Exhibit 10.5

SECOND AMENDMENT TO LEASE

This Second Amendment to Lease (this “Second Amendment”) is entered into as of
October 22, 2015, by and between NS WELLS ACQUISITION LLC, a Delaware limited
liability company (the “Landlord”), and KARYOPHARM THERAPEUTICS INC., a Delaware
corporation (the “Tenant”).

WHEREAS, Landlord and Tenant entered into that certain Office Lease Agreement
dated as of March 27, 2014, as amended by a First Amendment to Lease dated
December 31, 2014 (the “First Amendment”) (as amended, the “Lease”) for the
lease of certain premises containing 29,933 rentable square feet (the “Existing
Premises”) on the second (2nd) floor and certain premises containing 16,234
rentable square feet on the third (3rd) floor (the “Expansion Premises”) of the
building located at 85 Wells Avenue, Newton, MA 02459 (the “Building”), and
commonly known as 75-95 Wells Avenue;

WHEREAS, the Expansion Premises consists of “Expansion Premises A” containing
8,468 rentable square feet and “Expansion Premises B” containing 7,766 rentable
square feet;

WHEREAS, due a scrivener’s error, the Base Rent charts for the Existing Premises
and the Expansion Premises set forth in the First Amendment incorrectly included
a reference to an Extension Lease Year 2 for the Existing Premises and a Lease
Year 8 for the Expansion Premises;

WHEREAS, Landlord and Tenant desire to amend the Lease to (i) correct the
foregoing discrepancy, (ii) to restate the Base Rent charts for the Existing
Premises and the Expansion Premises, and (iii) to confirm the Commencement Dates
and Rent Commencement Dates for the Expansion Premises, and the Extended
Termination Date of the Lease, as set forth herein; and

WHEREAS, Landlord and Tenant desire to amend Section 4.B (Landlord’s Expansion
Premises Contribution) of the First Amendment to provide for the payment of the
Allowance in four installments in lieu of the payment method provided in said
section.

NOW, THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, Landlord and Tenant agree that the Lease is hereby amended as
follows:

1. Confirmation of Dates. Landlord and Tenant hereby confirm and agree that:

(i) The Expansion Premises A Commencement Date is January 1, 2015, and the
Expansion Premises A Rent Commencement Date is May 1, 2015;

(ii) The Expansion Premises B Commencement Date is June 1, 2015, and the
Expansion Premises B Rent Commencement Date is October 1, 2015; and

(iii) The Extended Termination Date of the Lease is September 30, 2022.

 

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2. Existing Premises. Section 1A(i) of the First Amendment is hereby deleted in
its entirety, and the below-listed Base Rent chart is hereby substituted
therefor:

 

  (i) Base Rent.

 

Period

   Annual Base
Rent      Monthly
Base Rent      Per Rentable
Square Foot  

12/1/21 – 9/30/22

   $ 942,889.50 *     $ 78,574.13       $ 31.50   

 

* Annualized

3. Expansion Premises A. Section 2B(i) of the First Amendment is hereby deleted
in its entirety, and the below-listed Base Rent chart is hereby substituted
therefor:

 

  (i) Base Rent.

 

Period

   Annual Base
Rent      Monthly
Base Rent      Per Rentable
Square Foot  

1/1/15 – 4/30/15

   $ -0-       $ -0-       $ -0-   

5/1/15 – 9/30/16

   $ 241,338.00 *     $ 20,111.50       $ 28.50   

10/1/16 – 9/30/17

   $ 245,572.00       $ 20,464.33       $ 29.00   

10/1/17 – 9/30/18

   $ 249,806.00       $ 20,817.17       $ 29.50   

10/1/18 – 9/30/19

   $ 254,040.00       $ 21,170.00       $ 30.00   

10/1/19 – 9/30/20

   $ 258,274.00       $ 21,522.83       $ 30.50   

10/1/20 – 9/30/21

   $ 262,508.00       $ 21,875.67       $ 31.00   

10/1/21 – 9/30/22

   $ 266,742.00       $ 22,228.50       $ 31.50   

 

* Annualized

4. Expansion Premises B. Section 3B(i) of the First Amendment is hereby deleted
in its entirety, and the below-listed Base Rent chart is hereby substituted
therefor:

 

  (i) Base Rent.

