Exhibit 10.259

SECOND AMENDMENT TO LEASE

THIS SECOND AMENDMENT TO LEASE(this Amendment) is
made and entered into as of November 5, 2007, by and between BRANDYWINE GRANDE C, L.P., a Delaware limited partnership (Landlord), and PPD DEVELOPMENT, LP, a Texas limited partnership
(Tenant).

A. Landlord and Tenant, as successor-in-interest to PPD Development, LLC, are parties to a certain Lease (as
amended, the Lease) dated as of July 1, 2001, as amended by a First Amendment to Lease dated as of March 9, 2007, for approximately 81,710 rentable square feet of space (the Original Premises) at
2240-2246 Dabney Road, Richmond, Virginia 23230, as more particularly described in the Lease.

B. Tenant desires to lease from Landlord,
and Landlord desires to lease to Tenant, certain additional premises known as Suites B and L (the Suites B and L Premises) in the Dabney IX building located at 2248 Dabney Road, Richmond, Virginia 23230 (the Dabney IX
Building), which additional premises are shown on the location plan attached hereto as Exhibit A. The parties hereby confirm that the Suites B and L Premises are 3,714 rentable square feet of space in the aggregate.

C. The portion of the Suites B and L Premises comprising Suite B contains 2,134 rentable square feet and is referred to herein as Suite
B. The portion of the Suites B and L Premises comprising Suite L contains 1,580 rentable square feet and is referred to herein as Suite L.

D. Landlord and Tenant wish to amend the Lease to, among other things, expand the Original Premises to include the Suites B and L Premises upon the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the mutual covenants and agreements contained herein, Landlord and Tenant hereby agree as follows:

1. Incorporation of Recitals; Definitions. The recitals set forth above are hereby incorporated herein by reference as if set forth in full in the
body of this Amendment. Capitalized terms used but not otherwise defined in this Amendment shall have the respective meanings given to them in the Lease.

2. Premises.

(a) Effective on the Suite B Commencement Date (as defined in Section 3(a)
below), as used in the Lease: (i) Premises shall mean, collectively, the Original Premises and Suite B; (ii) Tenants Allocated Share with respect to the Dabney IX Building shall mean 7.07%;
(iii) Buildings shall mean collectively the Dabney A-1 Building, the Dabney A-2 Building, the Dabney VII Building, and the Dabney IX Building; (iv) Project shall mean the Buildings, the land and all
other improvements located at 2240-2248 Dabney Road, Richmond, Virginia 23230; and (v) Rentable Area with respect to the Premises shall mean 83,844, and with respect to the Project shall mean 111,894.

(b) Effective on the Suite L Commencement Date (as defined in Section 3(b) below), as used in the Lease: (i) Premises
shall mean, collectively, the Original Premises and Suite L; (ii) Tenants Allocated Share with respect to the Dabney IX Building shall mean 5.23%; (iii) Buildings shall mean collectively the
Dabney A-1 Building, the Dabney A-2 Building, the Dabney VII Building, and the Dabney IX Building; (iv) Project shall mean the Buildings, the land and all other improvements located at 2240-2248 Dabney Road, Richmond,
Virginia 23230; and (v) Rentable Area with respect to the Premises shall mean 83,290, and with respect to the Project shall mean 111,894.

(c) Notwithstanding the foregoing, effective on the later of the Suite B Commencement Date and the Suite L Commencement Date, as used in the Lease: (i) Premises shall mean, collectively, the
Original Premises, Suite L, and Suite B; (ii) Tenants Allocated Share with respect to the Dabney IX Building shall mean 12.30%; (iii) Buildings shall mean collectively the Dabney A-1 Building,
the Dabney A-2 Building, the Dabney VII Building, and the Dabney IX Building; (iv) Project shall mean the Buildings, the land and all other improvements located at 2240-2248 Dabney Road, Richmond, Virginia 23230; and
(v) Rentable Area with respect to the Premises shall mean 85,424, and with respect to the Project shall mean 111,894.



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(d) Tenant acknowledges and agrees that, notwithstanding any provision of the Lease to the contrary,
Landlord shall have no obligation to make any improvements to the Suites B and L Premises in connection with this Amendment, and Tenant accepts them in their current AS IS condition.

