EXHIBIT 4.1


                         COMMON STOCK PURCHASE AGREEMENT

     THIS COMMON STOCK PURCHASE AGREEMENT ("Agreement") is made and entered into
as  of  November  21,  2007  (the  "Effective   Date"),  by  and  between  GERON
CORPORATION,  a Delaware  corporation  having its principal place of business at
230 Constitution  Drive,  Menlo Park,  California  94025 ("Geron"),  and Hongene
Biotechnology  Limited,  having its  principal  place of  business  at Room 203,
Building 8, No. 500 CaoBao Road, Shanghai, China, 200233; Tel: 0086-21-64757213,
0086-21-54971054 Fax: 0086-21-6470061 ("Manufacturer").

          A.   Geron and  Manufacturer  are the parties to that  certain  Master
               Manufacturing  Agreement  dated as of March 9, 2006 (the  "Supply
               Agreement"),   and   related   Addendum   Agreements   ("Addendum
               Agreement")  under  which  Geron has agreed to  purchase  certain
               products from  Manufacturer and Manufacturer has agreed to supply
               such products to Geron on the terms set forth therein.

          B.   Pursuant to Addendum  Agreement No. 3, dated as of July 30, 2007,
               and the First  Amendment  to the  Supply  Agreement,  dated as of
               November 9, 2007. Geron may pay the purchase price of products by
               delivery of shares of Geron's Common Stock (the "Shares").

THE PARTIES AGREE AS FOLLOWS:

   1. ISSUANCE OF SHARES; ADJUSTMENTS.

          1.1  As payment of the costs  specified in Addendum  Agreement  no. 3,
               Geron will issue and deliver certificates for 85,546 Shares. Upon
               issuance and delivery of the  certificate(s)  for the Shares, all
               Shares shall be duly  authorized and validly issued and represent
               fully paid shares of Geron's Common Stock.

   2. CLOSING; DELIVERY.

          2.1  The   consummation  of  the  transaction   contemplated  by  this
               Agreement (a  "Closing")  shall be held at such time and place as
               is mutually  agreed upon  between the  parties,  but in any event
               Geron shall make  commercially  reasonable  efforts to accomplish
               the Closing no later five (5) business  days after the  Effective
               Date hereof (the  "Closing  Date").  At the Closing,  Geron shall
               deliver to Manufacturer one or more certificates representing all
               of the  Shares,  which  Shares  shall  be  issued  in the name of
               Manufacturer  or  its  designee  and  in  such  denominations  as
               Manufacturer shall specify.

          2.2  Geron's obligations to issue and deliver the stock certificate(s)
               representing  the Shares to  Manufacturer at the Closing shall be
               subject  to the  following  conditions,  which  may be  waived by
               Geron:

                    2.2.1 the covenants and  obligations  that  Manufacturer  is
                         required to perform or to comply with  pursuant to this
                         Agreement,  at or prior to the Closing,  must have been
                         duly  performed  and  complied  with  in  all  material
                         respects; and

                    2.2.2 the    representations    and   warranties   made   by
                         Manufacturer  herein  shall be true and  correct in all
                         material respects as of the Closing Date.

          2.3  Manufacturer's   obligation  to  accept  delivery  of  the  stock
               certificate(s)  representing  the Shares at the Closing  shall be
               subject to the following conditions, any one or more of which may
               be waived by Manufacturer:

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                    2.3.1 the covenants and  obligations  that Geron is required
                         to  perform  or  to  comply   with   pursuant  to  this
                         Agreement,  at or prior to the Closing,  must have been
                         duly  performed  and  complied  with  in  all  material
                         respects;

                    2.3.2 Geron shall have  available  under its  Certificate of
                         Incorporation  sufficient  authorized  shares of Common
                         Stock to issue the Shares to Manufacturer; and

                    2.3.3 the representation and warranties made by Geron herein
                         shall be true and correct in all  material  respects as
                         of the Closing Date.

