Exhibit 4.1


 


THIS WARRANT HAS NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED OR ANY STATE SECURITIES LAWS. NO SALE OR DISPOSITION MAY BE EFFECTED WITHOUT (i) EFFECTIVE
REGISTRATION STATEMENTS RELATED THERETO, (ii) AN OPINION OF COUNSEL OR OTHER EVIDENCE, REASONABLY SATISFACTORY TO THE COMPANY,
THAT SUCH REGISTRATIONS ARE NOT REQUIRED, (iii) RECEIPT OF NO-ACTION LETTERS FROM THE APPROPRIATE GOVERNMENTAL AUTHORITIES,
OR (iv) OTHERWISE COMPLYING WITH THE PROVISIONS OF SECTION 7 OF THIS WARRANT.


 


MUSTANG BIO, INC.


 


WARRANT TO PURCHASE 72,046
SHARES


OF COMMON STOCK


 


(Loan A)


 


THIS CERTIFIES THAT,
for value received, HORIZON TECHNOLOGY FINANCE CORPORATION and its assignees are entitled to subscribe for and purchase 72,046
fully paid and nonassessable shares of stock (as adjusted pursuant to Section 4 hereof, the “Shares”) of MUSTANG
BIO, INC., a Delaware corporation (the “Company”), at the price of $3.47 per share (such price and such other price
as shall result, from time to time, from the adjustments specified in Section 4 hereof is herein referred to as the “Warrant
Price”), subject to the provisions and upon the terms and conditions hereinafter set forth. As used herein, (a) the
term “Shares” shall mean, Company’s current, publicly traded common stock (the “Common Stock”), and
any stock into or for which such Common Stock may hereafter be converted or exchanged; (b) the term “Date of Grant”
shall mean March __, 2019, and (c) the term “Other Warrants” shall mean any other warrants issued by the Company
in connection with the transaction with respect to which this Warrant was issued, and any warrant issued upon transfer or partial
exercise of or in lieu of this Warrant. The term “Warrant” as used herein shall be deemed to include Other Warrants
unless the context clearly requires otherwise.


 


1.             Term.
The purchase right represented by this Warrant is exercisable, in whole or in part, at any time and from time to time from the
Date of Grant through ten (10) years after the Date of Grant (the “Term”).


 


2.             Method
of Exercise; Payment; Issuance of New Warrant. Subject to Section 1 hereof, the purchase right represented by this Warrant
may be exercised by the holder hereof, in whole or in part and from time to time, at the election of the holder hereof, by (a) the
surrender of this Warrant (with the notice of exercise substantially in the form attached hereto as Exhibit A-1 duly completed
and executed) at the principal office of the Company and by the payment to the Company, by certified or bank check, or by wire
transfer to an account designated by the Company (a “Wire Transfer”) of an amount equal to the then applicable Warrant
Price multiplied by the number of Shares then being purchased; (b) if in connection with a registered public offering of the
Company’s securities, the surrender of this Warrant (with the notice of exercise form attached hereto as Exhibit A-2
duly completed and executed) at the principal office of the Company together with notice of arrangements reasonably satisfactory
to the Company for payment to the Company either by certified or bank check or by Wire Transfer from the proceeds of the sale of
shares to be sold by the holder in such public offering of an amount equal to the then applicable Warrant Price per share multiplied
by the number of Shares then being purchased; or (c) exercise of the “net issuance” right provided for in Section
10.1 hereof. The person or persons in whose name(s) any certificate(s) representing the Shares shall be issuable upon exercise
of this Warrant shall be deemed to have become the holder(s) of record of, and shall be treated for all purposes as the record
holder(s) of, the shares represented thereby (and such shares shall be deemed to have been issued) immediately prior to the close
of business on the date or dates upon which this Warrant is exercised. In the event of any exercise of the rights represented by
this Warrant, certificates for the shares of stock so purchased shall be delivered to the holder hereof as soon as possible and
in any event within thirty (30) days after such exercise and, unless this Warrant has been fully exercised or expired, a new Warrant
representing the portion of the Shares, if any, with respect to which this Warrant shall not then have been exercised shall also
be issued to the holder hereof as soon as possible and in any event within such thirty-day period; provided, however, at such time
as the Company is subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, if requested by
the holder of this Warrant, the Company shall cause its transfer agent to deliver the certificate representing Shares issued upon
exercise of this Warrant to a broker or other person (as directed by the holder exercising this Warrant) within the time period
required to settle any trade made by the holder after exercise of this Warrant.