3. Term.

(a) The Term for Suite B
shall commence on the date Landlord delivers possession of the Suite B to Tenant (the Suite B Commencement Date); provided if Landlord is unable to deliver possession of Suite B to Tenant on any particular date for any reason,
including without limitation the holdover of the current tenant, the Lease as amended hereby shall continue in effect and Landlord shall not be liable to Tenant or any third party for such inability. The Suite B Commencement Date and expiration date
of the Term shall be confirmed by Landlord and Tenant by the execution of a Confirmation of Lease Term (the COLT) in the form attached hereto as Exhibit B. If Tenant fails to execute or object to the COLT within ten
(10) business days of its delivery, Landlords determination of such dates shall be deemed accepted.

(b) The Term for Suite L
shall commence on the date Landlord executes this Amendment and delivers possession of Suite L to Tenant (the Suite L Commencement Date). The Suite L Commencement Date and expiration date of the Term shall be confirmed by Landlord
and Tenant by the execution of a Confirmation of Lease Term (the COLT) in the form attached hereto as Exhibit B. If Tenant fails to execute or object to the COLT within ten (10) business days of its delivery,
Landlords determination of such dates shall be deemed accepted.

(c) The Term for the Premises (collectively, the Original Premises
and the Suites B and L Premises) shall terminate on June 30, 2015.

4. Fixed Rent. Fixed Rent for Suite B is set forth below,
payable in the monthly installments as set forth below and otherwise in accordance with the terms of the Lease, as amended hereby:



|                                    |  |                      |         
|----------------------------------- |  | -------------------- | --------
|TIME PERIOD                         |  | MONTHLY INSTALLMENTS
|Suite B Commencement Date - 6/30/08 |  | $                    | 1,155.92
|7/1/08 - 6/30/09                    |  | $                    | 1,184.37
|7/1/09 - 6/30/10                    |  | $                    | 1,214.60
|7/1/10 - 6/30/11                    |  | $                    | 1,244.83
|7/1/11 - 6/30/12                    |  | $                    | 1,276.84
|7/1/12 - 6/30/13                    |  | $                    | 1,308.85
|7/1/13 - 6/30/14                    |  | $                    | 1,340.86
|7/1/14 - 6/30/15                    |  | $                    | 1,374.65



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Fixed Rent for Suite L is set forth below, payable in the monthly installments as set forth below and otherwise in
accordance with the terms of the Lease, as amended hereby:



|                                    |  |                      |         
|----------------------------------- |  | -------------------- | --------
|TIME PERIOD                         |  | MONTHLY INSTALLMENTS
|Suite L Commencement Date - 6/30/08 |  | $                    | 855.83  
|7/1/08 - 6/30/09                    |  | $                    | 876.90  
|7/1/09 - 6/30/10                    |  | $                    | 899.28  
|7/1/10 - 6/30/11                    |  | $                    | 921.67  
|7/1/11 - 6/30/12                    |  | $                    | 945.37  
|7/1/12 - 6/30/13                    |  | $                    | 969.07  
|7/1/13 - 6/30/14                    |  | $                    | 992.76  
|7/1/14 - 6/30/15                    |  | $                    | 1,017.78

Fixed Rent shall be payable by: (i) check to Landlord at P.O. Box 8538-363, Philadelphia, PA 19171; or
(ii) wire transfer of immediately available funds to the account at Wachovia Bank, NA, at Philadelphia, PA, account no. 2030000359075, ABA wire routing number 031201467 (ACH ARA routing number 031000503), or as otherwise directed in writing by
Landlord to Tenant.

5. Landlords Notice Address. Landlords Notice Address/Contact set forth in
Section 1(k) of the Lease is hereby deleted in its entirety and replaced with the following in lieu thereof:



|          |  |                                |  |                                        
|--------- |  | ------------------------------ |  | ---------------------------------------
|Landlord: |  | Brandywine Grande C, L.P.      |  | With a copy to:                        
|          |  | c/o Brandywine Realty Trust    |  | Brandywine Realty Trust                
|          |  | 300 Arboretum Place, Suite 330 |  | 555 East Lancaster Ave., Suite 100     
|          |  | Richmond, VA 23236             |  | Radnor, PA 19087                       
|          |  | Attn: William D. Redd          |  | Attn: Brad A. Molotsky, General Counsel

6. Brokerage Commission. Landlord and Tenant each represents and warrants to the other that
such party has had no dealings, negotiations or consultations with respect to the Premises or this transaction with any broker or finder. Each party shall indemnify and hold the other harmless from and against all liability, cost and expense,
including attorneys fees and court costs, arising out of any misrepresentation or breach of warranty under this Section.

