the "Act"),
      and are being issued to the undersigned by the Company in reliance upon the
      foregoing representation and warranty and (b) may not be resold except in
      accordance with the requirements of the Act, including Rule 144 under the Act,
      if applicable. The undersigned further consents to the placing of a legend
      on
      the certificates for the shares being purchased to the foregoing
      effect.

    


    


    
      	
              Date:

            	
              _______________

            	 	
              Signature:

            	
              ____________________

            
	 	 	 	 	 
	 	 	 	 	 
	 	 	 	
              Address:

            	
              ______________________

            


    

    


    


    
      
        
        

      

      
        6

        
          

        

      

      
        
        

      

    



    ASSIGNMENT

     

    FOR
      VALUE
      RECEIVED, _______________ hereby sells, assigns and transfers unto
      ____________________ the foregoing Option and all rights evidenced by such
      Option, and does irrevocably constitute and appoint _____________________,
      attorney, to transfer such Option on the books of
      ____________________.

    


    


    
      	
              Date:

            	
              _______________

            	 	
              Signature:

            	
              ____________________

            
	 	 	 	 	 
	 	 	 	 	 
	 	 	 	
              Address:

            	
              ______________________

            


    

    


    


     

    
      
        
        

      

      
        7

        
          

        

      

      
        
        

      

    



    PARTIAL
      ASSIGNMENT

    


    


    FOR
      VALUE
      RECEIVED, _______________ hereby assigns and transfers unto ____________________
      the right to purchase _______ shares of the Common Stock of ZIOPHARM, INC.
      covered by the foregoing Option, and a proportionate part of such Option and
      the
      rights evidenced by such Option, and does irrevocably constitute and appoint
      ____________________, attorney, to transfer that part of such Option on the
      books of ZIOPHARM, INC.

    


    


    
      	
              Date:

            	
              _______________

            	 	
              Signature:

            	
              ____________________

            
	 	 	 	 	 
	 	 	 	 	 
	 	 	 	
              Address:

            	
              ______________________

            


    

    
 

    
      
        
        

      

      
        8