EX-10.17



 Exhibit 10.17 

EMPLOYMENT AGREEMENT 

This EMPLOYMENT AGREEMENT (“Agreement”) is made and entered into as of December 7, 2015 (the “Effective
Date”) by and between M. Scot Roberts (“Roberts”) and Altimmune, Inc. (f/k/a Vaxin, Inc.), a Delaware corporation (“Altimmune”). 

WHEREAS, Roberts currently serves as the Chief Scientific Officer of Altimmune pursuant to that certain Offer Letter, by and
between Roberts and Altimmune, dated as of October 29, 2012 (the “Offer Letter”); 
 WHEREAS, in connection
with the execution of this Agreement, the Board of Directors of Altimmune (the “Board”) or an authorized committee thereof and Roberts desire to terminate and supersede in its entirety the Offer Letter as of the Effective
Date pursuant to the terms hereof to assure Altimmune of Roberts’ continued employment in an executive capacity and to compensate him therefor; and 

WHEREAS, Roberts acknowledges that, in executing this Agreement, he has had a reasonable opportunity to seek the advice of
independent legal and tax counsel, and has read and understood all of the terms and provisions of this Agreement. 
 NOW, THEREFORE,
in consideration of the mutual promises and covenants contained herein and for other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereto agree as follows: 

1. Titles, Duties and Responsibilities. 

(a) Title and Duties. During the Employment Period (as defined in Section 2 below), Roberts shall serve as Chief Scientific
Officer of Altimmune and shall have such duties, responsibilities and authority commensurate with such position, and such additional duties and responsibilities commensurate with such position as shall be determined from time to time by the Chief
Executive Officer of Altimmune (the “CEO”). 
 (b) Reporting Responsibilities. Roberts shall report directly to the
CEO. 
 (c) Conflicts of Interest and Compliance with Laws. Except as specifically set forth in this Section 1(c), during the
Employment Period, Roberts shall devote his entire time, attention, energies and business efforts to the affairs of Altimmune. Except as set forth below, during the Employment Period, Roberts shall not, without the prior written consent of the Board
(x) engage, directly or indirectly, in any other business activity that materially interferes with his duties as set forth in this Agreement and/or that creates a conflict of interest, (y) act as a proprietor, partner, director, officer,
executive, consultant, advisor, agent, representative or any other capacity of any entity other than Altimmune and its divisions, subsidiaries and other affiliated entities, regardless of whether such activity is for gain, profit or other pecuniary
advantage, or (z) allow or cause Altimmune to participate in any transaction with Roberts, any of his relatives (other than as employees of Altimmune), or any entity in which Roberts or any of his relatives has an interest. Roberts further
agrees that he shall not knowingly take any action, or authorize the taking of any action, that contravenes any applicable federal, state, municipal or other political subdivision ordinance, statute or rule, regulation or order of any jurisdiction.
Roberts agrees to immediately disclose to the Board any relationship, action or activity that may potentially be subject to the provisions of this Section 1(c). 







 2. Employment Term. Unless sooner terminated as provided elsewhere in this
Agreement, Roberts’ employment with Altimmune under this Agreement shall begin on the Effective Date and end at 11:59 p.m. Eastern Time on December 31, 2017 (the “Initial Employment Period”). Commencing on
January 1, 2018 and each January 1 thereafter (the “Extension Date”), this Agreement shall automatically renew on the terms and conditions as then in effect for additional successive periods of one (1) year unless
terminated by either party upon written notice to the other party not less than ninety (90) days prior to the Extension Date. The Initial Employment Period and any extension or renewal thereof shall be referred to herein together as the
“Employment Period.” Notwithstanding anything to the contrary contained herein, the Employment Period is subject to termination pursuant to Section 6 hereof. 

