Exhibit 4.3


 


THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”),
OR UNDER THE SECURITIES LAWS OF ANY STATE. THIS NOTE MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE
OF A REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO THIS NOTE UNDER SUCH ACT UNLESS SUCH REGISTRATION IS NOT REQUIRED PURSUANT
TO A VALID EXEMPTION THEREFROM UNDER THE ACT.


 


iBio, Inc.


 


Promissory
Note


 








	Face Amount: $XXX,000.001	February [__], 2020
	 	New York, NY







 


FOR VALUE RECEIVED,
the undersigned iBio, Inc., (the “Borrower”), promises to pay to the order of [___________], its successors
or assigns (the “Lender”), [_________] DOLLARS ($XXX,000) (the “Face Amount”) by August [__],
2020 (the “Maturity Date”) in accordance with the terms hereof as provided herein.


 


Section 1.               Maturity; Interest. The Face Amount shall be repaid in cash at the Maturity Date; provided,
that this Note may be prepaid in whole or in part at any time and from time-to-time upon three (3) prior business days’
written notice, without penalty. This Note shall not bear interest except as contemplated in Section 4 below.


 


Section 2.               Repayment; Reduction of Principal with Warrant Exercises.


 


(a)              Upon
the closing of an underwritten offering of securities resulting in at least $10 million in gross proceeds to Borrower, Borrower
shall repay, in cash, one hundred percent (100%) of the aggregate principal balance and interest due on this Note outstanding
as of the date of repayment. So long as no Event of Default has occurred, such repayment shall satisfy Borrower’s obligations
pursuant to this Note in full and this Note shall be of no further force and effect.


 


(b)             Borrower shall defease this Note upon any and all cash exercises of Borrower’s Series A Warrants and Series B Warrants
on a dollar for dollar basis for all amounts paid pursuant to such warrant exercises. Such repayments of this Note shall be made
within three (3) business days of each such exercise; provided that any exercise price payable to the Borrower as a result of
the Lender’s exercise of any Series A Warrants or Series B Warrants may be withheld by the Lender to the extent such amounts
do not exceed the outstanding amount of this Note and any amounts so withheld shall be deemed (a) a repayment of this Note and
(b) a payment of the exercise price pursuant to the exercised warrants.


 





 






1
Face Amount shall equal Lender’s pro rata portion of $3,300,000 calculated based on the aggregate number of Original Warrants
being exchanged pursuant to that certain Warrant Amendment and Exchange Agreement, dated as of February 20, 2020, by and between
the Borrower and the Lender relative to the aggregate number of Original Warrants being exchanged pursuant to agreements with Other
Holders being executed contemporaneously therewith.


 






    


     


    




 


Section 3.             Transferability.
This Note and any of the rights granted hereunder are freely transferable or assigned by Lender, in whole or in part, in its sole
discretion; provided, there is notice to the Borrower.


 


Section 4.              Event
of Default.


 


(a)             In the event
that any one of the following events shall occur (whatever the reason and whether it shall be voluntary or involuntary or effected
by operation of law or pursuant to any judgment, decree or order of any court, or any order, rule or regulation of any administrative
or governmental body), it shall be deemed an Event of Default:


 


(i)               Any
default in the payment of the principal of, interest on or other charges in respect of this Note, or any other note issued by
the Borrower for the benefit of the Lender, as and when the same shall become due and payable;


 


(ii)             
Borrower shall fail to observe or perform any other material covenant, agreement or warranty contained in, or otherwise
commit any breach or default of any provision of this Note or any other agreement between the Borrower and the Lender;


 


(iii)           
  There shall be a breach of any of the representations and warranties set forth in this Note or any transaction document
executed contemporaneously herewith; or


 


(iv)            
Borrower, shall commence, or there shall be commenced against Borrower any applicable bankruptcy or insolvency laws as now
or hereafter in effect or any successor thereto, or Borrower commences any other proceeding under any reorganization, arrangement,
adjustment of debt, relief of debtors, dissolution, insolvency or liquidation or similar law of any jurisdiction whether now or
hereafter in effect relating to Borrower or there is commenced against Borrower any such bankruptcy, insolvency or other proceeding
which remains undismissed for a period of sixty (60) days; or Borrower is adjudicated insolvent or bankrupt; or any order of relief
or other order approving any such case or proceeding is entered; or Borrower suffers any appointment of any custodian, private
or court appointed receiver or the like for it or any substantial part of its property which continues undischarged or unstayed
for a period of sixty (60) days; or Borrower makes a general assignment for the benefit of creditors; or Borrower shall fail to
pay or shall state that it is unable to pay or shall be liable to pay, its debts as they become due or by any act or failure to
act expressly indicate its consent to, approval of or acquiescence in any of the foregoing; or any corporate or other action is
taken by the Borrower for the purpose of effecting any of the foregoing.