   3. RESTRICTIONS ON RESALE OF SHARES.

          3.1  Legends.  Manufacturer  understands  and  acknowledges  that  the
               Shares are not  registered  under the Securities Act of 1933 (the
               "Act"),  and  that  under  the  Act  and  other  applicable  laws
               Manufacturer   may  be  required  to  hold  such  Shares  for  an
               indefinite  period of time. Each stock  certificate  representing
               Shares shall bear the following legends:

               "THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER
                THE  SECURITIES  ACT OF 1933,  AS AMENDED  (THE  "ACT").   ANY
                TRANSFER   OF  SUCH   SECURITIES  SHALL  BE  INVALID   UNLESS  A
                REGISTRATION    STATEMENT UNDER THE ACT IS IN EFFECT AS TO  SUCH
                TRANSFER OR, IN THE OPINION OF COUNSEL REASONABLY     ACCEPTABLE
                TO GERON, SUCH REGISTRATION IS UNNECESSARY FOR     SUCH TRANSFER
                TO COMPLY   WITH  THE  ACT. THE  SECURITIES  REPRESENTED  HEREBY
                ARE  SUBJECT  TO  THE  TERMS  OF  THE  COMMON  STOCK    PURCHASE
                AGREEMENT BY AND BETWEEN  GERON AND  MANUFACTURER  DATED   AS OF
                NOVEMBER  21, 2007. A COPY  OF THE  AGREEMENT  CAN BE   OBTAINED
                FROM THE  SECRETARY OF GERON."

          3.2  Limits On Sales. Manufacturer agrees that if it decides to resell
               some or all of the  Shares,  it will do so only  through  orderly
               sales  executed  through a top-tier  brokerage  house,  and in an
               appropriate  manner based upon whether the shares are  registered
               or unregistered, i.e., on the Nasdaq National Market or in a Rule
               144A compliant  transaction.  Manufacturer further agrees that it
               will not engage in short selling with respect to the Stock.

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   4. REGISTRATION RIGHTS

          4.1  Geron agrees to make commercially reasonable efforts to file with
               the Securities and Exchange Commission (the "Commission")  within
               ten (10)  business  days after the Closing  Date, a  registration
               statement under the Act (the "Registration  Statement"),  on Form
               S-3 or other appropriate form, so as to permit a non-underwritten
               public  offering  and  resale  of the  Shares  under  the  Act by
               Manufacturer.  Geron  agrees  to  diligently  pursue  making  the
               Registration Statement effective.  Geron will notify Manufacturer
               of the effectiveness of the Registration Statement within one (1)
               business day of receiving notice from the Commission.

          4.2  Geron  will   maintain  the   Registration   Statement   and  any
               post-effective  amendment  thereto  filed  under  this  Section 4
               effective  under the Act until the  earliest of (i) the date that
               none of the Shares  covered by such  Registration  Statement  are
               issued and outstanding, (ii) the date that all of the Shares have
               been sold pursuant to such Registration Statement, (iii) the date
               Manufacturer  receives an opinion of counsel  from  Geron,  which
               counsel shall be reasonably acceptable to Manufacturer,  that the
               Shares  may be sold  under  the  provisions  of Rule 144  without
               limitation as to volume,  (iv) the date that all Shares have been
               otherwise  transferred  to  persons  who may  trade  such  shares
               without  restriction under the Act, and Geron has delivered a new
               certificate  or other  evidence of ownership for such  securities
               not bearing a restrictive  legend, or (v) the date all Shares may
               be sold at any time, without volume or manner of sale limitations
               pursuant to Rule 144(k) or any similar  provision  then in effect
               under the Act in the opinion of counsel to Geron,  which  counsel
               shall be reasonably acceptable to Manufacturer.

