EXHIBIT 4.2



                         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 Lonza
Walkersville,  Inc.,  a  Delaware  corporation  having  its  principal  place of
business  at 8830 Biggs  Ford  Road,  Walkersville,  Maryland  21793  ("Lonza").
Capitalized  terms not otherwise defined herein shall have the meaning set forth
in the MSA and Project Order No. 1.

          A.   Geron and Cambrex Bio Science Walkersville, Inc. ("CBSW") entered
               that certain Master Services Agreement,  dated as of September 1,
               2005 (the  "MSA"),  pursuant  to which  CBSW  agreed  to  perform
               certain services on behalf of Geron related to the manufacture of
               a product  containing human cells intended for therapeutic use in
               humans on the terms set forth therein.

          B.   Geron and CBSW entered  into Project  Order No. 1 to the MSA (the
               "Project Order No. 1") effective  September 1, 2005,  pursuant to
               which Geron is entitled,  subject to certain  conditions,  to pay
               any  compensation  owed  to CBSW  for  Services  performed  under
               Project  Order No. 1 either in cash or in  Geron's  common  stock
               (the "Common Stock").

          C.   Subject to the terms and  conditions  of the Second  Amendment to
               Project  Order No.1,  dated as of March 1, 2006  ("Amendment  No.
               2"),  Geron and CBSW agreed that Geron shall,  subject to certain
               conditions,  be entitled to pay up to  US$4,500,000  for Services
               under Project Order No. 1 by delivery of Shares.

          D.   Effective  February 6, 2007,  Lonza  completed its acquisition of
               CBSW,  and assumed all rights and  obligations  of CBSW under the
               MSA and Project Order No. 1, as amended.

          E.   Subject to the terms and  conditions  of the Sixth  Amendment  to
               Project Order No.1, dated as of November 9, 2007, Geron and Lonza
               have agreed that Geron shall,  subject to certain conditions,  be
               entitled to pay an  additional  US$4,000,000  for Services  under
               Project Order No. 1 by delivery of Shares, for an aggregate total
               of up to US$8,500,000 payable in Stock.

THE PARTIES AGREE AS FOLLOWS:

                                       1
<PAGE>

     1. ISSUANCE OF SHARES; ADJUSTMENTS.

          1.1  As payment of the fifth Installment  Payment specified in Project
               Order No.  1,  Geron  will  issue and  deliver  certificates  for
               147,493 shares of Common Stock (the "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 no
               later than five (5)  business  days after the  Effective  Date of
               this Agreement (the "Closing Date"). At the Closing,  Geron shall
               deliver to Lonza one or more certificates representing all of the
               Shares,  which Shares shall be issued in the name of Lonza or its
               designee and in such denominations as Lonza shall specify.

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

               2.2.1 the  covenants  and  obligations  that Lonza 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 Lonza herein
                    shall be true and correct in all material respects as of the
                    Closing Date.

          2.3  Lonza'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
               Lonza:

               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 Lonza; and

               2.3.3 the  representations  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.  Lonza  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  Lonza  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 LONZA, DATED NOVEMBER 21,
                2007.   A  COPY  OF THE   AGREEMENT  CAN BE  OBTAINED  FROM  THE
                SECRETARY OF GERON."

                                       2
<PAGE>

          3.2  Limits on Sales.  Lonza  agrees that if it decides to resell some
               or all of the Shares, it will do so only in an appropriate manner
               through orderly sales executed through a top-tier brokerage firm,
               and based upon whether the shares are registered or unregistered,
               i.e., on the Nasdaq  National  Market or in a Rule 144A compliant
               transaction.

          3.3  Further Limitations.  Geron shall not be required (i) to transfer
               on its  books  any  Shares  that  have  been  sold  or  otherwise
               transferred  in  violation  of  any  of the  provisions  of  this
               Agreement  or  applicable  securities  laws;  or (ii) to treat as
               owner  of such  Shares  or to  accord  the  right  to vote or pay
               dividends  to any  purchaser  or other  transferee  to whom  such
               Shares shall have been so  transferred in violation of any of the
               provisions of this Agreement or applicable securities laws.