 

Period

   Annual Base
Rent      Monthly
Base Rent      Per Rentable
Square Foot  

6/1/15 – 9/30/15

   $ -0-       $ -0-       $ -0-   

10/1/15 – 9/30/16

   $ 221,331.00       $ 18,444.25       $ 28.50   

10/1/16 – 9/30/17

   $ 225,214.00       $ 18,767.83       $ 29.00   

10/1/17 – 9/30/18

   $ 229,097.00       $ 19,091.42       $ 29.50   

10/1/18 – 9/30/19

   $ 232,980.00       $ 19,415.00       $ 30.00   

10/1/19 – 9/30/20

   $ 236,863.00       $ 19,738.58       $ 30.50   

10/1/20 – 9/30/21

   $ 240,746.00       $ 20,062.17       $ 31.00   

10/1/21 – 9/30/22

   $ 244,629.00       $ 20,385.75       $ 31.50   

 

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5. Landlord’s Expansion Premises Contribution. Notwithstanding anything set
forth in Section 4.B of the First Amendment to the contrary and provided Tenant
furnishes Landlord with the required documentation set forth in said
Section 4.B, Landlord shall disburse the Allowance of $568,190.00 to Tenant in
four (4) installments as set forth below:

 

  •   1st Installment of $148,190.00: Paid; the receipt of which is hereby
confirmed by Tenant

 

  •   2nd Installment of $140,000.00: On or before October 30, 2015

 

  •   3rd Installment of $140,000.00: On or before November 30, 2015

 

  •   4th Installment of $140,000.00: On or before December 30, 2015

Landlord hereby acknowledges that Landlord has received all documentation
required under Section 4(B) of the First Amendment for all disbursements of the
Allowance including, without limitation, the 4th Installment, which is the final
disbursement, and the installments required above shall be paid on the dates set
forth above, notwithstanding anything to the contrary contained in the Lease or
in the First Amendment

6. Miscellaneous.

A. This Second Amendment, together with 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 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 Second
Amendment.

B. Except as herein modified or amended, the provisions, conditions and terms of
the Lease shall remain unchanged and in full force and effect.

C. In the case of any inconsistency between the provisions of the Lease and this
Second Amendment, the provisions of this Second Amendment shall govern and
control.

D. Submission of this Second Amendment by Landlord is not an offer to enter into
this Second Amendment but rather is a solicitation for such an offer by Tenant.
Landlord shall not be bound by this Second Amendment until Landlord has executed
and delivered the same to Tenant.

 

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E. The capitalized terms used in this Second Amendment shall have the same
definitions as set forth in the Lease to the extent that such capitalized terms
are defined therein and not redefined in this Second Amendment.

F. Tenant hereby represents to Landlord that Tenant has dealt with no broker in
connection with this Second Amendment. Tenant agrees to indemnify and hold
Landlord, its trustees, members, principals, beneficiaries, partners, officers,
directors, employees, mortgagee(s) and agents, and the respective principals and
members of any such agents (collectively, the “Landlord Related Parties”)
harmless from all claims of any brokers claiming to have represented Tenant in
connection with this Second Amendment. Landlord hereby represents to Tenant that
Landlord has dealt with no broker in connection with this Second Amendment.
Landlord agrees to indemnify and hold Tenant, its trustees, members, principals,
beneficiaries, partners, officers, directors, employees, and agents, and the
respective principals and members of any such agents (collectively, the “Tenant
Related Parties”) harmless from all claims of any brokers claiming to have
represented Landlord in connection with this Second Amendment.

G. Each signatory of this Second 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.

H. This Second Amendment may be executed in any number of counterparts, and when
each party has signed and delivered at least one such counterpart, each
counterpart shall be considered an original, and when taken together with other
signed counterparts, shall constitute one agreement, which shall be binding upon
and effective as to all parties. Facsimile and scanned signature shall be deemed
originals for all purposes.

[Signatures on following page]

 

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EXECUTED under seal as of the date first above written.

 

LANDLORD: NS WELLS ACQUISITION LLC, a Delaware limited liability company By:  
/s/ Joseph Adamo   Name: Joseph Adamo   Title: Joseph Adamo TENANT:

KARYOPHARM THERAPEUTICS INC.

a Delaware corporation

By:   /s/ Justin A. Renz   Name: Justin A. Renz   Title: EVP, CFO & Treasurer

 

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