          4.3  Geron, at its expense, shall furnish to Manufacturer with respect
               to the Shares  registered under the  Registration  Statement such
               reasonable  number  of  copies  of  the  Registration  Statement,
               prospectuses and preliminary  prospectuses in conformity with the
               requirements  of the Act and such other documents as Manufacturer
               may reasonably request, in order to facilitate the public sale or
               other  disposition  of all or any of the Shares by  Manufacturer,
               provided, however, that the obligation of Geron to deliver copies
               of prospectuses or preliminary prospectuses to Manufacturer shall
               be subject to the receipt by Geron of reasonable  assurances from
               Manufacturer  that  Manufacturer  will comply with the applicable
               provisions  of the Act and of such other  securities  or blue sky
               laws as may be  applicable  in  connection  with  any use of such
               prospectuses or preliminary prospectuses.

          4.4  All fees,  disbursements  and  out-of-pocket  expenses  and costs
               incurred by Geron in connection  with the  preparation and filing
               of the Registration  Statement under Section 4.1 and in complying
               with applicable securities and Blue Sky laws (including,  without
               limitation,  all  attorneys'  fees of  Geron)  shall  be borne by
               Geron.  Manufacturer  shall bear the cost of fees and expenses of
               Manufacturer's counsel.

          4.5  Geron will advise  Manufacturer  promptly  after it shall receive
               notice or obtain  knowledge  of the issuance of any stop order by
               the Commission  delaying or suspending the  effectiveness  of the
               Registration Statement or of the initiation of any proceeding for
               that  purpose,  and Geron  will use its  commercially  reasonable
               efforts to prevent  the  issuance  of any stop order or to obtain
               its withdrawal at the earliest possible moment if such stop order
               should be issued.

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          4.6  With a view to making  available to Manufacturer  the benefits of
               Rule 144 (or its successor rule) and any other rule or regulation
               of the  Commission  that may at the time permit  Manufacturer  to
               sell  the  Shares  to  the  public  without  registration,  Geron
               covenants  and agrees to:  (i) make and keep  public  information
               available, as those terms are understood and defined in Rule 144,
               until the  earliest  of (A) such date as all of the Shares may be
               resold  pursuant  to Rule  144(k)  or any other  rule of  similar
               effect  or (B) such  date as all of the  Shares  shall  have been
               resold;  and (ii) file with the Commission in a timely manner all
               reports and other  documents  required of Geron under the Act and
               under  the  Securities  Exchange  Act of 1934,  as  amended  (the
               "Exchange Act").

          4.7  Manufacturer  will  cooperate  with  Geron  in  all  respects  in
               connection with this Agreement,  including  timely  supplying all
               information  reasonably  requested by Geron (which shall  include
               all  information  regarding  Manufacturer  and proposed manner of
               sale of the Shares  required to be disclosed in any  Registration
               Statement)  and executing and returning all documents  reasonably
               requested in  connection  with the  registration  and sale of the
               Shares and entering into and performing their  obligations  under
               any  underwriting  agreement,  if the offering is an underwritten
               offering,   in  usual  and  customary  form,  with  the  managing
               underwriter  or  underwriters  of  such  underwritten   offering.
               Nothing in this Agreement shall obligate  Manufacturer to consent
               to be named as an underwriter in any Registration Statement.

