FIFTH AMENDMENT TO LEASE

Exhibit 10.12

[410 W Harrison/Fifth Amendment]

FIFTH AMENDMENT TO LEASE

THIS FIFTH AMENDMENT TO LEASE (this "Fifth Amendment") is made as of ______September 8_______, 2015 by and between ARE-SEATTLE NO. 10, LLC, a Delaware limited liability company ("Landlord"), and PHASERX INC., a Delaware corporation ("Tenant").

RECITALS

A.           Landlord and Tenant entered into that certain Lease Agreement dated as of February 9, 2010, as amended by that certain First Amendment to Lease dated as of July 1, 2010, that certain Second Amendment to Lease Agreement dated as of April 4, 2011, that certain Third Amendment to Lease (“Third Amendment”) dated as of October 1, 2014, and that certain Fourth Amendment to Lease (“Fourth Amendment”) dated as of May 21, 2015 (as amended, the "Lease"). Pursuant to the Lease, Tenant leases certain premises consisting of approximately 11,291 rentable square feet ("Premises") in a building located at 410 West Harrison, Seattle, Washington. 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.

B.        The Base Term of the Lease expires on February 29, 2016.

C.           Landlord and Tenant desire, subject to the terms and conditions set forth below, to amend the Lease to, among other things, (i) extend the Base Term of the Lease for a period of 6 months to expire on August 31, 2016, and (ii) extend the date by which Tenant must give Landlord written notice of its election to exercise is Extension Right.

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:

“Tenant shall have 1 right (an “Extension Right”) to extend the term of this Lease for 5 years (an “Extension Term") on the same terms and conditions as this Lease (other than with respect to Base Rent and the Work Letter) by giving Landlord written notice of its election to exercise the Extension Right on or before February 29, 2016.”

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[410 W Harrison/Fifth Amendment]

a.           This Fifth Amendment is 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 Fifth Amendment may be amended only by an agreement in writing, signed by the parties hereto.

b.           This Fifth Amendment is binding upon and shall inure to the benefit of the parties hereto, their respective agents, employees, representatives, officers, directors, divisions, subsidiaries, affiliates, assigns, heirs, successors in interest and shareholders.

c.           Tenant acknowledges that it has read the provisions of this Fifth Amendment, understands them, and is bound by them. Time is of the essence in this Fifth Amendment.

d.           This Fifth Amendment may be executed in any number of counterparts, each of which shall be deemed an original, but all of which when taken together shall constitute one and the same instrument. The signature page of any counterpart may be detached therefrom without impairing the legal effect of the signature(s) thereon provided such signature page is attached to any other counterpart identical thereto except having additional signature pages executed by other parties to this Fifth Amendment attached thereto.

e.           Except as amended and/or modified by this Fifth 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 Fifth Amendment. In the event of any conflict between the provisions of this Fifth Amendment and the provisions of the Lease, the provisions of this Fifth Amendment shall prevail. Whether or not specifically amended by this Fifth 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 Fifth Amendment.

[Signatures are on the next page]

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[410 W Harrison/Fifth Amendment]

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

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