Exhibit 4.1

Exhibit 4.1

THIS WARRANT AND THE UNDERLYING SECURITIES HAVE NOT BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR ANY APPLICABLE STATE SECURITIES LAWS AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND IN COMPLIANCE WITH APPLICABLE STATE SECURITIES LAWS OR BLUE SKY LAWS.

REGENERX BIOPHARMACEUTICALS, INC.

WARRANT TO PURCHASE COMMON STOCK

October ____, 2009

Void After September 30, 2014

THIS CERTIFIES THAT, for value received, CHAUMIERE-CONSULTADORIA & SERVICOS SDC UNIPESSOAL LDA, or its permitted registered assigns (the “Holder”), is entitled to subscribe for and purchase at the Exercise Price (defined below) from REGENERX BIOPHARMACEUTICALS, INC., a Delaware corporation (the “Company”) up to 609,756 shares of the common stock of the Company, par value $0.001 per share (the “Common Stock”). This Warrant has been issued pursuant to that certain Securities Purchase Agreement between the Company and the Holder dated as of September 30, 2009 (the “Purchase Agreement”).

1. DEFINITIONS.

Capitalized terms used herein but not otherwise defined herein shall have their respective meanings as set forth in the Purchase Agreement. As used herein, the following terms shall have the following respective meanings:

(a) “Business Day” means a day, other than a Saturday or Sunday, on which banks in New York City are open for the general transaction of business.

(b) “Exercise Period” shall mean the period commencing with the date that is six months after the date hereof and ending at 5:30 p.m. New York City time on September 30, 2014.

(d) “Exercise Date” shall have the meaning set forth in Section 3.1(b) hereof.

(e) “Exercise Shares” shall mean the shares of Common Stock issuable upon exercise of this Warrant.

(f) “Expiration Date” shall mean 5:30 p.m. New York City time on September 30, 2014.

(g) “Trading Day” shall mean (i) any day on which the Common Stock is listed or quoted and traded on its primary Trading Market, (ii) if the Common Stock is not then listed or quoted and traded on any Trading Market, then a day on which trading occurs on the OTC Bulletin Board (or any successor thereto), or (iii) if trading does not occur on the OTC Bulletin Board (or any successor thereto), any Business Day.

(h) “Trading Market” means whichever of the New York Stock Exchange, the NYSE Amex, the NASDAQ Global Select Market, the NASDAQ Global Market, the NASDAQ Capital Market or the OTC Bulletin Board on which the Common Stock is listed or quoted for trading on the date in question.

2. Reserved.

3. EXERCISE OF WARRANT.

3.1. Exercise of Warrant.

(a) The rights represented by this Warrant may be exercised in whole or in part at any time during the Exercise Period upon (i) delivery of an executed Notice of Exercise in the form attached hereto to the Company at its address set forth on the signature page hereto (or at such other address as it may designate by notice in writing to the Holder), (ii) surrender of this Warrant and (iii) payment of the Exercise Price for the number of Exercise Shares as to which this Warrant is being exercised. The delivery by (or on behalf of) the Holder of the Exercise Notice and the applicable Exercise Price as provided above shall constitute the Holder’s certification to the Company that its representations contained in Section 4.2(b), (c) and (d) of the Purchase Agreement are true and correct as of the Exercise Date as if remade in their entirety (or, in the case of any transferee Holder that is not a party to the Purchase Agreement, such transferee Holder’s certification to the Company that such representations are true and correct as to such assignee Holder as of the Exercise Date).

(b) With respect to each exercise of this Warrant pursuant to Section 3.1(a) above, the Exercise Date shall be deemed to be the date the Exercise Price is received by the Company. The Exercise Shares shall be deemed to have been issued, and Holder or any other person so designated to be named therein shall be deemed to have become a holder of record of such shares for all purposes, as of the Exercise Date. The person in whose name any certificate or certificates for Exercise Shares are to be issued upon exercise of this Warrant shall be deemed to have become the holder of record of such shares on the Exercise Date, irrespective of the date of delivery of such certificate or certificates, except that, if the date of such surrender and payment is a date when the stock transfer books of the Company are closed, such person shall be deemed to have become the holder of such shares at the close of business on the next succeeding date on which the stock transfer books are open.

