EXHIBIT 10.1


FIFTH AMENDMENT TO LEASE
AGREEMENT 

THIS FIFTH AMENDMENT (the
"FIFTH Amendment") is made and entered into as of September 15,
2015, by and between Exponent Realty, LLC, a Delaware limited liability company
("Landlord"), and Geron Corporation, a Delaware corporation ("Tenant").
Capitalized terms set forth herein and not otherwise expressly defined shall
have the meaning set forth in the Lease. 

RECITALS 

	     	A.      	Landlord
      and Tenant are parties to that certain Office Lease Agreement dated
      February 29, 2012 (the “Lease”), the First
      Amendment dated January 10, 2014 (the "First Amendment"), the Second Amendment dated January 31, 2014
      (the "Second Amendment")
      , the Third Amendment dated
      February 27, 2014 (the "Third Amendment"), and the Fourth Amendment dated May 9th, 2014 (the "Fourth
      Amendment”). Collectively,
      the Lease, First Amendment, Second Amendment, Third Amendment and Fourth
      Amendment are referred to herein as the “Lease”. Pursuant to the Fourth Amendment, Landlord
      has leased to Tenant (i) space currently containing approximately 23,802
      rentable square feet as set forth on EXHIBIT A to the Fourth Amendment
      (the "Premises") on the second floor of the building, k n own as suites
      2118, 2020, and 2070, located at 149 Commonwealth Dr., Menlo Park, CA
      94025 (the "Building").
		 
		B.	The Lease,
      by its terms, is due to expire on January 31, 2016 (the "Termination
      Date"), and the parties now
      desire to extend the lease term, reduce the amount of rentable square feet
      leased to Tenant and increase the cost per square foot on the following
      terms and conditions.


AGREEMENT 

NOW,
THEREFORE, in consideration of
the above recitals which by this reference are incorporated herein, the mutual
covenants and conditions contained herein and other valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, Landlord and Tenant
agree as follows: 

	     	1.       	Rentable Area (approximate). The Rentable Area set forth in section C.2a.
      of the BASIC LEASE
      PROVISIONS in the
      Information Sheet is hereby changed to read:
		 
			C.2.a.
      Rentable
      Area.
		 
			
      For the period from September 12,
      2015 to January 31, 2016, the Rentable Area shall consist of 20,930
      rentable square feet, consisting of the suites commonly known as Suites
      2070 and Suite 2020, as set forth in Exhibit A to this FIFTH Amendment.
      Tenant will vacate Suite 2118 by midnight on September 11,
2015.

      For the period from February 1,
      2016 to January 31, 2018, the Rentable Area shall consist of 14,485
      rentable square feet, consisting of the suite commonly known as Suite
      2070, as set forth in Exhibit A to this FIFTH Amendment. Tenant will
      vacate suite 2020 by midnight on January 31,
2016.











	     	2.       	Amendment Term. The Lease Term set forth in section C.3 of the BASIC LEASE PROVISIONS in the Information Sheet is hereby amended
      to add the FIFTH Amendment Term, as follows:
		 
			C.3.
      FIFTH Amendment Term: Two
      years (2) commencing on at 12:01 a.m. February 1, 2016 (the
      “FIFTH Amendment Term
      Commencement Date”) and
      ending at 12:00 p.m. on January 31, 2018 (the “Expiration Date”).
		 
		3.	Commencement Date. The Commencement date set forth in section C.4 of the
      BASIC LEASE PROVISIONS
      in the Information Sheet is
      hereby changed to add the FIFTH Amendment Term Commencement
  Date:
		 
			C.4.
      FIFTH Amendment Term Commencement Date February 1, 2016.
		 
		4.	Tenant's Building Percentage. Effective on the FIFTH Amendment Term
      Commencement Date , the Tenant's Building Percentage set forth in section
      C.5 of the BASIC LEASE
      PROVISIONS is hereby
      changed to read:
		 
			C.5.
      Tenant’s Building Percentage:
			From
      September 1, 2015 to September 11, 2015, Tenant’s Building Percentage
      shall be Fifteen and forty eight hundredth percent (15.48%)
		 
			From
      September 12, 2015 to January 31, 2016, Tenant’s Building Percentage shall
      be Thirteen and sixty one hundredth percent (13.61%)
		 
			From
      February 1, 2016 to January 31, 2018, Tenant’s Building Percentage shall
      be Nine and forty two hundredth percent
(09.42%)










	     	5.       	Base
      Rent. The Base Rent set
      forth in section C.6 of the BASIC LEASE PROVISIONS is hereby changed according to the following
  schedule:




	Period	Building	Rentable	Monthly	Periodic
		Percentage	Square	Rate Per	Base
      Rent
		 	Feet	RSF	
	September 1,
      2015 to September 11, 2015	15.48%	23,802	$3.10	$27,054.94
	September
      12, 2015 to September 30, 2015	13.61%	20,930	$3.10	$41,092.65





	Period	Building	Rentable	Monthly Rate	Monthly Base
		Percentage	Square	Per RSF	Rent
			Feet		
	October 1,
      2015 to January 31, 2016	13.61%	20,930	$3.10	$64,883.00
	February 1,
      2016 to January 31, 2018	9.42%	14,485	$3.80	$55,043.00




	     	6.       	Option To Extend. The Conditions to Exercise of Options set forth in section 4.E.(i)
      and 4.E(ii) of the LEASE shall be changed upon the FIFTH Amendment Term
      Commencement Date to read:
		 
			4.E(i)        Conditions to Exercise of Option. Provided
    that Tenant is not in default under this Lease at the time        of exercise of the option to extend or at the commencement
    of the exercise        term, Tenant shall have the right to extend the Term of the Lease for one        additional period of
    two (2) years (the “Sixth Extension Term”) commencing
    at 12:01a.m. on February 1, 2018        and expiring at 12:00p.m. on January 31, 2020.
		 
