Document:

Exhibit
10.2

SECURED
TERM PROMISSORY NOTE

	$5,000,000	Advance
    Date:  October 9, 2018
	 	Maturity
    Date: September 9, 2019

FOR
VALUE RECEIVED, Ondas Networks Inc., a Delaware corporation, for itself and each of its Subsidiaries (the “Borrower”)
hereby promises to pay to the order of Steward Capital Holdings, LP, a Delaware partnership, or the holder of this Note (the “Lender”)
at 3900 S. Overland Avenue, Springfield, MO 65807 or such other place of payment as the holder of this Secured Term Promissory
Note (this “Promissory Note”) may specify from time to time in writing, in lawful money of the United States of America,
the principal amount of Five Million Dollars ($5,000,000) or such lesser principal amount as Lender has advanced to Borrower,
together with interest as set forth in that certain Loan and Security Agreement dated March 9, 2018, by and among Borrower, its
Domestic Subsidiaries party thereto and Lender (as the same may from time to time be amended, modified or supplemented in accordance
with its terms, the “Loan Agreement”).

This
Promissory Note is the Term Note referred to in, and is executed and delivered in connection with, the Loan Agreement, and is
entitled to the benefit and security of the Loan Agreement and the other Loan Documents (as defined in the Loan Agreement), to
which reference is made for a statement of all of the terms and conditions thereof. All payments shall be made in accordance with
the Loan Agreement. All terms defined in the Loan Agreement shall have the same definitions when used herein, unless otherwise
defined herein. An Event of Default under the Loan Agreement shall constitute an Event of Default under this Promissory Note.

Borrower
waives presentment and demand for payment, notice of dishonor, protest and notice of protest under the UCC or any applicable law.
Borrower agrees to make all payments under this Promissory Note without setoff, recoupment or deduction and regardless of any
counterclaim or defense. This Promissory Note has been negotiated and delivered to Lender and is payable in the State of Missouri.
This Promissory Note shall be governed by and construed and enforced in accordance with, the laws of the State of Missouri, excluding
any conflicts of law rules or principles that would cause the application of the laws of any other jurisdiction.

BORROWER
FOR ITSELF AND

ON BEHALF OF ITS SUBSIDIARIES:

	                             ONDAS
    NETWORKS INC.
	 	 	 
		By:	/s/ Eric Brock                                            
	 	 	Eric Brock, Chief Executive OfficerExhibit 4.1

 

EXECUTION VERSION

 

Synthetic
Biologics, Inc.

 

and

 

Corporate
Stock Transfer, Inc., as

Warrant
Agent

 

Warrant
Agency Agreement

 

Dated
as of October 15, 2018

 

     

     

    

 

WARRANT
AGENCY AGREEMENT

 

WARRANT
AGENCY AGREEMENT, dated as of October 15, 2018 (“Agreement”), between Synthetic Biologics, Inc., a Nevada corporation
(the “Company”), and Corporate Stock Transfer, Inc., with offices located at 3200 Cherry Creek South Drive, Suite 430,
Denver, Colorado 80209 (the “Warrant Agent”).

 

WITNESSETH

 

WHEREAS, pursuant to a
registered offering by the Company of an aggregate of 2,520,000 Class A Units (each, a “Class A Unit” and collectively,
the “Class A Units”), each Class A Unit consisting of one share of the Company’s common stock, par value $0.001
per share (the “Common Stock”), and a warrant to purchase one share of Common Stock (each, a “Warrant”
and collectively, the “Warrants”), and an aggregate of 15,723 Class B Units (each, a “Class B Unit” and
collectively, the “Class B Units”), each Class B Unit consisting of one share of Series B Convertible Preferred Stock,
par value $0.001 per share (the “Preferred Stock”), and a Warrant to purchase the number of shares as would have been
issued to such purchaser if they had purchased Class A Units based on the public offering price, pursuant to an effective registration
statement on Form S-1, as amended (File No. 333-227400) (the “Registration Statement”), the Company wishes to issue
the Warrants in book entry form entitling the respective holders of the Warrants (the “Holders”, which term shall include
a Holder’s transferees, successors and assigns and “Holder” shall include, if the Warrants are held in “street
name,” a Participant (as defined below) or a designee appointed by such Participant) to purchase an aggregate of up to 18,620,998
shares of Common Stock (including Warrants potentially issued under the over-allotment option) upon the terms and subject to the
conditions hereinafter set forth (the “Offering”);

 

WHEREAS, the shares of
Common Stock, Preferred Stock and Warrants to be issued in connection with the Offering shall be immediately separable and will
be issued separately, but will be purchased together in the Offering; and

 

WHEREAS, the Company wishes
the Warrant Agent to act on behalf of the Company, and the Warrant Agent is willing so to act, in connection with the issuance,
registration, transfer, exchange, exercise and replacement of the Warrants and, in the Warrant Agent’s capacity as the Company’s
transfer agent, the delivery of the Warrant Shares (as defined below).

 

NOW, THEREFORE, in consideration
of the premises and the mutual agreements herein set forth, the parties hereby agree as follows:

 

Section 1.         Certain
Definitions. For purposes of this Agreement, the following terms have the meanings indicated:

 

(a)       “Business
Day” means any day except any Saturday, any Sunday, any day which is a federal legal holiday in the United States or any
day on which the New York Stock Exchange is authorized or required by law or other governmental action to close.

 

(b)       “Close
of Business” on any given date means 5:00 p.m., New York City time, on such date; provided, however, that if such date is
not a Business Day it means 5:00 p.m., New York City time, on the next succeeding Business Day.

 

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(c)       “Person”
means an individual, corporation, association, partnership, limited liability company, joint venture, trust, unincorporated organization,
government or political subdivision thereof or governmental agency or other entity.

 

(d)       “Warrant
Certificate” means a certificate issued to a Holder, representing such number of Warrant Shares as is indicated therein.

 

(e)       “Warrant
Shares” means the shares of Common Stock underlying the Warrants and issuable upon exercise of the Warrants.

 

All other capitalized terms
used but not otherwise defined herein shall have the meaning ascribed to such terms in the Warrant.

 

Section 2.          Appointment
of Warrant Agent. The Company hereby appoints the Warrant Agent to act as agent for the Company in accordance with the terms and
conditions hereof, and the Warrant Agent hereby accepts such appointment. The Company may from time to time appoint a Co-Warrant
Agent as it may, in its sole discretion, deem necessary or desirable. The Warrant Agent shall have no duty to supervise, and will
in no event be liable for the acts or omissions of, any co-Warrant Agent.

 

Section 3.          Global
Warrants.

 

(a)       The
Warrants shall be issuable in book entry form (the “Global Warrants”). All of the Warrants shall initially be represented
by one or more Global Warrants deposited with the Warrant Agent and registered in the name of Cede & Co., a nominee of The
Depository Trust Company (the “Depositary”), or as otherwise directed by the Depositary. Ownership of beneficial interests
in the Warrants shall be shown on, and the transfer of such ownership shall be effected through, records maintained by (i) the
Depositary or its nominee for each Global Warrant or (ii) institutions that have accounts with the Depositary (such institution,
with respect to a Warrant in its account, a “Participant”).

 

(b)       If
the Depositary subsequently ceases to make its book-entry settlement system available for the Warrants, the Company may instruct
the Warrant Agent regarding other arrangements for book-entry settlement. In the event that the Warrants are not eligible for,
or it is no longer necessary to have the Warrants available in, book-entry form, the Warrant Agent shall provide written instructions
to the Depositary to deliver to the Warrant Agent for cancellation each Global Warrant, and the Company shall instruct the Warrant
Agent to deliver to each Holder a Warrant Certificate.

 

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(c)       A
Holder has the right to elect at any time or from time to time a Warrant Exchange (as defined below) pursuant to a Warrant Certificate
Request Notice (as defined below). Upon written notice by a Holder to the Warrant Agent for the exchange of some or all of such
Holder’s Global Warrants for a Warrant Certificate evidencing the same number of Warrants, which request shall be in the
form attached hereto as Annex A (a “Warrant Certificate Request Notice” and the date of delivery of such Warrant Certificate
Request Notice by the Holder, the “Warrant Certificate Request Notice Date” and the deemed surrender upon delivery
by the Holder of a number of Global Warrants for the same number of Warrants evidenced by a Warrant Certificate, a “Warrant
Exchange”), the Warrant Agent shall promptly effect the Warrant Exchange and shall promptly issue and deliver to the Holder
a Warrant Certificate for such number of Warrants in the name set forth in the Warrant Certificate Request Notice. Such Warrant
Certificate shall be dated the original issue date of the Warrants and shall be manually executed by an authorized signatory of
the Company. In connection with a Warrant Exchange, the Company agrees to deliver, or to direct the Warrant Agent to deliver, the
Warrant Certificate to the Holder within three (3) Business Days of the Warrant Certificate Request Notice pursuant to the delivery
instructions in the Warrant Certificate Request Notice (“Warrant Certificate Delivery Date”). If the Company fails
for any reason to deliver to the Holder the Warrant Certificate subject to the Warrant Certificate Request Notice by the Warrant
Certificate Delivery Date, the Company shall pay to the Holder, in cash, as liquidated damages and not as a penalty, for each $1,000
of Warrant Shares evidenced by such Warrant Certificate (based on the VWAP (as defined in the Warrant) of the Common Stock on the
Warrant Certificate Request Notice Date), $10 per Business Day (increasing to $20 per Business Day on the fifth Business Day after
such liquidated damages begin to accrue) for each Business Day after such Warrant Certificate Delivery Date until such Warrant
Certificate is delivered or, prior to delivery of such Warrant Certificate, the Holder rescinds such Warrant Exchange. The Company
covenants and agrees that, upon the date of delivery of the Warrant Certificate Request Notice, the Holder shall be deemed to be
the holder of the Warrant Certificate and, notwithstanding anything to the contrary set forth herein, the Warrant Certificate shall
be deemed for all purposes to contain all of the terms and conditions of the Warrants evidenced by such Warrant Certificate and
the terms of this Agreement, other than Section 3(c), which shall not apply to the Warrants evidenced by a Warrant Certificate.
In the event a beneficial owner requests a Warrant Exchange, upon issuance of the paper Warrant Certificate, the Company shall
act as warrant agent and the terms of the paper Warrant Certificate so issued shall exclusively govern in respect thereof. For
purposes of clarity, if there is a conflict between the express terms of this Agreement and any Warrant Certificate with respect
to the terms of the Warrants, the terms of such Warrant Certificate shall govern and control.

 

Section 4.         Form
of Warrant. The Warrants, together with the form of election to purchase Common Stock (the “Exercise Notice”) and the
form of assignment to be printed on the reverse thereof, whether a Warrant Certificate or a Global Warrant, shall be substantially
in the form of Exhibit 1 hereto.

 

Section 5.        Countersignature
and Registration. The Warrants shall be executed on behalf of the Company by its Chief Executive Officer or Chief Financial Officer,
either manually or by facsimile signature, and have affixed thereto the Company’s seal or a facsimile thereof which shall
be attested by the Secretary or an Assistant Secretary of the Company, either manually or by facsimile signature. The Warrants
shall be countersigned by the Warrant Agent either manually or by facsimile signature and shall not be valid for any purpose unless
so countersigned. In case any officer of the Company who shall have signed a Warrant shall cease to be such officer of the Company
before countersignature by the Warrant Agent and issuance and delivery by the Company, such Warrant, nevertheless, may be countersigned
by the Warrant Agent, issued and delivered with the same force and effect as though the person who signed such Warrant had not
ceased to be such officer of the Company; and any Warrant may be signed on behalf of the Company by any person who, at the actual
date of the execution of such Warrant, shall be a proper officer of the Company to sign such Warrant, although at the date of the
execution of this Warrant Agreement any such person was not such an officer.

 

The Warrant Agent will
keep or cause to be kept, at one of its offices, or at the office of one of its agents, books for registration and transfer of
the Warrant Certificates issued hereunder. Such books shall show the names and addresses of the respective Holders of the Warrant
Certificates, the number of warrants evidenced on the face of each of such Warrant Certificate and the date of each of such Warrant
Certificate. The Warrant Agent will create a special account for the issuance of Warrant Certificates.