(c) Certificates for shares purchased hereunder shall be transmitted by the transfer agent of the Company to the Holder by crediting the account of the Holder’s prime broker with the Depository Trust Company through its Deposit Withdrawal Agent Commission system if the Company is a participant in such system, and otherwise by physical delivery to the address specified by the Holder in the Notice of Exercise within three business days from the delivery to the Company of the Notice of Exercise, surrender of this Warrant and payment of the aggregate Exercise Price as set forth above.

3.2. Issuance of New Warrants. Upon any partial exercise of this Warrant, the Company, at its expense, will forthwith and, in any event within five business days, issue and deliver to the Holder a new warrant or warrants of like tenor, registered in the name of the Holder, exercisable, in the aggregate, for the balance of the number of shares of Common Stock remaining available for purchase under the Warrant.

3.3. Payment of Taxes and Expenses. The Company shall pay any recording, filing, stamp or similar tax which may be payable in respect of any transfer involved in the issuance of, and the preparation and delivery of certificates (if applicable) representing, (i) any Exercise Shares purchased upon exercise of this Warrant and/or (ii) new or replacement warrants in the Holder’s name or the name of any transferee of all or any portion of this Warrant.

4. COVENANTS OF THE COMPANY.

4.1. Covenants as to Exercise Shares. The Company covenants and agrees that all Exercise Shares that may be issued upon the exercise of the rights represented by this Warrant will, upon issuance, be validly issued and outstanding, fully paid and nonassessable, and free from all taxes, liens and charges with respect to the issuance thereof. The Company further covenants and agrees that the Company will at all times during the Exercise Period, have authorized and reserved, free from preemptive rights, a sufficient number of shares of Common Stock to provide for the exercise of the rights represented by this Warrant. If at any time during the Exercise Period the number of authorized but unissued shares of Common Stock shall not be sufficient to permit exercise of this Warrant, the Company will take such corporate action as may, in the opinion of its counsel, be necessary to increase its authorized but unissued shares of Common Stock to such number of shares as shall be sufficient for such purposes.

4.2. No Impairment. Except to the extent as waived or consented to by the Holder, the Company will not, by amendment of its Certificate of Incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms to be observed or performed hereunder by the Company, but will at all times in good faith assist in the carrying out of all the provisions of this Warrant and in the taking of all such action as may be necessary or appropriate in order to protect the exercise rights of the Holder against impairment.

4.3. Notices of Record Date and Certain Other Events. In the event of any taking by the Company of a record of the holders of any class of securities for the purpose of determining the holders thereof who are entitled to receive any dividend (other than a cash dividend which is the same as cash dividends paid in previous quarters) or other distribution, the Company shall mail to the Holder, at least 10 days prior to the date on which any such record is to be taken for the purpose of such dividend or distribution, a notice specifying such date.

5. ADJUSTMENT OF EXERCISE PRICE AND EXERCISE SHARES.

(a) In the event of changes in the outstanding Common Stock of the Company by reason of stock dividends, split-ups, recapitalizations, reclassifications, combinations or exchanges of shares, separations, reorganizations, liquidations, consolidation, acquisition of the Company, or the like, the number, class and type of shares available under the Warrant in the aggregate and the Exercise Price shall be correspondingly adjusted to give the Holder of the Warrant, on exercise for the same aggregate Exercise Price, the total number, class, and type of shares or other property as the Holder would have owned had the Warrant been exercised prior to the event and had the Holder continued to hold such shares until the event requiring adjustment. The form of this Warrant need not be changed because of any adjustment in the number of Exercise Shares subject to this Warrant.

