Tenant shall be solely responsible for the payment of any and all taxes levied upon # personal property and trade fixtures located at the Premises and # any gross or net receipts of or sales by Tenant, and shall pay the same at least twenty (20) days prior to delinquency.

Tenant shall make no alterations, additions or improvements, other than the Tenant Improvements (which shall be subject to the Work Letter and not this Article 17, other than as expressly set forth in Section 17.7, 17.8, 17.9 and 17.12 below), in or to the Premises or engage in any construction, demolition, reconstruction, renovation or other work (whether major or minor) of any kind in, at or serving the Premises (“Alterations”) without Landlord’s prior written approval, which approval may be subject to the consent of one or more Lenders, if required under any applicable Loan Document, but which approval Landlord shall not otherwise unreasonably withhold, condition or delay; provided, however, that, in the event any proposed Alteration affects # any structural portions of the Building, including exterior walls, the roof, the foundation or slab, foundation or slab systems (including barriers and subslab systems) or the core of the Building, # the exterior of the Building or # any Building systems, including elevator, plumbing, HVAC, electrical, security, life safety and power, then Landlord may withhold its approval in its sole and absolute discretion. Tenant shall, in making any Alterations, use only those architects, contractors, suppliers and mechanics of which Landlord has given prior written approval, which approval shall not be unreasonably withheld, conditioned or delayed. In seeking Landlord’s approval, Tenant shall prepare and provide to Landlord for approval schematics and a general plan covering the Alterations (the “Draft Development Plans”), which shall contain sufficient information and detail concerning the nature and cost of such Alterations as Landlord may reasonably request; provided that Tenant shall not commence any such Alterations that require Landlord’s consent unless and until Tenant has received the written approval of Landlord and any and all Lenders whose consent is required under any applicable Loan Document. Landlord shall notify Tenant in writing within seven (7) business days after receipt of the Draft Development Plans whether Landlord approves or objects to the Draft Development Plans and of the manner, if any, in which the Draft Development Plans are unacceptable. Landlord’s failure to respond within such seven (7) business day period shall be deemed an approval by Landlord. If Landlord reasonably objects to the Draft Development Plans, then Tenant shall not proceed with the proposed Alterations unless Tenant revises the Draft Development Plans and causes Landlord’s objections to be remedied in the revised Draft Development Plans. Tenant shall then resubmit the revised Draft Development Plans to Landlord for approval. Landlord’s approval of or objection to revised Draft Development Plans and Tenant’s correction of the same shall be in accordance with this Section until Landlord has approved the Draft Development Plans in writing or been deemed to have approved them. The iteration of the Draft Development Plans that is approved or deemed approved by Landlord without objection shall be referred to herein as the “Approved Development Plans.” Tenant shall not proceed with the proposed Alteration unless Tenant then prepares final plans and specifications for the Alteration that are consistent with and are logical evolutions of the Approved Development Plans, including, without limitation, plans, specifications, bid proposals, certified stamped engineering drawings and calculations by Tenant’s engineer of record or architect of record (including connections to the Building’s structural system, modifications to the Building’s envelope, non-structural penetrations in slabs or walls, and modifications or tie-ins to life safety systems), work contracts, requests for laydown areas and such other information concerning the nature and cost of the Alterations as Landlord may reasonably request,. As soon as such final plans and specifications (“Alteration Plans”) are completed, Tenant shall deliver the same to Landlord for Landlord’s approval, which approval shall not be unreasonably withheld, conditioned or delayed; provided that Tenant shall not commence any such Alterations that require Landlord’s consent unless and until Tenant has received the written approval of Landlord of the Alteration Plans and any and all Lenders whose consent is required under any applicable Loan Document. In no event shall Tenant use or Landlord be required to approve any architects, consultants, contractors, subcontractors or material suppliers that Landlord reasonably believes could cause labor disharmony or may not have sufficient experience, in Landlord’s reasonable opinion, to perform work in an occupied Class “A” laboratory research building and in tenant-occupied lab areas.