 

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Section 6.         Transfer,
Split Up, Combination and Exchange of Warrant Certificates; Mutilated, Destroyed, Lost or Stolen Warrant Certificates. Subject
to the provisions of the Warrant and the last sentence of this first paragraph of Section 6 and subject to applicable law, rules
or regulations, or any “stop transfer” instructions the Company may give to the Warrant Agent, at any time after the
closing date of the Offering, and at or prior to the Close of Business on the Termination Date, any Warrant Certificate or Warrant
Certificates or Global Warrant or Global Warrants may be transferred, split up, combined or exchanged for another Warrant Certificate
or Warrant Certificates or Global Warrant or Global Warrants, entitling the Holder to purchase a like number of shares of Common
Stock as the Warrant Certificate or Warrant Certificates or Global Warrant or Global Warrants surrendered then entitled such Holder
to purchase. Any Holder desiring to transfer, split up, combine or exchange any Warrant Certificate or Global Warrant shall make
such request in writing delivered to the Warrant Agent, and shall surrender the Warrant Certificate or Warrant Certificates to
be transferred, split up, combined or exchanged at the principal office of the Warrant Agent, provided that no such surrender is
applicable to the Holder of a Global Warrant. Any requested transfer of Warrants, whether a Global Warrant or a Warrant Certificate,
shall be accompanied by reasonable evidence of authority of the party making such request that may be required by the Warrant Agent.
Thereupon the Warrant Agent shall, subject to the last sentence of this first paragraph of Section 6, countersign and deliver to
the Person entitled thereto any Warrant Certificate or Global Warrant, as the case may be, as so requested. The Company may require
payment from the Holder of a sum sufficient to cover any tax or governmental charge that may be imposed in connection with any
transfer, split up, combination or exchange of Warrants. The Company shall compensate the Warrant Agent per the fee schedule mutually
agreed upon by the parties hereto and provided separately on the date hereof.

 

Upon receipt by the Warrant
Agent of evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of a Warrant Certificate, which evidence
shall include an affidavit of loss, or in the case of mutilated certificates, the certificate or portion thereof remaining, and,
in case of loss, theft or destruction, of indemnity in customary form and amount, and satisfaction of any other reasonable requirements
established by Section 8-405 of the Uniform Commercial Code as in effect in the State of Nevada, and reimbursement to the Company
and the Warrant Agent of all reasonable expenses incidental thereto, and upon surrender to the Warrant Agent and cancellation of
the Warrant Certificate if mutilated, the Company will make and deliver a new Warrant Certificate of like tenor to the Warrant
Agent for delivery to the Holder in lieu of the Warrant Certificate so lost, stolen, destroyed or mutilated.

 

Section 7.         Exercise
of Warrants; Exercise Price; Termination Date.

 

(a)       The
Warrants shall be exercisable commencing on the Initial Exercise Date. The Warrants shall cease to be exercisable and shall terminate
and become void, and all rights thereunder and under this Agreement shall cease, at or prior to the Close of Business on the Termination
Date. Subject to the foregoing and to Section 7(b) below, the Holder of a Warrant may exercise the Warrant in whole or in part
upon providing the items required by Section 7(c) below to the Warrant Agent at the principal office of the Warrant Agent or to
the office of one of its agents as may be designated by the Warrant Agent from time to time. In the case of the Holder of a Global
Warrant, the Holder shall deliver the executed Exercise Notice and payment of the Exercise Price pursuant to Section 2(a) of the
Warrant. Notwithstanding any other provision in this Agreement, a holder whose interest in a Global Warrant is a beneficial interest
in a Global Warrant held in book-entry form through the Depositary (or another established clearing corporation performing similar
functions), shall effect exercises by delivering to the Depositary (or such other clearing corporation, as applicable) the appropriate
instruction form for exercise, complying with the procedures to effect exercise that are required by the Depositary (or such other
clearing corporation, as applicable). The Company acknowledges that the bank accounts maintained by the Warrant Agent in connection
with the services provided under this Agreement will be in its name and that the Warrant Agent may receive investment earnings
in connection with the investment at Warrant Agent risk and for its benefit of funds held in those accounts from time to time.
Neither the Company nor the Holders will receive interest on any deposits or Exercise Price.

 

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(b)       Upon
receipt of an Exercise Notice for a cashless exercise pursuant to Section 2(c) of the Warrant (each, a “Cashless Exercise”),
the Company will promptly calculate and transmit to the Warrant Agent the number of Warrant Shares issuable in connection with
such Cashless Exercise and deliver a copy of the Exercise Notice to the Warrant Agent, which shall issue such number of Warrant
Shares in connection with such Cashless Exercise.

 

(c)       Upon
the Warrant Agent’s receipt, at or prior to the Close of Business on the Termination Date set forth in a Warrant, of the
executed Exercise Notice, accompanied by payment of the Exercise Price pursuant to Section 2(a) of the Warrant, the shares to be
purchased (other than in the case of a Cashless Exercise), an amount equal to any applicable tax, governmental charge or expense
reimbursement referred to in Section 6 in cash, or by certified check or bank draft payable to the order of the Company and, in
the case of an exercise of a Warrant in the form of a Warrant Certificate for all of the Warrant Shares represented thereby, the
Warrant Certificate, the Warrant Agent shall cause the Warrant Shares underlying such Warrant to be delivered to or upon the order
of the Holder of such Warrant, registered in such name or names as may be designated by such Holder, no later than the Warrant
Share Delivery Date. If the Company is then a participant in the DWAC system of the Depositary and either (A) there is an effective
registration statement permitting the issuance of the Warrant Shares to or resale of the Warrant Shares by Holder or (B) the Warrant
is being exercised via Cashless Exercise, then the certificates for Warrant Shares shall be transmitted by the Warrant Agent to
the Holder by crediting the account of the Holder’s broker with the Depositary through its DWAC system. For the avoidance
of doubt, if the Company becomes obligated to pay any amounts to any Holders pursuant to Section 2(d)(i) or 2(d)(iv) of the Warrant,
such obligation shall be solely that of the Company and not that of the Warrant Agent. Notwithstanding anything else to the contrary
in this Agreement, except in the case of a Cashless Exercise, if any Holder fails to duly deliver payment to the Warrant Agent
of an amount equal to the aggregate Exercise Price of the Warrant Shares to be purchased upon exercise of such Holder’s Warrant
as set forth in Section 7(a) hereof, the Warrant Agent will not obligated to deliver certificates representing any such Warrant
Shares (via DWAC or otherwise) until following receipt of such payment, and the applicable Warrant Share Delivery Date shall be
deemed extended by one day for each day (or part thereof) until such payment is delivered to the Warrant Agent.

 

(d)       The
Warrant Agent shall deposit all funds received by it in payment of the Exercise Price for all Warrants in the account of the Company
maintained with the Warrant Agent for such purpose (or to such other account as directed by the Company in writing) and shall advise
the Company via telephone at the end of each day on which funds for the exercise of any Warrant are received of the amount so deposited
to its account. The Warrant Agent shall promptly confirm such telephonic advice to the Company in writing.

 

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(e)       In
case the Holder of any Warrant Certificate exercises fewer than all Warrants evidenced thereby and surrenders such Warrant Certificate
in connection with such partial exercise, a new Warrant Certificate evidencing the number of Warrant Shares equivalent to the number
of Warrant Shares remaining unexercised may be issued by the Warrant Agent to the Holder of such Warrant Certificate or to his
duly authorized assigns in accordance with Section 2(d)(ii) of the Warrant, subject to the provisions of Section 6 hereof.

 

Section 8.         Cancellation
and Destruction of Warrant Certificates. All Warrant Certificates surrendered for the purpose of exercise, transfer, split up,
combination or exchange shall, if surrendered to the Company or to any of its agents, be delivered to the Warrant Agent for cancellation
or in canceled form, or, if surrendered to the Warrant Agent, shall be canceled by it, and no Warrant Certificates shall be issued
in lieu thereof except as expressly permitted by any of the provisions of this Agreement. The Company shall deliver to the Warrant
Agent for cancellation and retirement, and the Warrant Agent shall so cancel and retire, any other Warrant Certificate purchased
or acquired by the Company otherwise than upon the exercise thereof. The Warrant Agent shall deliver all canceled Warrant Certificates
to the Company, or shall, at the written request of the Company, destroy such canceled Warrant Certificates, and in such case shall
deliver a certificate of destruction thereof to the Company, subject to any applicable law, rule or regulation requiring the Warrant
Agent to retain such canceled certificates.

 

Section 9.         Certain
Representations; Reservation and Availability of Shares of Common Stock or Cash.

 

(a)       This
Agreement has been duly authorized, executed and delivered by the Company and, assuming due authorization, execution and delivery
hereof by the Warrant Agent, constitutes a valid and legally binding obligation of the Company enforceable against the Company
in accordance with its terms, and the Warrants have been duly authorized, executed and issued by the Company and, assuming due
authentication thereof by the Warrant Agent pursuant hereto and payment therefor by the Holders as provided in the Registration
Statement, constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their
terms and entitled to the benefits thereof; in each case except as enforceability may be limited by bankruptcy, insolvency, reorganization,
moratorium and other similar laws relating to or affecting creditors’ rights generally or by general equitable principles
(regardless of whether such enforceability is considered in a proceeding in equity or at law).

 

(b)       As
of the date hereof and prior to the Offering, the authorized capital stock of the Company consists of (i) 200,000,000 shares of
authorized Common Stock, of which 7,208,320 shares of Common Stock are issued and outstanding, and (ii) 10,000,000 shares of authorized
preferred stock of which 120,000 are issued and outstanding. As of the date hereof there are 18,620,998 shares of Common Stock
reserved for issuance upon exercise of the Warrants inclusive of any Warrants the Underwriter may acquire upon exercise of its
over-allotment option described in the Registration Statement. Except as disclosed in the Registration Statement, there are no
other outstanding obligations, warrants, options or other rights to subscribe for or purchase from the Company any class of capital
stock of the Company.

 

(c)       The
Company covenants and agrees that it will cause to be reserved and kept available out of its authorized and unissued shares of
Common Stock or its authorized and issued shares of Common Stock held in its treasury, free from preemptive rights, the number
of shares of Common Stock that will be sufficient to permit the exercise in full of all outstanding Warrants.

 

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(d)       The
Warrant Agent will create a special account for the issuance of Common Stock upon the exercise of Warrants.

 

(e)       The
Company further covenants and agrees that it will pay when due and payable any and all federal and state transfer taxes and charges
which may be payable in respect of the original issuance or delivery of the Warrant Certificates or certificates evidencing Common
Stock upon exercise of the Warrants. The Company shall not, however, be required to pay any tax or governmental charge which may
be payable in respect of any transfer involved in the transfer or delivery of Warrant Certificates or the issuance or delivery
of certificates for Common Stock in a name other than that of the Holder of the Warrant Certificate evidencing Warrants surrendered
for exercise or to issue or deliver any certificate for shares of Common Stock upon the exercise of any Warrants until any such
tax or governmental charge shall have been paid (any such tax or governmental charge being payable by the Holder of such Warrant
Certificate at the time of surrender) or until it has been established to the Company’s reasonable satisfaction that no such
tax or governmental charge is due.

 

Section 10.       Common
Stock Record Date. Each Holder shall be deemed to have become the holder of record for the Warrant Shares pursuant to Section 2(d)(i)
of the Warrants.

 

Section 11.        Adjustment
of Exercise Price, Number of Shares of Common Stock or Number of the Company Warrants. The Exercise Price, the number of shares
covered by each Warrant and the number of Warrants outstanding are subject to adjustment from time to time as provided in Section
3 of the Warrant. In the event that at any time, as a result of an adjustment made pursuant to Section 3 of the Warrant, the Holder
of any Warrant thereafter exercised shall become entitled to receive any shares of capital stock of the Company other than shares
of Common Stock, thereafter the number of such other shares so receivable upon exercise of any Warrant shall be subject to adjustment
from time to time in a manner and on terms as nearly equivalent as practicable to the provisions with respect to the shares contained
in Section 3 of the Warrant, and the provisions of Sections 7, 9 and 13 of this Agreement with respect to the shares of Common
Stock shall apply on like terms to any such other shares. All Warrants originally issued by the Company subsequent to any adjustment
made to the Exercise Price pursuant to the Warrant shall evidence the right to purchase, at the adjusted Exercise Price, the number
of shares of Common Stock purchasable from time to time hereunder upon exercise of the Warrants, all subject to further adjustment
as provided herein.