 




    	 	 	 



     


    

 


3.             Stock
Fully Paid; Reservation of Shares. All Shares that may be issued upon the exercise of the rights represented by this Warrant
will, upon issuance pursuant to the terms and conditions herein, be fully paid and nonassessable, and free from all preemptive
rights and taxes, liens and charges with respect to the issue thereof. During the period within which the rights represented by
this Warrant may be exercised, the Company will at all times have authorized, and reserved for the purpose of the issue upon exercise
of the purchase rights evidenced by this Warrant, a sufficient number of shares of its Common Stock to provide for the exercise
of the rights represented by this Warrant.


 


4.             Adjustment
of Warrant Price and Number of Shares. The number and kind of securities purchasable upon the exercise of this Warrant and
the Warrant Price shall be subject to adjustment from time to time upon the occurrence of certain events, as follows:


 


(a)          Reclassification
or Merger. In case of any reclassification or change of securities of the class issuable upon exercise of this Warrant (other
than a change in par value, or from par value to no par value, or from no par value to par value, or as a result of a subdivision
or combination), or in case of any merger of the Company with or into another corporation (other than a merger with another corporation
in which the Company is the acquiring and the surviving corporation and which does not result in any reclassification or change
of outstanding securities issuable upon exercise of this Warrant), or in case of any sale of all or substantially all of the assets
of the Company, the Company, or such successor or purchasing corporation, as the case may be, shall duly execute and deliver to
the holder of this Warrant a new Warrant (in form and substance satisfactory to the holder of this Warrant), so that the holder
of this Warrant shall have the right to receive upon exercise of this Warrant, at a total purchase price not to exceed that payable
upon the exercise of the unexercised portion of this Warrant, and in lieu of the shares of Common Stock theretofore issuable upon
exercise of this Warrant, (i) the kind and amount of shares of stock, other securities, money and property receivable upon
such reclassification, change, merger or sale by a holder of the number of shares of Common Stock then purchasable under this Warrant,
or (ii) in the case of such a merger or sale in which the consideration paid consists all or in part of assets other than
securities of the successor or purchasing corporation, at the option of the holder of this Warrant, the securities of the successor
or purchasing corporation having a value at the time of the transaction equivalent to the value of the Common Stock purchasable
upon exercise of this Warrant at the time of the transaction. Any new Warrant shall provide for adjustments that shall be as nearly
equivalent as may be practicable to the adjustments provided for in this Section 4. The provisions of this Section 4(a) shall
similarly apply to successive reclassifications, changes, mergers and sales.


 




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(b)          Subdivision
or Combination of Shares. If the Company at any time while this Warrant remains outstanding and unexpired shall subdivide or
combine its outstanding shares of Common Stock, the Warrant Price shall be proportionately decreased and the number of Shares issuable
hereunder shall be proportionately increased in the case of a subdivision and the Warrant Price shall be proportionately increased
and the number of Shares issuable hereunder shall be proportionately decreased in the case of a combination.


 


(c)          Stock
Dividends and Other Distributions. If the Company at any time while this Warrant is outstanding and unexpired shall (i) pay
a dividend with respect to its Common Stock payable in Common Stock, then the Warrant Price shall be adjusted, from and after the
date of determination of shareholders entitled to receive such dividend or distribution, to that price determined by multiplying
the Warrant Price in effect immediately prior to such date of determination by a fraction (A) the numerator of which shall
be the total number of shares of Common Stock outstanding immediately prior to such dividend or distribution, and (B) the
denominator of which shall be the total number of shares of Common Stock outstanding immediately after such dividend or distribution;
or (ii) make any other distribution with respect to Common Stock (except any distribution specifically provided for in Sections 4(a)
and 4(b)), then, in each such case, provision shall be made by the Company such that the holder of this Warrant shall receive upon
exercise of this Warrant a proportionate share of any such dividend or distribution as though it were the holder of the Shares
as of the record date fixed for the determination of the shareholders of the Company entitled to receive such dividend or distribution.