   5.    INDEMNIFICATION.

          5.1  Geron agrees to indemnify  and hold  harmless  Manufacturer  (and
               each person, if any, who controls Manufacturer within the meaning
               of  Section  15 of the Act,  and each  officer  and  director  of
               Manufacturer)  against  any and all  losses,  claims,  damages or
               liabilities (or actions or proceedings in respect thereof), joint
               or several,  directly or indirectly  based upon or arising out of
               (i) any untrue  statement  or  alleged  untrue  statement  of any
               material  fact  contained  in  the  Registration  Statement,  any
               preliminary  prospectus,  final prospectus or summary  prospectus
               contained  therein or used in connection with the offering of the
               Shares,  or any  amendment  or  supplement  thereto,  or (ii) any
               omission or alleged omission to state a material fact required to
               be stated therein or necessary to make the statements therein not
               misleading;  and Geron will reimburse each such indemnified party
               for any legal or any other expenses  reasonably  incurred by them
               in  connection  with   investigating,   preparing,   pursuing  or
               defending  any such loss,  claim,  damage,  liability,  action or
               proceeding,  except  insofar  as any such  loss,  claim,  damage,
               liability,  action, proceeding or expense (A) arises out of or is
               based upon an untrue  statement  or alleged  untrue  statement or
               omission or alleged omission made in the Registration  Statement,
               any  such  preliminary  prospectus,  final  prospectus,   summary
               prospectus,  amendment  or  supplement  in  reliance  upon and in
               conformity  with  written  information   furnished  to  Geron  by
               Manufacturer  or  such  other  person  expressly  for  use in the
               preparation  thereof,  (B) the failure of  Manufacturer to comply
               with its  covenants and  agreements  contained in Sections 7.1 or
               7.5.2  hereof  or  (C)  any   misstatement  or  omission  in  any
               prospectus  that is corrected in any subsequent  prospectus  that
               was  delivered to  Manufacturer  prior to the  pertinent  sale or
               sales by Manufacturer.  Such indemnity shall remain in full force
               and  effect,   regardless  of  any  investigation  made  by  such
               indemnified party and shall survive the transfer of the Shares by
               Manufacturer.

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          5.2  Manufacturer  agrees to indemnify  and hold  harmless  Geron (and
               each person,  if any,  who  controls  Geron within the meaning of
               Section  15 of the Act,  each  officer  of Geron  who  signs  the
               Registration  Statement  and each  director  of  Geron)  from and
               against  losses,  claims,  damages or liabilities  (or actions or
               proceedings in respect  thereof),  joint or several,  directly or
               indirectly  based  upon or  arising  out of,  (i) any  failure of
               Manufacturer   to  comply  with  the  covenants  and   agreements
               contained  in  Sections  7.1 and 7.5.2  hereof or (ii) any untrue
               statement  of a  material  fact  contained  in  the  Registration
               Statement  or any  omission  of a material  fact  required  to be
               stated in the  Registration  Statement  or  necessary in order to
               make the statements in the Registration  Statement not misleading
               if such untrue  statement or omission  was made in reliance  upon
               and in conformity with written information  furnished to Geron by
               or on behalf of Manufacturer  specifically for use in preparation
               of  the   Registration   Statement;   provided,   however,   that
               Manufacturer  shall  not be  liable  in any such case for (A) any
               untrue  statement  or  omission  in the  Registration  Statement,
               prospectus,  or other such document which  statement is corrected
               by  Manufacturer  and  delivered  to Geron prior to the sale from
               which such loss occurred, (B) any untrue statement or omission in
               any  prospectus   which  is  corrected  by  Manufacturer  in  any
               subsequent  prospectus,  or supplement or amendment thereto,  and
               delivered  to Geron  prior to the sale or sales from which a loss
               or liability arose, or (C) any failure by Geron to fulfill any of
               its obligations under Section 5.1 hereof.