     4. REGISTRATION RIGHTS

                                       3
<PAGE>

          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 Lonza.
               Geron  agrees  to  diligently   pursue  making  the  Registration
               Statement  effective.  Geron  will make  commercially  reasonable
               efforts to notify Lonza of the  effectiveness of the Registration
               Statement  within one (1) business  day of receiving  notice from
               the Commission  declaring the Registration  Statement  effective,
               but no later  than the close of  business  (Pacific  Time) of the
               second  business  day  after  receipt  of such  notice  from  the
               Commission.

          4.2  Geron  shall  notify  Lonza as promptly as possible of any review
               initiated by the Commission with respect to any such Registration
               Statement.

          4.3  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
               Lonza  receives  an opinion of  counsel to Geron,  which  counsel
               shall be reasonably  acceptable to Lonza,  that the Shares may be
               sold  under the  provisions  of Rule 144,  (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 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
               Lonza.

          4.4  Geron, at its expense, shall furnish to Lonza 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 Lonza may
               reasonably  request,  in order to  facilitate  the public sale or
               other disposition of all or any of the Shares by Lonza, provided,
               however,  that  the  obligation  of Geron to  deliver  copies  of
               prospectuses  or  preliminary  prospectuses  to  Lonza  shall  be
               subject to the  receipt by Geron of  reasonable  assurances  from
               Lonza that Lonza 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.

          4.5  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.  Lonza  shall  bear the cost of all fees and  expenses  of
               Lonza's counsel.

          4.6  Geron will advise Lonza 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 as promptly as possible if such stop order should
               be issued.

                                       4
<PAGE>

          4.7  With a view to making available to Lonza the benefits of Rule 144
               (or its  successor  rule) and any other rule or regulation of the
               Commission  that may at the time permit  Lonza 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  Exchange  Act of
               1934, as amended.

          4.8  Lonza 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  Lonza 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 Lonza to consent to be
               named as an underwriter in any Registration Statement.

     5. INDEMNIFICATION.

                                       5
<PAGE>

          5.1  Geron  agrees to  indemnify  and hold  harmless  Lonza  (and each
               person,  if any, who controls Lonza within the meaning of Section
               15 of the Act, and each  officer and  director of Lonza)  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 arises out of or is based upon (A) 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 or on behalf of Lonza  expressly for use in
               the preparation  thereof, (B) the failure of Lonza 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
               Lonza  prior  to the  pertinent  sale or  sales  by  Lonza.  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 Lonza.

          5.2  Lonza  agrees to  indemnify  and hold  harmless  Geron  (and each
               person,  if any, who controls Geron within the meaning of Section
               15 of the Act,  and each  officer and 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 Lonza
               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 Lonza  specifically for use
               in preparation of the Registration Statement;  provided, however,
               that  Lonza  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 Lonza 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  Lonza  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.

                                       6
<PAGE>

          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 a party,  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.

          Geron hereby represents, warrants and covenants to Lonza as follow:

          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.   Geron  has  full  right,  power,  authority  and
               capacity  to enter  into this  Agreement  and to  consummate  the
               transactions  contemplated  hereby and  thereby and has taken all
               necessary  action  to  authorize  the  execution,   delivery  and
               performance of this Agreement.  Upon execution and delivery, this
               Agreement will constitute a valid and binding obligation of Geron
               enforceable against Geron in accordance with its terms, except as
               such  enforceability  may be  limited by  applicable  bankruptcy,
               insolvency,  reorganization,   moratorium,  fraudulent  transfer,
               liquidation or similar laws relating to, or affecting  generally,
               the  enforcement  of  creditor's  rights and remedies or by other
               equitable  principles of general application from time to time in
               effect.

                                       7
<PAGE>

          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 foregoing. 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 LONZA.

