Exhibit 4.1

COMMON STOCK PURCHASE WARRANT

REGENERX BIOPHARMACEUTICALS, INC.

Issuance Date: January 7, 2011
Warrant Shares: 740,741		Initial Exercise Date: July 7, 2011

          THIS COMMON STOCK PURCHASE WARRANT (the “ Warrant ”) certifies that, for value received, Lincoln Park Capital Fund, LLC (the “ Holder ”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time on or after July 7, 2011 (the “ Initial Exercise Date ”) and on or prior to the close of business on the fifth anniversary of the Issuance Date (the “ Termination Date ”) but not thereafter, to subscribe for and purchase from RegeneRx Biopharmaceuticals, Inc., a Delaware corporation (the “ Company ”), up to 740,741 shares (the “ Warrant Shares ”) of Common Stock The purchase price of one share of Common Stock under this Warrant shall be equal to the Exercise Price, as defined in Section 2(b).

      Section 1 . Definitions . Capitalized terms used and not otherwise defined herein shall have the meanings set forth in that certain Securities Purchase Agreement (the “ Purchase Agreement ”), dated January 5, 2011, by and betweeen the Company and the Holder.

      Section 2 . Exercise .

     a) Exercise of Warrant . Exercise of the purchase rights represented by this Warrant may be made, in whole or in part, at any time or times on or after the Initial Exercise Date and on or before the Termination Date by delivery to the Company (or such other office or agency of the Company as it may designate by notice in writing to the registered Holder at the address of the Holder appearing on the books of the Company) of a duly executed facsimile copy of the Notice of Exercise Form annexed hereto; and, within three (3) Business Days of the date said Notice of Exercise is delivered to the Company, the Company shall have received payment of the aggregate Exercise Price of the shares thereby purchased by wire transfer or cashier’s check drawn on a United States bank or, if available, pursuant to the cashless exercise procedure specified in Section 2(c) below. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender this Warrant to the Company until the Holder has purchased all of the Warrant Shares available hereunder and the Warrant has been exercised in full, in which case, the Holder shall surrender this Warrant to the Company for cancellation within three (3) Business Days of the date the final Notice of Exercise is delivered to the Company. Partial exercises of this Warrant resulting in purchases of a portion of the total number of Warrant Shares available hereunder shall have the effect of lowering the outstanding number of Warrant Shares purchasable hereunder in an amount equal to the applicable number of Warrant Shares purchased. The Holder and the Company shall maintain records showing the number of Warrant Shares purchased and the date of such purchases. The Company shall deliver any objection to any Notice of Exercise Form within one (1) Business Day of receipt of such notice. In the event of any dispute or discrepancy, the records of the Holder shall be controlling and determinative in the absence of manifest error. The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares available for purchase hereunder at any given time may be less than the amount stated on the face hereof.

     b) Exercise Price . The exercise price per share of the Common Stock under this Warrant shall be $0.38 , subject to adjustment hereunder (the “ Exercise Price ”).

     c) Cashless Exercise . If at the time of exercise hereof there is no effective registration statement registering, or the prospectus contained therein is not available for the issuance of the Warrant Shares to the Holder and all of the Warrant Shares are not then registered for sale by Holder (or the prospectus contained therein is not available for use), then this Warrant may also be exercised, in whole or in part, at such time by means of a “cashless exercise” in which the Holder shall be entitled to receive a certificate for the number of Warrant Shares equal to the quotient obtained by dividing [(A-B) (X)] by (A), where:

     “ VWAP ” means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or quoted on the Principal Market, the daily volume weighted average price of the Common Stock for such date (or the nearest preceding date) on the Principal Market as reported by Bloomberg L.P. (based on a Business Day from 8:30 a.m. (Central Standard Time to 3:02 p.m. (Central Standard Time), (b) if the Common Stock is not then listed or quoted for trading on the OTC Bulletin Board and if prices for the Common Stock are then reported in the “Pink Sheets” published by Pink OTC Markets, Inc. (or a similar organization or agency succeeding to its functions of reporting prices), the most recent bid price per share of the Common Stock so reported, or (c) in all other cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the Holder and reasonably acceptable to the Company, the fees and expenses of which shall be paid by the Company.