 


(d)          Adjustment
of Number of Shares. Upon each adjustment in the Warrant Price, the number of Shares purchasable hereunder shall be adjusted,
to the nearest whole share, to the product obtained by multiplying the number of Shares purchasable immediately prior to such adjustment
in the Warrant Price by a fraction, the numerator of which shall be the Warrant Price immediately prior to such adjustment and
the denominator of which shall be the Warrant Price immediately thereafter.


 


5.             Notice
of Adjustments. Whenever the Warrant Price or the number of Shares purchasable hereunder shall be adjusted pursuant to Section 4
hereof, the Company shall make a certificate signed by its chief financial officer setting forth, in reasonable detail, the event
requiring the adjustment, the amount of the adjustment, the method by which such adjustment was calculated, and the Warrant Price
and the number of Shares purchasable hereunder after giving effect to such adjustment, and shall cause copies of such certificate
to be mailed (without regard to Section 13 hereof, by first class mail, postage prepaid) to the holder of this Warrant.


 




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6.             Fractional
Shares. No fractional shares of Common Stock will be issued in connection with any exercise hereunder, but in lieu of such
fractional shares the Company shall make a cash payment therefor based on the fair market value of the Common Stock on the date
of exercise as reasonably determined in good faith by the Company’s Board of Directors.


 


7.             Compliance
with Securities Act; Disposition of Warrant or Shares of Common Stock.


 


(a)          Compliance
with Securities Act. The holder of this Warrant, by acceptance hereof, agrees that this Warrant, and the Shares to be issued
upon exercise hereof are being acquired for investment and that such holder will not offer, sell or otherwise dispose of this Warrant,
or any Shares except under circumstances which will not result in a violation of the Securities Act of 1933, as amended (the “Act”)
or any applicable state securities laws. Upon exercise of this Warrant, unless the Shares being acquired are registered under the
Act and any applicable state securities laws or an exemption from such registration is available, the holder hereof shall confirm
in writing that the Shares so purchased are being acquired for investment and not with a view toward distribution or resale in
violation of the Act and shall confirm such other matters related thereto as may be reasonably requested by the Company. This Warrant
and all Shares issued upon exercise of this Warrant (unless registered under the Act and any applicable state securities laws)
shall be stamped or imprinted with a legend in substantially the following form:


 


“THE SECURITIES EVIDENCED HEREBY
HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE SECURITIES LAWS. NO SALE OR DISPOSITION
MAY BE EFFECTED WITHOUT (i) EFFECTIVE REGISTRATION STATEMENTS RELATED THERETO, (ii) AN OPINION OF COUNSEL OR OTHER EVIDENCE,
REASONABLY SATISFACTORY TO THE COMPANY, THAT SUCH REGISTRATIONS ARE NOT REQUIRED, (iii) RECEIPT OF NO-ACTION LETTERS FROM
THE APPROPRIATE GOVERNMENTAL AUTHORITIES, OR (iv) OTHERWISE COMPLYING WITH THE PROVISIONS OF SECTION 7 OF THE WARRANT
UNDER WHICH THESE SECURITIES WERE ISSUED, DIRECTLY OR INDIRECTLY.”


 


Said legend shall be
removed by the Company, upon the request of a holder, at such time as the restrictions on the transfer of the applicable security
shall have terminated. In addition, in connection with the issuance of this Warrant, the holder specifically represents to the
Company by acceptance of this Warrant as follows:


 


(1)         The
holder is aware of the Company’s business affairs and financial condition, and has acquired information about the Company
sufficient to reach an informed and knowledgeable decision to acquire this Warrant. The holder is acquiring this Warrant for its
own account for investment purposes only and not with a view to, or for the resale in connection with, any “distribution”
thereof in violation of the Act.


