Expansion Option. Provided that Tenant is not in default (beyond applicable notice or cure period(s)) of its obligations under this Lease at the time Tenant makes such election or at the time that the Expansion Space (as defined below) is added to this Lease, Tenant shall have the one-time right to expand the Premises (the “Expansion Option”) to include one full contiguous floor of the Building consisting of approximately 54,090 rentable square feet (the “Expansion Space”) effective during the first Lease Year by providing prior written notice (the “Expansion Notice”) to Landlord at least six (6) months prior to the date (the “Expansion Delivery Date”) within the first Lease Year that Tenant seeks to add the Expansion Space to the Premises. Within 15 days following the delivery of the Expansion Notice, Landlord shall notify EAST\174041517.9

Expansion Premises. Commencing on the Expansion Commencement Date and continuing throughout the Expansion Term, Tenant shall pay to Landlord monthly installments of Base Rent for the Expansion Premises as follows:

Expansion Premises. Commencing on the Expansion Commencement Date, Tenant shall pay Tenant's Share of Direct Expenses in connection with the Expansion Premises in accordance with the terms of the Lease, provided that with respect to the calculation of Tenant's Share of Direct Expenses in connection with the Expansion Premises, Tenant's Share shall equal 100% of the 300 Building.

License Expansion. In the event Licensee would like to expand the license granted in this Section 2.1 beyond the Field, it shall provide Merck with a reasonably detailed development plan including evidence of existing resources and capabilities, and proposed terms relating thereto. Merck will consider any such proposed requests from Licensee in good faith.

Expansion Premises. Commencing on the Expansion Commencement Date and continuing throughout the Expansion Term, Tenant shall pay to Landlord monthly installments of Base Rent for the Expansion Premises as follows, but otherwise in accordance with the terms of the Lease:

Expansion Premises. Except as specifically set forth in this Section 5.2, commencing on the Expansion Commencement Date, Tenant shall pay Tenant's Pro Rata Share of Operating Expenses in connection with the Expansion Premises in accordance with the terms of the Lease (as amended by the last sentence of Section 7 of the Second Amendment), provided that with respect to the calculation of Tenant's Pro Rata Share of Operating Expenses in connection with the Expansion Premises, the following shall apply:

Expansion Improvements. Except as specifically set forth herein, Landlord shall not be obligated to provide or pay for any improvement work or services related to the improvement of the Expansion Premises, and Tenant shall accept the Expansion Premises in its presently existing, "as-is" condition. Notwithstanding the foregoing, Landlord shall construct the improvements in the Expansion Premises pursuant to the terms of the Tenant Work Letter and shall deliver the Expansion Premises to Tenant in good condition and in compliance with applicable laws to the extent necessary to maintain or obtain a certificate of occupancy (or its legal equivalent) for the Expansion Premises.

EXPANSION OPTION. Tenant shall have the option (the "Expansion Option") to lease Suite 150 on the first floor of the Building containing approximately 40,971 square feet of rentable area shown on Exhibit G-1 to this Lease (the "Expansion Space") if: # Landlord receives written notice (the "Expansion Notice") from Tenant of the exercise of its Expansion Option at least 18 months prior to the commencement of the term for the Expansion Space, which commencement shall be at any time after the 30th month of the initial Term; # Tenant is not in Default under the Lease beyond any applicable cure periods at the time that Landlord receives the Expansion Notice; # no part of the Premises is sublet (except pursuant to a Permitted Transfer as described in [Section 9.1(e)] hereof) at the time Landlord receives the Expansion Notice; # the Lease has not been assigned (except pursuant to a Permitted Transfer as described in [Section 9.1(e)] hereof) prior to the date that Landlord receives the Expansion Notice; and # Landlord has not delivered a First Right Notice to Tenant pursuant to Section 4, below, of this Exhibit G.

Expansion Premises. Effective as of the Expansion Commencement Date (as defined below), the Premises shall include the entire rentable area located on the 4th floor of the Building, comprising approximately 28,957 rentable square feet (the "Expansion Premises"). From and after the Expansion Commencement Date, all references in the Existing Lease to "Premises" shall mean the Existing Premises and the Expansion Premises. For the avoidance of doubt, all rights of Lessee applicable to the Premises shall apply equally to the Expansion Premises, including, without limitation, 58 (Access), 60 (Non-Disturbance) and 61 (No Relocation); provided, however, the annual original 600 HVAC after-hours usage threshold pursuant to [Section 11.3] shall now apply to the entire Premises. (For clarification purposes, an additional after-hours usage of 600 hours will not be granted.)

Expansion Premises. Effective as of Expansion Commencement Date, the Existing Lease shall be amended to provide that the Base Rent for the Expansion Premises is as follows: