EXHIBIT 4.3

COMMON STOCK PURCHASE
AGREEMENT

     THIS COMMON STOCK PURCHASE AGREEMENT
(“Agreement”) is made and entered into as of November 6, 2009 (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 ReSearch Pharmaceutical Services, Inc., a Delaware corporation having its
principal place of business at 520 Virginia Drive, Fort Washington,
Pennsylvania, 19034 (“COMPANY”). 

		A.		
      Geron and COMPANY are the parties
      to that certain Master Agreement dated as of November 6, 2009 (the
      “Master Agreement”), and a related Project Agreement No. 1 (the
      “Project Agreement”) under which Geron and COMPANY have agreed that
      COMPANY will perform certain services on behalf of Geron on the terms set
      forth therein.

	      		      	
		B.		
      Pursuant to the Master Agreement,
      Geron has agreed to make payment for such services through the delivery of
      shares of Geron’s Common Stock (the “Shares”) to COMPANY, pursuant to
      the terms and conditions of the Master Agreement, the Project Agreement,
      and this Agreement.



THE PARTIES AGREE AS FOLLOWS:


	1.	ISSUANCE OF SHARES;
      ADJUSTMENTS. 
	 
	 	1.1	As payment of the price
      specified in the Project Agreement, Geron will issue and deliver to
      COMPANY certificates for 195,331 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. 
	 
	2.	CLOSING;
      DELIVERY. 
	 
	 	2.1	The consummation of the
      transaction contemplated by this Agreement (the “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 than five (5) business days after the Effective Date (the
      "Closing Date”). At the Closing, Geron shall deliver to COMPANY one or more
      certificates representing all of the Shares, which Shares shall be issued
      in the name of COMPANY or its designee and in such denominations as
      COMPANY shall specify. 
	 
	 	2.2	Geron’s obligations to
      issue and deliver the stock certificate(s) representing the Shares to
      COMPANY at the Closing shall be subject to the following conditions, which
      may be waived by Geron: 
	          	          	             	
	 	 	2.2.1	the covenants and obligations
      that COMPANY 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 COMPANY herein shall be true and correct in all
      material respects as of the Closing Date. 
	 
	 	2.3	COMPANY’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 COMPANY: 
	 
	 	 	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, as amended and restated to date (the
      “Certificate of
      Incorporation”), sufficient authorized
      shares of Common Stock to issue the Shares to COMPANY; 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. 


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	3.	RESTRICTIONS ON
      RESALE OF SHARES.
	          	          	
	 	3.1	Legends. COMPANY understands and acknowledges that the Shares
      are not registered under the Securities Act of 1933, as amended (the
      “Act”), and that under the Act and other applicable laws COMPANY may be
      required to hold such Shares for an indefinite period of time. Each stock
      certificate representing Shares shall bear the following legend:
  
	 
	 	 	“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 RESEARCH PHARMACEUTICAL
      SERVICES, INC., DATED AS OF NOVEMBER 6, 2009. A COPY OF THE AGREEMENT CAN
      BE OBTAINED FROM THE SECRETARY OF GERON.”
	 
	 	 	The legend set forth above shall
      be removed upon written request by COMPANY, and Geron shall make
      commercially reasonable efforts to issue, or to cause its transfer agent
      to issue, as soon as practicable but in any event within five (5) trading
      days after receipt of such written request by COMPANY, a certificate or
      certificates without such legend to COMPANY, if, unless otherwise required
      by blue sky or state securities laws, (i) the sale of Shares is registered
      under the Act (including registration pursuant to Rule 416 thereunder);
      (ii) COMPANY provides Geron with an opinion of counsel, in form, substance
      and scope customary for opinions of counsel in comparable transactions, to
      the effect that a public sale or transfer of the Shares may be made
      without registration under the Act; or (iii) COMPANY provides to Geron
      such documentation and information as may be reasonably requested by Geron
      to permit counsel for Geron to render an opinion, in form, substance and
      scope customary for opinions of counsel in comparable transactions, that
      the Shares can be sold under Rule 144.
	 
	 	3.2	Limits on Sales.
      COMPANY 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. COMPANY further agrees that
      hedging transactions involving the Shares shall not be conducted by
      COMPANY unless in compliance with the Act, and any hedging transactions
      conducted by COMPANY shall not involve short sales of the Geron’s Common
      Stock.
	 	 	