3. Salary, Bonus and Other Compensation. During Roberts’ employment, Altimmune shall provide the following salary,
bonus and other compensation to Roberts: 
 (a) Base Compensation. Altimmune shall pay Roberts an initial annual base salary of Two
Hundred Thousand Dollars ($200,000) per annum (or, upon the consummation of a Qualified IPO (as defined in Exhibit A hereto), the base salary shall be Two Hundred Twenty Thousand Dollars ($220,000) per annum) (such salary, as applicable,
“Base Salary”), payable in substantially equal installments in accordance with Altimmune’s normal payroll practices. Roberts’ compensation shall be evaluated and adjusted by the Compensation Committee of the Board (the
“Committee”) on at least an annual basis, provided that in no event shall Roberts’ Base Salary be reduced while this Agreement is in effect. 

(b) Annual Bonus. In addition to the Base Salary, during each year of the Employment Period, Roberts will be eligible for an annual
cash bonus (“Annual Bonus”) with a target award equal to thirty percent (30%) of the Base Salary. The Annual Bonus will be subject to all of the terms and conditions of the applicable bonus plan. The actual Annual Bonus payouts will
be based on achievement of the individual and/or company performance criteria established for the applicable fiscal year by the Committee in its sole and absolute discretion. Roberts must be actively employed on December 31st of the applicable fiscal year to be eligible for an Annual Bonus payment. The Annual Bonus shall be paid no later than the March 15th of the
fiscal year immediately following the fiscal year in which such Annual Bonus was earned. 
 (c) Equity Awards. Roberts will be
entitled to participate in the Altimmune 2016 Omnibus Incentive Plan or such other equity based long-term incentive compensation plan, program or arrangement generally made available to senior executive officers of Altimmune from time to time, as
determined by the Committee in its sole and absolute discretion. 
 4. Benefits. During the Employment Period, Roberts shall be
eligible for participation in and shall receive all benefits under welfare benefit, savings and retirement plans provided by Altimmune (including, but not limited to, life insurance, disability insurance, medical insurance, dental insurance)
to the extent applicable generally to senior executives of Altimmune, and consistent with the following specific agreements: 

  
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 (a) Vacation. Roberts will be entitled to twenty (20) days of paid vacation and six
(6) days of personal and sick leave each year during the Employment Period. Roberts is permitted to carry over a maximum of twelve (12) days of personal and sick leave per year, subject to applicable law. 

(b) Health, Life, Vision and Disability Insurance. Roberts will be entitled to participate in all health, vision and dental insurance
programs provided by Altimmune to the extent applicable generally to senior executives of Altimmune. 
 5. Reimbursement of Business
Expenses. Altimmune shall reimburse Roberts for all reasonable and customary out-of-pocket business expenses incurred by Roberts in the course of his
duties (to include monthly expenses to maintain cellular telephone service), in accordance with Altimmune’s policies as in effect from time to time. Roberts shall be required to submit to Altimmune appropriate documentation supporting such out-of-pocket business expenses as a prerequisite to reimbursement in accordance with such policies. Notwithstanding anything herein to the contrary or otherwise, except to
the extent any expense or reimbursement described in this Agreement does not constitute a “deferral of compensation” within the meaning of Section 409A of the Code and the Treasury regulations and other guidance issued thereunder, any
expense or reimbursement described in this Agreement shall meet the following requirements: (i) the amount of expenses eligible for reimbursement provided to Roberts during any calendar year will not affect the amount of expenses eligible for
reimbursement to Roberts in any other calendar year; (ii) the reimbursements for expenses for which Roberts is entitled to be reimbursed shall be made on or before the last day of the calendar year following the calendar year in which the
applicable expense is incurred; (iii) the right to payment or reimbursement or in-kind benefits hereunder may not be liquidated or exchanged for any other benefit; and (iv) the reimbursements shall
be made pursuant to objectively determinable and nondiscretionary company policies and procedures regarding such reimbursement of expenses. 