          5.3  Promptly after receipt by any indemnified person of a notice of a
               claim  or the  beginning  of  any  action  in  respect  of  which
               indemnity is to be sought against an indemnifying person pursuant
               to this  Section  5, such  indemnified  person  shall  notify the
               indemnifying   person  in   writing  of  such  claim  or  of  the
               commencement  of such  action,  but the omission to so notify the
               indemnifying  party will not relieve it from any liability  which
               it may have to any indemnified party under this Section 5 (except
               to the extent that such omission materially and adversely affects
               the  indemnifying  party's ability to defend such action) or from
               any liability otherwise than under this Section 5. Subject to the
               provisions  hereinafter  stated, in case any such action shall be
               brought against an indemnified  person,  the indemnifying  person
               shall be entitled to participate therein, and, to the extent that
               it shall elect by written  notice  delivered  to the  indemnified
               party  promptly  after  receiving the aforesaid  notice from such
               indemnified  party,  shall be  entitled  to  assume  the  defense
               thereof, with counsel reasonably satisfactory to such indemnified
               person.  After  notice  from  the  indemnifying  person  to  such
               indemnified person of its election to assume the defense thereof,
               such indemnifying  person shall not be liable to such indemnified
               person  for  any  legal  expense  subsequently  incurred  by such
               indemnified  person  in  connection  with  the  defense  thereof,
               provided, however, that if there exists or shall exist a conflict
               of  interest  that would make  inappropriate,  in the  reasonable
               opinion  of  counsel  to the  indemnified  person,  for the  same
               counsel  to  represent  both  the  indemnified  person  and  such
               indemnifying  person or any affiliate or associate  thereof,  the
               indemnified person shall be entitled to retain its own counsel at
               the expense of such indemnifying person; provided,  however, that
               no  indemnifying  person  shall be  responsible  for the fees and
               expenses  of  more  than  one  separate  counsel  (together  with
               appropriate  local counsel) for all  indemnified  parties.  In no
               event shall any  indemnifying  person be liable in respect to any
               amounts paid in settlement of any action unless the  indemnifying
               person  shall  have  approved  the terms of such  settlement.  No
               indemnifying  person shall,  without the prior written consent of
               the indemnified  person,  effect any settlement of any pending or
               threatened  proceeding in respect of which any indemnified person
               is or could have been a party and indemnification could have been
               sought  hereunder  by  such  indemnified   person,   unless  such
               settlement includes an unconditional  release of such indemnified
               person from all  liability on claims that are the subject  matter
               of such proceeding.

          5.4  The provisions of this Section 5 shall survive the termination of
               this Agreement.

   6. REPRESENTATIONS AND ACKNOWLEDGEMENT OF GERON.

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         Geron hereby represents, warrants and covenants to Manufacturer as
follows:

          6.1  Organization,  Good  Standing  and  Qualification.   Geron  is  a
               corporation duly organized, validly existing and in good standing
               under the laws of the  State of  Delaware  and has all  requisite
               corporate  power and  authority  to carry on its  business as now
               conducted  and as presently  proposed to be  conducted.  Geron is
               duly qualified to transact  business and is in good standing as a
               foreign  corporation in each jurisdiction in which the failure to
               so qualify would have a material  adverse  effect on its business
               or properties.

          6.2  Authorization.  All  corporate  action on the part of Geron,  its
               officers,   directors   and   stockholders   necessary   for  the
               authorization,  execution  and  delivery of this  Agreement,  the
               performance  of  all  obligations  of  Geron  hereunder  and  the
               authorization, issuance and delivery of the Shares has been taken
               or will be taken prior to the Closing,  and this Agreement,  when
               executed and delivered will constitute  valid and legally binding
               obligations  of Geron,  enforceable  against  Geron in accordance
               with their  terms,  except as limited by  applicable  bankruptcy,
               insolvency, reorganization, moratorium, fraudulent conveyance and
               other  laws  of  general  application  affecting  enforcement  of
               creditors' rights  generally,  as limited by laws relating to the
               availability of specific performance,  injunctive relief or other
               equitable remedies.

          6.3  Valid Issuance of Common Stock. The Shares, when issued, sold and
               delivered   in   accordance   with  the  terms   hereof  for  the
               consideration   expressed  herein,   will  be  duly  and  validly
               authorized and issued,  fully paid and  nonassessable and free of
               restrictions  on  transfer  other than  restrictions  on transfer
               under this Agreement and applicable state and federal  securities
               laws.

          6.4  Legal  Proceedings  and  Orders.   There  is  no  action,   suit,
               proceeding or investigation  pending or threatened  against Geron
               that  questions  the  validity of this  Agreement or the right of
               Geron  to  enter  into  this   Agreement  or  to  consummate  the
               transactions contemplated hereby, nor is Geron aware of any basis
               for any of the forgoing.  Geron is neither a party nor subject to
               the provisions of any order, writ, injunction, judgment or decree
               of any court or government agency or  instrumentality  that would
               affect the  ability of Geron to enter into this  Agreement  or to
               consummate the transactions contemplated hereby.