 


(2)         The
holder understands that this Warrant has not been registered under the Act in reliance upon a specific exemption therefrom, which
exemption depends upon, among other things, the bona fide nature of the holder’s investment intent as expressed herein.


 




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(3)         The
holder further understands that this Warrant must be held indefinitely unless subsequently registered under the Act and qualified
under any applicable state securities laws, or unless exemptions from registration and qualification are otherwise available. The
holder is aware of the provisions of Rule 144, promulgated under the Act.


 


(4)         The
holder is an “accredited investor” as such term is defined in Rule 501 of Regulation D promulgated under
the Act.


 


(b)          Disposition
of Warrant or Shares. With respect to any offer, sale or other disposition of this Warrant or any Shares acquired pursuant
to the exercise of this Warrant prior to registration of such Warrant or Shares, the holder hereof agrees to give written notice
to the Company prior thereto, describing briefly the manner thereof, together with a written opinion of such holder’s counsel,
or other evidence, if reasonably satisfactory to the Company, to the effect that such offer, sale or other disposition may be effected
without registration or qualification (under the Act as then in effect or any federal or state securities law then in effect) of
this Warrant or the Shares and indicating whether or not under the Act certificates for this Warrant or the Shares to be sold or
otherwise disposed of require any restrictive legend as to applicable restrictions on transferability in order to ensure compliance
with such law. Upon receiving such written notice and reasonably satisfactory opinion or other evidence, the Company, as promptly
as practicable but no later than fifteen (15) days after receipt of the written notice, shall notify such holder that such holder
may sell or otherwise dispose of this Warrant or such Shares, all in accordance with the terms of the notice delivered to the Company.
If a determination has been made pursuant to this Section 7(b) that the opinion of counsel for the holder or other evidence
is not reasonably satisfactory to the Company, the Company shall so notify the holder promptly with details thereof after such
determination has been made. Notwithstanding the foregoing, this Warrant or such Shares may, as to such federal laws, be offered,
sold or otherwise disposed of in accordance with Rule 144 or 144A under the Act, provided that the Company shall have been
furnished with such information as the Company may reasonably request to provide a reasonable assurance that the provisions of
Rule 144 or 144A have been satisfied. Each certificate representing this Warrant or the Shares thus transferred (except a
transfer pursuant to Rule 144 or 144A) shall bear a legend as to the applicable restrictions on transferability in order to
ensure compliance with such laws, unless in the aforesaid opinion of counsel for the holder, such legend is not required in order
to ensure compliance with such laws. The Company may issue stop transfer instructions to its transfer agent in connection with
such restrictions.


 


(c)          Applicability
of Restrictions. Neither any restrictions of any legend described in this Warrant nor the requirements of Section 7(b)
above shall apply to any transfer of, or grant of a security interest in, this Warrant (or the Common Stock obtainable upon exercise
thereof) or any part hereof (i) to a partner of the holder if the holder is a partnership or to a member of the holder if
the holder is a limited liability company, (ii) to a partnership of which the holder is a partner or to a limited liability
company of which the holder is a member, (iii) to any affiliate of the holder if the holder is a corporation, (iv) notwithstanding
the foregoing, to any corporation, company, limited liability company, limited partnership, partnership, or other person managed
or sponsored by Horizon Technology Finance Corporation ("HRZN") or in which HRZN has an interest, (v) or to a lender
to the holder or any of the foregoing; provided, however, in any such transfer, if applicable, the transferee shall
on the Company’s request agree in writing to be bound by the terms of this Warrant as if an original holder hereof.