7.
OFAC. Tenant represents, warrants and covenants that neither Tenant nor any of its partners, officers, directors, members or shareholders: (i) is listed on the Specially Designated Nationals and Blocked Persons List maintained by the
Office of Foreign Asset Control, Department of the Treasury (OFAC) pursuant to Executive Order No. 13224, 66 Fed. Reg. 49079 (Sept. 25, 2001) (Order) and all applicable provisions of Title III of the USA
Patriot Act (Public Law No. 107-56 (October 26, 2001)); (ii) is listed on the Denied Persons List and Entity List maintained by the United States Department of Commerce; (iii) is listed on the List of Terrorists and List of Disbarred
Parties maintained by the United States Department of State; (iv) is listed on any list or qualification of Designated Nationals as defined in the Cuban Assets Control Regulations 31 C.F.R. Part 515; (v) is listed on any other
publicly available list of terrorists, terrorist organizations or narcotics traffickers maintained by the United States Department of State, the United States Department of Commerce or any other governmental authority or pursuant to the Order, the
rules and regulations of OFAC (including without limitation the Trading with the Enemy Act, 50 U.S.C. App. 1-44; the International Emergency Economic Powers Act, 50 U.S.C. §§ 1701-06; the unrepealed provision of the Iraq Sanctions Act,
Publ.L. No. 101-513; the United Nations Participation Act, 22 U.S.C. § 2349 as-9; The Cuban Democracy Act, 22 U.S.C. §§ 6001-10; The Cuban Liberty and Democratic Solidarity Act, 18 U.S.C. §§ 2332d and 233; and The
Foreign Narcotic Kingpin Designation Act, Publ. L. No. 106-120 and 107-108, all as may be amended from time to time); or any other applicable requirements contained in any enabling legislation or other Executive Orders in respect of the Order
(the Order and such other rules, regulations, legislation or orders are collectively called the Orders); (vi) is engaged in



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activities prohibited in the Orders; or (vii) has been convicted, pleaded nolo contendere, indicted, arraigned or custodially detained on charges
involving money laundering or predicate crimes to money laundering, drug trafficking, terrorist-related activities or other money laundering predicate crimes or in connection with the Bank Secrecy Act (31 U.S.C. §§ 5311 et seq.). Tenant
shall defend, indemnify, and hold harmless Landlord from and against any and all claims, damages, losses, risks, liabilities, and expenses (including attorney's fees and costs) arising from or related to any breach of the foregoing representation,
warranty and covenant. The breach of this representation, warranty and covenant by Tenant shall be an immediate Event of Default under this Lease without cure.

8. Effect of Amendment; Ratification. Landlord and Tenant hereby acknowledge and agree that, except as provided in this Amendment, the Lease has not been modified, amended, canceled, terminated, released,
superseded or otherwise rendered of no force or effect. The Lease as hereby amended is hereby ratified and confirmed by the parties hereto, and every provision, covenant, condition, obligation, right, term and power contained in and under the Lease,
as amended herein, shall continue in full force and effect, affected by this Amendment only to the extent of the amendments and modifications set forth above, and each shall continue to be binding upon and inure to the benefit of the heirs,
executors, administrators, successors and assigns of each party hereto.

9. Authority. Each of Landlord and Tenant represents and
warrants to the other that the individual executing this Amendment on such partys behalf is authorized to do so.

[SIGNATURES ON
FOLLOWING PAGE]



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



|                          |  |  |  |                           |  |                                
|------------------------- |  |  |  | ------------------------- |  | -------------------------------
|WITNESS:                  |  |  |  | LANDLORD:                
|                          |  |  |  | BRANDYWINE GRANDE C, L.P.
|                          |  |  | 
|                          |  |  |  | By:                       |  | Brandywine Grande C Corp.,     
|                          |  |  |  |                           |  | its general partner            
|                          |  |  | 
|/s/ Bridget Shannon       |  |  |  | By:                       |  | /s/ K. Suzanne Stumpl          
|Bridget Shannon           |  |  |  | Name:                     |  | K. Suzanne Stumpl              
|Regional Accountant       |  |  |  | Title:                    |  | Vice President Asset Management
|                          |  |  |  | Date:                     |  | January 10, 2008               
|                          |  | 
|WITNESS:                  |  |  |  | TENANT:                  
|                          |  |  |  | PPD DEVELOPMENT, LP      
|                          |  |  | 
|/s/ Chuck Munn            |  |  |  | By:                       |  | /s/ William J. Sharbaugh       
|Chuck Munn                |  |  |  | Name:                     |  | William J. Sharbaugh           
|Assistant General Counsel |  |  |  | Title:                    |  | Chief Operating Officer        
|                          |  |  |  | Date:                     |  | February 19, 2008              



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