	 	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.
	 
	 	3.4	Notwithstanding anything to the
      contrary herein, COMPANY is not required to hold the Shares for a minimum
      term and reserves the right to dispose of the Shares pursuant to the
      Registration Statement (as defined below) or in accordance with Rule 144
      or other equivalent provision then in effect under the Act.
	 
	4.	REGISTRATION
      RIGHTS
	 
	 	4.1	Geron shall use commercially
      reasonable efforts to file with the Securities and Exchange Commission
      (the “Commission”) as soon as practicable, but in no event later than
      ten (10) business days following the Closing Date, a registration
      statement on Form S-3 (or, if Form S-3 is not then available, on such form
      of registration statement as is then available to effect a registration of
      the Shares, each such registration statement being the “Registration Statement”) covering the resale of the Shares under the Act by COMPANY.
      Geron shall use commercially reasonable efforts to cause the Registration
      Statement required to be filed pursuant to this Section 4.1 to become
      effective as soon as reasonably practicable. Geron shall respond promptly
      to any and all comments made by the staff of the Commission to any
      Registration Statement required to be filed under this Agreement, and
      shall submit to the Commission, promptly, and in any event before the
      close of business on the business day immediately following Geron’s
      receipt of notice (either by telephone or in writing) that no review of
      such Registration will be made by the Commission or that the staff of the
      Commission has no further comments on such Registration Statement, as the
      case may be a request for acceleration of the effectiveness of such
      Registration Statement to a date and time as soon as practicable. Geron
      will notify COMPANY of the effectiveness of the Registration Statement as
      soon as practicable and in no event later than one (1) business day after
      receiving notice from the Commission declaring the Registration Statement
      effective.


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		4.2	Geron will make commercially
      reasonable efforts to prepare, file and maintain the Registration
      Statement and any post-effective amendment or supplement thereto filed or
      required to be 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 COMPANY receives an opinion of counsel from Geron, which
      counsel shall be reasonably acceptable to COMPANY, that the Shares may be
      sold under the provisions of Rule 144 or any similar provision then in
      effect under the Act (without restriction except as otherwise set forth in
      this Agreement), or (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 (the
      “Registration Period”). 
	          	          	
		4.3	Geron, at its expense, shall
      furnish to COMPANY with respect to the Shares registered under the
      Registration Statement such reasonable number of copies of the
      Registration Statement in conformity with the requirements of the Act and
      such other documents as COMPANY may reasonably request, in order to
      facilitate the public sale or other disposition of all or any of the
      Shares by COMPANY, provided, however, that the obligation of Geron to
      deliver copies of the Registration Statement and such other documents to
      COMPANY shall be subject to the receipt by Geron of reasonable assurances
      from COMPANY that COMPANY will comply with the applicable provisions of
      the Act and of such other securities or, subject to Section 4.4 hereof,
      blue sky or state securities laws as may be applicable in connection with
      any use of the Registration Statement and such other documents.
  
		 
		4.4	Geron shall use commercially
      reasonable efforts to (i) register the Shares covered by any Registration
      Statement under such other securities or blue sky laws of such
      jurisdictions in the United States as COMPANY reasonably requests, (ii)
      prepare and file in those jurisdictions such amendments (including
      post-effective amendments) to such registrations as may be necessary to
      maintain the effectiveness thereof during the Registration Period, or
      (iii) obtain exemption from such other securities or blue sky laws.
      All fees, disbursements and out-of-pocket expenses and costs incurred by
      Geron in connection with the preparation and filing of any 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. COMPANY shall bear the cost of all fees
      and expenses of COMPANY’s counsel.
		 	
		4.5	Geron shall use commercially
      reasonable efforts (i) to prevent the issuance of any stop order or other
      suspension of effectiveness of any Registration Statement covering the
      Shares, and (ii) if such order is issued, to obtain the withdrawal of such
      order at the earliest practicable time. Geron will promptly notify COMPANY
      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, the initiation of any proceeding for that
      purpose, or the resolution of such delay, suspension or proceeding.
    