 




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8.             Rights
as Shareholders; Information. No holder of this Warrant, as such, shall be entitled to vote or receive dividends or be deemed
the holder of Shares or any other securities of the Company which may at any time be issuable upon the exercise hereof for any
purpose, nor shall anything contained herein be construed to confer upon the holder of this Warrant, as such, any of the rights
of a shareholder of the Company or any right to vote for the election of directors or upon any matter submitted to shareholders
at any meeting thereof, or to receive notice of meetings, or to receive dividends or subscription rights or otherwise until this
Warrant shall have been exercised and the Shares purchasable upon the exercise hereof shall have become deliverable, as provided
herein. Notwithstanding the foregoing, the Company will transmit to the holder of this Warrant (a) such information, documents
and reports as are generally distributed to the holders of any class or series of the securities of the Company concurrently with
the distribution thereof to the shareholders, (b) any stock purchase (or similar) agreement to which the Company is a party entered
into on or after the Date of Grant, (c) each amendment to, or amended and restated, Charter filed by the Company with the Secretary
of State of any jurisdiction, and (d) on the first day of each calendar quarter, the Company’s then current capitalization
table, showing all issued and outstanding equity securities of the Company, together with all options or warrants to purchase such
equity securities issued by the Company.


 


9.             Registration
Rights. The Shares issuable hereunder initially shall be exempt from registration under the Securities Act. Following a period
of six months after the Date of Grant, upon the request of the holder hereof, Company shall promptly prepare, file and use its
reasonable efforts to cause to become effective as soon as practicable thereafter, a registration statement on Form S-1 or
such other form as may be appropriate to be filed with the SEC by Company under the Act (together with any amendments or supplements
thereto, whether prior to or after the effective date thereof, the “Registration Statement”) covering the public resale
in the United States of the Shares to be issued pursuant to this Warrant, and Company shall use its reasonable efforts to keep
the Registration Statement continuously effective during the Term. Any such registration shall be subject to the customary terms
and conditions used in connection with resale prospectuses. Company’s obligations under this Section are contingent upon
Holder providing promptly all information concerning such Holder and its proposed plan of distribution as Company may reasonably
request in connection with any of the foregoing. Company may by written notice to the Holder immediately suspend the use of any
resale prospectus for a period not to exceed sixty consecutive days in any one instance and for a period not to exceed one hundred
twenty calendar days in any twelve-month period (each, a “Suspension Period”) at any time that (i) Company becomes
engaged in a business activity or negotiation or any other event has occurred or is anticipated which is not disclosed in that
prospectus which Company reasonably believes should be disclosed therein under applicable law and which Company desires to keep
confidential for business purposes or (ii) Company determines that a particular disclosure so determined to be required to
be disclosed therein be premature or would adversely affect Company or its business or prospects. Company will use its commercially
reasonable efforts to ensure that the use of the Registration Statement may be resumed as soon as practicable. Company shall bear
all costs and expenses associated with the registration of the Shares as specified in this Section and the preparation and filing
of the Registration Statement, including, without limitation, all printing expenses, legal fees and disbursement of Company’s
outside counsel, commissions, NASDAQ and blue sky registration filing fees and transfer agents’ and registrars’ fees,
but not including underwriting commissions or similar charges and legal fees and disbursements of counsel to Holder.


 




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10.           Additional
Rights.


 


10.1         Right
to Convert Warrant into Stock: Net Issuance.


 


(a)          Right
to Convert. In addition to and without limiting the rights of the holder under the terms of this Warrant, the holder shall
have the right to convert this Warrant or any portion thereof (the “Conversion Right”) into shares of Common Stock
as provided in this Section 10.1 at any time or from time to time during the term of this Warrant. Upon exercise of the Conversion
Right with respect to a particular number of shares subject to this Warrant (the “Converted Warrant Shares”), the Company
shall deliver to the holder (without payment by the holder of any exercise price or any cash or other consideration) that number
of shares of fully paid and nonassessable Common Stock as is determined according to the following formula:


 


X = B - A 


  Y


 


	Where:    	X =	the number of Shares that shall
be issued to holder



 


		Y =	the fair market value of one Share



 


		A =	the aggregate Warrant Price of the specified number of Shares immediately prior to the exercise
of the Conversion Right (i.e., the number of Shares multiplied by the Warrant Price)



 


		B =	the aggregate fair market value of the specified number of Shares (i.e., the number of Shares
multiplied by the fair market value of one Share)



 


No fractional shares
shall be issuable upon exercise of the Conversion Right, and, if the number of shares to be issued determined in accordance with
the foregoing formula is other than a whole number, the Company shall pay to the holder an amount in cash equal to the fair market
value of the resulting fractional share on the Conversion Date (as hereinafter defined). For purposes of Section 10 of this
Warrant, shares issued pursuant to the Conversion Right shall be treated as if they were issued upon the exercise of this Warrant.