 

Section 12.        Certification
of Adjusted Exercise Price or Number of Shares of Common Stock. Whenever the Exercise Price or the number of shares of Common Stock
issuable upon the exercise of each Warrant is adjusted as provided in Section 11 or 13, the Company shall (a) promptly prepare
a certificate setting forth the Exercise Price of each Warrant as so adjusted, and a brief statement of the facts accounting for
such adjustment, (b) promptly file with the Warrant Agent and with each transfer agent for the Common Stock a copy of such certificate
and (c) instruct the Warrant Agent to send a brief summary thereof to each Holder of a Warrant.

 

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Section 13.        Fractional
Shares of Common Stock.

 

(a)       The
Company shall not issue fractions of Warrants or distribute a Global Warrant or Warrant Certificates that evidence fractional Warrants.
Whenever any fractional Warrant would otherwise be required to be issued or distributed, the actual issuance or distribution shall
reflect a rounding of such fraction either up or down to the nearest whole Warrant.

 

(b)       The
Company shall not issue fractions of shares of Common Stock upon exercise of Warrants or distribute stock certificates that evidence
fractional shares of Common Stock. Whenever any fraction of a share of Common Stock would otherwise be required to be issued or
distributed, the actual issuance or distribution in respect thereof shall be made in accordance with Section 2(d)(v) of the Warrant.

 

Section 14.         Conditions
of the Warrant Agent’s Obligations. The Warrant Agent accepts its obligations herein set forth upon the terms and conditions
hereof, including the following to all of which the Company agrees and to all of which the rights hereunder of the Holders from
time to time of the Warrant shall be subject:

 

(a)       Compensation
and Indemnification. The Company agrees promptly to pay the Warrant Agent the compensation detailed on Exhibit 2 hereto for all
services rendered by the Warrant Agent and to reimburse the Warrant Agent for reasonable out-of-pocket expenses (including reasonable
counsel fees) incurred without gross negligence, bad faith or willful misconduct by the Warrant Agent in connection with the services
rendered hereunder by the Warrant Agent. The Company also agrees to indemnify the Warrant Agent for, and to hold it harmless against,
any loss, liability or expense incurred without gross negligence, bad faith or willful misconduct on the part of the Warrant Agent,
arising out of or in connection with its acting as Warrant Agent hereunder, including the reasonable costs and expenses of defending
against any claim of such liability.

 

(b)       Agent
for the Company. In acting under this Warrant Agreement and in connection with the Warrant Certificates, the Warrant Agent is acting
solely as agent of the Company and does not assume any obligations or relationship of agency or trust for or with any of the Holders
of Warrant Certificates or beneficial owners of Warrants.

 

(c)       Counsel.
The Warrant Agent may consult with counsel satisfactory to it, which may include counsel for the Company, and the written advice
of such counsel shall be full and complete authorization and protection in respect of any action taken, suffered or omitted by
it hereunder in good faith and in accordance with the advice of such counsel.

 

(d)       Documents.
The Warrant Agent shall be protected and shall incur no liability for or in respect of any action taken or omitted by it in reliance
upon any Warrant Certificate, notice, direction, consent, certificate, affidavit, statement or other paper or document reasonably
believed by it to be genuine and to have been presented or signed by the proper parties.

 

(e)       Certain
Transactions. The Warrant Agent, and its officers, directors and employees, may become the owner of, or acquire any interest in,
Warrants, with the same rights that it or they would have if it were not the Warrant Agent hereunder, and, to the extent permitted
by applicable law, it or they may engage or be interested in any financial or other transaction with the Company and may act on,
or as depositary, trustee or agent for, any committee or body of Holders of Warrant Securities or other obligations of the Company
as freely as if it were not the Warrant Agent hereunder. Nothing in this Warrant Agreement shall be deemed to prevent the Warrant
Agent from acting as trustee under any indenture to which the Company is a party.

 

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(f)       No
Liability for Interest. Unless otherwise agreed with the Company, the Warrant Agent shall have no liability for interest on any
monies at any time received by it pursuant to any of the provisions of this Agreement or of the Warrant Certificates.

 

(g)       No
Liability for Invalidity. The Warrant Agent shall have no liability with respect to any invalidity of this Agreement or any of
the Warrant Certificates (except as to the Warrant Agent’s countersignature thereon).

 

(h)       No
Responsibility for Representations. The Warrant Agent shall not be responsible for any of the recitals or representations herein
or in the Warrant Certificates (except as to the Warrant Agent’s countersignature thereon), all of which are made solely
by the Company.

 

(i)       No
Implied Obligations. The Warrant Agent shall be obligated to perform only such duties as are herein and in the Warrants specifically
set forth and no implied duties or obligations shall be read into this Agreement or the Warrants against the Warrant Agent. The
Warrant Agent shall not be under any obligation to take any action hereunder which may tend to involve it in any expense or liability,
the payment of which within a reasonable time is not, in its reasonable opinion, assured to it. The Warrant Agent shall not be
accountable or under any duty or responsibility for the use by the Company of any of the Warrants authenticated by the Warrant
Agent and delivered by it to the Company pursuant to this Agreement or for the application by the Company of the proceeds of the
Warrants. The Warrant Agent shall have no duty or responsibility in case of any default by the Company in the performance of its
covenants or agreements contained herein or in the Warrants or in the case of the receipt of any written demand from a Holder of
a Warrant Certificate with respect to such default, including, without limiting the generality of the foregoing, any duty or responsibility
to initiate or attempt to initiate any proceedings at law.

 

Section 15.         Purchase
or Consolidation or Change of Name of Warrant Agent. Any corporation into which the Warrant Agent or any successor Warrant Agent
may be merged or with which it may be consolidated, or any corporation resulting from any merger or consolidation to which the
Warrant Agent or any successor Warrant Agent shall be party, or any corporation succeeding to the corporate trust business of the
Warrant Agent or any successor Warrant Agent, shall be the successor to the Warrant Agent under this Agreement without the execution
or filing of any paper or any further act on the part of any of the parties hereto, provided that such corporation would be eligible
for appointment as a successor Warrant Agent under the provisions of Section 17. In case at the time such successor Warrant Agent
shall succeed to the agency created by this Agreement any of the Warrants shall have been countersigned but not delivered, any
such successor Warrant Agent may adopt the countersignature of the predecessor Warrant Agent and deliver such Warrants so countersigned;
and in case at that time any of the Warrants shall not have been countersigned, any successor Warrant Agent may countersign such
Warrants either in the name of the predecessor Warrant Agent or in the name of the successor Warrant Agent; and in all such cases
such Warrants shall have the full force provided in the Warrants and in this Agreement.

 

In case at any time the
name of the Warrant Agent shall be changed and at such time any of the Warrants shall have been countersigned but not delivered,
the Warrant Agent may adopt the countersignature under its prior name and deliver Warrants so countersigned; and in case at that
time any of the Warrants shall not have been countersigned, the Warrant Agent may countersign such Warrants either in its prior
name or in its changed name; and in all such cases such Warrants shall have the full force provided in the Warrants and in this
Agreement.

 

    	 	10	 

     

    

  

Section 16.        Duties
of Warrant Agent. The Warrant Agent undertakes the duties and obligations imposed by this Agreement upon the following terms and
conditions, all of which the Company, by its acceptance hereof, shall be bound:

 

(a)       The
Warrant Agent may consult with legal counsel reasonably acceptable to the Company (who may be legal counsel for the Company), and
the opinion of such counsel shall be full and complete authorization and protection to the Warrant Agent as to any action taken
or omitted by it in good faith and in accordance with such opinion.

 

(b)       Whenever
in the performance of its duties under this Agreement the Warrant Agent shall deem it necessary or desirable that any fact or matter
be proved or established by the Company prior to taking or suffering any action hereunder, such fact or matter (unless other evidence
in respect thereof be herein specifically prescribed) may be deemed to be conclusively proved and established by a certificate
signed by the Chief Executive Officer or Chief Financial Officer of the Company; and such certificate shall be full authentication
to the Warrant Agent for any action taken or suffered in good faith by it under the provisions of this Agreement in reliance upon
such certificate.

 

(c)       Subject
to the limitation set forth in Section 14, the Warrant Agent shall be liable hereunder only for its own gross negligence, bad faith
or willful misconduct, or for a breach by it of this Agreement.

 

(d)       The
Warrant Agent shall not be liable for or by reason of any of the statements of fact or recitals contained in this Agreement or
in the Warrants (except its countersignature thereof) by the Company or be required to verify the same, but all such statements
and recitals are and shall be deemed to have been made by the Company only.

 

(e)       The
Warrant Agent shall not be under any responsibility in respect of the validity of this Agreement or the execution and delivery
hereof (except the due execution hereof by the Warrant Agent) or in respect of the validity or execution of any Warrant (except
its countersignature thereof); nor shall it be responsible for any breach by the Company of any covenant or condition contained
in this Agreement or in any Warrant; nor shall it be responsible for the adjustment of the Exercise Price or the making of any
change in the number of shares of Common Stock required under the provisions of Section 11 or 13 or responsible for the manner,
method or amount of any such change or the ascertaining of the existence of facts that would require any such adjustment or change
(except with respect to the exercise of Warrants evidenced by Warrant Certificates after actual notice of any adjustment of the
Exercise Price); nor shall it by any act hereunder be deemed to make any representation or warranty as to the authorization or
reservation of any shares of Common Stock to be issued pursuant to this Agreement or any Warrant or as to whether any shares of
Common Stock will, when issued, be duly authorized, validly issued, fully paid and nonassessable.

 

(f)       Each
party hereto agrees that it will perform, execute, acknowledge and deliver or cause to be performed, executed, acknowledged and
delivered all such further and other acts, instruments and assurances as may reasonably be required by the other party hereto for
the carrying out or performing by any party of the provisions of this Agreement.

 

    	 	11	 

     

    

  

(g)       The
Warrant Agent is hereby authorized to accept instructions with respect to the performance of its duties hereunder from the Chief
Executive Officer or Chief Financial Officer of the Company, and to apply to such officers for advice or instructions in connection
with its duties, and it shall not be liable and shall be indemnified and held harmless for any action taken or suffered to be taken
by it in good faith in accordance with instructions of any such officer, provided Warrant Agent carries out such instructions without
gross negligence, bad faith or willful misconduct.

 

(h)       The
Warrant Agent and any shareholder, director, officer or employee of the Warrant Agent may buy, sell or deal in any of the Warrants
or other securities of the Company or become pecuniarily interested in any transaction in which the Company may be interested,
or contract with or lend money to the Company or otherwise act as fully and freely as though it were not Warrant Agent under this
Agreement. Nothing herein shall preclude the Warrant Agent from acting in any other capacity for the Company or for any other legal
entity.

 

(i)       The
Warrant Agent may execute and exercise any of the rights or powers hereby vested in it or perform any duty hereunder either itself
or by or through its attorney or agents, and the Warrant Agent shall not be answerable or accountable for any act, default, neglect
or misconduct of any such attorney or agents or for any loss to the Company resulting from any such act, default, neglect or misconduct,
provided reasonable care was exercised in the selection and continued employment thereof.