(b) If at any time following delivery by Holder to the Company of a Notice of Exercise but prior to issuance of the applicable Exercise Shares, the holders of Common Stock of the Company (or any shares of stock or other securities at the time receivable upon the exercise of this Warrant) shall have received or become entitled to receive, without payment therefor:

(i) Common Stock or any shares of stock or other securities which are at any time directly or indirectly convertible into or exchangeable for Common Stock, or any rights or options to subscribe for, purchase or otherwise acquire any of the foregoing by way of dividend or other distribution (other than a dividend or distribution covered in Section 5(a) above),

(ii) any cash paid or payable otherwise than as a cash dividend, or

(iii) Common Stock or additional stock or other securities or property (including cash) by way of spinoff, split-up, reclassification, combination of shares or similar corporate rearrangement (other than shares of Common Stock pursuant to Section 5(a) above),

then and in each such case, the Holder hereof will be entitled to receive, in addition to the number of shares of Common Stock receivable pursuant to the Notice of Exercise, and without payment of any additional consideration therefor, the amount of stock and other securities and property (including cash in the cases referred to in clauses (ii) and (iii) above) which such Holder would hold on the date of such exercise had such Holder been the holder of record of such Common Stock as of the date on which holders of Common Stock received or became entitled to receive such shares or all other additional stock and other securities and property.

(c) Upon the occurrence of each adjustment pursuant to this Section 5, the Company at its expense will, at the written request of the Holder, promptly compute such adjustment in accordance with the terms of this Warrant and prepare a certificate setting forth such adjustment, including a statement of the adjusted Exercise Price and adjusted number or type of Exercise Shares or other securities issuable upon exercise of this Warrant (as applicable), describing the transactions giving rise to such adjustments and showing in detail the facts upon which such adjustment is based. Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder and to the Company’s transfer agent.

6. FRACTIONAL SHARES.

No fractional shares shall be issued upon the exercise of this Warrant as a consequence of any adjustment pursuant hereto. All Exercise Shares (including fractions) issuable upon exercise of this Warrant may be aggregated for purposes of determining whether the exercise would result in the issuance of any fractional share. If, after aggregation, the exercise would result in the issuance of a fractional share, the Company shall, in lieu of issuance of any fractional share, pay the Holder otherwise entitled to such fraction a sum in cash equal to the product resulting from multiplying the then current fair market value of an Exercise Share by such fraction.

7. NO STOCKHOLDER RIGHTS.

Other than as provided in Section 3.1(a) or otherwise herein, this Warrant in and of itself shall not entitle the Holder to any voting rights or other rights as a stockholder of the Company.

8. TRANSFER OF WARRANT.

Subject to applicable laws and the restrictions on transfer set forth on the first page of this Warrant and set forth in the Purchase Agreement, including, without limitation, Section 5 thereof, this Warrant and all rights hereunder are transferable, by the Holder in person or by duly authorized attorney, upon delivery of this Warrant and the form of assignment attached hereto to any transferee designated by Holder. The transferee shall sign an investment letter in form and substance reasonably satisfactory to the Company and its counsel.

9. LOST, STOLEN, MUTILATED OR DESTROYED WARRANT.

If this Warrant is lost, stolen, mutilated or destroyed, the Company may, on such terms as to indemnity or otherwise as it may reasonably impose (which shall, in the case of a mutilated Warrant, include the surrender thereof), issue a new Warrant of like denomination and tenor as the Warrant so lost, stolen, mutilated or destroyed. Any such new Warrant shall constitute an original contractual obligation of the Company, whether or not the allegedly lost, stolen, mutilated or destroyed Warrant shall be at any time enforceable by anyone.