 


(b)          Method
of Exercise. The Conversion Right may be exercised by the holder by the surrender of this Warrant at the principal office of
the Company together with a written statement (which may be in the form of Exhibit A-1 or Exhibit A-2 hereto) specifying
that the holder thereby intends to exercise the Conversion Right and indicating the number of shares subject to this Warrant which
are being surrendered (referred to in Section 10.1(a) hereof as the Converted Warrant Shares) in exercise of the Conversion
Right. Such conversion shall be effective upon receipt by the Company of this Warrant together with the aforesaid written statement,
or on such later date as is specified therein (the “Conversion Date”), and, at the election of the holder hereof, may
be made contingent upon the closing of the sale of the Company’s Common Stock to the public in a public offering pursuant
to a Registration Statement under the Act (a “Public Offering”). Certificates for the shares issuable upon exercise
of the Conversion Right and, if applicable, a new warrant evidencing the balance of the shares remaining subject to this Warrant,
shall be issued as of the Conversion Date and shall be delivered to the holder within thirty (30) days following the Conversion
Date.


 




    	 	- 7 -	 



     


    

 


(c)          Determination
of Fair Market Value. For purposes of this Section 10.1, “fair market value” of a share of Common Stock as
of a particular date (the “Determination Date”) shall mean:


 


(i)          If
the Conversion Right is exercised in connection with and contingent upon a Public Offering, and if the Company’s Registration
Statement relating to such Public Offering (“Registration Statement”) has been declared effective by the Securities
and Exchange Commission, then the initial “Price to Public” specified in the final prospectus with respect to such
offering.


 


(ii)         If
the Conversion Right is not exercised in connection with and contingent upon a Public Offering, then as follows:


 


(A)         If
traded on a securities exchange, the fair market value of the Common Stock shall be deemed to be the average of the closing prices
of the Common Stock on such exchange over the five trading days immediately prior to the Determination Date;


 


(B)         If
traded on the NASDAQ Stock Market or other over-the-counter system, the fair market value of the Common Stock shall be deemed to
be the average of the closing prices of the Common Stock over the five trading days immediately prior to the Determination Date;
and


 


(C)         If
there is no public market for the Common Stock, then fair market value shall be determined by mutual agreement of the holder of
this Warrant and the Company.


 


If closing prices or closing bid prices
are no longer reported by a securities exchange or other trading system, the closing price or closing bid price shall be that which
is reported by such securities exchange or other trading system at 4:00 p.m. New York City time on the applicable trading day.


 


10.2         Exercise
Prior to Expiration.  To the extent this Warrant is not previously exercised as to all of the Shares subject hereto, and if
the fair market value of one share of the Common Stock is greater than the Warrant Price then in effect, this Warrant shall be
deemed automatically exercised pursuant to Section 10.1 above (even if not surrendered) immediately before its expiration.
For purposes of such automatic exercise, the fair market value of one share of the Common Stock upon such expiration shall be determined
pursuant to Section 10.1(c). To the extent this Warrant or any portion thereof is deemed automatically exercised pursuant
to this Section 10.2, the Company agrees to promptly notify the holder hereof of the number of Shares, if any, the holder
hereof is to receive by reason of such automatic exercise.


 


11.           Representations
and Warranties. The Company represents and warrants to the holder of this Warrant as follows:


 




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(a)          This
Warrant has been duly authorized and executed by the Company and is a valid and binding obligation of the Company enforceable in
accordance with its terms, subject to laws of general application relating to bankruptcy, insolvency and the relief of debtors
and the rules of law or principles at equity governing specific performance, injunctive relief and other equitable remedies.


 


(b)          The
Shares have been duly authorized and reserved for issuance by the Company and, when issued in accordance with the terms hereof,
will be validly issued, fully paid and nonassessable and free from preemptive rights.