 

Section 17.        Change
of Warrant Agent. The Warrant Agent may resign and be discharged from its duties under this Agreement upon 30 days’ notice
in writing sent to the Company and to each transfer agent of the Common Stock, and to the Holders of the Warrant Certificates.
The Company may remove the Warrant Agent or any successor Warrant Agent upon 30 days’ notice in writing, sent to the Warrant
Agent or successor Warrant Agent, as the case may be, and to each transfer agent of the Common Stock, and to the Holders of the
Warrant Certificates. If the Warrant Agent shall resign or be removed or shall otherwise become incapable of acting, the Company
shall appoint a successor to the Warrant Agent. If the Company shall fail to make such appointment within a period of 30 days after
such removal or after it has been notified in writing of such resignation or incapacity by the resigning or incapacitated Warrant
Agent or by the Holder of a Warrant Certificate (who shall, with such notice, submit his Warrant Certificate for inspection by
the Company), then the Holder of any Warrant Certificate may apply to any court of competent jurisdiction for the appointment of
a new Warrant Agent. Any successor Warrant Agent, whether appointed by the Company or by such a court, shall be a corporation organized
and doing business under the laws of the United States or of a state thereof, in good standing, which is authorized under such
laws to exercise corporate trust powers and is subject to supervision or examination by federal or state authority and which has
at the time of its appointment as Warrant Agent a combined capital and surplus of at least $50,000,000. After appointment, the
successor Warrant Agent shall be vested with the same powers, rights, duties and responsibilities as if it had been originally
named as Warrant Agent without further act or deed; but the predecessor Warrant Agent shall deliver and transfer to the successor
Warrant Agent any property at the time held by it hereunder, and execute and deliver any further assurance, conveyance, act or
deed necessary for the purpose. Not later than the effective date of any such appointment, the Company shall file notice thereof
in writing with the predecessor Warrant Agent and each transfer agent of the Common Stock, and mail a notice thereof in writing
to the Holders of the Warrant Certificates. However, failure to give any notice provided for in this Section 17, or any defect
therein, shall not affect the legality or validity of the resignation or removal of the Warrant Agent or the appointment of the
successor Warrant Agent, as the case may be.

 

    	 	12	 

     

    

  

Section 18.        Issuance
of New Warrants. Notwithstanding any of the provisions of this Agreement or of the Warrants to the contrary, the Company may, at
its option, issue a new Global Warrant or Warrant Certificates, if any, evidencing Warrants in such form as may be approved by
its Board of Directors to reflect any adjustment or change in the Exercise Price per share and the number or kind or class of shares
of stock or other securities or property purchasable under the Global Warrant or Warrant Certificates, if any, made in accordance
with the provisions of this Agreement.

 

Section 19.        Notices.
Notices or demands authorized by this Agreement to be given or made (i) by the Warrant Agent or by the Holder of any Warrant Certificate
to or on the Company, (ii) subject to the provisions of Section 17, by the Company or by the Holder of any Warrant Certificate
to or on the Warrant Agent or (iii) by the Company or the Warrant Agent to the Holder of any Warrant Certificate, shall be deemed
given (a) on the date delivered, if delivered personally, (b) on the first Business Day following the deposit thereof with Federal
Express or another recognized overnight courier, if sent by Federal Express or another recognized overnight courier, (c) on the
fourth Business Day following the mailing thereof with postage prepaid, if mailed by registered or certified mail (return receipt
requested), and (d) the time of transmission, if such notice or communication is delivered via facsimile or email attachment at
or prior to 5:30 p.m. (New York City time) on a Business Day and (e) the next Business Day after the date of transmission, if such
notice or communication is delivered via facsimile or email attachment on a day that is not a Business Day or later than 5:30 p.m.
(New York City time) on any Business Day, in each case to the parties at the following addresses (or at such other address for
a party as shall be specified by like notice):

 

(a)       If
to the Company, to:

 

Synthetic Biologics,
Inc.

9605 Medical Center
Drive, Suite 270

Rockville, Maryland
20850

Attention: 

 

(b)       If
to the Warrant Agent, to:

 

Corporate Stock
Transfer, Inc.

3200 Cherry Creek
South Drive, Suite 430

Denver, Colorado 80209

Attention: Carylyn Bell

 

For any notice delivered
by email to be deemed given or made, such notice must be followed by notice sent by overnight courier service to be delivered on
the next business day following such email, unless the recipient of such email has acknowledged via return email receipt of such
email.

 

(c)       If
to the Holder of any Warrant Certificate, to the address of such Holder as shown on the registry books of the Company. Any notice
required to be delivered by the Company to the Holder of any Warrant may be given by the Warrant Agent on behalf of the Company.
Notwithstanding any other provision of this Agreement, where this Agreement provides for notice of any event to a Holder of any
Warrant Certificate, for a Global Warrant, such notice shall be sufficiently given if given to the Depositary (or its designee)
pursuant to the procedures of the Depositary or its designee.

 

    	 	13	 

     

    

  

Section 20.         Supplements
and Amendments.

 

(a)       The
Company and the Warrant Agent may from time to time supplement or amend this Agreement without the approval of any Holders of Warrant
Certificates in order to cure any ambiguity, to correct or supplement any provision contained herein which may be defective or
inconsistent with any other provisions herein, or to make any other provisions with regard to matters or questions arising hereunder
which the Company and the Warrant Agent may deem necessary or desirable and which shall not adversely affect the interests of the
Holders of the Warrants Certificates in any material respect.

 

(b)       In
addition to the foregoing, with the consent of Holders of Warrants, the Company and the Warrant Agent may modify this Agreement
for the purpose of adding any provisions to or changing in any manner or eliminating any of the provisions of this Warrant Agreement
or modifying in any manner the rights of the Holders of the Warrant Certificates; provided, however, that no modification of the
terms (including but not limited to the adjustments described in Section 11) upon which the Warrants are exercisable or reducing
the percentage required for consent to modification of this Agreement may be made without the consent of the Holder of each outstanding
warrant certificate affected thereby. As a condition precedent to the Warrant Agent’s execution of any amendment, the Company
shall deliver to the Warrant Agent a certificate from a duly authorized officer of the Company that states that the proposed amendment
complies with the terms of this Section 20.

 

Section 21.       Successors.
All covenants and provisions of this Agreement by or for the benefit of the Company or the Warrant Agent shall bind and inure to
the benefit of their respective successors and assigns hereunder.

 

Section 22.       Benefits
of this Agreement. Nothing in this Agreement shall be construed to give any Person other than the Company, the Holders of Warrant
Certificates and the Warrant Agent any legal or equitable right, remedy or claim under this Agreement; but this Agreement shall
be for the sole and exclusive benefit of the Company, the Warrant Agent and the Holders of the Warrant Certificates.

 

Section 23.        Governing
Law. This Agreement and each Warrant issued hereunder shall be governed by, and construed in accordance with, the laws of the State
of New York without giving effect to the conflicts of law principles thereof.

 

Section 24.        Counterparts.
This Agreement may be executed in any number of counterparts and each of such counterparts shall for all purposes be deemed to
be an original, and all such counterparts shall together constitute but one and the same instrument.

 

Section 25.       Captions.
The captions of the sections of this Agreement have been inserted for convenience only and shall not control or affect the meaning
or construction of any of the provisions hereof.

 

Section 26.        Information.
The Company agrees to promptly provide to the Holders of the Warrants any information it provides to all holders of the Common
Stock, except to the extent any such information is publicly available on the EDGAR system (or any successor thereof) of the Securities
and Exchange Commission.

 

    	 	14	 

     

    

  

Section 27.        Force
Majeure. Notwithstanding anything to the contrary contained herein, Warrant Agent shall not be liable for any delays or failures
in performance resulting from acts beyond its reasonable control including, without limitation, acts of God, terrorist acts, shortage
of supply, breakdowns or malfunctions, interruptions or malfunction of computer facilities, or loss of data due to power failures
or mechanical difficulties with information storage or retrieval systems, labor difficulties, war, or civil unrest, it being understood
that the Warrant Agent shall use reasonable best efforts which are consistent with accepted practices in the banking industry to
resume performance as soon as practicable under the circumstances.

 

********************

 

(Signature
Page Follows)

 

    	 	15	 

     

    

 

IN WITNESS WHEREOF, the
parties hereto have caused this Agreement to be duly executed as of the day and year first above written.

 

	 	SYNTHETIC BIOLOGICS, INC.
	 	 	 
	 	By:	/s/ Steven A. Shallcross
	 	Name:	Steven A. Shallcross
	 	Title:	Interim Chief Executive Officer and Chief Financial Officer
	 	 	 
	 	CORPORATE STOCK TRANSFER, INC.
	 	 	 
	 	By:	/s/ Carylyn Bell
	 	Name:	Carylyn Bell
	 	Title:	President

 

    	 	16	 

     

    

  

Annex
A: Form of Warrant Certificate Request Notice

 

WARRANT
CERTIFICATE REQUEST NOTICE

 

To: Corporate
Stock Transfer, Inc. as Warrant Agent for Synthetic Biologics, Inc. (the “Company”)

 

The undersigned
Holder of Common Stock Purchase Warrants (“Warrants”) in the form of Global Warrants issued by the Company hereby elects
to receive a Warrant Certificate evidencing the Warrants held by the Holder as specified below:

 

		1.	Name of Holder of Warrants in form of Global Warrants: _____________________________

 

		2.	Name of Holder in Warrant Certificate (if different from name of Holder of Warrants in
form of Global Warrants): ________________________________

 

		3.	Number of Warrants in name of Holder in form of Global Warrants: ___________________

 

		4.	Number of Warrants for which Warrant Certificate shall be issued: __________________

 

		5.	Number of Warrants in name of Holder in form of Global Warrants after issuance of Warrant
Certificate, if any: ___________

 

		6.	Warrant Certificate shall be delivered to the following address:

 

__________________________________

 

__________________________________

 

__________________________________

 

__________________________________

 

The undersigned
hereby acknowledges and agrees that, in connection with this Warrant Exchange and the issuance of the Warrant Certificate, the
Holder is deemed to have surrendered the number of Warrants in form of Global Warrants in the name of the Holder equal to the number
of Warrants evidenced by the Warrant Certificate.

 

[SIGNATURE OF HOLDER]

 

Name of Investing Entity:
___________________________________________________________________

 

Signature of Authorized Signatory
of Investing Entity: _____________________________________________

 

Name of Authorized Signatory:
_______________________________________________________________

 

Title of Authorized Signatory:
________________________________________________________________

 

Date: ______________________________________________________________________________

 

    	 	17	 

     

    

  

Exhibit
1: Form of Warrant

 

    	 	18	 

     

    

  

COMMON
STOCK PURCHASE WARRANT

 

SYNTHETIC
BIOLOGICS, INC.

 

Warrant
Shares: _______ Initial Exercise Date: October 15, 2018

 

THIS
COMMON STOCK PURCHASE WARRANT (the “Warrant”) certifies that, for value received, _____________ or its assigns (the
 “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set
forth, at any time on or after October 15, 2018 (the “Initial Exercise Date”) and on or prior to 5:00 p.m. (New York
City time) on October 15, 2023 (the “Termination Date”) but not thereafter, to subscribe for and purchase from Synthetic
Biologics, Inc., a Nevada corporation (the “Company”), up to ______ shares (as subject to adjustment hereunder, the
 “Warrant Shares”) of Common Stock. The purchase price of one share of Common Stock under this Warrant shall be equal
to the Exercise Price, as defined in Section 2(b). This Warrant shall initially be issued and maintained in the form of a security
held in book-entry form and the Depository Trust Company or its nominee (“DTC”) shall initially be the sole registered
holder of this Warrant, subject to a Holder’s right to elect to receive a Warrant in certificated form pursuant to the terms
of the Warrant Agency Agreement, in which case this sentence shall not apply.

 

Section 1. Definitions.
In addition to the terms defined elsewhere in this Warrant, the following terms have the meanings indicated in this Section 1:

 

“Affiliate”
means any Person that, directly or indirectly through one or more intermediaries, controls or is controlled by or is under common
control with a Person, as such terms are used in and construed under Rule 405 under the Securities Act.