10. NOTICES, ETC.

All notices required or permitted hereunder shall be in writing and shall be deemed effectively given: (a) upon personal delivery to the party to be notified, (b) when sent by confirmed telex or facsimile if sent during normal business hours of the recipient, if not, then on the next business day, (c) five days after having been sent by registered or certified mail, return receipt requested, postage prepaid, or (d) one day after deposit with a nationally recognized overnight courier, specifying next day delivery, with written verification of receipt. All communications shall be sent to the Company at the address listed on the signature page hereto and to Holder at the applicable address set forth on the applicable signature page to the Purchase Agreement or at such other address as the Company or Holder may designate by 10 days advance written notice to the other parties hereto.

11. ACCEPTANCE.

Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

12. GOVERNING LAW.

This Warrant and all rights, obligations and liabilities hereunder shall be governed by the laws of the State of Delaware.

13. AMENDMENT OR WAIVER.

Any term of this Warrant may be amended or waived (either generally or in a particular instance and either retroactively or prospectively) with the written consent of the Company and the Holder. No waivers of any term, condition or provision of this Warrant, in any one or more instances, shall be deemed to be, or construed as, a further or continuing waiver of any such term, condition or provision.

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IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its duly authorized officer as of October _____, 2009.


REGENERX BIOPHARMACEUTICALS, INC.
By:
	Name:	J.J. Finkelstein
	Title:	President and Chief Executive Officer

NOTICE OF EXERCISE

TO: REGENERX BIOPHARMACEUTICALS, INC.

(1) The undersigned hereby elects to purchase shares of the Common Stock of REGENERX BIOPHARMACEUTICALS, INC. (the “Company”) pursuant to the terms of the attached Warrant, and tenders herewith payment of the exercise price in full, together with all applicable transfer taxes, if any.

(2) Please issue a certificate or certificates representing said shares of Common Stock of the Company in the name of the undersigned or in such other name as is specified below:

(Name)

(Address)

(3) The undersigned represents that (i) the aforesaid shares of Common Stock are being acquired for the account of the undersigned 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; (ii) the undersigned is aware of the Company’s business affairs and financial condition and has acquired sufficient information about the Company to reach an informed and knowledgeable decision regarding its investment in the Company; (iii) the undersigned is experienced in making investments of this type and has such knowledge and background in financial and business matters that the undersigned is capable of evaluating the merits and risks of this investment and protecting the undersigned’s own interests; (iv) the undersigned understands that the shares of Common Stock issuable upon exercise of this Warrant have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), by reason of a specific exemption from the registration provisions of the Securities Act, which exemption depends upon, among other things, the bona fide nature of the investment intent as expressed herein, and, because such securities have not been registered under the Securities Act, they must be held indefinitely unless subsequently registered under the Securities Act or an exemption from such registration is available; (v) the undersigned is aware that the aforesaid shares of Common Stock may not be sold pursuant to Rule 144 adopted under the Securities Act unless certain conditions are met and until the undersigned has held the shares for the number of years prescribed by Rule 144, that among the conditions for use of the Rule is the availability of current information to the public about the Company; and (vi) the undersigned agrees not to make any disposition of all or any part of the aforesaid shares of Common Stock unless and until there is then in effect a registration statement under the Securities Act covering such proposed disposition and such disposition is made in accordance with said registration statement, or the undersigned has provided upon the Company’s reasonable request, an opinion of counsel satisfactory to the Company, stating that such registration is not required.


(Date)		(Signature)

		(Print name)

ASSIGNMENT FORM

(To assign the foregoing Warrant, execute this form and supply required information.
Do not use this form to purchase shares.)

FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced thereby are hereby assigned to


Name:
		(Please Print)

Address:
		(Please Print)

Dated: , 20

Holder’s Signature:

Holder’s Address:

NOTE: The signature to this Assignment Form must correspond with the name as it appears on the face of the Warrant, without alteration or enlargement or any change whatever. Officers of corporations and those acting in a fiduciary or other representative capacity should file proper evidence of authority to assign the foregoing Warrant.