6. Termination Provisions. 

(a) Termination by Altimmune for Cause or Termination by Roberts without Good Reason. Altimmune may terminate Roberts’ employment
immediately for Cause (as defined below) and Roberts may terminate his employment at any time without Good Reason upon providing Altimmune at least thirty (30) days advance written notice. Upon such termination, Altimmune shall provide Roberts
with the following: (i) payment of any accrued Base Salary through and including the date of Roberts’ termination to the extent not theretofore paid; (ii) any accrued and unused vacation pay through and including the date of
Roberts’ termination; (iii) any unreimbursed business expenses in accordance with Section 5 hereof, and (iv) such accrued and vested rights or benefits as may be due to Roberts under any Altimmune sponsored employee benefits plans
payable in accordance with the terms and conditions of such plans (the payments and benefits referred to in subclauses (i) through (iv) above shall be collectively referred to as the “Accrued Obligations”). Except as provided
in this Section 6(a), termination pursuant to this Section 6(a) shall terminate any other rights Roberts may have under this Agreement and shall relieve Altimmune of any other obligations it may have under this Agreement. 

  
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 For purposes of this Agreement, termination for Cause shall mean the termination of Roberts’
employment by Altimmune due to: (i) a material breach by Roberts of his fiduciary duties to Altimmune; (ii) a material breach by Roberts of this Agreement after being given written notice of such breach and a failure to cure within thirty
(30) days of such notice; (iii) Roberts’ willful failure or refusal to follow Altimmune’s written policies after being given written notice of said failure or refusal and a failure to cure within thirty (30) days of such notice;
(iv) Roberts’ conviction of, or plea of guilty or nolo contendere, to a felony; and/or (v) Roberts’ continuing and willful refusal to act as directed by the Board or CEO (other than refusal resulting from incapacity due to
physical or mental illness), after written notice is delivered to Roberts within sixty (60) days of such refusal which identifies said refusal and sets forth a plan of corrective action and a failure to cure within thirty (30) days of such
notice. 
 (b) Termination by Altimmune without Cause or Resignation by Roberts for Good Reason. Altimmune may terminate
Roberts’ employment without Cause at any time upon prior written notice to Roberts and Roberts may terminate his employment for Good Reason (as defined below). Upon such termination, subject to Roberts’ continued compliance with the
restrictive covenants set forth in Section 7, Altimmune shall provide Roberts with the following: 
 (i) continued payment of the Cash
Severance Amount (as defined below) in equal monthly installments during the applicable severance period (as determined below) following the effective date of such termination and otherwise payable in accordance with Altimmune’s normal payroll
practices. As used herein, the “Cash Severance Amount” shall be equal to six (6) months of Roberts’ Base Salary existing at the time of such termination payable over the six (6) month period following such
termination, except that if such termination occurs within the one (1) year period commencing on the occurrence of a Change in Control (as defined below), the Cash Severance Amount shall instead be equal to the sum of twelve (12) months of
Roberts’ Base Salary (existing at the time of such termination) plus Roberts’ target Annual Bonus for the year of termination, payable over the twelve (12) month period following such termination; 

(ii) subject to Roberts’ timely election, and the availability, of continuation coverage under Part 6 of Title I of the Employment
Retirement Income Security Act of 1974 (as amended) and Section 4980B of the Code (“COBRA”), Altimmune will pay monthly, on Roberts’ behalf, a portion of the cost of such coverage for the six (6) months after the date
of such termination, which payments will be equal to the amount of the monthly premium for such coverage, less the amount that Roberts would have been required to pay if Roberts had remained an active employee of Altimmune (the “COBRA
Assistance”); provided, however, if at any time Altimmune determines that the COBRA Assistance would result in a violation of the non-discrimination rules under Section 105(h)(2) of
the Internal Revenue Code of 1986, as amended (the “Code”) or any other applicable laws, statute or regulation of similar effect (including, but not limited to, the 2010 Patient Protection and Affordable Care Act, as amended by the
2010 Health Care and Education Reconciliation Act), then in lieu of providing the COBRA Assistance, Altimmune will instead pay Roberts fully taxable cash payments equal to, and paid at the same time as, the COBRA Assistance would have otherwise been
paid, subject to applicable tax withholdings; 

  
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 (iii) any unpaid prior year’s Annual Bonus, payable by Altimmune to Roberts at the same
time annual bonuses in respect of the prior year are generally paid to senior executives of Altimmune; 
 (iv) the Accrued Obligations; and