 


(c)          A
true and correct copy of the Company’s Certificate of Incorporation, as amended through the Date of Grant has been provided
to Holder (the “Charter”). The rights, preferences, privileges and restrictions granted to or imposed upon the classes
and series of the Company’s capital stock and the holders thereof are as set forth in the Charter.


 


(d)          The
execution and delivery of this Warrant are not, and the issuance of the Shares upon exercise of this Warrant in accordance with
the terms hereof will not be, inconsistent with the Company’s Charter or by-laws, do not and will not contravene any law,
governmental rule or regulation, judgment or order applicable to the Company, and do not and will not conflict with or contravene
any provision of, or constitute a default under, any indenture, mortgage, contract or other instrument of which the Company is
a party or by which it is bound or require the consent or approval of, the giving of notice to, the registration or filing with
or the taking of any action in respect of or by, any Federal, state or local government authority or agency or other person, except
for the filing of notices pursuant to federal and state securities laws, which filings will be effected by the time required thereby.


 


(e)          There
are no actions, suits, audits, investigations or proceedings pending or, to the knowledge of the Company, threatened against the
Company in any court or before any governmental commission, board or authority which, if adversely determined, could have a material
adverse effect on the ability of the Company to perform its obligations under this Warrant.


 


(f)          The
number of shares of Common Stock of the Company outstanding on the date hereof, on a fully diluted basis (assuming the conversion
of all outstanding convertible securities and the exercise of all outstanding options and warrants), does not exceed 36,300,000
shares.


 


12.           Modification
and Waiver. This Warrant and any provision hereof may be changed, waived, discharged or terminated only by an instrument in
writing signed by the party against which enforcement of the same is sought.


 


13.           Notices.
Any notice, request, communication or other document required or permitted to be given or delivered to the holder hereof or the
Company shall be delivered, or shall be sent by certified or registered mail, postage prepaid, to each such holder at its address
as shown on the books of the Company or to the Company at the address indicated therefor on the signature page of this Warrant.


 




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14.           Binding
Effect on Successors. This Warrant shall be binding upon any corporation succeeding the Company by merger, consolidation or
acquisition of all or substantially all of the Company’s assets, and all of the obligations of the Company relating to the
Shares issuable upon the exercise or conversion of this Warrant shall survive the exercise, conversion and termination of this
Warrant and all of the covenants and agreements of the Company shall inure to the benefit of the successors and assigns of the
holder hereof.


 


15.           Lost
Warrants or Stock Certificates. The Company covenants to the holder hereof that, upon receipt of evidence reasonably satisfactory
to the Company of the loss, theft, destruction or mutilation of this Warrant or any stock certificate and, in the case of any such
loss, theft or destruction, upon receipt of an indemnity reasonably satisfactory to the Company, or in the case of any such mutilation
upon surrender and cancellation of such Warrant or stock certificate, the Company will make and deliver a new Warrant or stock
certificate, of like tenor, in lieu of the lost, stolen, destroyed or mutilated Warrant or stock certificate.


 


16.           Descriptive
Headings. The descriptive headings of the various Sections of this Warrant are inserted for convenience only and do not constitute
a part of this Warrant. The language in this Warrant shall be construed as to its fair meaning without regard to which party drafted
this Warrant.


 


17.           Governing
Law. This Warrant shall be construed and enforced in accordance with, and the rights of the parties shall be governed by, the
laws of the State of Delaware.


 


18.           Survival
of Representations, Warranties and Agreements. All representations and warranties of the Company and the holder hereof contained
herein shall survive the Date of Grant, the exercise or conversion of this Warrant (or any part hereof) or the termination or expiration
of rights hereunder. All agreements of the Company and the holder hereof contained herein shall survive indefinitely until, by
their respective terms, they are no longer operative.


 


19.           Remedies.
In case any one or more of the covenants and agreements contained in this Warrant shall have been breached, the holders hereof
(in the case of a breach by the Company), or the Company (in the case of a breach by a holder), may proceed to protect and enforce
their or its rights either by suit in equity and/or by action at law, including, but not limited to, an action for damages as a
result of any such breach and/or an action for specific performance of any such covenant or agreement contained in this Warrant.


