Document:

Exhibit 10.1

                        [PLX Technology, Inc. Letterhead]

December 29, 2006

Arthur Whipple
854 Renetta Court
Los Altos, CA 94024

Dear Arthur:

PLX Technology is pleased to provide you with an offer of employment for the
position of Vice President & Chief Financial Officer reporting directly to Mike
Salameh, Chief Executive Officer and President. This is an exempt position with
a starting base salary of $17,500.00 per month, paid on a semi-monthly basis
($210,000.00, if annualized). You will also participate in our 2007 Executive
Bonus Plan. Under this plan, you will have an opportunity to earn a substantial
cash bonus provided the plan's objectives are achieved. The details of this plan
will be communicated to you after joining the company and after Board approval
of the 2007 Executive Bonus Plan in January 2007. However, PLX will guarantee
you a minimum bonus of $40,000.00 payable in full no later than February 15,
2008 from the 2007 Executive Bonus Plan (subject to normal payroll withholding
and other standard Executive Bonus Plan provisions).

In addition, you will receive an option to purchase 100,000 shares of the
Company's Common Stock under the PLX Technology Stock Incentive Plan, subject to
approval by the Company's Board of Directors. In accordance with the Company's
Stock Option Policy, your option grant price will be the closing price of the
stock on the first business day of the month following your employment start
date. In accordance with the terms of the PLX Technology Stock Option Agreement,
you will vest in one-fourth (25%) of your option grant shares at the first
anniversary of your grant date. The remaining three-fourths (75%) of your option
grant shares will vest at a rate of 2.083% each month for the next three years
after the first anniversary of your grant date.

The Company offers a comprehensive benefit program that includes medical,
dental, vision, life insurances, long-term disability plan, a 401K Savings &
Retirement plan and paid time-off for vacation and illness. Details of these
benefits are included in the enclosed benefits summary document.

We look forward to you joining PLX and believe that the relationship will be
mutually rewarding. However, please be aware that the employment relationship is
at will and either party may terminate the relationship at any time for any
reason, with or without cause. This is a full and complete agreement between PLX
Technology, Inc. and Arthur Whipple.

This offer is contingent upon you successfully completing a background check and
executing the Company's standard Proprietary Information Agreement, a copy of
which is attached.

We request that you acknowledge your acceptance by signing and returning a copy
of this letter and the enclosed Proprietary Information Agreement, with your
indicated start date. This offer will remain in effect until the end of the
business day Friday, January 5, 2007.

If you have any questions regarding this offer, our benefit program or the
company in general, please contact me directly at (408) 328-3502.

Sincerely,

/s/ Mike Salameh
----------------

Mike Salameh
Chief Executive Officer & President

--------------------------------------------------------------------------------
I accept this offer of employment:

/s/ Arthur O. Whipple                          February 12, 2007
-----------------------------------            ----------------------------
Name                                           Start Date
--------------------------------------------------------------------------------EXHIBIT 4.1

                         COMMON STOCK PURCHASE AGREEMENT

         THIS COMMON STOCK PURCHASE AGREEMENT ("Agreement") is made and entered
into as of January 10, 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 MPI
Research, Inc., a Michigan corporation having its principal place of business at
54943 North Main Street, Mattawan, MI 49071 ("MPI").

         A.       Geron and MPI are the parties to that certain Master Agreement
                  dated as of December 12, 2003 (the "Master Agreement"), and
                  related Services ServicesAgreements ("Services Agreement")
                  under which Geron and MPI have agreed that MPI will perform
                  certain services on behalf of Geron on the terms set forth
                  therein.

         B.       Pursuant to Amendment No. 2 to the Agreement, dated November
                  22, 2006 ("Amendment No. 2"), Geron may pay for the price of
                  such services 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 price specified in Amendment No. 2, Geron
                  will issue and deliver certificates for 111,857 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 five (5) business days after the Effective Date
                  hereof (the "Closing Date"). At the Closing, Geron shall
                  deliver to MPI one or more certificates representing all of
                  the Shares, which Shares shall be issued in the name of MPI or
                  its designee and in such denominations as MPI shall specify.

