EXHIBIT 10
NON-NEGOTIABLE PROMISSORY NOTE
July 29, 2016
$20,000,000
                                                                                                                     Rockville,
Maryland
FOR VALUE RECEIVED, Emergent BioSolutions Inc., a Delaware corporation
("Maker"), promises to pay to Aptevo Therapeutics Inc., a Delaware corporation
("Holder"), by wire transfer of immediately available funds to an account
designated in writing by Holder at least two Business Days prior to the Payment
Date (as defined below), the principal sum of $20,000,000, payable on the
Payment Date.  "Payment Date"  means a date specified in a written notice
delivered by Holder to Maker that is (a) at least 60 days after the date of
delivery of such written notice and (b) between the date that is six (6) months
after the Distribution Date and the first (1st) anniversary of the Distribution
Date.  Capitalized terms used herein and not otherwise defined herein shall have
the respective meanings ascribed to such terms in the Separation Agreement (as
defined below).
No interest shall accrue on this Note.
This Note shall become immediately due and payable without notice or demand upon
the occurrence at any time of any of the following events of default
(individually, "an Event of Default" and collectively, "Events of Default"):
(1)
default in the payment when due of any amounts owing under this Note which
default continues for a period of three (3) Business Days;

(2)
the liquidation or dissolution of Maker;

(3)
the institution against Maker of any proceedings under the United States
Bankruptcy Code or any other federal or state bankruptcy, reorganization,
receivership, insolvency or other similar law affecting the rights of creditors
generally, which proceeding is not dismissed within 90 days of filing; or

(4)
the institution by Maker of any proceedings under the United States Bankruptcy
Code or any other federal or state bankruptcy, reorganization, receivership,
insolvency or other similar law affecting the rights of creditors generally or
the making by Maker of a composition or an assignment or trust mortgage for the
benefit of creditors.

This Note may be prepaid in whole or in part at any time or from time to time. 
Any such prepayment shall be without premium or penalty.
The provisions of Article VIII and Article XI (except Section 11.3) of the
Separation and Distribution Agreement entered into or to be entered into between
Maker and Holder (the "Separation Agreement") are incorporated herein by this
reference, as if set forth in full herein, mutatis mutandis.  This Note
constitutes an Ancillary Agreement, and the remedies expressly set forth in the
Separation Agreement shall be the sole and exclusive remedies of the parties
with respect to this Note.  If the Distribution Date does not occur by December
31, 2016, this Note shall be null and void ab initio.
Holder may not assign or transfer this Note (or any interest herein).  Subject
to the preceding sentence, this Note will be binding upon and inure to the
benefit of the parties hereto and their respective successors.
[SIGNATURE PAGE FOLLOWS]

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IN WITNESS WHEREOF, the parties hereto have executed this Note as of the date
first written above.

   
EMERGENT BIOSOLUTIONS INC., as Maker
           
By:
 /s/ Robert Kramer
     
Name:Robert Kramer
     
Title:Chief Financial Officer and Treasurer

   
APTEVO THERAPEUTICS INC., as Holder
 
   
By:
 /s/ Marvin L. White
     
Name:Marvin L. White
     
Title:President and Chief Executive Officer