			4.E(ii)
      Notice of Exercise. If
      Tenant elects to extend this Lease for the Sixth Extension Term, Tenant
      shall deliver written notice (“Exercise Notice”) of its exercise of the option to extend to Landlord not earlier
      than 180 days and not less than 150 days prior to the FIFTH Amendment
      Expiration Date. Tenant’s failure to deliver the Exercise Notice in a
      timely manner shall be deemed a waiver of Tenant’s rights to extend the
      Term of the Lease.
		 
		7.	Rent. Paragraph
      5.E. (i) of the Lease is hereby amended to add the following
      sentence:
		 	
		
      “The monthly Base rent during the Sixth Extension Term shall
      increase by three percent (3%) on an annual basis as set forth in the
      following schedule: 





	Period	Rentable	Monthly	Monthly
		Square Feet	Rate Per	Base
      Rent
		 	RSF	 
	February 1,
      2018 to January 31, 2019	14,485	$3.91	$56,636.35
	February 1,
      2019 to January 31, 2020	14,485	$4.03	$58,374.55











	     	8.      	Miscellaneous.
		 
			8.1      	This FIFTH
      Amendment, which is hereby incorporated into and made a part of the Lease,
      sets forth the entire agreement between the parties with respect to the
      matters set forth herein. There have been no additional oral or written
      representations or agreements. Under no circumstances shall Tenant be
      entitled to any further Rent abatement, improvement allowance, leasehold
      improvements, or other work to the Premises, or any similar economic
      incentives that may have been provided Tenant in connection with entering
      into the Lease, unless specifically set forth in this Fifth Amendment.
      Tenant may disclose the terms and conditions of the Lease, as amended by
      this FIFTH Amendment, if required by applicable law which shall include
      the requirements of the United States Securities and Exchange
      Commission.
		 
			8.2	Except as
      herein modified or amended, the provisions, conditions and terms of the
      Lease shall remain unchanged and in full force and effect.
		 
			8.3	In the
      case of any inconsistency between the provisions of the Lease, and this
      FIFTH Amendment, the provisions of this FIFTH Amendment shall govern and
      control.
		 
			8.4	Submission
      of this fifth Amendment by Landlord is not an offer to enter into this
      FIFTH Amendment but rather is a solicitation for such an offer by Tenant.
      Landlord shall not be bound by this FIFTH Amendment until Tenant and
      Landlord have executed this FIFTH Amendment and Landlord has delivered the
      same to Tenant.
		 
			8.5	Tenant
      hereby represents to Landlord that Tenant has dealt with no real estate
      brokers or agents in connection with this FIFTH Amendment. Tenant agrees
      to indemnify and hold Landlord, its members, principals, beneficiaries,
      partners, officers, directors, employees, mortgagee(s) and agents, and the
      respective principals and members of any such real estate brokers or
      agents (collectively, the "Landlord Related Parties") harmless from all claims of any real estate brokers or agents
      claiming to have represented Tenant in connection with this FIFTH
      Amendment. Landlord hereby represents to Tenant that Landlord has dealt
      with no real estate brokers or agents in connection with this FIFTH
      Amendment. Landlord agrees to indemnify and hold Tenant, its members,
      principals, beneficiaries, partners, officers, directors, employees, and
      agents, and the respective principals and members of any such real estate
      brokers or agents (collectively, the "Tenant Related Parties") harmless from all claims of any real estate brokers or agents
      claiming to have represented Landlord in connection with this FIFTH
      Amendment.
		 
			8.6	Each
      signatory of this FIFTH Amendment represents hereby that he or she has the
      authority to execute and deliver the same on behalf of the party hereto
      for which such signatory is acting.


[SIGNATURES ARE ON
FOLLOWING PAGE] 








IN WITNESS WHEREOF,
Landlord and Tenant have duly
executed this FIFTH Amendment as of the day and year first above written.


			             	LANDLORD:	
				 	 
				EXPONENT REALTY, L.L.C.,	
		 		a
      Delaware limited liability company	
				 	
		Date:
      Sep 15, 2015		By:
    	/s/ Richard L.
      Schlenker	
				 		
				Name:   	Richard L. Schlenker	
				 		
				Title:	Executive Vice
      President and	
					Chief Financial
      Officer	
		 	
		 	
				TENANT:	
				 	
				GERON CORPORATION,	
				A Delaware corporation	
		 	
		Date: 15/Sep
      15		By:
    	/s/ John A.
      Scarlett  	
				 	
				Name:	John A. Scarlett, M.D.	
					 	
				Title:	President and CEO	










EXHIBIT
A
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