 (v) if such termination occurs within the one (1) year period commencing on the occurrence of a Change in Control, accelerated
vesting of all unvested equity awards then outstanding and held by Roberts (for the avoidance of doubt, if such termination does not occur during such one (1) year period, then any accelerated vesting of unvested equity awards shall be at the
discretion of the Committee). 
 For purposes of this Agreement, resignation for Good Reason shall mean the resignation by Roberts of his
employment due to: (a) a reduction in Roberts’ Base Salary or target Annual Bonus opportunity; (b) a material diminution in Roberts’ authority, duties or responsibilities; or (c) a relocation by Altimmune of Roberts’
principal place of business for the performance of his duties under this Agreement to a location that is anywhere outside of a 50-mile radius of Gaithersburg, Maryland; provided, however, that
Roberts must notify Altimmune within ninety (90) days of the occurrence of any of the foregoing conditions that he considers to be a “Good Reason” condition and provide Altimmune with thirty (30) days in which to cure the
condition. If Roberts fails to provide this notice and cure period prior to his resignation, or resigns more than six (6) months after the initial existence of the condition, his resignation will not be deemed to be for “Good Reason.”

 For purposes of this Agreement, “Change in Control” means the occurrence of either (i) an acquisition from
stockholders of Altimmune (including through purchase, reorganization, merger, consolidation or similar transaction), directly or indirectly, in one or more transactions by a Person (other than any Person or group of Persons consisting solely of
shareholders of Altimmune as of the date immediately prior to the consummation of the transaction) of beneficial ownership (within the meaning of Rule 13d-3 under the Exchange Act) of securities representing
50% or more of the combined voting power of the securities of Altimmune entitled to vote generally in the election of directors of the Board, calculated on a fully diluted basis after giving effect to such acquisition, or (ii) the sale or other
disposition, directly or indirectly, of all or substantially all of the assets of Altimmune and its subsidiaries, taken as a whole, to any Person (other than any Person or group of Persons consisting solely of shareholders of Altimmune as of the
date immediately prior to the consummation of the transaction). For the avoidance of doubt, a transaction effected primarily for the purpose of (x) an equity financing of Altimmune, (y) the reincorporation of Altimmune in a different
state, or (z) the formation of a holding company that will be owned exclusively by Altimmune’s stockholders, shall not be a Change in Control for purposes of this Agreement. A “Person” means any individual, entity or group within
the meaning of Section 13(d)(3) or 14(d)(2) of the Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder, other than employee benefit plans sponsored or maintained by Altimmune and by entities controlled by
Altimmune or an underwriter of the capital stock of Altimmune in a registered public offering. 

  
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 (c) Death or Disability. Roberts’ employment shall terminate automatically upon
Roberts’ death. Subject to applicable law, Altimmune may terminate Roberts’ employment due to Roberts’ Disability (as defined below). Upon any such termination, Altimmune shall provide Roberts (or his estate as the case may be) with
the Accrued Obligations through the date of termination. The term “Disability” shall mean Roberts becoming physically or mentally disabled such that he is unable to perform his duties to Altimmune for a period of 90 consecutive
days. 
 (d) Expiration of Employment Term. In the event notice of termination is provided by Roberts in accordance with
Section 2, Roberts’ employment shall terminate upon the expiration of the Employment Period. Upon such termination, Altimmune shall provide Roberts with the Accrued Obligations through the date of termination and his Annual Bonus. 

(e) Limits. Notwithstanding anything herein to the contrary, Altimmune’s obligation to make any payments or benefits to Roberts
upon termination of his employment under the circumstances described in Section 6(b) (other than the Accrued Obligations) and 6(d) (other than the Accrued Obligations) is conditioned upon Roberts’ execution, delivery and non-revocation of a valid and enforceable release of claims arising in connection with Roberts’ employment and termination or resignation of employment with Altimmune and its affiliates (the
“Release”) that becomes effective not later than sixty (60) days after the date of such termination or resignation of employment. Altimmune shall provide the form of the Release to Roberts within seven (7) days following
the date of Roberts’ termination or resignation of employment. Subject to the foregoing and Section 21 hereof, the Cash Severance Amount will commence to be paid to Roberts on the sixtieth (60th) day following Roberts’ termination or
resignation of employment, and such first payment shall include payment of any amounts that would otherwise be due prior thereto. On any termination entitling Roberts to the payments and benefits under Section 6(b) or 6(d), Altimmune and its
affiliates shall have no further obligation to make payments under this Agreement other than as specifically provided for in such section. 