     d) Mechanics of Exercise .

     i.  Delivery of Certificates Upon Exercise . Certificates for shares purchased hereunder shall be transmitted by the Transfer Agent to the Holder by crediting the account of the Holder’s prime broker with the Depository Trust Company through its Deposit Withdrawal Agent Commission (“ DWAC ”) system if the Company is then a participant in such system and either (A) there is an effective Registration Statement permitting the issuance of the Warrant Shares to or resale of the Warrant Shares by Holder or (B) this Warrant is being exercised via cashless exercise, and otherwise by physical delivery to the address specified by the Holder in the Notice of Exercise by the date that is three (3) Business Days after the latest of (A) the delivery to the Company of the Notice of Exercise Form, (B) surrender of this Warrant (if required) and (C) payment of the aggregate Exercise Price as set forth above (including by cashless exercise, if permitted) (such date, the “ Warrant Share Delivery Date ”). This Warrant shall be deemed to have been exercised on the first date on which all of the foregoing have been delivered to the Company. The Warrant 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 date the Warrant has been exercised, with payment to the Company of the Exercise Price (or by cashless exercise, if permitted) and all taxes required to be paid by the Holder, if any, pursuant to Section 2(d)(vi) prior to the issuance of such shares, having been paid. If the Company fails

for any reason to deliver to the Holder certificates evidencing the Warrant Shares subject to a Notice of Exercise by the Warrant Share Delivery Date, the Company shall pay to the Holder, in cash, as liquidated damages and not as a penalty, for each $1,000 of Warrant Shares subject to such exercise (based on the VWAP of the Common Stock on the date of the applicable Notice of Exercise), $10 per Business Day (increasing to $20 per Business Day on the fifth Business Day after such liquidated damages begin to accrue) for each Business Day after such Warrant Share Delivery Date until such certificates are delivered or Holder rescinds such exercise.

     ii.  Delivery of New Warrants Upon Exercise . If this Warrant shall have been exercised in part, the Company shall, at the request of a Holder and upon surrender of this Warrant certificate, at the time of delivery of the certificate or certificates representing Warrant Shares, deliver to Holder a new Warrant evidencing the rights of Holder to purchase the unpurchased Warrant Shares called for by this Warrant, which new Warrant shall in all other respects be identical with this Warrant.

     iii.  Rescission Rights . If the Company fails to cause the Transfer Agent to transmit to the Holder a certificate or the certificates representing the Warrant Shares pursuant to Section 2(d)(i) by the Warrant Share Delivery Date, then, the Holder will have the right to rescind such exercise.

     iv.  Compensation for Buy-In on Failure to Timely Deliver Certificates Upon Exercise . In addition to any other rights available to the Holder, if the Company fails to cause the Transfer Agent to transmit to the Holder a certificate or the certificates representing the Warrant Shares pursuant to an exercise on or before the Warrant Share Delivery Date, and if after such date the Holder is required by its broker to purchase (in an open market transaction or otherwise) or the Holder’s brokerage firm otherwise purchases, shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “ Buy-In ”), then the Company shall (A) pay in cash to the Holder the amount, if any, by which (x) the Holder’s total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (1) the number of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue times (2) the price at which the sell order giving rise to such purchase obligation was executed, and (B) at the option of the Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored (in which case such exercise shall be deemed rescinded) or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its exercise and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an attempted exercise of shares of Common Stock with an aggregate sale price giving rise to such purchase obligation of $10,000, under clause (A) of the immediately preceding sentence the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company written notice indicating the amounts payable to the Holder in respect of the Buy-In and, upon request of the Company, evidence of the amount of such loss. Nothing herein shall limit a Holder’s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely deliver certificates representing shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof.

     v.  No Fractional Shares or Scrip . No fractional shares or scrip representing fractional shares shall be issued upon the exercise of this Warrant. As to any fraction of a share which the Holder would otherwise be entitled to purchase upon such exercise, the Company shall, at its election, either pay a cash adjustment in respect of such final fraction in an amount equal to such fraction multiplied by the Exercise Price or round up to the next whole share.