 

“Bid
Price” means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock
is then listed or quoted on a Trading Market, the bid price of the Common Stock for the time in question (or the nearest preceding
date) on the Trading Market on which the Common Stock is then listed or quoted as reported by Bloomberg L.P. (based on a Trading
Day from 9:30 a.m. (New York City time) to 4:02 p.m. (New York City time)), (b) if OTCQB or OTCQX is not a Trading Market, the
volume weighted average price of the Common Stock for such date (or the nearest preceding date) on OTCQB or OTCQX as applicable,
(c) if the Common Stock is not then listed or quoted for trading on OTCQB or OTCQX and if prices for the Common Stock are then
reported in the “Pink Sheets” published by OTC Markets Group, Inc. (or a similar organization or agency succeeding
to its functions of reporting prices), the most recent bid price per share of the Common Stock so reported, or (d) in all other
cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the
Holders of a majority in interest of the Warrants then outstanding and reasonably acceptable to the Company, the fees and expenses
of which shall be paid by the Company.

 

“Board
of Directors” means the board of directors of the Company.

 

    	 	19	 

     

    

  

“Business
Day” means any day except any Saturday, any Sunday, any day which is a federal legal holiday in the United States or any
day on which banking institutions in the State of New York are authorized or required by law or other governmental action to close.

 

“Commission”
means the United States Securities and Exchange Commission.

 

“Common
Stock” means the common stock of the Company, par value $0.001 per share, and any other class of securities into which such
securities may hereafter be reclassified or changed.

 

“Common
Stock Equivalents” means any securities of the Company or the Subsidiaries which would entitle the holder thereof to acquire
at any time Common Stock, including, without limitation, any debt, preferred stock, right, option, warrant or other instrument
that is at any time convertible into or exercisable or exchangeable for, or otherwise entitles the holder thereof to receive, Common
Stock.

 

“Exchange
Act” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

 

“Exempt
Issuance” means the issuance of (a) shares of Common Stock or options to employees, officers or directors of the Company
pursuant to any stock or option plan duly adopted for such purpose, by a majority of the non-employee members of the Board of Directors
or a majority of the members of a committee of non-employee directors established for such purpose for services rendered to the
Company, (b) securities upon the exercise or exchange of or conversion of any securities issued under the Registration Statement
and/or other securities exercisable or exchangeable for or convertible into shares of Common Stock issued and outstanding on the
date of this Warrant, provided that such securities have not been amended since the date of this Warrant to increase the number
of such securities or to decrease the exercise price, exchange price or conversion price of such securities (other than in connection
with stock splits or combinations) or to extend the term of such securities, and (c) securities issued pursuant to acquisitions
or strategic transactions approved by a majority of the disinterested directors of the Company, provided that such securities are
issued as “restricted securities” (as defined in Rule 144) and carry no registration rights that require or permit
the filing of any registration statement in connection therewith, and provided that any such issuance shall only be to a Person
(or to the equityholders of a Person) which is, itself or through its subsidiaries, an operating company or an owner of an asset
in a business synergistic with the business of the Company and shall provide to the Company additional benefits in addition to
the investment of funds, but shall not include a transaction in which the Company is issuing securities primarily for the purpose
of raising capital or to an entity whose primary business is investing in securities; it being agreed and understood that issuances
pursuant the Company’s agreement with Cedars-Sinai Medical Center are Exempt Issuances.

 

“Person”
means an individual or corporation, partnership, trust, incorporated or unincorporated association, joint venture, limited liability
company, joint stock company, government (or an agency or subdivision thereof) or other entity of any kind.

 

“Registration
Statement” means the Company’s registration statement on Form S-1, as amended (File No. 333-227400).

 

    	 	20	 

     

    

  

“Securities
Act” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

 

“Trading
Day” means a day on which the Common Stock is traded on a Trading Market.

 

“Trading
Market” means any of the following markets or exchanges on which the Common Stock is listed or quoted for trading on the
date in question: the NYSE American, the Nasdaq Capital Market, the Nasdaq Global Market, the Nasdaq Global Select Market, the
New York Stock Exchange, OTCQB or OTCQX (or any successors to any of the foregoing.

 

“Transfer
Agent” means Corporate Stock Transfer, Inc., the current transfer agent of the Company, with a mailing address of 3200 Cherry
Creek South Drive, Suite 430, Denver, Colorado 80209 and a facsimile number of 303-282-5800, and any successor transfer agent of
the Company.

 

“VWAP”
means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed
or quoted on a Trading Market, the daily volume weighted average price of the Common Stock for such date (or the nearest preceding
date) on the Trading Market on which the Common Stock is then listed or quoted as reported by Bloomberg L.P. (based on a Trading
Day from 9:30 a.m. (New York City time) to 4:02 p.m. (New York City time)), (b) if OTCQB or OTCQX is not a Trading Market, the
volume weighted average price of the Common Stock for such date (or the nearest preceding date) on OTCQB or OTCQX as applicable,
(c) if the Common Stock is not then listed or quoted for trading on OTCQB or OTCQX and if prices for the Common Stock are then
reported in the “Pink Sheets” published by OTC Markets Group, Inc. (or a similar organization or agency succeeding
to its functions of reporting prices), the most recent bid price per share of the Common Stock so reported, or (d) in all other
cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the
holders of a majority in interest of the Warrants then outstanding and reasonably acceptable to the Company, the fees and expenses
of which shall be paid by the Company.

 

“Warrant
Agency Agreement” means that certain warrant agency agreement, dated on or about the Initial Exercise Date, between the Company
and the Warrant Agent.

 

“Warrant
Agent” means the Transfer Agent and any successor warrant agent of the Company.

 

“Warrants”
means this Warrant and other Common Stock purchase warrants issued by the Company pursuant to the Registration Statement.

 

    	 	21	 

     

    

  

Section 2. Exercise.

 

a)             Exercise
of Warrant. Exercise of the purchase rights represented by this Warrant may be made, in whole or in part, at any time or times
on or after the Initial Exercise Date and on or before the Termination Date by delivery to the Company of a duly executed facsimile
copy or PDF copy submitted by e-mail (or e-mail attachment) of the Notice of Exercise in the form annexed hereto (the “Notice
of Exercise”). Within the earlier of (i) two (2) Trading Days and (ii) the number of Trading Days comprising the Standard
Settlement Period (as defined in Section 2(d)(i) herein) following the date of exercise as aforesaid, the Holder shall deliver
the aggregate Exercise Price for the shares specified in the applicable Notice of Exercise by wire transfer or cashier’s
check drawn on a United States bank unless the cashless exercise procedure specified in Section 2(c) below is specified in the
applicable Notice of Exercise. No ink-original Notice of Exercise shall be required, nor shall any medallion guarantee (or other
type of guarantee or notarization) of any Notice of Exercise be required. Notwithstanding anything herein to the contrary, the
Holder shall not be required to physically surrender this Warrant to the Company until the Holder has purchased all of the Warrant
Shares available hereunder and the Warrant has been exercised in full, in which case, the Holder shall surrender this Warrant to
the Company for cancellation within three (3) Trading Days of the date on which the final Notice of Exercise is delivered to the
Company. Partial exercises of this Warrant resulting in purchases of a portion of the total number of Warrant Shares available
hereunder shall have the effect of lowering the outstanding number of Warrant Shares purchasable hereunder in an amount equal to
the applicable number of Warrant Shares purchased. The Holder and the Company shall maintain records showing the number of Warrant
Shares purchased and the date of such purchases. The Company shall deliver any objection to any Notice of Exercise within one (1)
Trading Day of receipt of such notice. The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that,
by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number
of Warrant Shares available for purchase hereunder at any given time may be less than the amount stated on the face hereof.

 

Notwithstanding
the foregoing in this Section 2(a), a holder whose interest in this Warrant is a beneficial interest in certificate(s) representing
this Warrant held in book-entry form through DTC (or another established clearing corporation performing similar functions), shall
effect exercises made pursuant to this Section 2(a) by delivering to DTC (or such other clearing corporation, as applicable) the
appropriate instruction form for exercise, complying with the procedures to effect exercise that are required by DTC (or such other
clearing corporation, as applicable), subject to a Holder’s right to elect to receive a Warrant in certificated form pursuant
to the terms of the Warrant Agency Agreement, in which case this sentence shall not apply, provided, however, a beneficial holder
shall have all of the rights and remedies of a “Holder” hereunder.

 

b)            Exercise
Price. The exercise price per share of the Common Stock under this Warrant shall be $1.38, subject to adjustment hereunder (the
 “Exercise Price”).

 

c)            Cashless
Exercise. If at any time after the date hereof, there is no effective registration statement registering, or no current prospectus
available for, the issuance of the Warrant Shares to the Holder, then this Warrant may only be exercised, in whole or in part,
at such time by means of a “cashless exercise” in which the Holder shall be entitled to receive a number of Warrant
Shares equal to the quotient obtained by dividing [(A-B) (X)] by (A), where:

 

    	 	22	 

     

    

  

(A) =
as applicable: (i) the VWAP on the Trading Day immediately preceding the date of the applicable Notice of Exercise if such Notice
of Exercise is (1) both executed and delivered pursuant to Section 2(a) hereof on a day that is not a Trading Day or (2) both executed
and delivered pursuant to Section 2(a) hereof on a Trading Day prior to the opening of “regular trading hours” (as
defined in Rule 600(b)(64) of Regulation NMS promulgated under the federal securities laws) on such Trading Day, (ii) at the option
of the Holder, either (y) the VWAP on the Trading Day immediately preceding the date of the applicable Notice of Exercise or (z)
the Bid Price of the Common Stock on the principal Trading Market as reported by Bloomberg L.P. as of the time of the Holder’s
execution of the applicable Notice of Exercise if such Notice of Exercise is executed during “regular trading hours”
on a Trading Day and is delivered within two (2) hours thereafter (including until two (2) hours after the close of “regular
trading hours” on a Trading Day) pursuant to Section 2(a) hereof or (iii) the VWAP on the date of the applicable Notice of
Exercise if the date of such Notice of Exercise is a Trading Day and such Notice of Exercise is both executed and delivered pursuant
to Section 2(a) hereof after the close of “regular trading hours” on such Trading Day;

 

(B) =
the Exercise Price of this Warrant, as adjusted hereunder; and

 

(X)
= the number of Warrant Shares that would be issuable upon exercise of this Warrant in accordance with the terms of this Warrant
if such exercise were by means of a cash exercise rather than a cashless exercise.

 

If Warrant
Shares are issued in such a cashless exercise, the parties acknowledge and agree that in accordance with Section 3(a)(9) of the
Securities Act, the Warrant Shares shall take on the registered characteristics of the Warrants being exercised. The Company agrees
not to take any position contrary to this Section 2(c).

 

Notwithstanding
anything herein to the contrary, on the Termination Date, this Warrant shall be automatically exercised via cashless exercise pursuant
to this Section 2(c).

 

		d)	Mechanics of Exercise.

 

		i.	Delivery of Warrant Shares Upon Exercise. The Company shall
cause the Warrant Shares purchased hereunder to be transmitted by the Transfer Agent to the Holder by crediting the account of
the Holder’s or its designee’s balance account with The Depository Trust Company through its Deposit or Withdrawal
at Custodian system (“DWAC”) if the Company is then a participant in such system and either (A) there is an effective
registration statement permitting the issuance of the Warrant Shares to or resale of the Warrant Shares by Holder or (B) this Warrant
is being exercised via cashless exercise, and otherwise by physical delivery of a certificate, registered in the Company’s
share register in the name of the Holder or its designee, for the number of Warrant Shares to which the Holder is entitled pursuant
to such exercise to the address specified by the Holder in the Notice of Exercise by the date that is the earliest of (i) two (2)
Trading Days after the delivery to the Company of the Notice of Exercise, (ii) one (1) Trading Day after delivery of the aggregate
Exercise Price to the Company and (iii) the number of Trading Days comprising the Standard Settlement Period after the delivery
to the Company of the Notice of Exercise (such date, the “Warrant Share Delivery Date”), all subject to receipt of
any cash payments required by the Holder. Upon delivery of the Notice of Exercise, the Holder shall be deemed for all corporate
purposes to have become the holder of record of the Warrant Shares with respect to which this Warrant has been exercised, irrespective
of the date of delivery of the Warrant Shares, provided that payment of the aggregate Exercise Price (other than in the case of
a cashless exercise) is received within the earlier of (i) two (2) Trading Days and (ii) the number of Trading Days comprising
the Standard Settlement Period following delivery of the Notice of Exercise. If the Company fails for any reason to deliver to
the Holder the Warrant Shares subject to a Notice of Exercise by the Warrant Share Delivery Date, the Company shall pay to the
Holder, in cash, as liquidated damages and not as a penalty, for each $1,000 of Warrant Shares subject to such exercise (based
on the VWAP of the Common Stock on the date of the applicable Notice of Exercise), $10 per Trading Day (increasing to $20 per Trading
Day on the fifth Trading Day after such liquidated damages begin to accrue) for each Trading Day after such Warrant Share Delivery
Date until such Warrant Shares are delivered or Holder rescinds such exercise. The Company agrees to maintain a transfer agent
that is a participant in the FAST program so long as this Warrant remains outstanding and exercisable. As used herein, “Standard
Settlement Period” means the standard settlement period, expressed in a number of Trading Days, on the Company’s primary
Trading Market with respect to the Common Stock as in effect on the date of delivery of the Notice of Exercise.