(f) Resignation from All Positions. Unless the parties otherwise agree in writing, upon the termination or resignation of Roberts’
employment with Altimmune for any reason, Roberts shall be deemed to have resigned, as of the date of such termination or resignation, from and with respect to all positions Roberts then holds as an officer, director or employee with Altimmune and
any of its affiliates. 
 7. Secrecy, Non-Solicitation and
Non-Competition. 
 (a) Secrecy. During the Employment Period and thereafter, Roberts
covenants and agrees that he will not, except in performance of Roberts’ obligations to Altimmune, or with the prior written consent of Altimmune pursuant to the authority granted by a resolution of the Board, directly or indirectly, disclose
any secret or confidential information that he may learn or has learned by reason of his association with Altimmune or use any such information. The term “secret or confidential information” includes, without limitation, information not
previously disclosed to the public or to the trade by Altimmune’s management with respect to Altimmune’s products, facilities and methods, trade secrets and other intellectual property, systems, procedures, manuals, confidential reports,
product price lists, customer lists, member lists, financial information (including the revenues, costs or profits associated with any Altimmune’s products), business plans, prospects, employee or 

  
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 employees, compensation, or opportunities but shall exclude any information already in the public domain which
has been disclosed to the public during the normal course of Altimmune’s business. Notwithstanding anything herein to the contrary, nothing in this Agreement shall be construed to prohibit Roberts from reporting possible violations of federal
or state law or regulations to any governmental agency or entity, including but not limited to the Department of Justice, the Securities and Exchange Commission, the Congress, and any agency Inspector General, or making other disclosures that are
protected under the whistleblower provisions of federal or state law or regulation. Roberts does not need the prior authorization of Altimmune to make any such reports or disclosures and Roberts is not required to notify Altimmune that he made such
reports or disclosures. 
 (b) Non-solicitation of Clients and Customers. Roberts covenants
and agrees that during the Employment Period and for a period of six (6) months thereafter, he will not solicit, either directly or indirectly, any customer or client of Altimmune on behalf of any direct competitor of Altimmune for the purpose
of diverting business from Altimmune. This Agreement extends to prevent Roberts from soliciting on behalf of Roberts or any other individual or entity that seeks to compete with Altimmune. 

(c) Non-solicitation of Employees. Roberts covenants and agrees that during the Employment
Period and for a period of six (6) months thereafter, he shall not directly or indirectly, on his behalf or on behalf of any person or other entity, solicit or induce, or attempt to solicit or induce, any person who is an employee of Altimmune,
to terminate his or her employment with Altimmune. 
 (d) Noncompetition. Roberts covenants and agrees that during the Employment
Period and for a period of six (6) months thereafter, he will not directly or indirectly work for or engage in sales, marketing or related activities on behalf of himself or any other person or entity that is a direct competitor of Altimmune.

 (e) Equitable Relief. Roberts acknowledges and agrees that the services performed by him are special, unique and extraordinary in
that, by reason of Roberts’ employment, Roberts may acquire confidential information and trade secrets concerning the operation of Altimmune, or that Roberts may have contact with or obtain knowledge of Altimmune’s members or prospects,
the use or disclosure of which could cause Altimmune substantial loss and damages, which could not be readily calculated and for which no remedy at law would be adequate. Accordingly, Roberts acknowledges and agrees that Altimmune shall be entitled
to obtain a temporary restraining order and/or a preliminary or permanent injunction restraining Roberts from engaging in activities prohibited by this Section 7 or such other relief as may be required to specifically enforce any of the
covenants in this Section 7. Roberts acknowledges and agrees that Altimmune shall be entitled to its attorneys’ fees and court costs should Altimmune successfully pursue legal action to enforce its rights under this Section 7. 