		 
		4.6	With a view to making available
      to COMPANY the benefits of Rule 144 (or its successor rule) and any other
      rule or regulation of the Commission that may at the time permit COMPANY
      to sell the Shares to the public without registration, Geron covenants and
      agrees to make commercially reasonable efforts to: (i) make and keep
      current 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 without registration or restriction pursuant to Rule
      144 or any other rule of similar effect or (B) such date as all of the
      Shares shall have been resold; (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”); and (iii) furnish to COMPANY so long as COMPANY holds the
      Shares, promptly upon request (A) a written statement by Geron that it
      reasonably believes that it has complied with the reporting requirements
      of Rule 144, the Act, and the Exchange Act, (B) a copy of Geron’s most
      recent annual or quarterly report and such other reports and documents so
      filed by Geron, and (C) such other information as may be reasonably
      requested to permit COMPANY to sell the Shares under Rule 144 without
      registration.


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	 	4.7	COMPANY 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 COMPANY and its 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. Nothing in this Agreement
      shall obligate COMPANY to consent to be named as an underwriter in any
      Registration Statement. 
	          	          	
	5.	INDEMNIFICATION. 
	 
	 	5.1	Geron agrees to indemnify and
      hold harmless COMPANY (and each person, if any, who controls COMPANY
      within the meaning of Section 15 of the Act, and each officer and director
      of COMPANY) 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 exhibit, amendment, supplement, or document
      filed therewith or incorporated by reference thereto, (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, or (iii) any
      violation or alleged violation by Geron of the Act, the Exchange Act or
      any other law (including, without limitation, any state securities or blue
      sky laws, rule or regulation relating to the offer or sale of the Shares;
      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, exhibit,
      amendment, supplement, or document filed therewith or incorporated by
      reference thereto in reliance upon and in conformity with written
      information furnished to Geron by or on behalf of COMPANY or such other
      person expressly for use in the preparation thereof, (B) the failure of
      COMPANY to comply with its covenants and agreements contained in Section
      7.1 or 7.5.3 hereof or (C) any misstatement or omission in any prospectus
      that is corrected in any subsequent prospectus that was delivered to
      COMPANY prior to the pertinent sale or sales by COMPANY. 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 COMPANY. 
	 
	 	5.2	COMPANY 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 Section 20 of the Exchange 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 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 COMPANY specifically for
      use in preparation of the Registration Statement; provided, however, that
      COMPANY 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 COMPANY 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 COMPANY 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.


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	 	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,
      ACKNOWLEDGMENTS AND COVENANTS OF GERON. 
	 
	 	Geron hereby
      represents, warrants and covenants to COMPANY 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 its 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.


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	 	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. 
	 
	 	6.5	No Conflicts; Consents.
      The execution, delivery and performance
      of this Agreement by Geron and the consummation of the transactions
      contemplated hereby will not (i) result in a violation of the Certificate
      of Incorporation or Geron’s bylaws, (ii) to Geron’s knowledge, conflict
      with, or constitute a default (or an event that with notice or lapse of
      time or both would become a default) under, or give to others any rights
      of termination, amendment (including, without limitation, the triggering
      of any anti-dilution provisions), acceleration or cancellation of, any
      agreement, indenture or instrument to which Geron or any of its
      subsidiaries is a party, or (iii) to Geron’s knowledge, result in a
      violation of any law, rule, regulation, order, judgment or decree
      (including the Act, the Exchange Act, and blue sky or state securities
      laws) applicable to Geron. Except as may be required under the Act in
      connection with the Geron’s obligations under this Agreement and as may be
      required for compliance with applicable state securities or blue sky laws,
      Geron is not required to obtain any consent, approval, authorization or
      order of, or make any filing or registration with, any court or
      governmental agency or any regulatory or self-regulatory agency or other
      third party in order for it to execute, deliver or perform any of its
      obligations under this Agreement. 
	 
	 	6.6	Listing. Geron’s Common Stock is currently listed for trading on
      the Nasdaq Global Market. To Geron’s knowledge as of the Effective Date,
      Geron is not in violation of the listing requirements of the Nasdaq Global
      Market, and has not received any notice regarding the delisting of the
      Common Stock from the Nasdaq Global Market. Geron has secured the listing
      of the Shares on the Nasdaq Global Market (subject to official notice of
      issuance). During the Registration Period, Geron shall use commercially
      reasonable efforts to continue the listing and trading of its Common Stock
      on the Nasdaq Global Market and shall comply in all material respects with
      the reporting, filing, and other obligations under the bylaws and rules of
      the Nasdaq Global Market. 
	 