          Lonza hereby represents, warrants, acknowledges and agrees that:

                                       8
<PAGE>

          7.1  Investment.  Lonza  is  acquiring  the  Shares  for  Lonza's  own
               account,  and not directly or  indirectly  for the account of any
               other person.  Lonza 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. Lonza has consulted with its own attorney,
               accountant,  or investment  advisor as Lonza has deemed advisable
               with respect to the investment and has determined its suitability
               for Lonza. Lonza 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.  In
               connection with the transactions  contemplated  hereunder,  Geron
               may disclose to Lonza information which may constitute  material,
               non-public  information  regarding  Geron,  and  Lonza  agrees to
               maintain in confidence any such information;  provided,  however,
               such  information  shall not include  information  (a) that is or
               becomes  part of the  public  domain,  (b)  that  was in  Lonza's
               possession without any obligation of confidentiality prior to the
               date Geron  disclosed such  information to Lonza,  or (c) that is
               supplied  to Lonza by a third  party  which is not subject to any
               restriction of confidentiality  or non-disclosure.  Lonza has had
               access to such financial and other information as is necessary in
               order  for  Lonza  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  Lonza has had access.  Lonza  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.  Lonza 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. Lonza 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  Lonza's  risk
               capital  means and is not so great in relation  to Lonza's  total
               financial  resources as would  jeopardize the personal  financial
               needs of Lonza in the event such investment were lost in whole or
               in part.

          7.5  Unregistered Securities. Lonza acknowledges that:

                    7.5.1 Lonza 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.   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.

                                       9
<PAGE>

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

          7.6  Authorization.   Lonza  has  full  right,  power,  authority  and
               capacity  to enter  into this  Agreement  and to  consummate  the
               transactions  contemplated  hereby and  thereby and has taken all
               necessary  action  to  authorize  the  execution,   delivery  and
               performance of this Agreement.  Upon execution and delivery, this
               Agreement will constitute a valid and binding obligation of Lonza
               enforceable against Lonza in accordance with its terms, except as
               such  enforceability  may be  limited by  applicable  bankruptcy,
               insolvency,  reorganization,   moratorium,  fraudulent  transfer,
               liquidation or similar laws relating to, or affecting  generally,
               the  enforcement  of  creditor's  rights and remedies or by other
               equitable  principles of general application from time to time in
               effect.

     8.   TAX ADVICE.  Lonza acknowledges that Lonza 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.  Lonza 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: Chief Financial Officer
                                            Telephone:        (650) 473-7700
                                            Facsimile:        (650) 473-7750



                  With a copy to:           Geron Corporation
                                            230 Constitution Drive
                                            Menlo Park, California  94025
                                            Attention: Senior Director, Legal
                                            Telephone:        (650) 473-7775
                                            Facsimile:        (650) 566-7181



                  To Lonza at:              Lonza Walkersville, Inc.
                                            8830 Biggs Ford Road
                                            Walkersville, Maryland 21793
                                            Attention:  Tim Harrigan
                                            Telephone:        (301) 898-7025
                                            Facsimile:        (301) 845-6099

                                       10
<PAGE>

                  With a copy to:           Lonza America Inc.
                                            25 Commerce Drive
                                            Allendale, New Jersey 07401
                                            Attention: Assistant General Counsel
                                            Telephone:        (201) 316-9422
                                            Facsimile:        (201) 378-5630

     10.  BINDING EFFECT.  This Agreement shall be binding upon the heirs, legal
          representatives and successors of Geron and of Lonza.

     11.  GOVERNING  LAW. This  Agreement  shall be governed by and construed in
          accordance  with the laws of the  State of  Delaware,  without  giving
          effect to its conflicts of laws provisions.

     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 MSA, and Project Order No. 1
          thereto as amended,  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.



                      REST OF PAGE INTENTIONALLY LEFT BLANK



                                       11

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the Effective Date.

                                     Geron Corporation


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

                                     LonzaWalkersville, Inc.


                                      /s/ Shawn P. Cavanagh
                                     -------------------------------------------
                                     By:      Shawn P. Cavanagh
                                     Title:   President


                                     LonzaWalkersville, Inc.


                                     /s/ Vinny DiVito
                                     -------------------------------------------
                                     By:      Vinny DiVito
                                     Title:   Chief Financial Officer


                                       12