Amendment, dated January 31, 2020, to Lease Agreement, dated as of November 16, 2006, by and between the Registrant and ARE-480 Arsenal Street, LLC, as amended

EXHIBIT 10.20

NINTH AMENDMENT TO LEASE

THIS NINTH AMENDMENT TO LEASE (this “Ninth Amendment”) is made as of January 31, 2020 by and between ARE-480 ARSENAL STREET, LLC, a Delaware limited liability company (“Landlord”), and TETRAPHASE PHARMACEUTICALS, INC., a Delaware corporation (“Tenant”).

RECITALS

ALandlord and Tenant are parties to that certain Lease Agreement dated as of November 16, 2006, as amended by that certain First Amendment to Lease dated as of September 9, 2011, as further amended by that certain Second Amendment to Lease dated as of March 15, 2012, as further amended by that certain Third Amendment to Lease dated as of September 18, 2012, as further amended by that certain Fourth Amendment to Lease dated as of November 20, 2013, as further amended by that certain Fifth Amendment to Lease dated as of September 4, 2014, as further amended by that certain Sixth Amendment to Lease dated as of March 24, 2015, as further amended by that certain Seventh Amendment to Lease dated as of June 18, 2015, and as further amended by that certain Eighth Amendment to Lease dated as of November 29, 2018 (as amended, the “Lease”) Pursuant to the Lease, Tenant leases certain premises containing approximately 37,438 rentable square feet (the “Premises”) in a building located at 480 Arsenal Street, Watertown, Massachusetts (“Building”) The Premises are more particularly described In the Lease. Capitalized terms used herein without definition shall have the meanings defined for such terms in the Lease.

BLandlord and Tenant desire, subject to the terms and cond1t1ons set forth below, to, among other things, reflect the surrender of a portion of the Premises consisting of approximately 15,899 rentable square feet of the Project, as more particularly shown on Exhibit A attached hereto (the “Surrender Premises”) as of 11:59 p.m. on January 31, 2020 (the “Surrender Date”).

NOW, THEREFORE, in consideration of the foregoing Recitals, which are incorporated herein by this reference, the mutual promises and conditions contained herein, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Landlord and Tenant hereby agree as follows:

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“Premises: That certain portion of the Building, containing approximately 21,539 rentable square feet, consisting of: (i) approximately 13,711 rentable square feet (the “Second Expansion Premises”), and (ii) approximately 7,828 rentable square feet (the “Third Expansion Premises”), all as shown on Exhibit A.”

“Rentable Area of Premises: 21,539 sq ft.”

Commencing on February 1, 2020, Exhibit A of the Lease shall be amended to delete the Surrender Premises.

“Tenant’s Share of Operating Expenses: 15.30%”

a.This Ninth Amendment 1s the entire agreement between the parties with respect to the subject matter hereof and supersedes all prior and contemporaneous oral and written agreements and discussions This Ninth Amendment may be amended only by an agreement in writing, signed by the parties hereto.

b.Landlord and Tenant each represents and warrants that it has not dealt with any broker, agent or other person (collectively, “Broker”) in connection with the transaction reflected in this Ninth Amendment and that no Broker brought about this transaction Landlord and Tenant each hereby agree to indemnify and hold the other harmless from and against any claims by any Broker claiming a commission or other form of compensation by virtue of having dealt with Tenant or Landlord, as applicable, with regard to this leasing transaction.

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c.This Ninth Amendment is binding upon and shall inure to the benefit of the parties hereto, and their respective successors and assigns.

d.This Ninth Amendment may be executed in 2 or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument Counterparts may be delivered via facsimile, electronic mall (including pdf or any electronic signature process complying with the U.S. federal ESIGN Act of 2000) or other transmission method and any counterpart so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes Electronic signatures shall be deemed original signatures for purposes of this Ninth Amendment and all matters related thereto, with such electronic signatures having the same legal effect as original signatures.

e.Except as amended and/or modified by this Ninth Amendment, the Lease is hereby ratified and confirmed and all other terms of the Lease shall remain in full force and effect, unaltered and unchanged by this Ninth Amendment in the event of any conflict between the provisions of this Ninth Amendment and the provisions of the Lease, the prov1s1ons of this Ninth Amendment shall prevail whether or not specifically amended by this Ninth Amendment, all of the terms and provisions of the Lease are hereby amended to the extent necessary to give effect to the purpose and Intent of this Ninth Amendment.

[Signatures are on the next page]

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IN WITNESS WHEREOF, the parties hereto have executed this Ninth Amendment as of the day and year first above written.

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