(f) Return of Property. Upon termination or resignation of Roberts’ employment with Altimmune, Roberts shall promptly supply to
Altimmune all property, keys, notes, memoranda, writings, lists, files, reports, customer lists, correspondence, tapes, disks, cards, surveys, maps, logs, machines, technical data and any other tangible product or document which has been produced
by, received by or otherwise submitted to Roberts during or prior to his employment with Altimmune, and any copies thereof in Roberts’ (or capable of being reduced to Roberts’) possession. 

  
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 (g) Survival. Any termination of Roberts’ employment, of the Employment Period or of
this Agreement (or breach of this Agreement by Altimmune or Roberts) shall have no effect on the continuing operation of this Section 7. 

8. Governing Law. This Agreement is made and entered into in the State of Maryland, without regard to conflict of laws
rules, and the laws of the State of Maryland shall govern its validity and interpretation in the performance by the parties of their respective duties and obligations. 

9. Entire Agreement. This Agreement constitutes the entire agreement between the parties with respect to the matters
described herein and supersedes all prior agreements and understandings both written and oral, among the parties with respect to the subject matter hereof (including, without limitation, the Offer Letter), and there are no representation, warranties
or commitments, other than those in writing executed by the parties hereto. 
 10. Consent to Venue. Any dispute, controversy,
or claim arising out of or relating to this Agreement or the breach thereof, arising out of or relating in any way to the employment of Roberts or termination thereof, shall be brought in the Federal courts located in the State of Maryland;
provided, however, that if any of the aforementioned courts is found to lack subject matter jurisdiction, then to the exclusive jurisdiction of the state courts in the State of Maryland. By executing and delivering this Agreement, each party, for
itself or himself and in connection with its or his properties, irrevocably (a) accepts generally and unconditionally the exclusive jurisdiction and venue of such courts; (b) waives any defense of forum non conveniens; (c) agrees that
service of all process in any such proceeding in any such court may be made by registered or certified mail, return receipt requested, to the applicable party at its address provided herein; and (d) agrees that service as provided in clause
(c) above is sufficient to confer personal jurisdiction over the applicable party in any such proceeding in any such court, and otherwise constitutes effective and binding service in every respect. 

11. WAIVER OF JURY TRIAL. EACH PARTY HERETO IRREVOCABLY AND UNCONDITIONALLY WAIVES ANY RIGHT TO TRIAL BY JURY IN ANY
DISPUTE, CONTROVERSY OR CLAIM, WHETHER SOUNDING IN CONTRACT, TORT OR OTHERWISE, AMONG THE PARTIES HERETO ARISING OUT OF OR RELATING IN ANY WAY TO THE EMPLOYMENT OF ROBERTS OR TERMINATION THEREOF OR FOR ANY COUNTERCLAIM THEREIN. THE PARTIES HERETO
MAY FILE AN ORIGINAL COUNTERPART OR A COPY OF THIS AGREEMENT WITH ANY COURT OF COMPETENT JURISDICTION AS PROVIDED HEREIN AS WRITTEN EVIDENCE OF THE CONSENT OF THE PARTIES HERETO TO THE WAIVER OF THEIR RIGHT TO TRIAL BY JURY. 

12. Assistance in Litigation. Roberts shall make himself available, upon the request of Altimmune, to testify or otherwise
assist in litigation, arbitration, or other disputes involving Altimmune, or any of the directors, officers, executives, subsidiaries, or parent corporations of Altimmune, at no additional cost during the Employment Period and at any time following
the 

  
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 termination of Roberts’ employment for any reason; provided, however, in the event such request is made by
Altimmune after the Employment Period, Roberts shall be reimbursed for any reasonable out-of-pocket expenses incurred with respect thereto and shall also be paid a
reasonable daily stipend based on his Base Salary at the time of termination. 
 13. Notices. Any notice or communication
required or permitted to be given to the parties shall be delivered personally or sent by registered or certified mail, postage prepaid and return receipt requested, and addressed or delivered as follows, or to such other address as the party
addressed may have substituted by notice pursuant to this Section. 
  

	 	(a)	If to Altimmune, to: 

 Altimmune, Inc. 