 

    	 	23	 

     

    

  

		ii.	Delivery of New Warrants Upon Exercise. If this Warrant shall
have been exercised in part, the Company shall, at the request of a Holder and upon surrender of this Warrant certificate, at the
time of delivery of the Warrant Shares, deliver to the Holder a new Warrant evidencing the rights of the Holder to purchase the
unpurchased Warrant Shares called for by this Warrant, which new Warrant shall in all other respects be identical with this Warrant.

 

		iii.	Rescission Rights. If the Company fails to cause the Transfer
Agent to transmit to the Holder the Warrant Shares pursuant to Section 2(d)(i) by the Warrant Share Delivery Date, then the Holder
will have the right to rescind such exercise.

 

		iv.	Compensation for Buy-In on Failure to Timely Deliver Warrant
Shares Upon Exercise. In addition to any other rights available to the Holder, if the Company fails to cause the Transfer Agent
to transmit to the Holder the Warrant Shares in accordance with the provisions of Section 2(d)(i) above pursuant to an exercise
on or before the Warrant Share Delivery Date, and if after such date the Holder is required by its broker to purchase (in an open
market transaction or otherwise) or the Holder’s brokerage firm otherwise purchases, shares of Common Stock to deliver in
satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “Buy-In”),
then the Company shall (A) pay in cash to the Holder the amount, if any, by which (x) the Holder’s total purchase price (including
brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (1) the
number of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue times
(2) the price at which the sell order giving rise to such purchase obligation was executed, and (B) at the option of the Holder,
either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored (in
which case such exercise shall be deemed rescinded) or deliver to the Holder the number of shares of Common Stock that would have
been issued had the Company timely complied with its exercise and delivery obligations hereunder. For example, if the Holder purchases
Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an attempted exercise of shares of Common
Stock with an aggregate sale price giving rise to such purchase obligation of $10,000, under clause (A) of the immediately preceding
sentence the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company written notice indicating
the amounts payable to the Holder in respect of the Buy-In and, upon request of the Company, evidence of the amount of such loss.
Nothing herein shall limit a Holder’s right to pursue any other remedies available to it hereunder, at law or in equity including,
without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely
deliver shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof.

 

    	 	24	 

     

    

  

		v.	No Fractional Shares or Scrip. No fractional shares or scrip
representing fractional shares shall be issued upon the exercise of this Warrant. As to any fraction of a share which the Holder
would otherwise be entitled to purchase upon such exercise, the Company shall, at its election, either pay a cash adjustment in
respect of such final fraction in an amount equal to such fraction multiplied by the Exercise Price or round up to the next whole
share.

 

		vi.	Charges, Taxes and Expenses. Issuance of Warrant Shares shall
be made without charge to the Holder for any issue or transfer tax or other incidental expense in respect of the issuance of such
Warrant Shares, all of which taxes and expenses shall be paid by the Company, and such Warrant Shares shall be issued in the name
of the Holder or in such name or names as may be directed by the Holder; provided, however, that in the event that Warrant Shares
are to be issued in a name other than the name of the Holder, this Warrant when surrendered for exercise shall be accompanied by
the Assignment Form attached hereto duly executed by the Holder and the Company may require, as a condition thereto, the payment
of a sum sufficient to reimburse it for any transfer tax incidental thereto. The Company shall pay all Transfer Agent fees required
for same-day processing of any Notice of Exercise and all fees to the Depository Trust Company (or another established clearing
corporation performing similar functions) required for same-day electronic delivery of the Warrant Shares.

 

		vii.	Closing of Books. The Company will not close its stockholder
books or records in any manner which prevents the timely exercise of this Warrant, pursuant to the terms hereof.

 

    	 	25	 

     

    

  

e)             Holder’s
Exercise Limitations. The Company shall not effect any exercise of this Warrant, and a Holder
shall not have the right to exercise any portion of this Warrant, pursuant to Section 2 or otherwise, to the extent that after
giving effect to such issuance after exercise as set forth on the applicable Notice of Exercise, the Holder (together with the
Holder’s Affiliates, and any other Persons acting as a group together with the Holder or any of the Holder’s Affiliates
(such Persons, “Attribution Parties”)), would beneficially own in excess of the Beneficial Ownership Limitation (as
defined below). For purposes of the foregoing sentence, the number of shares of Common Stock beneficially owned by the Holder and
its Affiliates and Attribution Parties shall include the number of shares of Common Stock issuable upon exercise of this Warrant
with respect to which such determination is being made, but shall exclude the number of shares of Common Stock which would be issuable
upon (i) exercise of the remaining, nonexercised portion of this Warrant beneficially owned by the Holder or any of its Affiliates
or Attribution Parties and (ii) exercise or conversion of the unexercised or nonconverted portion of any other securities of the
Company (including, without limitation, any other Common Stock Equivalents) subject to a limitation on conversion or exercise analogous
to the limitation contained herein beneficially owned by the Holder or any of its Affiliates or Attribution Parties. Except as
set forth in the preceding sentence, for purposes of this Section 2(e), beneficial ownership shall be calculated in accordance
with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder, it being acknowledged by the Holder
that the Company is not representing to the Holder that such calculation is in compliance with Section 13(d) of the Exchange Act
and the Holder is solely responsible for any schedules required to be filed in accordance therewith. To the extent that the limitation
contained in this Section 2(e) applies, the determination of whether this Warrant is exercisable (in relation to other securities
owned by the Holder together with any Affiliates and Attribution Parties) and of which portion of this Warrant is exercisable shall
be in the sole discretion of the Holder, and the submission of a Notice of Exercise shall be deemed to be the Holder’s determination
of whether this Warrant is exercisable (in relation to other securities owned by the Holder together with any Affiliates and Attribution
Parties) and of which portion of this Warrant is exercisable, in each case subject to the Beneficial Ownership Limitation, and
the Company shall have no obligation to verify or confirm the accuracy of such determination. In addition, a determination as to
any group status as contemplated above shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and
regulations promulgated thereunder. For purposes of this Section 2(e), in determining the number of outstanding shares of Common
Stock, a Holder may rely on the number of outstanding shares of Common Stock as reflected in (A) the Company’s most recent
periodic or annual report filed with the Commission, as the case may be, (B) a more recent public announcement by the Company or
(C) a more recent written notice by the Company or the Transfer Agent setting forth the number of shares of Common Stock outstanding.
Upon the written or oral request of a Holder, the Company shall within one Trading Day confirm orally and in writing to the Holder
the number of shares of Common Stock then outstanding. In any case, the number of outstanding shares of Common Stock shall be determined
after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by the Holder or its Affiliates
or Attribution Parties since the date as of which such number of outstanding shares of Common Stock was reported. The “Beneficial
Ownership Limitation” shall be 4.99% (or, upon election by a Holder prior to the issuance of and Warrants, 9.99%) of the
number of shares of the Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock issuable
upon exercise of this Warrant. The Holder, upon notice to the Company, may increase or decrease the Beneficial Ownership Limitation
provisions of this Section 2(e), provided that the Beneficial Ownership Limitation in no event exceeds 9.99% of the number of shares
of the Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock upon exercise of this
Warrant held by the Holder and the provisions of this Section 2(e) shall continue to apply. Any increase in the Beneficial Ownership
Limitation will not be effective until the 61st day after such notice is delivered to the Company. The provisions of this paragraph
shall be construed and implemented in a manner otherwise than in strict conformity with the terms of this Section 2(e) to correct
this paragraph (or any portion hereof) which may be defective or inconsistent with the intended Beneficial Ownership Limitation
herein contained or to make changes or supplements necessary or desirable to properly give effect to such limitation. The limitations
contained in this paragraph shall apply to a successor holder of this Warrant.

 

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Section 3. Certain
Adjustments.

 

a)            Adjustment
Upon Issuance of Shares of Common Stock. If the Company or any Subsidiary thereof, as applicable, at any time while this Warrant
is outstanding, shall sell or grant any option to purchase, or otherwise dispose of or issue (or announce any offer, sale, grant
or any option to purchase or other disposition) any Common Stock or Common Stock Equivalents, at an effective price per share less
than the Exercise Price then in effect (such lower price, the “Base Share Price” and such issuances collectively, a
 “Dilutive Issuance”) (it being understood and agreed that if the Company sells securities as a unit, any warrant included
in the unit shall be deemed to have an effective price equal to its exercise price and any common stock include in the unit shall
be deemed to have an effective price equal to the unit price and if the holder of the Common Stock or Common Stock Equivalents
so issued shall at any time, whether by operation of purchase price adjustments, reset provisions, floating conversion, exercise
or exchange prices or otherwise, or due to warrants, options or rights per share which are issued in connection with such issuance,
be entitled to receive shares of Common Stock at an effective price per share that is less than the Exercise Price, such issuance
shall be deemed to have occurred for less than the Exercise Price on such date of the Dilutive Issuance at such effective price),
then simultaneously with the consummation (or, if earlier, the announcement) of each Dilutive Issuance (i) (excluding securities
issued pursuant to any at-the-market or similar agreement, including but not limited to, the agreement the Company entered into
on August 5, 2016 (as such agreement may be amended or replaced) with FBR Capital Markets & Co. now known as B. Riley FBR,
Inc. (each such issuance, an “ATM Issuance”)), the Exercise Price shall be reduced and only reduced to equal the Base
Share Price; (ii) involving securities issued pursuant to an ATM Issuance, the Exercise Price shall be reduced and only reduced
to the greater of the Base Share Price or fifty percent (50%) of the Exercise Price; provided, however that during the two year
period after issuance of this Warrant, the Company shall not issue any securities pursuant to an ATM Issuance at a price below
fifty percent (50%) of the Exercise Price. Notwithstanding the foregoing, no adjustments shall be made, paid or issued under this
Section 3(a) in respect of an Exempt Issuance. The Company shall notify the Holder, in writing, no later than the Trading Day following
the issuance or deemed issuance of any Common Stock or Common Stock Equivalents subject to this Section 3(a), indicating therein
the applicable issuance price, or applicable reset price, exchange price, conversion price and other pricing terms (such notice,
the “Dilutive Issuance Notice”). For purposes of clarification, whether or not the Company provides a Dilutive Issuance
Notice pursuant to this Section 3(a), upon the occurrence of any Dilutive Issuance, the Holder is entitled to receive a number
of Warrant Shares based upon the Base Share Price regardless of whether the Holder accurately refers to the Base Share Price in
the Notice of Exercise. The Company shall have no right to voluntarily lower the exercise or conversion price of any security outstanding
on the date of issuance of the Warrant below the Exercise Price other than in accordance with the terms of such security without
the approval of holders of a majority of the Warrants.

