EXHIBIT 10.4


 


Philip MacNeill

Chief Financial Officer


 


Dear Philip:


 


On
behalf of PharmAthene, Inc. (“Company”), I am pleased to provide you with this letter agreement (“Agreement”)
setting forth the various terms and conditions of a retention arrangement which the Company is prepared to offer you effective
immediately. As explained herein, although you will remain an “at-will” employee, the Company has agreed to pay you
certain bonuses for remaining employed through certain milestones described below. During your employment, you will be paid at
your current salary rate.


 


Retention
Severance & Bonus: Unless you terminate employment as described below or the Company terminates your employment for Cause
(as defined below), if you remain continuously employed by the Company on a full-time basis on and after the Signing Date of this
Agreement, and are still employed on the dates specified below, you will become entitled to the following cash payments (subject
to normal tax withholdings):


 


		(a)	Severance Payment: If you remain employed through (i) the closing of the anticipated merger
with Altimmune, Inc. (“Altimmune”) , (ii) the completion of the preparation of the Company’s year-end financial
statements, including the filing of the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 and your
signing of the related Certification of Principal Financial Officer, pursuant to SEC Rule 13a-14(a)/15d-14(a) and Certification
Pursuant to Section 1350 of Chapter 63 of Title 18 of the United States Code, and (iii) the earlier of (A) the preparation and
filing of the Company’s proxy statement for its 2017 regular annual meeting of stockholders or (B) the filing of an amendment
to the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 providing the information in Items 10-14
of that form, the Company will pay you a one-time lump sum cash amount of $93,094.61; and



 


		(b)	Bonus Payment: If you remain employed through the closing of the anticipated merger with
Altimmune, the Company will pay you a one-time lump sum bonus cash amount of $67,235.The foregoing bonus payment amount shall not
be payable if the merger is not consummated for any reason



 


Thee above payments
shall be paid to you within thirty (30) days of meeting the required pre-conditions for payment.


 


Termination
Without Cause. The Company may terminate your employment at any time Without Cause. In the event you are terminated by the
Company Without Cause you will be eligible to receive the Severance Payment and the Bonus Payment provided for herein. These payments
will be paid to you within 30 days of your termination.


 


Voluntary/For
Cause Termination: If you voluntarily terminate employment or if the Company terminates you for Cause (which is defined below),
you will not be entitled to any additional payments after the effective date of such termination (including the Severance Payment
and the Bonus Payment described above), other than what you have already received. Moreover, if you stop performing your employment
duties on a full-time basis, the Company may treat the date that it determines you stopped performing your duties full-time as
a date of your voluntary termination for purposes of this Agreement. In the event you resign your employment due to an involuntary
reduction of your salary, your resignation will be deemed to be involuntary and will be treated as a Termination Without Cause.


 






     


     


    

 


“Cause”
means (i) your willful and substantial misconduct that is materially injurious to the Company and is either repeated after written
notice from the Company specifying the misconduct or is continuing and not corrected within 20 days after written notice from the
Company specifying the misconduct, (ii) your repeated neglect of duties or failure to act which can reasonably be expected to affect
materially and adversely the business or affairs of the Company after written notice from the Company specifying the neglect or
failure to act, (iii) your material breach of any of the provisions contained in your Confidentiality and Non-Solicitation Agreement
or of any of the Company’s policies, (iv) the commission by you of any material fraudulent act with respect to the business
and affairs of the Company, (v) your conviction of (or plea of nolo contendere to) a crime constituting a felony, (vi) demonstrable
gross negligence, or (vii) habitual insobriety or use of illegal drugs by you while performing your duties under this Agreement
which adversely affects the performance your duties under this Agreement.


 


Miscellaneous:
This Agreement is the sole and entire statement of the retention arrangement the Company is proposing and will be governed
by the laws of the State of Maryland, without application of conflicts of laws provisions that would otherwise apply the substantive
law of another jurisdiction.


 


Finally,
please understand that this Agreement does not constitute an employment contract guaranteeing employment for any set period of
time. Your employment is “at-will,” and this Agreement does not alter or affect in any way the Company’s right
to terminate your employment at any time, with or without Cause, or your right to terminate employment with the Company at any
time, in your discretion.


 


We
are looking forward to the opportunity of continuing our relationship with you and sincerely hope these terms are agreeable to
you. If so, please signify you acceptance of this Agreement by signing the attached copy of
this letter and returning that executed copy to me.


 





	 	Sincerely,	 
	 	 	 	 
	 	By:	/s/ John Gill	 
	 	 	John Gill	 
	 	 	Chief Executive Officer	 







 


I have read
the terms of this Agreement and, by signing below, hereby signify my acceptance of these terms.


 





	 	Philip MacNeill	 
	 	 	 
	 	Date: January 14, 2017	 
	 	 	 
	 	/s/ Philip MacNeill	 
	 	Employee Signature