     vi.  Charges, Taxes and Expenses . Issuance of certificates for Warrant Shares shall be made without charge to the Holder for any issue or transfer tax or other incidental expense in respect of the issuance of such certificate, all of which taxes and expenses shall be paid by the Company, and such certificates shall be issued in the name of the Holder or in such name or names as may be directed by the Holder; provided , however , that in the event certificates for Warrant Shares are to be issued in a name other than the name of the Holder, this Warrant when surrendered for exercise shall be accompanied by the Assignment Form attached hereto duly executed by the Holder and the Company may require, as a condition thereto, the payment of a sum sufficient to reimburse it for any transfer tax incidental thereto.

     vii.  Closing of Books . The Company will not close its stockholder books or records in any manner which prevents the timely exercise of this Warrant, pursuant to the terms hereof.

     e) Holder’s Exercise Limitations . The Company shall not effect any exercise of this Warrant, and a Holder shall not have the right to exercise any portion of this Warrant, pursuant to Section 2 or otherwise, to the extent that after giving effect to such issuance after exercise as set forth on the applicable Notice of Exercise, the Holder (together with the Holder’s Affiliates, and any other Persons acting as a group together with the Holder or any of the Holder’s Affiliates), would beneficially own in excess of the Beneficial Ownership Limitation (as defined below). For purposes of the foregoing sentence, the number of shares of Common Stock beneficially owned by the Holder and its Affiliates shall include the number of shares of Common Stock issuable upon exercise of this Warrant with respect to which such determination is being made, but shall exclude the number of shares of Common Stock which would be issuable upon (i) exercise of the remaining, nonexercised portion of this Warrant beneficially owned by the Holder or any of its Affiliates and (ii) exercise or conversion of the unexercised or nonconverted portion of any other securities of the Company (including, without limitation, any other securities of the Company which would entitle the holder thereof to acquire at any time Common Stock, including, without limitation, any debt, preferred stock, rights, options, warrants or other instrument that is at any time convertible into or exercisable or exchangeable for, or otherwise entitles the holder thereof to receive, Common Stock) subject to a limitation on conversion or exercise analogous to the limitation contained herein beneficially owned by the Holder or any of its Affiliates. Except as set forth in the preceding sentence, for purposes of this Section 2(e), beneficial ownership shall be calculated in accordance with Section 13(d) of the 1934 Act and the rules and regulations promulgated thereunder, it being acknowledged by the Holder that the Company is not representing to the Holder that such calculation is in compliance with Section 13(d) of the 1934 Act and the Holder is solely responsible for any schedules required to be filed in accordance therewith. To the extent that the limitation contained in this Section 2(e) applies, the determination of whether this Warrant is exercisable (in relation to other securities owned by the Holder together with any Affiliates) and of which portion of this Warrant is exercisable shall be in the sole discretion of the Holder, and the submission of a Notice of Exercise shall be deemed to be the Holder’s determination of whether this Warrant is exercisable (in relation to other securities owned by the Holder together with any Affiliates) and of which portion of this Warrant is exercisable, in each case subject to the Beneficial Ownership Limitation, and the Company shall have no obligation to verify or confirm the accuracy of such determination. In addition, a determination as to any group status as contemplated above shall be determined in accordance with Section 13(d) of the 1934 Act and the rules and regulations promulgated thereunder. For purposes of this Section 2(e), in determining the number of outstanding shares of Common Stock, a Holder may rely on the number of outstanding shares of Common Stock as reflected in (A) the Company’s most recent periodic or annual report filed with the Commission, as the case may be, (B) a more recent public announcement by the Company or (C) a more recent written notice by the Company or the Transfer Agent setting forth the number of shares of Common Stock outstanding. Upon the written or oral request of a Holder, the Company shall within two Business Days confirm orally and in writing to the Holder the number of shares of Common Stock then outstanding. In any case, the number of outstanding shares of Common Stock shall be determined after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by the