Alterations. Other than any alterations which constitute the Project, ​’s prior approval shall be required in connection with any alterations to any Improvements # that could reasonably be expected to have a Material Adverse Effect, # the cost of which (including any related alteration, improvement or replacement) is reasonably anticipated to exceed the Alteration Threshold, # that are structural in nature, which approval may be granted or withheld in ​’s reasonable discretion, or # made during the continuance of an Event of Default (any of the foregoing, a “Material Alteration”). If the total unpaid amounts incurred and to be incurred with respect to any alterations to the Improvements from and after Completion of the Project shall at any time exceed the Alteration Threshold (unless the cost of such Material Alteration is eligible for disbursement from the Replacement Reserve Account, in which case ​ shall be given a credit for amounts on deposit in the Replacement Reserve Account), ​ shall promptly deliver to ​ as security for the payment of such amounts and as additional security for ​’s obligations under the Loan Documents any of the following: # cash, # a Letter of Credit acceptable to ​, # securities acceptable to ​, or # a completion bond acceptable to ​. Such security shall be in an amount equal to one hundred twenty-five percent (125%) of the excess of the total unpaid amounts incurred and to be incurred with respect to such alterations to the Improvements over the Alteration Threshold (such security, the “Alterations Security”). Upon substantial completion of any Material Alteration, # ​ shall provide evidence satisfactory to ​ that # the Material Alteration was constructed in accordance with applicable Legal Requirements, # all contractors, subcontractors, materialmen and professionals who provided work, materials or services in connection with the Material Alteration have been paid in full and have delivered unconditional releases of liens, and # all material licenses and permits necessary for the use, operation and occupancy of the Material Alteration (other than those which depend on the performance of tenant improvement work) have been issued and # provided no Event of Default is then continuing, any remaining Alterations Security shall be promptly returned to ​. Prior to substantial completion of any Material Alteration, to the extent the Alterations Security shall exceed one hundred twenty-five percent (125%) of the excess of the total unpaid amounts incurred and to be incurred with respect to any such Material Alteration, ​ shall be entitled to a release of such excess Alterations Security (e.g., the amount by which such Alterations Security exceeds one hundred twenty-five percent (125%) of the excess of the total unpaid amounts incurred and to be incurred with respect to any such Material Alteration) in accordance with [Section 7.4.2] hereof, applied mutatis mutandis.

ALTERATIONS. LESSEE parties shall not make structural alterations, additions, or improvements of any kind to the premises, but LESSEE may make nonstructural alterations, additions, or improvements with LESSOR’S prior written consent fallowed alterations”). All allowed alterations shall be at LESSEE’S expense and shall conform with LESSOR’S building standards and construction specifications or will be subject to restoration charges, If LESSOR or its agents provide(s) any services or maintenance in connection with allowed alterations and/or the review thereof, LESSEE will promptly pay any just invoice(s). LESSEE shall obtain, prior to the commencement of any work, a lien waiver from any contractor(s) performing work at the premises. LESSEE shall not permit mechanics’ liens or similar liens to remain upon the premises in connection with any work performed or claimed to have been performed at the direction of LESSEE and shall cause any such lien to be released or removed forthwith without cost to LESSOR. All allowed alterations shall become part of the premises and the property of LESSOR. LESSOR shall have the right at any time to make additions to the building, to change the arrangement of parking areas, stairs, or walkways, or otherwise to alter common areas or the exterior of the building. LESSEE shall move its furniture, furnishings, equipment, inventory, and other property as required by LESSOR to enable LESSOR to carry out the above-described work.

None of the Borrowers shall alter or cause or permit the alteration of any Improvements at any Property without the Agent’s prior Approval; provided, however, that if no Default has occurred and remains outstanding and if no Event of Default has occurred, such Approval shall not be unreasonably withheld, conditioned or delayed in connection with any alteration that # is not reasonably likely to result in a Material Adverse Change or an adverse effect of a material nature on the Net Cash Flow from the relevant Property, # complies with all Legal Requirements, including without limitation, Legal Requirements regarding environmental matters, landmarks and zoning, # is not reasonably likely to affect any structural component of the Improvements or the exterior of any building constituting a part of any Improvements or materially affect any utility or HVAC system contained in any Improvements, # have an aggregate cost, for all alterations pending or being actively pursued in respect of a Property at any time, of less than SEVEN HUNDRED FIFTY THOUSAND DOLLARS AND ZERO CENTS ($750,000.00) and # have an aggregate cost, with respect to all the Properties undergoing alterations at any time, of less than five percent (5%) of the Outstanding Principal Balance (each of clauses (D) and (E), a “Major Alteration Threshold”). For the avoidance of doubt, the Agent may require that the Borrowers deliver additional security to the Agent for the Borrowers’ obligations under the Loan Documents as a condition to the Agent’s approval of any alteration that would exceed either Major Alteration Threshold.