	 	6.7	S-3 Eligibility.
      As of the Effective Date, Geron is
      eligible to register the resale of its Common Stock on a registration
      statement on Form S-3 under the Act. 
	 
	7.	REPRESENTATIONS,
      ACKNOWLEDGMENTS AND COVENANTS OF COMPANY. 
	 
	 	COMPANY hereby
      represents, warrants, and covenants that: 
	 
	 	7.1	Investment. COMPANY is acquiring the Shares for its own account, and
      not directly or indirectly for the account of any other person. COMPANY is
      acquiring the Shares for investment purposes only and not with a present
      view towards the public sale or distribution thereof, except pursuant to
      sales that are exempt from the registration requirements of the Act and/or
      sales registered under the Act. COMPANY understands that it must
      bear the economic risk of this investment, and that Geron has no present
      intention of registering the resale of the Shares other than as
      contemplated by this Agreement.


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		7.2	Access to
      Information. COMPANY has consulted with
      its own attorney, accountant, or investment advisor as COMPANY has deemed
      advisable with respect to the investment and has determined its
      suitability for COMPANY. COMPANY 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 COMPANY information which
      may constitute material, non-public information regarding Geron, and
      COMPANY 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 COMPANY’s possession
      without any obligation of confidentiality prior to the date Geron
      disclosed such information to COMPANY, (c) that is supplied to COMPANY by
      a third party which is not subject to any restriction of confidentiality
      or non-disclosure, or (d) that COMPANY is required to disclose pursuant to
      a subpoena or other order from a court or other government body of
      competent jurisdiction, provided that COMPANY shall promptly provide prior
      written notice of such required disclosure to Geron, and shall cooperate
      by performing such actions as Geron may reasonably request to permit Geron
      to seek to obtain a protective or other order maintaining the
      confidentiality of such material, non-public information. COMPANY has had
      access to such financial and other information as is necessary in order
      for COMPANY 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 COMPANY has had access. COMPANY
      acknowledges that neither Geron nor any of its officers, directors,
      employees, agents, representatives, or advisors have made any
      representation or warranty concerning the Shares other than those
      specifically expressed herein.
		 	
		7.3	Business and
      Financial Expertise. COMPANY further
      represents and warrants that it has such business or financial expertise
      as to be able to evaluate its investment in Geron and accept delivery of
      the Shares. 
		 	
		7.4	Speculative
      Investment. COMPANY 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 COMPANY’s risk capital means
      and is not so great in relation to COMPANY’s total financial resources as
      would jeopardize the personal financial needs of COMPANY in the event such
      investment were lost in whole or in part. 
		 
		7.5	Unregistered
      Securities. COMPANY acknowledges
      that: 
	          	          	             	
		 	7.5.1	COMPANY 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 under any applicable state law regulating securities and,
      therefore, the Shares cannot and will not be sold unless they are
      subsequently registered under any such act or an exemption therefrom is
      available, except as set forth in this Agreement. 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	COMPANY hereby certifies that it is an “Accredited Investor”
      as that term is defined in Rule 501 under the Act.
	          	          	             	
	 	7.6	Authorization.
      COMPANY 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 COMPANY enforceable against COMPANY 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.
      COMPANY acknowledges that COMPANY has
      not relied and will not rely upon Geron or Geron’s counsel with respect to
      any tax consequences related to the ownership or disposition of the
      Shares. COMPANY 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: Senior Director, Legal 
			Telephone: 
       	(650)
      473-7700 
			Facsimile:
    	(650)
      473-7750 
		 		
	To COMPANY
      at:	       	ReSearch Pharmaceutical Services, Inc.
			520
      Virginia Drive 
			Fort
      Washington, Pennsylvania 19034
			Attention: Corporate Counsel
			Telephone: 
       	(215)
      540-0700
			Facsimile:
    	(215)
      540-0770




	10.	BINDING EFFECT.
      This Agreement shall be binding upon
      the heirs, legal representatives and successors of Geron and of
      COMPANY. 
	          	
	11.	GOVERNING LAW.
      This Agreement shall be governed by and
      construed in accordance with the laws of the State of Delaware.
  
	 
	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.
  


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	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, the Master Agreement,
      and the Project Agreement 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.


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     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


 

	
      ReSearch Pharmaceutical
      Services, Inc.

	 
 
	   /s/ Daniel
      M. Perlman	
	By:	Daniel M. Perlman
	Title:       	CEO




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