 

    	 	27	 

     

    

  

b)            Stock
Dividends and Splits. If the Company, at any time while this Warrant is outstanding: (i) pays a stock dividend or otherwise makes
a distribution or distributions on shares of its Common Stock or any other equity or equity equivalent securities payable in shares
of Common Stock (which, for avoidance of doubt, shall not include any shares of Common Stock issued by the Company upon exercise
of this Warrant), (ii) subdivides outstanding shares of Common Stock into a larger number of shares, (iii) combines (including
by way of reverse stock split) outstanding shares of Common Stock into a smaller number of shares or (iv) issues by reclassification
of shares of the Common Stock any shares of capital stock of the Company, then in each case the Exercise Price shall be multiplied
by a fraction of which the numerator shall be the number of shares of Common Stock (excluding treasury shares, if any) outstanding
immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately
after such event, and the number of shares issuable upon exercise of this Warrant shall be proportionately adjusted such that the
aggregate Exercise Price of this Warrant shall remain unchanged. Any adjustment made pursuant to this Section 3(b) shall become
effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution
and shall become effective immediately after the effective date in the case of a subdivision, combination or re-classification.

 

c)            Subsequent
Rights Offerings. In addition to any adjustments pursuant to Sections 3(a) and 3(b) above, if at any time the Company grants, issues
or sells any Common Stock Equivalents or rights to purchase stock, warrants, securities or other property pro rata to the record
holders of any class of shares of Common Stock (the “Purchase Rights”), then the Holder will be entitled to acquire,
upon the terms applicable to such Purchase Rights, the aggregate Purchase Rights which the Holder could have acquired if the Holder
had held the number of shares of Common Stock acquirable upon complete exercise of this Warrant (without regard to any limitations
on exercise hereof, including without limitation, the Beneficial Ownership Limitation) immediately before the date on which a record
is taken for the grant, issuance or sale of such Purchase Rights, or, if no such record is taken, the date as of which the record
holders of shares of Common Stock are to be determined for the grant, issue or sale of such Purchase Rights (provided, however,
that, to the extent that the Holder’s right to participate in any such Purchase Right would result in the Holder exceeding
the Beneficial Ownership Limitation, then the Holder shall not be entitled to participate in such Purchase Right to such extent
(or beneficial ownership of such shares of Common Stock as a result of such Purchase Right to such extent) and such Purchase Right
to such extent shall be held in abeyance for the Holder until such time, if ever, as its right thereto would not result in the
Holder exceeding the Beneficial Ownership Limitation).

 

    	 	28	 

     

    

  

d)            Pro
Rata Distributions. During such time as this Warrant is outstanding, if the Company shall declare or make any dividend or other
distribution of its assets (or rights to acquire its assets) to holders of shares of Common Stock, by way of return of capital
or otherwise (including, without limitation, any distribution of cash, stock or other securities, property or options by way of
a dividend, spin off, reclassification, corporate rearrangement, scheme of arrangement or other similar transaction) (a “Distribution”),
at any time after the issuance of this Warrant, then, in each such case, the Holder shall be entitled to participate in such Distribution
to the same extent that the Holder would have participated therein if the Holder had held the number of shares of Common Stock
acquirable upon complete exercise of this Warrant (without regard to any limitations on exercise hereof, including without limitation,
the Beneficial Ownership Limitation) immediately before the date of which a record is taken for such Distribution, or, if no such
record is taken, the date as of which the record holders of shares of Common Stock are to be determined for the participation in
such Distribution (provided, however, that, to the extent that the Holder's right to participate in any such Distribution would
result in the Holder exceeding the Beneficial Ownership Limitation, then the Holder shall not be entitled to participate in such
Distribution to such extent (or in the beneficial ownership of any shares of Common Stock as a result of such Distribution to such
extent) and the portion of such Distribution shall be held in abeyance for the benefit of the Holder until such time, if ever,
as its right thereto would not result in the Holder exceeding the Beneficial Ownership Limitation). To the extent that this Warrant
has not been partially or completely exercised at the time of such Distribution, such portion of the Distribution shall be held
in abeyance for the benefit of the Holder until the Holder has exercised this Warrant.

 

e)            Fundamental
Transaction. If, at any time while this Warrant is outstanding, (i) the Company, directly or indirectly, in one or more related
transactions effects any merger or consolidation of the Company with or into another Person, (ii) the Company, directly or indirectly,
effects any sale, lease, license, assignment, transfer, conveyance or other disposition of all or substantially all of its assets
in one or a series of related transactions, (iii) any, direct or indirect, purchase offer, tender offer or exchange offer (whether
by the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to sell, tender or exchange
their shares for other securities, cash or property and has been accepted by the holders of 50% or more of the outstanding Common
Stock, (iv) the Company, directly or indirectly, in one or more related transactions effects any reclassification, reorganization
or recapitalization of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted
into or exchanged for other securities, cash or property, or (v) the Company, directly or indirectly, in one or more related transactions
consummates a stock or share purchase agreement or other business combination (including, without limitation, a reorganization,
recapitalization, spin-off or scheme of arrangement) with another Person or group of Persons whereby such other Person or group
acquires more than 50% of the outstanding shares of Common Stock (not including any shares of Common Stock held by the other Person
or other Persons making or party to, or associated or affiliated with the other Persons making or party to, such stock or share
purchase agreement or other business combination) (each a “Fundamental Transaction”), then, upon any subsequent exercise
of this Warrant, the Holder shall have the right to receive, for each Warrant Share that would have been issuable upon such exercise
immediately prior to the occurrence of such Fundamental Transaction, at the option of the Holder (without regard to any limitation
in Section 2(e) on the exercise of this Warrant), the number of shares of Common Stock of the successor or acquiring corporation
or of the Company, if it is the surviving corporation, and any additional consideration (the “Alternate Consideration”)
receivable as a result of such Fundamental Transaction by a holder of the number of shares of Common Stock for which this Warrant
is exercisable immediately prior to such Fundamental Transaction (without regard to any limitation in Section 2(e) on the exercise
of this Warrant). For purposes of any such exercise, the determination of the Exercise Price shall be appropriately adjusted to
apply to such Alternate Consideration based on the amount of Alternate Consideration issuable in respect of one share of Common
Stock in such Fundamental Transaction, and the Company shall apportion the Exercise Price among the Alternate Consideration in
a reasonable manner reflecting the relative value of any different components of the Alternate Consideration. If holders of Common
Stock are given any choice as to the securities, cash or property to be received in a Fundamental Transaction, then the Holder
shall be given the same choice as to the Alternate Consideration it receives upon any exercise of this Warrant following such Fundamental
Transaction. The Company shall cause any successor entity in a Fundamental Transaction in which the Company is not the survivor
(the “Successor Entity”) to assume in writing all of the obligations of the Company under this Warrant in accordance
with the provisions of this Section 3(e) pursuant to written agreements in form and substance reasonably satisfactory to the Holder
and approved by the Holder (without unreasonable delay) prior to such Fundamental Transaction and shall, at the option of the Holder,
deliver to the Holder in exchange for this Warrant a security of the Successor Entity evidenced by a written instrument substantially
similar in form and substance to this Warrant which is exercisable for a corresponding number of shares of capital stock of such
Successor Entity (or its parent entity) equivalent to the shares of Common Stock acquirable and receivable upon exercise of this
Warrant (without regard to any limitations on the exercise of this Warrant) prior to such Fundamental Transaction, and with an
exercise price which applies the exercise price hereunder to such shares of capital stock (but taking into account the relative
value of the shares of Common Stock pursuant to such Fundamental Transaction and the value of such shares of capital stock, such
number of shares of capital stock and such exercise price being for the purpose of protecting the economic value of this Warrant
immediately prior to the consummation of such Fundamental Transaction), and which is reasonably satisfactory in form and substance
to the Holder. Upon the occurrence of any such Fundamental Transaction, the Successor Entity shall succeed to, and be substituted
for (so that from and after the date of such Fundamental Transaction, the provisions of this Warrant referring to the “Company”
shall refer instead to the Successor Entity), and may exercise every right and power of the Company and shall assume all of the
obligations of the Company under this Warrant with the same effect as if such Successor Entity had been named as the Company herein.

 

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f)            Calculations.
All calculations under this Section 3 shall be made to the nearest cent or the nearest 1/100th of a share, as the case may be.
For purposes of this Section 3, the number of shares of Common Stock deemed to be issued and outstanding as of a given date shall
be the sum of the number of shares of Common Stock (excluding treasury shares, if any) issued and outstanding.

 

 

		g)	Notice to Holder.

 

		i.	Adjustment to Exercise Price. Whenever the Exercise Price
is adjusted pursuant to any provision of this Section 3, the Company shall promptly deliver to the Holder by facsimile or email
a notice setting forth the Exercise Price after such adjustment and any resulting adjustment to the number of Warrant Shares and
setting forth a brief statement of the facts requiring such adjustment.

 

		ii.	Notice to Allow Exercise by Holder. If (A) the Company shall
declare a dividend (or any other distribution in whatever form) on the Common Stock, (B) the Company shall declare a special nonrecurring
cash dividend on or a redemption of the Common Stock, (C) the Company shall authorize the granting to all holders of the Common
Stock rights or warrants to subscribe for or purchase any shares of capital stock of any class or of any rights, (D) the approval
of any stockholders of the Company shall be required in connection with any reclassification of the Common Stock, any consolidation
or merger to which the Company is a party, any sale or transfer of all or substantially all of the assets of the Company, or any
compulsory share exchange whereby the Common Stock is converted into other securities, cash or property, or (E) the Company shall
authorize the voluntary or involuntary dissolution, liquidation or winding up of the affairs of the Company, then, in each case,
the Company shall cause to be delivered by facsimile or email to the Holder at its last facsimile number or email address as it
shall appear upon the Warrant Register of the Company, at least 5 calendar days prior to the applicable record or effective date
hereinafter specified, a notice stating (x) the date on which a record is to be taken for the purpose of such dividend, distribution,
redemption, rights or warrants, or if a record is not to be taken, the date as of which the holders of the Common Stock of record
to be entitled to such dividend, distributions, redemption, rights or warrants are to be determined or (y) the date on which such
reclassification, consolidation, merger, sale, transfer or share exchange is expected to become effective or close, and the date
as of which it is expected that holders of the Common Stock of record shall be entitled to exchange their shares of the Common
Stock for securities, cash or other property deliverable upon such reclassification, consolidation, merger, sale, transfer or share
exchange; provided that the failure to deliver such notice or any defect therein or in the delivery thereof shall not affect the
validity of the corporate action required to be specified in such notice; provided further that no notice shall be required if
the information is disseminated in a press release or document filed with the SEC. To the extent that any notice provided in this
Warrant constitutes, or contains, material, non-public information regarding the Company or any of the Subsidiaries, the Company
shall simultaneously file such notice with the Commission pursuant to a Current Report on Form 8-K. The Holder shall remain entitled
to exercise this Warrant during the period commencing on the date of such notice to the effective date of the event triggering
such notice except as may otherwise be expressly set forth herein.

 

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Section 4. Transfer
of Warrant.

 

a)            Transferability.
This Warrant and all rights hereunder are transferable, in whole or in part, upon surrender of this Warrant at the principal office
of the Company or its designated agent, together with a written assignment of this Warrant substantially in the form attached hereto
duly executed by the Holder or its agent or attorney and funds sufficient to pay any transfer taxes payable upon the making of
such transfer. Upon such surrender and, if required, such payment, the Company shall execute and deliver a new Warrant or Warrants
in the name of the assignee or assignees, as applicable, and in the denomination or denominations specified in such instrument
of assignment, and shall issue to the assignor a new Warrant evidencing the portion of this Warrant not so assigned, and this Warrant
shall promptly be cancelled. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender
this Warrant to the Company unless the Holder has assigned this Warrant in full, in which case, the Holder shall surrender this
Warrant to the Company within three (3) Trading Days of the date on which the Holder delivers an assignment form to the Company
assigning this Warrant in full. The Warrant, if properly assigned in accordance herewith, may be exercised by a new holder for
the purchase of Warrant Shares without having a new Warrant issued.

 

b)            New
Warrants. This Warrant may be divided or combined with other Warrants upon presentation hereof at the aforesaid office of the Company,
together with a written notice specifying the names and denominations in which new Warrants are to be issued, signed by the Holder
or its agent or attorney. Subject to compliance with Section 4(a), as to any transfer which may be involved in such division or
combination, the Company shall execute and deliver a new Warrant or Warrants in exchange for the Warrant or Warrants to be divided
or combined in accordance with such notice. All Warrants issued on transfers or exchanges shall be dated the original issuance
date and shall be identical with this Warrant except as to the number of Warrant Shares issuable pursuant thereto.

