AMENDMENT AGREEMENT AMENDMENT AGREEMENT (this Agreement ), dated as of September [ ], 2021 by and among Quoin Pharmaceuticals, Inc., a Delaware corporation, with headquarters located at 42127 Pleasant Forest Ct, Ashburn,

AMENDMENT AGREEMENT (this

"Agreement"), dated as of September [ ], 2021 by and among Quoin Pharmaceuticals, Inc., a Delaware corporation,

with headquarters located at 42127 Pleasant Forest Ct, Ashburn, VA 20148 ("Quoin"), Cellect Biotechnology Ltd., an Israeli

company, with headquarters located at 23 Hata'as Street, Kfar Saba, Israel 44425 ("Cellect") and the investor listed

on the signature page attached hereto (the "Holder"). Capitalized terms used herein and not otherwise defined herein

shall have the respective meanings set forth in the Primary Financing SPA, the Bridge SPA, the RRA or the Warrants (each as defined below),

connection with the Securities Purchase Agreement (as amended, the "Primary Financing SPA") by and among Quoin, Cellect

and the Holder, dated as of March 24, 2021, (x) Quoin has agreed to issue to the Initial Purchased Shares and the Additional Purchased

Shares and (y) Cellect has agreed to issue to the Holder Series A Warrants, Series B Warrants and Series C Warrants, in the forms attached

as Exhibits B-1, B-2 and B-3, respectively, to the Primary Financing SPA (as amended, collectively, the "Primary Financing Warrants"),

which are exercisable to purchase ADSs of Cellect (as exercised, collectively, the "Primary Financing Warrant Shares")

in accordance with the terms of the Primary Financing Warrants.

connection with the Securities Purchase Agreement (as amended, the "Bridge SPA") by and between Quoin and the Holder,

dated as of March 24, 2021, Quoin issued to the Holder (i) on March 25, 2021 (x) senior secured notes and (y) warrants, in the form

attached as Exhibit B to the Bridge SPA (as amended, the "First Bridge Warrants"), which are exercisable to purchase

shares of Quoin's common stock, in accordance with the terms of the First Bridge Warrants, which will be exchanged for warrants (the "First

Exchange Warrants") to purchase ADSs of Cellect (as exercised, collectively, the "First Exchange Warrant Shares")

upon the consummation of the transactions contemplated pursuant to that certain Agreement and Plan of Merger, dated as of March 24, 2021,

by and among Quoin, Cellect and CellMSC, Inc., a Delaware corporation and wholly owned subsidiary of Cellect (as amended, the "Merger

Agreement"), (ii) on April 23, 2021 (x) senior secured notes and (y) warrants, in the form attached as Exhibit B to the Bridge

SPA (as amended, the "Second Bridge Warrants"), which are exercisable to purchase shares of Quoin's common stock, in

accordance with the terms of the Second Bridge Warrants, which will be exchanged for warrants (the "Second Exchange Warrants")

to purchase ADSs of Cellect (as exercised, collectively, the "Second Exchange Warrant Shares") upon the consummation

of the transactions contemplated pursuant to the Merger Agreement and (iii) on May 24, 2021 (x) senior secured notes and (y) warrants,

in the form attached as Exhibit B to the Bridge SPA (as amended, the "Third Bridge Warrants" and together with the First

Bridge Warrants and the Second Bridge Warrants, the "Bridge Warrants"), which are exercisable to purchase shares of Quoin's

common stock, in accordance with the terms of the Third Bridge Warrants, which will be exchanged for warrants (the "Third Exchange

Warrants" and together with the First Exchange Warrants and the Second Exchange Warrants, the "Exchange Warrants")

to purchase ADSs of Cellect (as exercised, collectively, the "Third Exchange Warrant Shares" and together with the First

Exchange Warrants Shares and the Second Exchange Warrant Shares, the "Exchange Warrant Shares") upon the consummation

of the transactions contemplated pursuant to the Merger Agreement.

Primary Financing Warrants, the Bridge Warrants and the Exchange Warrants contain certain reset provisions that may increase the number

of Primary Financing Warrant Shares, the Bridge Warrant Shares and Exchange Warrant Shares, respectively, issuable pursuant to such warrants

and may decrease the Exercise Price (as defined in the Primary Financing Warrants, the Bridge Warrants and the Exchange Warrants) of such

warrants that may lead to the Primary Financing Warrants and the Exchange Warrants being treated as liabilities for accounting purposes,

although it was desired by Quoin, Cellect and the Holder when entering into the Primary Financing SPA and the Bridge SPA that such warrants

be treated as equity for accounting purposes. Therefore, pursuant to this Agreement, Quoin, Cellect and the Holder wish (i) to amend (x)

the form of the Primary Financing Warrants attached as Exhibits B-1, B-2 and B-3 to the Primary Financing SPA as set forth on Exhibits

A-1, A-2 and A-3 attached hereto and (y) the form of the Exchange Warrants attached as Exhibit F to the Primary Financing

SPA as set forth on Exhibit B attached hereto, all pursuant to the terms and conditions set forth herein.

and the Holder also are parties to that certain Registration Rights Agreement, dated as of March 24, 2021 (as amended, the "RRA")

and have determined to amend certain provisions under the RRA as set forth herein.

amendments, transactions and other provisions of this Agreement shall be effective (the "Effective Date") upon receipt

by each party to this Agreement of this Agreement duly executed and delivered by such other parties to this Agreement.