Alterations and Tenant’s Property. Any alterations, additions, or improvements made to the Premises by or on behalf of Tenant, including additional locks or bolts of any kind or nature upon any doors or windows in the Premises, but excluding installation, removal or realignment of furniture systems (other than removal of furniture systems owned or paid for by Landlord) not involving any modifications to the structure or connections (other than by ordinary plugs or jacks) to Building Systems (as defined in Section 13) (“Alterations”) shall be subject to Landlord’s prior written consent, which may be given or withheld in Landlord’s sole discretion if any such Alteration affects the structure or Building Systems and shall not be otherwise be unreasonably withheld, conditioned or delayed. Tenant may construct nonstructural Alterations in the Premises without Landlord’s prior approval if the aggregate cost of all such work in any 12 month period does not exceed $25,000.00 (a “Notice-Only Alteration”), provided Tenant notifies Landlord in writing of such intended Notice-Only Alteration, and such notice shall be accompanied by plans, specifications, work contracts and such other information concerning the nature and cost of the Notice-Only Alteration as may be reasonably requested by Landlord, which notice and accompanying materials shall be delivered to Landlord not less than 15 business days in advance of any proposed construction. If Landlord approves any Alterations, Landlord may impose such reasonable conditions on Tenant in connection with the commencement, performance and completion of such Alterations as Landlord may deem appropriate in Landlord’s reasonable discretion. Any request for approval of an Alteration shall be in writing, delivered not less than 15 business days in advance of any proposed construction, and accompanied by plans, specifications, bid proposals, work contracts and such other information concerning the nature and cost of the alterations as may be reasonably requested by Landlord, including the identities and mailing addresses of all persons performing work or supplying materials. Landlord’s right to review plans and specifications and to monitor construction shall be solely for its own benefit, and Landlord shall have no duty to ensure that such plans and specifications or construction comply with applicable Legal Requirements. Tenant shall cause, at its sole cost and expense, all Alterations to comply with insurance requirements and with Legal Requirements and shall implement at its sole cost and expense any alteration or modification required by Legal Requirements as a result of any Alterations. Tenant shall pay to Landlord, as Additional Rent, on demand an amount equal to 3% of all charges incurred by Tenant or its contractors or agents in connection with any Alteration costing in excess of $50,000 to cover Landlord’s overhead and expenses for plan review, coordination, scheduling and supervision. Before Tenant begins any Alteration, Landlord may post on and about the Premises notices of non-responsibility pursuant to applicable law. Tenant shall reimburse Landlord for, and indemnify and hold Landlord harmless from, any expense incurred by Landlord by reason of faulty work done by Tenant or its contractors, delays caused by such work, or inadequate cleanup.

Halt any Tenant Improvements and Alterations and order Tenant’s contractors, subcontractors, consultants, designers and material suppliers to stop work;

Tenant Improvements, Alterations and Personal Property. In the event of any damage or destruction of the Premises or the Building, under no circumstances shall Landlord be required to repair any injury or damage to, or make any repairs to or replacements of, Tenant Improvements, Alterations or Tenant’s equipment, furniture, furnishings, trade fixtures or personal property.

Minor Alterations. Notwithstanding the foregoing, Landlord’s consent shall not be required for any Minor Alterations (as defined below), provided that Tenant shall provide Landlord at least ten (10) days’ notice prior to commencing such Minor Alterations, and such Minor Alterations shall otherwise comply with the provisions of this Paragraph 12. As used herein, a “Minor Alteration” is any Alteration that satisfies all of the following criteria: # is not visible from the exterior of the Premises or Building; # will not affect the Base Building Systems or structural portions of the Building (including exterior walls and shear walls); and # does not cost more than One Hundred Thousand Dollars ($100,000) per project.

Fourteenth Floor Alterations. If Tenant desires to perform alterations to the Fourteenth Floor Additional Premises (the “Fourteenth Floor Alterations”). the provisions of Paragraph 1.b.ii. above, regarding the construction of the Third Floor Alterations in the Third Floor Additional Premises, shall apply thereto with references therein to the “Third Floor Additional Premises” and the “Third Floor Alterations” being deemed, for purposes of this paragraph, to refer, respectively, to the “Fourteenth Floor Additional Premises” and the “Fourteenth Floor Alterations.”