MARINA
BIOTECH, INC.


17870
Castleton Street, Suite 250


City
of Industry, California 91748


 


December
22, 2017


 


River
Charitable Remainder Unit Trust,


FBO
Isaac Blech, July 20, 1987,


Isaac
Blech Trustee


4
World Trade Center


150
Greenwich Street, 49th Floor


New
York, New York 10007


 


Dear
Mr. Blech:


 


Reference
is hereby made to that certain Convertible Promissory Note in the aggregate principal amount of $500,000 (the “Note”)
issued by Marina Biotech, Inc., a Delaware corporation (the “Company”), to River Charitable Remainder Unit
Trust, FBO Isaac Blech, July 20, 1987, Isaac Blech Trustee (“Holder”) on November 22, 2017 pursuant to that
certain Note Purchase Agreement dated as of November 22, 2017 by and between the Company and Holder (the “Purchase Agreement”).
Capitalized terms used but not defined herein shall have the respective meanings ascribed to such terms in the Purchase Agreement
and/or the Note, as the context requires.


 


By
executing below, Holder and the Company hereby agree to delete the first sentence of Section 2 of the Note in its entirety and
to replace such first sentence of Section 2 of the Note in its entirety with the following:


 


“Interest
on the unpaid principal amount shall accrue beginning on the issue date set forth above at a rate equal to eight percent (8%)
per annum computed on the basis of the actual number of days elapsed and a year of 365 days from the date of this Note until the
principal amount and all interest accrued thereon are paid or converted as provided in Section 3 hereof; provided, that
if the Company does not consummate the Qualified Financing on or before February 15, 2018 (which deadline may be extended by fifteen
(15) days upon mutual agreement between the Company and the placement agent with respect to the Qualified Financing), then the
interest rate shall increase to twenty percent (20%) per annum, with such increased interest rate increasing by an additional
two percent (2%) every month thereafter until this Note is repaid in full (up to a maximum interest rate of thirty percent (30%)).”


 


Except
as expressly set forth herein, all of the other terms, conditions, covenants and provisions contained in the Purchase Agreement
and the Note are, and shall continue to be, in full force and effect and are hereby ratified ad confirmed in all respects.


 






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This
letter agreement and its enforcement shall be governed by, and construed in accordance with, the laws of the State of New York,
without regard to conflicts-of-law principles.


 


This
letter agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, admissible into
evidence, and all of which together shall be deemed to be a single instrument. If any signature is delivered by facsimile transmission
or by e-mail delivery of a “.pdf” format data file, such signature shall create a valid and binding obligation of
the party executing (or on whose behalf such signature is executed) with the same force and effect as if such facsimile or “.pdf”
signature page were an original thereof.


 


[remainder
of page intentionally left blank; signature page follows]


 




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Please
acknowledge your agreement with the foregoing by signing in the space provided below.


 


	 	MARINA
    BIOTECH, INC.
	 	 	 
	 	By:	/s/
    Vuong Trieu
	 	Name:	Vuong
    Trieu
	 	Title:	Executive
    Chairman


 


AGREED
AND ACCEPTED:


 


River
Charitable Remainder Unit Trust,


FBO
Isaac Blech, July 20, 1987,


Isaac
Blech Trustee


 


	By:	/s/
    Isaac Blech	 
	Name:	Isaac
    Blech	 
	Title:	Trustee	 


 




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