 

c)            Warrant
Register. The Warrant Agent (or, in the event a Holder elects to receive a Warrant in certificated form, the Company) shall register
this Warrant, upon records to be maintained by the Company for that purpose (the “Warrant Register”), in the name of
the record Holder hereof from time to time. The Warrant Agent and the Company may deem and treat the registered Holder of this
Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other
purposes, absent actual notice to the contrary.

 

Section 5. Miscellaneous.

 

a)             No
Rights as Stockholder Until Exercise. This Warrant does not entitle the Holder to any voting rights, dividends or other rights
as a stockholder of the Company prior to the exercise hereof as set forth in Section 2(d)(i), except as expressly set forth in
Section 3.

 

b)            Loss,
Theft, Destruction or Mutilation of Warrant. The Company covenants that upon receipt by the Company of evidence reasonably satisfactory
to it of the loss, theft, destruction or mutilation of this Warrant or any stock certificate relating to the Warrant Shares, and
in case of loss, theft or destruction, of indemnity or security reasonably satisfactory to it (which, in the case of the Warrant,
shall not include the posting of any bond), and upon surrender and cancellation of such Warrant or stock certificate, if mutilated,
the Company will make and deliver a new Warrant or stock certificate of like tenor and dated as of such cancellation, in lieu of
such Warrant or stock certificate.

 

c)            Saturdays,
Sundays, Holidays, etc. If the last or appointed day for the taking of any action or the expiration of any right required or granted
herein shall not be a Business Day, then, such action may be taken or such right may be exercised on the next succeeding Business
Day.

 

    	 	31	 

     

    

  

		d)	Authorized Shares.

 

The Company
covenants that, during the period the Warrant is outstanding, it will reserve from its authorized and unissued Common Stock a sufficient
number of shares to provide for the issuance of the Warrant Shares upon the exercise of any purchase rights under this Warrant.
The Company further covenants that its issuance of this Warrant shall constitute full authority to its officers who are charged
with the duty of issuing the necessary Warrant Shares upon the exercise of the purchase rights under this Warrant. The Company
will take all such reasonable action as may be necessary to assure that such Warrant Shares may be issued as provided herein without
violation of any applicable law or regulation, or of any requirements of the Trading Market upon which the Common Stock may be
listed. The Company covenants that all Warrant Shares which may be issued upon the exercise of the purchase rights represented
by this Warrant will, upon exercise of the purchase rights represented by this Warrant and payment for such Warrant Shares in accordance
herewith, be duly authorized, validly issued, fully paid and nonassessable and free from all taxes, liens and charges created by
the Company in respect of the issue thereof (other than taxes in respect of any transfer occurring contemporaneously with such
issue).

 

Except
and to the extent as waived or consented to by the Holder, the Company shall not by any action, including, without limitation,
amending its certificate of incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution,
issue or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms
of this Warrant, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such
actions as may be necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without
limiting the generality of the foregoing, the Company will (i) not increase the par value of any Warrant Shares above the amount
payable therefor upon such exercise immediately prior to such increase in par value, (ii) take all such action as may be necessary
or appropriate in order that the Company may validly and legally issue fully paid and nonassessable Warrant Shares upon the exercise
of this Warrant and (iii) use commercially reasonable efforts to obtain all such authorizations, exemptions or consents from any
public regulatory body having jurisdiction thereof, as may be, necessary to enable the Company to perform its obligations under
this Warrant.

 

Before
taking any action which would result in an adjustment in the number of Warrant Shares for which this Warrant is exercisable or
in the Exercise Price, the Company shall obtain all such authorizations or exemptions thereof, or consents thereto, as may be necessary
from any public regulatory body or bodies having jurisdiction thereof.

 

e)            Governing
Law. All questions concerning the construction, validity, enforcement and interpretation of this Warrant shall be governed by and
construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts
of law thereof. Each party agrees that all legal proceedings concerning the interpretations, enforcement and defense of the transactions
contemplated by this Warrant (whether brought against a party hereto or their respective affiliates, directors, officers, shareholders,
partners, members, employees or agents) shall be commenced exclusively in the state and federal courts sitting in the City of New
York. Each party hereby irrevocably submits to the exclusive jurisdiction of the state and federal courts sitting in the City of
New York, Borough of Manhattan for the adjudication of any dispute hereunder or in connection herewith or with any transaction
contemplated hereby or discussed herein, and hereby irrevocably waives, and agrees not to assert in any suit, action or proceeding,
any claim that it is not personally subject to the jurisdiction of any such court, that such suit, action or proceeding is improper
or is an inconvenient venue for such proceeding. Each party hereby irrevocably waives personal service of process and consents
to process being served in any such suit, action or proceeding by mailing a copy thereof via registered or certified mail or overnight
delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Warrant and agrees that
such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed
to limit in any way any right to serve process in any other manner permitted by law. If either party shall commence an action,
suit or proceeding to enforce any provisions of this Warrant, the prevailing party in such action, suit or proceeding shall be
reimbursed by the other party for their reasonable attorneys’ fees and other costs and expenses incurred with the investigation,
preparation and prosecution of such action or proceeding.

 

    	 	32	 

     

    

  

f)             Restrictions.
The Holder acknowledges that the Warrant Shares acquired upon the exercise of this Warrant, if not registered and the Holder does
not utilize cashless exercise, will have restrictions upon resale imposed by state and federal securities laws.

 

g)            Nonwaiver
and Expenses. No course of dealing or any delay or failure to exercise any right hereunder on the part of Holder shall operate
as a waiver of such right or otherwise prejudice the Holder’s rights, powers or remedies. Without limiting any other provision
of this Warrant, if the Company willfully and knowingly fails to comply with any provision of this Warrant, which results in any
material damages to the Holder, the Company shall pay to the Holder such amounts as shall be sufficient to cover any costs and
expenses including, but not limited to, reasonable attorneys’ fees, including those of appellate proceedings, incurred by
the Holder in collecting any amounts due pursuant hereto or in otherwise enforcing any of its rights, powers or remedies hereunder.

 

Notices.
Any and all notices or other communications or deliveries to be provided by the Holders hereunder including, without limitation,
any Notice of Exercise, shall be in writing and delivered personally, by facsimile or e-mail, or sent by a nationally recognized
overnight courier service, addressed to the Company, at Synthetic Biologics, Inc., 9605 Medical Center Drive, Suite 270, Rockville,
Maryland 20850 Attention: Chief Executive Officer, email address: sshallcross@syntheticbiologics.com, or such other facsimile number,
email address or address as the Company may specify for such purposes by notice to the Holders. Any and all notices or other communications
or deliveries to be provided by the Company hereunder shall be in writing and delivered personally, by facsimile or e-mail, or
sent by a nationally recognized overnight courier service addressed to each Holder at the facsimile number, e-mail address or address
of such Holder appearing on the books of the Company. Any notice or other communication or deliveries hereunder shall be deemed
given and effective on the earliest of (i) the time of transmission, if such notice or communication is delivered via facsimile
at the facsimile number or via e-mail at the e-mail address set forth in this Section prior to 5:30 p.m. (New York City time) on
any date, (ii) the next Trading Day after the time of transmission, if such notice or communication is delivered via facsimile
at the facsimile number or via e-mail at the e-mail address set forth in this Section on a day that is not a Trading Day or later
than 5:30 p.m. (New York City time) on any Trading Day, (iii) the second Trading Day following the date of mailing, if sent by
U.S. nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required
to be given. To the extent that any notice provided hereunder constitutes, or contains, material, non-public information regarding
the Company or any subsidiaries, the Company shall simultaneously file such notice with the Commission pursuant to a Current Report
on Form 8-K.

 

    	 	33	 

     

    

  

h)            Limitation
of Liability. No provision hereof, in the absence of any affirmative action by the Holder to exercise this Warrant to purchase
Warrant Shares, and no enumeration herein of the rights or privileges of the Holder, shall give rise to any liability of the Holder
for the purchase price of any Common Stock or as a stockholder of the Company, whether such liability is asserted by the Company
or by creditors of the Company.

 

i)              Remedies.
The Holder, in addition to being entitled to exercise all rights granted by law, including recovery of damages, will be entitled
to specific performance of its rights under this Warrant. The Company agrees that monetary damages would not be adequate compensation
for any loss incurred by reason of a breach by it of the provisions of this Warrant and hereby agrees to waive and not to assert
the defense in any action for specific performance that a remedy at law would be adequate.

 

j)              Successors
and Assigns. Subject to applicable securities laws, this Warrant and the rights and obligations evidenced hereby shall inure to
the benefit of and be binding upon the successors and permitted assigns of the Company and the successors and permitted assigns
of Holder. The provisions of this Warrant are intended to be for the benefit of any Holder from time to time of this Warrant and
shall be enforceable by the Holder or holder of Warrant Shares.

 

k)             Amendment.
This Warrant may be modified or amended or the provisions hereof waived with the written consent of the Company and the Holder.

 

l)              Severability.
Wherever possible, each provision of this Warrant shall be interpreted in such manner as to be effective and valid under applicable
law, but if any provision of this Warrant shall be prohibited by or invalid under applicable law, such provision shall be ineffective
to the extent of such prohibition or invalidity, without invalidating the remainder of such provisions or the remaining provisions
of this Warrant.

 

m)            Headings.
The headings used in this Warrant are for the convenience of reference only and shall not, for any purpose, be deemed a part of
this Warrant.

 

n)            Warrant
Agency Agreement. If this Warrant is held in global form through DTC (or any successor depositary), this Warrant is issued subject
to the Warrant Agency Agreement. To the extent any provision of this Warrant conflicts with the express provisions of the Warrant
Agency Agreement, the provisions of this Warrant shall govern and be controlling.

 

********************

 

(Signature
Page Follows)

 

    	 	34	 

     

    

  

IN WITNESS
WHEREOF, the Company has caused this Warrant to be executed by its officer thereunto duly authorized as of the date first above
indicated.

 

	 	SYNTHETIC BIOLOGICS, INC.
	 	 	 
	 	By:	
	 	 	Name:
	 	 	Title:

 

    	 	35	 

     

    

  

NOTICE
OF EXERCISE

 

TO: [
       ]

 

(1) The
undersigned hereby elects to purchase ________ Warrant Shares of the Company pursuant to the terms of the attached Warrant (only
if exercised in full), and tenders herewith payment of the exercise price in full, together with all applicable transfer taxes,
if any.

 

(2) Payment
shall take the form of (check applicable box):

 

 ̈
in lawful money of the United States; or

 

 ̈
if permitted the cancellation of such number of Warrant Shares as is necessary, in accordance
with the formula set forth in subsection 2(c), to exercise this Warrant with respect to the maximum number of Warrant Shares purchasable
pursuant to the cashless exercise procedure set forth in subsection 2(c).

 

(3) Please
issue said Warrant Shares in the name of the undersigned or in such other name as is specified below:

 

_______________________________

 

The Warrant
Shares shall be delivered to the following DWAC Account Number:

 

_______________________________

 

_______________________________

 

_______________________________

 

[SIGNATURE OF HOLDER]

 

Name of Investing Entity:
_______________________________________________________________________

Signature of Authorized Signatory
of Investing Entity: _________________________________________________

Name of Authorized Signatory:
___________________________________________________________________

Title of Authorized Signatory:
____________________________________________________________________

Date: _______________________________________________________________________________________

 

     

     

    

  

EXHIBIT
B

 

ASSIGNMENT
FORM

 

(To assign
the foregoing Warrant, execute this form and supply required information. Do not use this form to purchase shares.)

 

FOR VALUE
RECEIVED, the foregoing Warrant and all rights evidenced thereby are hereby assigned to

 

	Name:	 
	 	(Please Print)
	 	 
	Address:	 
	 	(Please Print)
	Phone Number:	 
	 	 
	Email Address:	 

 

Dated: _______________ __,
______

 

Holder’s Signature:______________________

 

Holder’s Address:_______________________

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