19 Firstfield Road, Suite 200 

Gaithersburg, Maryland 20878 

ATTN: Chief Executive Officer 
  

	 	(b)	If to Roberts, to: 

 The last address on file with Altimmune at the time of Notice. 

14. Binding Agreement. This Agreement shall inure to the benefit of and be enforceable by Roberts and his personal or
legal representatives, executors, administrators, successors, heirs, distributees, devises and legatees. This Agreement shall inure to the benefit of and be enforceable by Altimmune and any of its successors and assigns. Altimmune will require any
successor (whether direct or indirect, by purchase, merger, consolidation or otherwise) to all or substantially all of the business and/or assets of Altimmune to assume expressly and agree to satisfy all of the obligations under this Agreement in
the same manner and to the same extent that Altimmune would be required to satisfy such obligations if no such succession had taken place. As used in this Agreement, “Altimmune” shall mean “Altimmune” as hereinbefore defined and
any successor to its respective businesses and/or assets as aforesaid which assumes and agrees to perform this Agreement by operation of law or otherwise. 

15. Amendment. This Agreement may not be amended or modified otherwise than by a written agreement executed by Roberts and
the Chairman of the Board or their respective successors and legal representatives. 
 16. Construction. This Agreement shall
not be construed against any party by reason of the drafting or preparation hereof. 
 17. Captions. The captions of
this Agreement are inserted for convenience and are not part of the Agreement. 
 18. Severability. In case any one or
more of the provisions contained in this Agreement shall for any reason be held to be invalid, illegal, or unenforceable in any other respect, such invalidity, illegality or unenforceability shall not affect any other provision of this
Agreement. This Agreement shall be construed as if such invalid, illegal or unenforceable provision had never been part of the Agreement and there shall be deemed substituted therefore such other provision as will most nearly accomplish the intent
of the parties to the extent permitted by the applicable law. 

  
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 19. Survivorship. Upon the expiration or other termination of this Agreement or
termination of Roberts’ employment for any reason, the respective rights and obligations of the parties hereto shall survive such expiration or other termination to the extent necessary to carry out the intentions of the parties under this
Agreement. 
 20. Withholding. Altimmune may withhold from any amounts payable under this Agreement such Federal, state,
local or foreign taxes as shall be required to be withheld pursuant to any applicable law or regulation. 
 21. Section 409A.

 (a) Although Altimmune does not guarantee the tax treatment of any payments or benefits provided under this Agreement, it is intended
that this Agreement will comply with, or be exempt from, Code Section 409A to the extent this Agreement (or any benefit or payment provided hereunder) is subject thereto, and this Agreement shall be interpreted on a basis consistent with such
intent. 
 (b) Notwithstanding any provision to the contrary in this Agreement, if Roberts is deemed on the date of his “separation
from service” (within the meaning of Treas. Reg. Section 1.409A-1(h)) with Altimmune to be a “specified employee” (within the meaning of Treas. Reg.
Section 1.409A-1(i)), then with regard to any payment or benefit that is considered non-qualified deferred compensation under Code Section 409A payable on
account of a “separation from service” that is required to be delayed pursuant to Code Section 409A(a)(2)(B) of the Code (after taking into account any applicable exceptions to such requirement), such payment or benefit shall be made
or provided on the date that is the earlier of (i) the date immediately following the expiration of the six-month period measured from the date of Roberts’ “separation from service,” and
(ii) the date of Roberts’ death (the “Delay Period”). Upon the expiration of the Delay Period, all payments and benefits delayed pursuant to this Section 21(b) (whether they would have otherwise been payable in a
single sum or in installments in the absence of such delay) shall be paid or reimbursed to Roberts in a lump sum and any remaining payments and benefits due under this Agreement shall be paid or provided in accordance with the normal payment dates
specified for them herein. 
 (c) Notwithstanding any provision of this Agreement to the contrary, for purposes of any provision of this
Agreement providing for the payment of any amounts or benefits upon or following a termination of employment that are considered deferred compensation under Code Section 409A, references to Roberts’ “termination of employment”
(and corollary terms) with Altimmune shall be construed to refer to Roberts’ “separation from service” (within the meaning of Treas. Reg. Section 1.409A-1(h)) with Altimmune. 

