FOURTH LEASE AMENDMENT TO LEASE AGREEMENT

Exhibit 10.248

FOURTH LEASE AMENDMENT TO LEASE AGREEMENT

THIS FOURTH AMENDMENT TO LEASE AGREEMENT (hereinafter referred to as the ^“ Amendment”) is made as of the      day of              2005, by and between DUKE REALTY LIMITED PARTNERSHIP , an Indiana limited partnership doing business in North Carolina as Duke Realty of Indiana Limited Partnership, successor by merger to Weeks Realty, L.P. (hereinafter referred to as “Landlord”) and PPD DEVELOPMENT LP, a Texas limited partnership and successor in interest to PPD Development, Inc. (hereinafter referred to as “Tenant”).

WITNESSETH:

WHEREAS, pursuant to a Lease Agreement dated June 26, 1998 by and between Landlord and Tenant, as amended by that certain First Lease Amendment to Lease Agreement dated October 28, 1998, and as amended by that certain Second Amendment to Lease Agreement dated October 1, 2002, and as further amended by that certain Third Lease Amendment to Lease Agreement dated September 22, 2003 (the Lease Agreement, and all amendments thereto shall be referred to herein collectively as the ^“ Lease”), Landlord leased to Tenant certain premises consisting of approximately 79,062 rentable square feet (the ^“ Original Premises”) in a building located on certain land (the ^“ Land”) which had been provided the address of 4023 Paramount Parkway, but is now known as 3900 South Paramount Parkway, Morrisville, Wake County, North Carolina 27560, all as more particularly described in the Lease; and

WHEREAS, the parties hereto desire to amend the Lease, among other things, to expand the Premises by approximately 4,657 rentable square feet in Suite 150 of the Building (the “150 Additional Space”) and provide for an additional tenant improvement allowance ; and

NOW, THEREFORE, for and in consideration of Ten Dollars ($10.00) paid by Landlord and Tenant to one another, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by Landlord and Tenant, Landlord and Tenant amend the Agreement as follows:

1. Premises and Term.

(a) Premises. Effective September 1, 2005 (the ^“ Expansion Date”), subparagraph (a) of Article 1 of the Lease is hereby amended to provide that Tenant shall lease the Original Premises and the 150 Additional Space which together shall consist of 83,719 rentable square feet of space and which space shall hereinafter collectively be referred to as the “Premises”.

(b) Term. Subparagraph (a) of Article 1 of the Lease is hereby modified to reflect that the term of the 150 Additional Space shall commence on the Expansion Date, and shall expire on November 8, 2013 (the ^“ Expansion Term”) which shall be coterminous with the existing Lease Term.

2. Base Rent, Operating Expenses and Security Deposit.

On November 8, 2008, Tenant’s Base Rent for the entire Premises shall be adjusted to the then current Market Rent (as defined in the Lease) and taking into account the readjustment of the operating expenses as set out in Paragraph 2(b) of the Second Amendment; provided, however, that in no event shall the Base Rent per square foot, as adjusted, be less than Tenant’s then current rent.”

(b) Operating Expenses. Tenant shall not be charged Operating Expenses on the 150 Additional Space for the period beginning September 1, 2005 through and including November 15, 2005; provided, however, that if any such expenses were incurred solely as a result of Tenant’s occupancy, then Tenant shall be responsible for such particular Operating Expenses. Effective on November 15, 2005, Tenant’s proportionate share of taxes and operating expenses shall be 70.3% and shall be calculated consistently with the provision of paragraph 2(b)(ii) of the Lease.

3. 150 Additional Space Improvements.