NOW, THEREFORE, in consideration

of the premises and the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which

are hereby acknowledged, Quoin, Cellect and the Holder hereby agree as follows:

Amendments. As of the Effective Date:

the form of the Primary Financing Warrants attached

as Exhibits B-1, B-2 and B-3 to the Primary Financing SPA shall be amended and restated as set forth in Exhibits A-1, A-2

and A-3 attached hereto;

the form of the Exchange Warrants attached as

Exhibit F to the Primary Financing SPA shall be amended and restated as set forth in Exhibit B attached hereto;

the fourth recital of the form of the Securities

Escrow Agreement attached as Exhibit A to the Primary financing SPA is hereby amended and restated, as follows (additions are indicated

by bold blue font and deletions with strikethrough red font):

pursuant to the Merger, the outstanding shares of Quoin Common Stock will be converted into and exchanged for American Depositary

Shares (the "Cellect ADSs"), each representing one hundred

(100) four hundred (400) ordinary shares, no par value per share, of Cellect;"

the form of the capacity notice attached as (i)

Exhibit C attached to the form of the Securities Escrow Agreement attached as Exhibit A to the Primary financing SPA and (ii) Exhibit

D to the Primary financing SPA, is hereby amended and restated, as follows (additions are indicated by bold blue font and deletions with

strikethrough red font):

holder hereby exercises the right to receive_________ American Depositary Shares, each representing one hundred (100)

four hundred (400) of the Company's ordinary shares, no par value per share (the "Capacity Shares"), of

[Quoin Pharmaceuticals, Ltd.], an Israeli company (formerly known as Cellect Biotechnology Ltd.) (the "Company") and

hereby directs the Company and The Bank of New York Mellon (the "Escrow Agent") to deliver to the undersigned via free

delivery / free receive such number of Capacity Shares as set forth below, in each case, in accordance with the terms of (i) that certain

Securities Purchase Agreement dated as of March 24, 2021, by and among the Company, Quoin Pharmaceuticals, Inc., a Delaware corporation

("Quoin") and the Buyers listed on the signature pages attached thereto, as amended, supplemented or otherwise modified

from time to time and (ii) that certain Securities Escrow Agreement, dated as of March [__], 2021, by and among the Company,

Quoin, the Escrow Agent and the undersigned (Account #:[ ], Account Name: BNY Mellon Quoin Escrow FBO Altium Growth Fund, LP )."

Recital C of the Primary Financing SPA is hereby

amended and restated, as follows (additions are indicated by bold blue font and deletions with strikethrough red font):

PublicCo hereby agrees to issue to each Buyer, upon the terms and conditions stated in this Agreement, (i) warrants, in the form attached

hereto as Exhibit B-1 (the "Series A Warrants"), representing the right to acquire an initial amount of American

Depositary Shares ("ADSs" or "American Depositary Shares"), each representing one hundred (100)

four hundred (400) PublicCo ordinary shares, no par value per share (the "PublicCo Ordinary Shares")

equal to one hundred percent (100%) of the quotient determined by dividing the Purchase Price (as defined below) paid by such

Buyer on the Shares Closing Date by the lower of the Closing Per Share Price and the Initial Per Share Price (each as defined below)

4,276,252 (subject to further adjustments as set forth therein) (such ADSs issuable upon exercise of the Series A Warrants, collectively,

the "Series A Warrant Shares"), (ii) warrants, in the form attached hereto as Exhibit B-2 (the "Series

B Warrants"), representing the right to acquire an initial amount of ADSs equal to one hundred percent (100%) of the

quotient determined by dividing the Purchase Price paid by such Buyer on the Shares Closing Date, by the lower of the Closing Per Share

Price and the Initial Per Share Price 4,276,252 (subject to further adjustments as set forth therein) (such ADSs issuable

upon exercise of the Series B Warrants, collectively, the "Series B Warrant Shares") and (iii) warrants, in the form

attached hereto as Exhibit B-3 (the "Series C Warrants" and together with the Series A Warrants and the Series

B Warrants, the "Warrants"), representing the right to acquire (x) an initial amount of ADSs equal to one hundred

percent (100%) of the quotient determined by dividing each Buyer's Series C Warrants' dollar amount set forth opposite such Buyer's name

in column (3) on the Schedule of Buyers, by the lower of the Closing Per Share Price and the Initial Per Share Price 2,389,670

(subject to further adjustments as set forth therein) (such ADSs issuable upon exercise of the Series C Warrants, collectively, the

"Series C Warrant Shares" and together with the Series A Warrant Shares and the Series B Warrant Shares, the "Warrant

Shares") and (y) an additional amount of Series A Warrants and Series B Warrants, each to purchase a number of ADSs determined

pursuant to the terms thereof (such ADSs, are also referred to herein and in the other Transaction Documents as "Series A Warrant

Shares" and "Series B Warrant Shares", respectively)."

Section 1(c)(i) of the Primary Financing SPA is

hereby amended and restated, as follows (additions are indicated by bold blue font and deletions with strikethrough red font):

to Issue Warrants. On the Warrant Closing Date (as defined below), PublicCo shall issue to each Buyer for no additional consideration,

Series A Warrants, Series B Warrants and Series C Warrants each to acquire (x) an initial amount of ADSs equal to 4,276,252 (subject

to further adjustments as set forth therein)one hundred percent (100%) of the quotient determined by dividing the Purchase