   7. REPRESENTATIONS AND ACKNOWLEDGMENTS OF MANUFACTURER.

   Manufacturer hereby represents, warrants, acknowledges and agrees that:

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          7.1  Investment.    Manufacturer   is   acquiring   the   Shares   for
               Manufacturer's  own account,  and not directly or indirectly  for
               the account of any other  person.  Manufacturer  is acquiring the
               Shares  for  investment  and not with a view to  distribution  or
               resale  thereof,  except  in  compliance  with  the  Act  and any
               applicable state law regulating securities.

          7.2  Access to  Information.  Manufacturer  has consulted with its own
               attorney,  accountant,  or investment advisor as Manufacturer has
               deemed   advisable   with  respect  to  the  investment  and  has
               determined its suitability for Manufacturer. Manufacturer has had
               the opportunity to ask questions of, and to receive answers from,
               appropriate executive officers of Geron with respect to the terms
               and conditions of the transactions  contemplated  hereby and with
               respect to the business, affairs, financial condition and results
               of  operations  of  Geron.  Manufacturer  has had  access to such
               financial  and other  information  as is  necessary  in order for
               Manufacturer  to make a fully informed  decision as to investment
               in Geron,  and has had the  opportunity  to obtain any additional
               information  necessary to verify any of such information to which
               Manufacturer  has  had  access.  Manufacturer  acknowledges  that
               neither  Geron  nor any of its  officers,  directors,  employees,
               agents, representatives, or advisors have made any representation
               or warranty other than those specifically expressed herein.

          7.3  Business and Financial Expertise. Manufacturer further represents
               and warrants that it has such business or financial  expertise as
               to be able to evaluate  its  investment  in Geron and purchase of
               the Shares.

          7.4  Speculative  Investment.   Manufacturer   acknowledges  that  the
               investment  in  Geron   represented   by  the  Shares  is  highly
               speculative  in nature and is subject to a high degree of risk of
               loss in whole or in part; the amount of such investment is within
               Manufacturer's risk capital means and is not so great in relation
               to Manufacturer's  total financial  resources as would jeopardize
               the personal  financial  needs of  Manufacturer in the event such
               investment were lost in whole or in part.

          7.5  Unregistered Securities. Manufacturer acknowledges that:

                    7.5.1 Manufacturer must bear the economic risk of investment
                         for an  indefinite  period of time  because  the Shares
                         have not been  registered  under the Act and  therefore
                         cannot   and   will  not  be  sold   unless   they  are
                         subsequently  registered  under the Act or an exemption
                         from such registration is available.  Geron has made no
                         agreements,  covenants or  undertakings  whatsoever  to
                         register  any of the  Shares  under the Act,  except as
                         provided  in  Section  4  above.   Geron  has  made  no
                         representations,  warranties or covenants whatsoever as
                         to  whether  any  exemption  from the  Act,  including,
                         without limitation,  any exemption for limited sales in
                         routine  brokers'  transactions  pursuant  to Rule  144
                         under  the  Act,  will  become  available  and any such
                         exemption  pursuant to Rule 144, if  available  at all,
                         will not be  available  unless:  (i) a  public  trading
                         market then exists in Geron's common stock,  (ii) Geron
                         has complied with the information  requirements of Rule
                         144, and (iii) all other terms and  conditions  of Rule
                         144 have been satisfied.

                    7.5.2 Transfer  of the  Shares  has not been  registered  or
                         qualified  under any  applicable  state law  regulating
                         securities and,  therefore,  the Shares cannot and will
                         not be sold unless they are subsequently  registered or
                         qualified under any such act or an exemption  therefrom
                         is available.  Geron has made no agreements,  covenants
                         or  undertakings  whatsoever to register or qualify any
                         of the  Shares  under any such  act.  Geron has made no
                         representations,  warranties or covenants whatsoever as
                         to whether any exemption  from any such act will become
                         available.

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                    7.5.3 Manufacturer   hereby   certifies   that   it   is  an
                         "Accredited  Investor"  as that term is defined in Rule
                         501 under the Act.