(a) Landlord shall provide Tenant with a tenant improvement allowance for the construction of the tenant improvements to the 150 Additional Space in the amount of Twelve and 00/100 Dollars ($12.00) per rentable square foot of the 150 Additional Space (the “150 Additional Space Improvement Allowance”). The 150 Additional Space Improvement Allowance shall be applied toward construction, engineering, professional, telecommunication, design, project management, plan review, permits, architecture, voice and data cabling and other costs and expenses associated with the 150 Additional Space Improvements (as hereinafter defined) to the 150 Additional Space and shall be paid by Landlord upon the receipt of proper documentation from Tenant that such work has been done. Landlord shall be responsible for the payment of all costs and expense associated with improvements to the 150 Additional Space up to the 150 Additional Space Improvement Allowance. Any cost or expense incurred by Landlord and approved by Tenant in connection with the 150 Additional Space Improvements to the 150 Additional Space in excess of the 150 Additional Space Improvement Allowance (the “Excess”) shall be borne by Tenant and shall be paid by Tenant to Landlord within thirty (30) days of Tenant’s receipt of an invoice from Landlord providing sufficient detail and documentation for such costs and expenses. Failure by Tenant to pay any portion of the Excess as aforesaid is an event of default hereunder. If the tenant has not used the 150 Additional Space Improvement Allowance within the first year of the Effective Date or the 150 Additional Space Improvement Allowance exceeds the Cost Statement (as hereinafter defined) (taking into account any increases or decreases resulting from any Change Orders), such savings shall be the property of Tenant.

(b) Following the date of this Amendment, Tenant will work with a space planner to develop a space plan for the 150 Additional Space that is reasonably acceptable to Landlord (the ^“ Space Plan”). Within thirty (30) days after Landlord’s receipt of the Space Plan, Tenant shall prepare and submit to Landlord a set of plans and specifications and/or construction drawings (the “Plans and Specifications”) prepared by an architect reasonably acceptable to Landlord covering all work to be performed by Landlord in constructing the leasehold improvements to the 150 Additional Space in accordance with the Space Plan (the ^“ 150 Additional Space Improvements”). Landlord shall participate in the design meetings with Tenant’s architect to maintain Landlord’s building standard and to provide preconstruction cost estimating. Landlord shall have ten (10) days after receipt of the Plans and Specifications in which to review the Plans and Specifications and to give Tenant written notice of Landlord’s approval of the Plans and Specifications or its requested changes to the Plans and Specifications. Tenant shall have no right to request any leasehold improvements or any changes to the Plans and Specifications that would materially alter the 150 Additional Space, the exterior appearance or basic nature of the Building, or the Building systems. If Landlord fails to approve or request changes to the Plans and Specifications within ten (10) days after its receipt of the Plans and Specifications, then Landlord shall be deemed to have approved the Plans and Specifications and the same shall thereupon be final. If Landlord requests any changes to the Plans and Specifications, Tenant shall make those changes which are reasonably requested by Landlord and shall within ten (10) business days of its receipt of such request submit the revised portion of the Plans and Specifications to Landlord. Landlord may not thereafter disapprove the revised portions of the Plans and Specifications unless Tenant has unreasonably failed to incorporate reasonable comments of Landlord and, subject to the foregoing, the Plans and Specifications, as modified by said revisions, shall be deemed to be final upon the submission of said revisions to Landlord. Landlord shall at all times in its review of the Plans and Specifications, and of any revisions thereto, act reasonably and in good faith. Landlord agrees to confirm Landlord’s consent to the Plans and Specifications in writing within three (3) business days following Tenant’s written request therefor.

(c) Following Landlord’s approval (or deemed approval) of the Plans and Specifications, Landlord shall solicit competitive bids from at least three (3) subcontractors for each major trade. Landlord shall provide Tenant with Landlord’s form for prequalifying subcontractors, attached hereto as Exhibit A and incorporated herein, and its current list of approved subcontractors for each major trade, attached hereto as Exhibit B and incorporated herein. Tenant shall have the right to provide Landlord with a proposed subcontractor for each major trade which may or may not be on Landlord’s approved list, and provided such subcontractor meets with Landlord’s reasonable approval, such subcontractor shall have the right to enter a bid. Landlord shall also obtain a description of the base warranty and any extended warranty terms relating to any equipment, machinery, trade fixtures or other personal property to be installed in connection with the 150 Additional Space Improvements. Landlord and Tenant shall review the bids and warranties, if applicable, jointly and Tenant shall select one subcontractor for each item bid. Promptly foll