 


20.           No
Impairment of Rights. The Company will not, by amendment of its Charter or through any other means, 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 action as may be necessary or appropriate in order to protect the rights of the
holder of this Warrant against impairment.


 


21.           Severability.
The invalidity or unenforceability of any provision of this Warrant in any jurisdiction shall not affect the validity or enforceability
of such provision in any other jurisdiction, or affect any other provision of this Warrant, which shall remain in full force and
effect.


 




    	 	- 10 -	 



     


    

 


22.           Recovery
of Litigation Costs. If any legal action or other proceeding is brought for the enforcement of this Warrant, or because of
an alleged dispute, breach, default, or misrepresentation in connection with any of the provisions of this Warrant, the successful
or prevailing party or parties shall be entitled to recover reasonable attorneys’ fees and other costs incurred in that action
or proceeding, in addition to any other relief to which it or they may be entitled.


 


23.           Entire
Agreement; Modification. This Warrant constitutes the entire agreement between the parties pertaining to the subject matter
contained in it and supersedes all prior and contemporaneous agreements, representations, and undertakings of the parties, whether
oral or written, with respect to such subject matter.


 


[Remainder of page intentionally
blank. Signature page follows.]


 




    	 	- 11 -	 



     


    

 


The Company has caused this Warrant to be
duly executed and delivered as of the Date of Grant specified above.


 


	 	MUSTANG BIO, INC. 
	 	 	 
	 	By:	/s/ Manuel Litchman, M.D.
	 	Name:	Manuel Litchman, M.D.
	 	Title:	President and CEO
	 	Address:	377 Plantation Street
	 	 	Worcester, MA 01605


 


[SIGNATURE PAGE TO COMMON STOCK WARRANT (LOAN A)]


 




    	 	 	 



     


    

 


EXHIBIT A-1


 


NOTICE OF EXERCISE


 


		To:	MUSTANG BIO, INC. (the “Company”)



 


1.            The
undersigned hereby:


 


		 ̈	elects to purchase ________ shares of Common Stock of the Company pursuant to the terms of the attached Warrant, and
                                                                                                                            tenders herewith payment of the purchase price of such shares in full, or



 


		 ̈	elects to exercise its net issuance rights pursuant to Section 10.1 of the attached Warrant with respect to
                                                                                                                            ________ shares of Common Stock.



 


2.            Please
issue a certificate or certificates representing ________ shares in the name of the undersigned or in such other name or names
as are specified below:


 


	 
	(Name)
	 
	 
	 
	 
	(Address)


 


3.            The
undersigned represents that the aforesaid shares are being acquired for the account of the undersigned for investment and not with
a view to, or for resale in connection with, the distribution thereof and that the undersigned has no present intention of distributing
or reselling such shares, all except as in compliance with applicable securities laws.


 


	 	 
	 	(Signature)


 


	 	 
	(Date)	 


 




    	 	 	 



     


    

 


EXHIBIT A-2


 


NOTICE OF EXERCISE


 


		To:	MUSTANG BIO, INC. (the “Company”)



 


1.            Contingent
upon and effective immediately prior to the closing (the “Closing”) of the Company’s public offering contemplated
by the Registration Statement on Form S___, filed ________, 20__, the undersigned hereby:


 


 ̈           elects
to purchase ________ shares of Common Stock of the Company (or such lesser number of shares as may be sold on behalf of the
undersigned at the Closing) pursuant to the terms of the attached Warrant, or


 


 ̈           elects
to exercise its net issuance rights pursuant to Section 10.1 of the attached Warrant with respect to________shares of Common
Stock.


 


2.            Please
deliver to the custodian for the selling shareholders a stock certificate representing such________shares.


 


3.            The
undersigned has instructed the custodian for the selling shareholders to deliver to the Company $________ or, if less, the
net proceeds due the undersigned from the sale of shares in the aforesaid public offering. If such net proceeds are less than
the purchase price for such shares, the undersigned agrees to deliver the difference to the Company prior to the Closing.


 


	 	 
	 	(Signature)


 


	 	 
	(Date)