Landlord's Consent to Alterations. Tenant may not make any improvements, alterations, additions or changes to the Premises or any mechanical, plumbing or HVAC facilities or systems pertaining to the Premises (collectively, the "Alterations") without first procuring the prior written consent of Landlord to such Alterations, which consent shall be requested by Tenant not less than ten (10) business days prior to the commencement thereof, and which consent shall not be unreasonably withheld by Landlord, provided it shall be deemed reasonable for Landlord to withhold its consent to any Alteration which adversely affects the structural portions or the systems or equipment of the Building or is visible from the exterior of the Building. Notwithstanding the foregoing, Tenant shall be permitted to make Alterations following ten (10) business days' notice to Landlord (as to Alterations costing more than $10,000 only), but without Landlord's prior consent, to the extent that such Alterations # do not affect the building systems or equipment (other than minor changes such as adding or relocating electrical outlets and thermostats), # are not visible from the exterior of the Building, and # cost less than $100,000.00 for a particular job of work. The construction of the Tenant Improvements to the Premises shall be governed by the terms of the Tenant Work Letter and not the terms of this Article 8.

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.

Except as expressly provided in this Lease or by applicable laws or regulations, the Tenant may not alter or make repairs to the Premises without the Landlord’s prior written consent. Unless otherwise set forth in this Lease, any authorized alterations or repairs, including any fixtures installed as a part of such alterations or reparations, will, at the Landlord’s option and in the Landlord’s sole discretion, become the Landlord’s property upon the expiration or termination of this Lease; provided, however, that the Landlord may require the Tenant to remove any such fixtures at the Tenant’s cost on the termination or expiration of this Lease. The Tenant shall perform all authorized alterations or reparations to the Premises diligently in a good and workmanlike manner, and in compliance with all applicable laws, ordinances, regulations and rules of any public or private authority having jurisdiction over the Premises. The Tenant shall keep the Premises free of all claims for labor performed on and material delivered to the Premises.

Improvements. Subtenant shall use the Subleased Premises in its current configuration as of the Commencement Date, and shall not have the right to make any substantial alterations or improvements to the Subleased Premises without Sublandlord’s prior written consent. To the extent Sublandlord permits any such alterations or improvements, such alterations shall be in accordance with the Master Lease, and shall be made only with the prior written consent of both Master Landlord and Sublandlord. Notwithstanding the foregoing, subject to Master Landlord’s consent and Sublandlord’s review of final detailed plans, Subtenant may perform (in compliance with the terms of Section 8 of the Master Lease, as incorporated herein) and surrender at the end of the Term, the alterations described in Exhibit D hereto, at Subtenant’s sole cost and expense.

Landlord’s Authorized Representative. Landlord designates, as Landlord’s authorized representative (“Landlord’s Authorized Representative”), Maureen McCaffrey as the individual authorized by Landlord to approve on behalf of Landlord all plans, drawings and other matters for which the approval of Landlord is required or contemplated pursuant to this ES Work Letter. Tenant shall not be obligated to respond to or act upon any such item until such item has been initialed or signed or submitted in writing (as applicable) by Landlord’s Authorized Representative. Landlord may change Landlord’s Authorized Representative and/or name additional persons to serve as Landlord’s Authorized Representative (provided that Tenant may rely upon the authorization of any one of such persons) upon one (1) business day’s prior written notice to Tenant. Landlord agrees that Landlord’s Authorized Representative(s) shall be reasonably available to meet and consult with Tenant’s Authorized Representative in person (in the vicinity of the Property) or by phone (at the election of Tenant’s Authorized Representative) upon reasonable prior notice by Tenant.

Third Floor Alterations. Tenant has advised Landlord that Tenant desires to perform certain alterations to the Third Floor Additional Premises prior to commencing business therein, other than the work required by this Amendment to be performed by Landlord (the “Third Floor Alterations”). Prior to commencing construction of the Third Floor Alterations, Tenant shall furnish to Landlord, for Landlord’s reasonable approval, working drawings that # show the lay-out of the alterations and finishes, # separately note any proposed structural work or extraordinary electrical, plumbing or HVAC requirements, # conform to Landlord’s base building requirements and construction requirements then applicable to the Building (the “Condition of Construction”) and applicable building codes and other local, state or federal law, ordinance, rule, regulation, code, or order of any governmental entity or insurance requirements (collectively, “Legal Requirements”), and # are in sufficient detail as to enable the selected contractor to obtain all necessary governmental permits for commencement of the Third Floor Alterations and to secure complete bids from qualified contractors to perform the work. (Landlord will, at Tenant’s request, review any interim space plans, prior to Tenant’s completion of the aforementioned working drawings.) The working drawings, as approved in writing by Tenant and Landlord, are hereinafter called the “Final Plans.” Any subsequent revisions to the Final Plans shall be subject to Landlord’s prior written approval, which approval shall not be unreasonably withheld.

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.”