Exhibit 10.15


 


PROMISSORY NOTE


 


	Principal: $184,895.00	August 28, 2019


 


KBL Merger Corp. IV,
a Delaware corporation (“Maker”), promises to pay to the order of CannBioRx Life Sciences Corp., a Delaware
corporation (“Payee”), the principal sum of $184,895.00 (the “Principal Amount”)
in lawful money of the United States of America, on the terms and conditions described below. Capitalized terms used but not defined
in this promissory note (this “Note”) shall have the meanings ascribed to them in that certain Business
Combination Agreement (the “Business Combination Agreement”) by and among Maker, Payee, Katexco Pharmaceuticals
Corp., a British Columbia corporation, CannBioRex Pharmaceuticals Corp., a British Columbia corporation, 180 Therapeutics L.P.,
a Delaware limited partnership, KBL Merger Sub, Inc., a Delaware corporation, and Lawrence Pemble, in his capacity as the stockholder
representative.


 


1. Principal.
The principal balance of this Note shall be payable on the earlier of (i) consummation of Maker’s Business Combination (whether
pursuant to the Business Combination Agreement or otherwise) and (ii) the liquidation of Maker in the event it does not consummate
a Business Combination. Maker hereby agrees that upon the consummation of an Alternative Business Combination pursuant to Section
7.3(a)(i) of the Business Combination Agreement, in addition to the repayment of the principal amount of this Note in accordance
with this Section 1, it will use its reasonable efforts to cause the Sponsor to comply with its obligations under Section 7(a)(i)
of the Business Combination Agreement to cause the Founder Shares Escrow Agent to transfer to Tyche Capital LLC a number of Escrowed
Founder Shares equal in value to three times the amount of the Covered Expense Loans, with each Escrowed Founder Share valued at
the Per Share Redemption Price (subject to equitable adjustment for stock splits, stock dividends, share exchanges, etc.).


 


2. Required
Prepayment. In the event that the Business Combination has not been consummated by the later of (a) the third Automatic Extension
or (b) the Additional Extension, as applicable, then promptly (but in any event within three Business Days) thereafter, Maker will
use any remaining funds in escrow with the Expense Escrow Agent to prepay the balance of this Note.


 


3. Interest.
No interest shall accrue on the unpaid principal balance of this Note.


 


4. Application
of Payments. All payments shall be applied first to payment in full of any costs incurred in the collection of any sum due
under this Note, including (without limitation) reasonable attorneys’ fees, then to the payment in full of any late charges
and finally to the reduction of the unpaid principal balance of this Note.


 


5. Events
of Default. The following shall constitute Events of Default:


 


(a) Failure
to Make Required Payments. Failure by Maker to pay the principal of this Note within five (5) Business Days following the date
when due.


 


(b) Voluntary
Bankruptcy, Etc. The commencement by Maker of a voluntary case under the Federal Bankruptcy Code, as now constituted or hereafter
amended, or any other applicable federal or state bankruptcy, insolvency, reorganization, rehabilitation or other similar law,
or the consent by it to the appointment of or taking possession by a receiver, liquidator, assignee, trustee, custodian, sequestrator
(or other similar official) of Maker or for any substantial part of its property, or the making by it of any assignment for the
benefit of creditors, or the failure of Maker generally to pay its debts as such debts become due.


 




     


     


    

 


(c) Involuntary Bankruptcy, Etc. The entry
of a decree or order for relief by a court having jurisdiction in the premises in respect of Maker in an involuntary case
under the Federal Bankruptcy Code, as now or hereafter constituted, or any other applicable federal or state bankruptcy,
insolvency or other similar law, or appointing a receiver, liquidator, assignee, custodian, trustee, sequestrator (or similar
official) of Maker or for any substantial part of its property, or ordering the winding-up or liquidation of its affairs, and
the continuance of any such decree or order unstayed and in effect for a period of 60 consecutive days.


 


6. Remedies.


 


(a) Upon
the occurrence of an Event of Default specified in Section 5(a), Payee may, by written notice to Maker, declare this Note
to be due and payable, whereupon the principal amount of this Note, and all other amounts payable thereunder, shall become immediately
due and payable without presentment, demand, protest or other notice of any kind, all of which are hereby expressly waived, anything
contained herein or in the documents evidencing the same to the contrary notwithstanding.


