EXHIBIT 10.6


EXHIBIT A


CONVERTIBLE PROMISSORY NOTE


THIS NOTE AND THE SECURITIES ISSUABLE UPON THE CONVERSION HEREOF HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, HYPOTHECATED OR OTHERWISE
TRANSFERRED EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR AN OPINION
OF COUNSEL SATISFACTORY TO THE COMPANY THAT REGISTRATION IS NOT REQUIRED UNDER SUCH ACT OR UNLESS SOLD IN ACCORDANCE WITH RULE
144 UNDER SUCH ACT.





	No. 5	Date of Issuance
	$111,000	December 11, 2015





FOR VALUE RECEIVED, Capstone Therapeutics, Corp., a Delaware corporation
(the “Company”), hereby promises to pay MSI BVF SPV, LLC (the “Lender”), the principal sum
of one hundred and eleven thousand dollars ($111,000)], with simple interest on the outstanding principal amount at the rate of
5% per annum, computed on the basis of the actual number of days elapsed and a year of 365 days. Notwithstanding the foregoing,
in the event that an Event of Default has occurred and remains continuing, interest shall instead accrue at a rate of 12% per annum.
Interest accrual shall commence with the date hereof and shall continue on the outstanding principal until paid in full or converted.
Any portion of the accrued interest may be paid at the election of the Company prior to conversion or the maturity date, provided,
however, that no such early payment shall be required. This Note is one of a series of Notes issued pursuant to that certain Securities
Purchase Agreement, dated December, 11, 2015 by and among the Company, the Lender and certain other investors (the “Purchase
Agreement”) and is entitled to the benefits of and is subject to the terms contained in that Purchase Agreement. Capitalized
terms not defined herein shall have the meaning set forth in the Purchase Agreement.


1.                 
Maturity. Unless earlier converted into Conversion Shares pursuant to Section
2.2 of the Purchase Agreement, the outstanding principal and accrued interest shall be due and payable by the Company on demand
at any time after the Maturity Date.


Payment; Pre-Payment.
All payments shall be made in lawful money of the United States of America at the principal office of the Company, or at such other
place as the holder hereof may from time to time designate in writing to the Company. Payment shall be credited first to accrued
interest due and payable and any remainder applied to principal. The principal and accrued interest under this Note may be prepaid
by the Company without penalty only (i) on or after the expiration of the Preemptive Right, upon 30 days prior notice to the Note
Holder or (ii) with the prior written consent of the Majority Note Holders, and upon any such prepayment, interest will no longer
continue to accrue on any prepaid principal amounts.


Security. The obligations
under this Note shall be secured by the Collateral, as set forth in the Purchase Agreement. 






     


     

    

Priority. The security
interest in the Collateral will be subordinate to all secured indebtedness of the Company, to the extent in existence prior to
the date of this Note, including secured indebtedness to banks and other financial institutions engaged in the business of lending
money.


Conversion of the Notes.
This Note and any amounts due hereunder shall be convertible into Conversion Shares in accordance with the terms of Section 2.2
of the Purchase Agreement. As promptly as practicable after the conversion of this Note, the Company at its expense shall issue
and deliver to the holder of this Note, upon surrender of this Note, a certificate or certificates for the number of full Conversion
Shares issuable upon such conversion.


Governing Law. This
Note shall be governed by and construed under the internal laws of the State of California, without regard to conflict-of-law principles.
Notwithstanding any provision of this Note to the contrary, this Note shall be (to the extent necessary to satisfy the requirements
of Section 22062(b)(3)(D) of the California Financial Code) subject to the implied covenant of good faith and fair dealing arising
under Section 1655 of the California Civil Code.


Successors and Assigns.
This Note applies to, inures to the benefit of and binds the successors and assigns of the Parties hereto. Notwithstanding the
forgoing, any transfer of this Note may be effected only in accordance with the Purchase Agreement. In accordance the Purchase
Agreement, this Note may be transferred only upon its surrender to the Company for registration of transfer, duly endorsed, or
accompanied by a duly executed written instrument of transfer in form satisfactory to the Company. Thereupon, a new Note for the
same principal amount and interest shall be issued to, and registered in the name of, the transferee. Interest and principal are
payable only to the registered holder of this Note. The Lender and any subsequent holder of this Note receives this Note subject
to the foregoing terms and conditions, as well as all other terms and conditions contained in this Note and in the Purchase Agreement,
and agrees to comply with all such terms and conditions for the benefit of the Company and any other Lenders.


Titles and Subtitles.
The titles and subtitles used in this Note are used for convenience only and are not to be considered in construing or interpreting
this Note.


Amendments and Waivers; Resolutions of Dispute; Notice.
The amendment or waiver of any term of this Note, the resolution of any controversy or claim arising out of or relating to this
Note and the provision of notice shall be governed and conducted pursuant to the terms of the Purchase Agreement.


Severability. If any
provision of this Note is held to be unenforceable under applicable law, such provision shall be excluded from this Note and the
balance of this Note shall be interpreted as if such provision were so excluded and shall be enforceable in accordance with its
terms.


Expenses. If any Action
at law or in equity is necessary to enforce the terms of this Note, the prevailing party shall be entitled to reasonable attorneys’
fees, costs and disbursements in addition to any other relief to which such party may be entitled.






     


     

    

Counterparts. This
Note may be executed in two or more counterparts, each of which shall be deemed an original and all of which together shall constitute
one instrument. Any counterpart delivered electronically by .pdf transmission or by facsimile shall be binding to the same extent
as an original counterpart with regard to any agreement subject to the terms hereof or any amendment thereto.


Pari Passu Notes.
Lender acknowledges and agrees that the payment of all or any portion of the outstanding principal amount of this Note and all
interest hereon shall be pari passu in right of payment and in all other respects to the other Notes issued pursuant to the Purchase
Agreement or pursuant to the terms of such Notes. In the event Lender receives payments in excess of its pro rata share of the
Company’s payments to the holders of all of the Notes, then Lender shall hold in trust all such excess payments for the benefit
of the holders of the other Notes and shall pay such amounts held in trust to such other lenders upon demand by such lenders.


This Note may be executed in one or more counterparts, each of
which shall be deemed an original, but all of which together shall constitute one and the same instrument. The parties have executed
this Note as of the date first written above.


 





	 	 	Capstone Therapeutics Corp.
	 	 	 
	 	 	 
	 	 	By:	/s/ John M. Holliman, III
	 	 	Name:	John M. Holliman, III
	 	 	Title:	Executive Chairman