     8.   TAX ADVICE. Manufacturer acknowledges that manufacturer has not relied
          and will not rely upon Geron or Geron's  counsel  with  respect to any
          tax consequences related to the ownership, purchase, or disposition of
          the Shares.  Manufacturer  assumes  full  responsibility  for all such
          consequences and for the preparation and filing of all tax returns and
          elections which may or must be filed in connection with the Shares.

     9.   NOTICES.  Any  notice or other  communication  required  or  permitted
          hereunder  shall be in  writing  and shall be deemed to have been duly
          given on the date of delivery if delivered personally or by facsimile,
          or one day, not including  Saturdays,  Sundays,  or national holidays,
          after sending if sent by national overnight delivery service,  or five
          days, not including  Saturdays,  Sundays, or national holidays,  after
          mailing if mailed by first class  United  States  mail,  certified  or
          registered  with  return  receipt  requested,   postage  prepaid,  and
          addressed as follows:

                  To Geron at:               Geron Corporation
                                             230 Constitution Drive
                                             Menlo Park, California  94025
                                             Attention: General Counsel
                                             Telephone:        (650) 473-7700
                                             Facsimile:        (650) 473-7750

                  To Manufacturer at:        Hongene Biotechnology Limited
                                             Room 203, Building 8
                                             No. 500 CaoBao Road
                                             Shanghai, China, 200233
                                             Telephone: 0086-21-64757213 or
                                                        0086-21-54971054
                                             Facsimile: 0086-21-6470061

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     10.  BINDING EFFECT.  This Agreement shall be binding upon the heirs, legal
          representatives and successors of Geron and of Manufacturer; provided,
          however,  that  Manufacturer  may not assign any rights or obligations
          under this Agreement.

     11.  GOVERNING  LAW. This  Agreement  shall be governed by and construed in
          accordance with the laws of the State of California.

     12.  INVALID PROVISIONS.  In the event that any provision of this Agreement
          is found to be invalid or otherwise  unenforceable by a court or other
          tribunal   of   competent    jurisdiction,    such    invalidity    or
          unenforceability  shall  not  be  construed  as  rendering  any  other
          provision  contained  herein  invalid or  unenforceable,  and all such
          other  provisions  shall be given  full  force and  effect to the same
          extent as though  the  invalid  and  unenforceable  provision  was not
          contained herein.

     13.  COUNTERPARTS.  This  Agreement  may  be  executed  in  any  number  of
          identical counterparts, each of which shall be deemed an original, but
          all of which together shall constitute one and the same instrument.

     14.  AMENDMENTS.  This  Agreement or any  provision  hereof may be changed,
          waived,  or  terminated  only by a statement in writing  signed by the
          party against whom such change,  waiver or termination is sought to be
          enforced.

     15.  FUTURE COOPERATION.  Each of the parties hereto agrees to cooperate at
          all times from and after the date  hereof  with  respect to all of the
          matters  described  herein,  and to execute such further  assignments,
          releases, assumptions,  amendments of the Agreement, notifications and
          other  documents  as may be  reasonably  requested  for the purpose of
          giving effect to, or evidencing or giving notice of, the  transactions
          contemplated by this Agreement.

     16.  ENTIRE AGREEMENT.  This Agreement and the Supply Agreement,  including
          Addendum  Agreement No. 3 thereto,  constitute the entire agreement of
          the  parties  pertaining  to the  Shares and  supersede  all prior and
          contemporaneous agreements, representations, and understandings of the
          parties with respect thereto.

         IN WITNESS WHEREOF, the parties hereto have executed this Common Stock
Purchase Agreement as of the date first above written.

                                     Geron Corporation


                                      /s/ David L. Greenwood
                                     -------------------------------------------
                                     By:      David L. Greenwood
                                     Title:   Executive Vice President and Chief
                                              Financial Officer

                                     Hongene Biotechnology Limited

                                      /s/ Jiang Wei
                                     -------------------------------------------
                                     By:      Jiang Wei
                                     Title:   General Manager


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