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

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

         2.3      MPI'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 MPI:

                  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;

                                       1
<PAGE>

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

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

    3.   RESTRICTIONS ON RESALE OF SHARES.

         3.1      Legends. MPI 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 MPI 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,
                  DATED AS OF JANUARY 10, 2007. A COPY OF THE AGREEMENT CAN BE
                  OBTAINED FROM THE SECRETARY OF GERON."

         3.2      Limits on Sales. MPI 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. MPI further
                  agrees that it will not engage in short selling with respect
                  to the Stock.

    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 MPI. Geron agrees to diligently pursue
                  making the Registration Statement effective. Geron will notify
                  MPI 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 MPI receives an opinion of counsel from Geron,
                  which counsel shall be reasonably acceptable to MPI, 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 MPI.

                                       2
<PAGE>

         4.3      Geron, at its expense, shall furnish to MPI 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 MPI
                  may reasonably request, in order to facilitate the public sale
                  or other disposition of all or any of the Shares by MPI,
                  provided, however, that the obligation of Geron to deliver
                  copies of prospectuses or preliminary prospectuses to MPI
                  shall be subject to the receipt by Geron of reasonable
                  assurances from MPI that MPI 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. MPI shall bear the cost of fees and
                  expenses of MPI's counsel.

         4.5      Geron will advise MPI 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.

         4.6      With a view to making available to MPI the benefits of Rule
                  144 (or its successor rule) and any other rule or regulation
                  of the Commission that may at the time permit MPI 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.

         4.7      MPI 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 MPI 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 MPI to
                  consent to be named as an underwriter in any Registration
                  Statement.

    5.   INDEMNIFICATION.

         5.1      Geron agrees to indemnify and hold harmless MPI (and each
                  person, if any, who controls MPI within the meaning of Section
                  15 of the Act, and each officer and director of MPI) 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

                                       3
<PAGE>

                  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 MPI or such other person expressly for use in the
                  preparation thereof, (B) the failure of MPI 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 MPI prior to the pertinent sale or sales by MPI.
                  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 MPI.

         5.2      MPI 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
                  MPI 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 on behalf of MPI specifically for use in preparation of the
                  Registration Statement; provided, however, that MPI 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 MPI 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 MPI 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 define
                  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;

                                       4
<PAGE>

                  provided, however, that no indemnifying person shall be
                  responsible for the fees and expenses of more than on 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.

         Geron hereby represents, warrants and covenants to MPI 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. All corporate action on the party 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
                  this 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 MPI.

         MPI hereby represents, warrants, acknowledges and agrees that:

                                       5
<PAGE>

         7.1      Investment. MPI is acquiring the Shares for MPI's own account,
                  and not directly or indirectly for the account of any other
                  person. MPI 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. MPI has consulted with its own
                  attorney, accountant, or investment advisor as MPI has deemed
                  advisable with respect to the investment and has determined
                  its suitability for MPI. MPI 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. MPI has had access to such
                  financial and other information as is necessary in order for
                  MPI 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 MPI has had access. MPI 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. MPI 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. MPI 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
                  MPI's risk capital means and is not so great in relation to
                  MPI's total financial resources as would jeopardize the
                  personal financial needs of MPI in the event such investment
                  were lost in whole or in part.

         7.5      Unregistered Securities.  MPI acknowledges that:

                  7.5.1    MPI 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.

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

                                       6
<PAGE>

    8.   TAX ADVICE. MPI acknowledges that MPI 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. MPI
         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 MPI at:        MPI Research, Inc.
                                    54943 North Main Street
                                    Mattawan, MI 49071
                                    Telephone: 269.668.3336
                                    Facsimile: 269.668.4151

    10.  BINDING EFFECT. This Agreement shall be binding upon the heirs, legal
         representatives and successors of Geron and of MPI; provided, however,
         that MPI 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.

                                       7
<PAGE>

    16.  ENTIRE AGREEMENT. This Agreement and the Master Agreement, including
         Amendment No. 2 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 J. Earp
                                        ----------------------------------------
                                        By:      David J. Earp
                                        Title:   Senior Vice President Business
                                                 Development and Chief Patent
                                                 Counsel

                                        MPI Research, Inc.

                                        /s/ Andrejs Dumpis
                                        ------------------
                                        By:      Andrejs Dumpis
                                        Title:   Chief Financial Officer

                                       8

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00116-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00116-of-00352.parquet"}]]