 


(b) Upon
the occurrence of an Event of Default specified in Sections 5(b) and 5(c), the unpaid principal balance of, and all other sums
payable with regard to, this Note shall automatically and immediately become due and payable, in all cases without any action on
the part of Payee.


 


7. Waivers. Maker and any endorsers and
guarantors of, and sureties for, this Note waive presentment for payment, demand, notice of dishonor, protest, and notice of
protest with regard to the Note, all errors, defects and imperfections in any proceedings instituted by Payee under the terms
of this Note, and all benefits that might accrue to Maker by virtue of any present or future laws exempting any property,
real or personal, or any part of the proceeds arising from any sale of any such property, from attachment, levy or sale under
execution, or providing for any stay of execution, exemption from civil process, or extension of time for payment; and Maker
agrees that any real estate that may be levied upon pursuant to a judgment obtained by virtue hereof, on any writ of
execution issued hereon, may be sold upon any such writ in whole or in part in any order desired by Payee.


 


8. Unconditional Liability. Maker hereby
waives all notices in connection with the delivery, acceptance, performance, default, or enforcement of the payment of this
Note, and agrees that its liability shall be unconditional, without regard to the liability of any other party, and shall not
be affected in any manner by any indulgence, extension of time, renewal, waiver or modification granted or consented to by
Payee, and consents to any and all extensions of time, renewals, waivers, or modifications that may be granted by Payee with
respect to the payment or other provisions of this Note, and agrees that any additional makers, endorsers, guarantors, or
sureties may become parties hereto without notice to them or affecting their liability hereunder.


 


9. Notices. Any notice called for hereunder
shall be delivered in the manner set forth in Section 9.3 of the Business Combination Agreement.


 


10. Construction; Venue. This Note shall
be construed and enforced in accordance with the domestic, internal law, but not the law of conflict of laws, of the State of
New York. Any action, claim, suit or other legal proceeding relating to this Note shall be brought exclusively in the state
or federal courts located in New York County, State of New York (or any appellate courts therefrom). The parties expressly
waive any objection based on personal jurisdiction, venue or forum non conveniens.


 


11. Severability.
Any provision contained in this Note which is prohibited or unenforceable in any jurisdiction shall, as to such
jurisdiction, be ineffective to the extent of such prohibition or unenforceability without invalidating the remaining
provisions hereof, and any such prohibition or unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.


 






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12. Miscellaneous.
This Note will not be assignable or transferable by either Maker or Payee without the prior written consent of the other, and any
purported assignment or transfer without such consent shall be null and void ab initio. This Note, together with the Business Combination
Agreement, constitutes the full and entire understanding and agreement between the parties with regard to the subject matter hereof
and supersedes all prior understandings or agreements with respect thereto. No amendments or modifications of or changes to this
Note or waiver of the terms and conditions hereof will be binding upon Maker or Payee, unless approved in writing and signed by
both Maker and Payee.


 


13. Trust
Fund Waiver. Payee hereby acknowledges that the waiver against Maker’s Trust Account (and distributions therefrom) contained
in Section 9.18 of the Business Combination Agreement continues in full force and effect and will apply to this Note and Maker’s
obligations hereunder.


 


[Signature Page Follows]


 






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IN WITNESS WHEREOF,
Maker, intending to be legally bound hereby, has caused this Note to be duly executed the day and year first above written.


 


	 	KBL MERGER CORP. IV
	 	 
	 	By:	 /s/ Marlene Krauss, M.D.
	 	Name:  	Marlene Krauss, M.D.
	 	Title:	Chief Executive Officer


 


Acknowledged and agreed effective as of the day
and year first written above:


  


	CANNBIORX LIFE SCIENCES CORP.	 
	 	 
	By:	 /s/ Prof. Sir Marc Feldmann	 
	Name:  	 Prof. Sir Marc Feldmann	 
	Title:	Chairman	 


 


[Signature Page
to Operating Expenses Promissory Note]