 


(b)           Upon
the occurrence of an Event of Default, the Lender shall give the Borrower notice of such occurrence, at which time the Borrower
shall have five (5) business days from receipt of such notice to pay the outstanding amount of the Note in full. In the event
that full payment is not made upon the expiry of the five (5) day period, a default penalty equal to two percent (2%) of the Face
Amount per month during the period of Default (the “Default Penalty”). Lender may then, at its sole discretion
declare the entire then outstanding Face Amount of this Note and the Default Penalty immediately due and payable (a “Default
Declaration”), in which event the Lender may, at its sole discretion take any action it deems necessary to recover amounts
due under this Note.


 






    2


     


    







 


(c)           Upon
the occurrence of an Event of Default, in addition to the Face Amount of the Note and
the Default Penalty, the Lender shall be entitled to recover all of its costs, fees (including without limitation, reasonable
attorney’s fees and disbursements), and expenses relating collection and enforcement Note, including all costs and expenses
incurred by it in enforcing its rights under the Note and any transaction document entered into contemporaneously herewith.


 


(d)           The
failure of Lender to exercise any of its rights hereunder in any particular instance shall not constitute a waiver of the same
or of any other right in that or any subsequent instance with respect to Lender or any subsequent holder. Lender need not provide
and Borrower hereby waives any presentment, demand, protest or other notice of any kind, and Lender may immediately and without
expiration of any grace period enforce any and all of its rights and remedies hereunder and all other remedies available to it
under applicable law. The remedies available to the Lender upon the occurrence of an Event of Default shall be cumulative.


 


Section 5.              Notices.
Any and all notices, service of process or other communications or deliveries required or permitted to be given or made pursuant
to any of the provisions of this Note shall be deemed to have been duly given or made for all purposes when hand delivered or
sent by certified or registered mail, return receipt requested and postage prepaid, overnight mail or courier as follows: 


 


If to Lender,
at:


 


Attn:


Or such
other address as may be given to the Borrower from time to time


 


If to Borrower,
at:


 


iBio, Inc.


 


Attn:


Or such
other address as may be given to the Lender from time to time


 


Section 6.              Usury. This Note is hereby expressly limited so that in no event whatsoever, whether by reason of acceleration of
maturity of the loan evidenced hereby or otherwise, shall the amount paid or agreed to be paid to the Lender hereunder for the
loan, use, forbearance or detention of money exceed that permissible under applicable law. If at any time the performance of any
provision of this Note or of any other agreement or instrument entered into in connection with this Note involves a payment exceeding
the limit of the interest that may be validly charged for the loan, use, forbearance or detention of money under applicable law,
then automatically and retroactively, ipso facto, the obligation to be performed shall be reduced to such limit, it being the specific
intent of the Borrower and the Lender that all payments under this Note are to be credited first to interest as permitted by law,
but not in excess of (i) the agreed rate of interest set forth herein or therein or (ii) that permitted by law, whichever
is the lesser, and the balance toward the reduction of principal. The provision of this Section 6 shall never be superseded or
waived and shall control every other provision of this Note and all other agreements and instruments between the Borrower and the
Lender entered into in connection with this Note. To the extent permitted by applicable law, Borrower waives any right to assert
the defense of usury.  


 






    3


     


    

 


Section 7.              Governing
Law; Waiver of Jury Trial. This Note and the provisions hereof are to be construed according to and are governed by the laws
of the State of New York, without regard to principles of conflicts of laws thereof. Borrower agrees that the New York State Supreme
Court located in the County of New York, State of New York shall have exclusive jurisdiction in connection with any dispute concerning
or arising out of this Note or otherwise relating to the parties relationship. In any action, lawsuit or proceeding brought to
enforce or interpret the provisions of this Note and/or arising out of or relating to any dispute between the parties, Lender
shall be entitled to recover all of its costs and expenses relating collection and enforcement of this Note (including without
limitation, reasonable attorney’s fees and disbursements) in addition to any other relief to which Lender may be entitled
and all costs of collection, including any legal fees associated with this Note will be paid by the Borrower. Each party agrees
that any process or notice to be served or delivered in connection with any action, lawsuit or proceeding brought hereunder may
be accomplished in accordance with the notice provisions set forth above or as otherwise provided by applicable law. BORROWER
HEREBY WAIVES TRIAL BY JURY IN ANY ACTION, PROCEEDING, CLAIM OR COUNTERCLAIM, WHETHER IN CONTRACT OR TORT, AT LAW OR IN EQUITY,
ARISING OUT OF OR IN ANY WAY RELATING TO THIS NOTE.


 


Section 8.              Successors
and Assigns. Subject to applicable securities laws, this Note and the rights and obligations evidenced hereby shall inure
to the benefit of and be binding upon the successors of Borrower and the successors and assigns of Lender.


 


Section 9.              Amendment. This Note may be modified or amended or the provisions hereof waived only with the written consent of
Lender and Borrower.  


 


Section 10.            Severability.
Wherever possible, each provision of this Note shall be interpreted in such manner as to be effective and valid under applicable
law, but if any provision of this Note 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 Note.


 


[SIGNATURE PAGE TO
FOLLOW]


 



    4


     


    




 


IN WITNESS WHEREOF,
Borrower has caused this Promissory Note to be duly authorized officer and/or such individual borrower as of the date first above
indicated.


 


 


	 	
        iBio, Inc.

	 	 
	 	By:	 
	 	 	Name:
	 	 	Title:


 



    5