(d) Whenever payments under this Agreement are to be made in installments, each such installment shall be deemed to be a separate payment for
purposes of Code Section 409A. Whenever a payment under this Agreement specifies a payment period with reference to a number of days (e.g., “payment shall be made within thirty (30) days following the date of termination”), the
actual date of payment within the specified period shall be within the sole discretion of Altimmune. Notwithstanding anything herein, Roberts shall be responsible for payment of any applicable personal tax liabilities associated with the receipt of
income or benefits pursuant to this Agreement. 

  
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 22. Section 280G. 

(a) Notwithstanding anything contained in this Agreement to the contrary, (i) to the extent that any payment or distribution of any type
to or for the benefit of Roberts by Altimmune, any affiliate thereof, any person or entity who acquires ownership or effective control of Altimmune or ownership of a substantial portion of Altimmune’s assets (within the meaning of
Section 280G of the Code and the regulations thereunder), or any affiliate of such person or entity, whether paid or payable or distributed or distributable pursuant to the terms of this Agreement or otherwise (the “Payments”)
constitutes “parachute payments” (within the meaning of Section 280G of the Code), and if (ii) such aggregate Payments would, if reduced by all federal, state and local taxes applicable thereto, including the excise tax imposed
under Section 4999 of the Code (the “Excise Tax”), be less than the amount Roberts would receive, after all taxes, if Roberts received aggregate Payments equal (as valued under Section 280G of the Code) to only three times
Roberts’ “base amount” (within the meaning of Section 280G of the Code), less $1.00, then (iii) such Payments shall be reduced (but not below zero) if and to the extent necessary so that no Payments to be made or benefit to
be provided to Roberts shall be subject to the Excise Tax; provided, however, that, solely to the extent applicable, Altimmune shall use its reasonable best efforts to obtain shareholder approval of the Payments provided for in this
Agreement in a manner intended to satisfy requirements of the “shareholder approval” exception to Section 280G of the Code and the regulations promulgated thereunder, such that payment may be made to Roberts of such Payments without
the application of an Excise Tax. If the Payments are so reduced, Altimmune shall reduce or eliminate the Payments (x) by first reducing or eliminating the portion of the Payments which are not payable in cash (other than that portion of the
Payments subject to clause (z) hereof), (y) then by reducing or eliminating cash payments (other than that portion of the Payments subject to clause (z) hereof) and (z) then by reducing or eliminating the portion of the Payments
(whether payable in cash or not payable in cash) to which Treasury Regulation § 1.280G-1 Q/A 24(c) (or successor thereto) applies, in each case in reverse order beginning with payments or benefits which
are to be paid the farthest in time. 
 (b) The determination of whether the Payments shall be reduced as provided in Section 22(a)
hereof and the amount of such reduction shall be made at Altimmune’s expense by an independent public accounting firm of national reputation selected by Altimmune (the “Accounting Firm”). The Accounting Firm shall provide its
determination (the “Determination”), together with detailed supporting calculations and documentation, to Altimmune and Roberts within ten (10) days after Roberts’ final day of employment. If the Accounting Firm determines
that no Excise Tax is payable by Roberts with respect to the Payments, it shall furnish Roberts with an opinion reasonably acceptable to him that no Excise Tax will be imposed with respect to any such payments and, absent manifest error, such
Determination shall be binding, final and conclusive upon Altimmune and Roberts. 
 23. Counterparts. This Agreement may be
executed simultaneously in two or more counterparts, each of which shall be deemed an original, but all of which shall together constitute one in the same Agreement. 

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

							
	ALTIMMUNE, INC.:	  		  	M. SCOT ROBERTS:
				
	By:	  	 /s/ William Enright
	  		  	 /s/ M. Scot Roberts

		  	Chief Executive Officer	  		  	
				
	Date:	  	7 Dec 2015	  		  	Date: 07 Dec 2015


  
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 Exhibit A 

A “Qualified IPO” shall mean an initial public offering of Altimmune’s common stock with gross proceed to Altimmune of at least
$25 million from new investors at a valuation of at least $125 million. 

  
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