Holder or its Affiliates since the date as of which such number of outstanding shares of Common Stock was reported. The “ Beneficial Ownership Limitation ” shall be 4.99% of the number of shares of the Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock issuable upon exercise of this Warrant. The Holder, upon not less than 61 days’ prior notice to the Company, may increase or decrease the Beneficial Ownership Limitation provisions of this Section 2(e), provided that the Beneficial Ownership Limitation in no event exceeds 9.99% of the number of shares of the Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock upon exercise of this Warrant held by the Holder and the provisions of this Section 2(e) shall continue to apply. Any such increase or decrease will not be effective until the 61st day after such notice is delivered to the Company. The provisions of this paragraph shall be construed and implemented in a manner otherwise than in strict conformity with the terms of this Section 2(e) to correct this paragraph (or any portion hereof) which may be defective or inconsistent with the intended Beneficial Ownership Limitation herein contained or to make changes or supplements necessary or desirable to properly give effect to such limitation. The limitations contained in this paragraph shall apply to a successor holder of this Warrant. For purposes of the Warrant, “ Affiliate ” has the meaning set forth in Rule 12b-2 of the regulations promulgated under the 1934 Act.

      Section 3 . Certain Adjustments .

     a) Stock Dividends and Splits . If the Company, at any time while this Warrant is outstanding: (i) pays a stock dividend or otherwise makes a distribution or distributions on shares of its Common Stock or any other equity or equity equivalent securities payable in shares of Common Stock (which, for avoidance of doubt, shall not include any shares of Common Stock issued by the Company upon exercise of this Warrant), (ii) subdivides outstanding shares of Common Stock into a larger number of shares, (iii) combines (including by way of reverse stock split) outstanding shares of Common Stock into a smaller number of shares, or (iv) issues by reclassification of shares of the Common Stock any shares of capital stock of the Company, then in each case the Exercise Price shall be multiplied by a fraction of which the numerator shall be the number of shares of Common Stock (excluding treasury shares, if any) outstanding immediately before such event and of which the denominator shall be the number of shares of Common Stock outstanding immediately after such event, and the number of shares issuable upon exercise of this Warrant shall be proportionately adjusted such that the aggregate Exercise Price of this Warrant shall remain unchanged. Any adjustment made pursuant to this Section 3(a) shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution and shall become effective immediately after the effective date in the case of a subdivision, combination or re-classification.

     b) Subsequent Rights Offerings . If the Company, at any time while the Warrant is outstanding, shall issue rights, options or warrants to all holders of Common Stock (and not to the Holders) entitling them to subscribe for or purchase shares of Common Stock at a price per share less than the VWAP on the record date mentioned below, then, the Exercise Price shall be multiplied by a fraction, of which the denominator shall be the number of shares of the Common Stock outstanding on the date of issuance of such rights, options or warrants plus the number of additional shares of Common Stock offered for subscription or purchase, and of which the numerator shall be the number of shares of the Common Stock outstanding on the date of issuance of such rights, options or warrants plus the number of shares which the aggregate offering price of the total number of shares so offered (assuming receipt by the Company in full of all consideration payable upon exercise of such rights, options or warrants) would purchase at such VWAP. Such adjustment shall be made whenever such rights, options or warrants are issued, and shall become effective immediately after the record date for the determination of stockholders entitled to receive such rights, options or warrants.

     c) Pro Rata Distributions . If the Company, at any time while this Warrant is outstanding, shall distribute to all holders of Common Stock (and not to the Holders) evidences of its indebtedness or assets (including cash and cash dividends) or rights or warrants to subscribe for or purchase any security other than the Common Stock), then in each such case the Exercise Price shall be adjusted by multiplying the Exercise Price in effect immediately prior to the record date fixed for determination of stockholders entitled to receive such distribution by a fraction of which the denominator shall be the VWAP determined as of the record date mentioned above, and of which the numerator shall be such VWAP on such record date less the then per share fair market value at such record date of the portion of such assets or evidence of indebtedness so distributed applicable to one outstanding share of the Common Stock as determined by the Board of Directors in good faith. In either case the adjustments shall be described in a statement provided to the Holder of the portion of assets or evidences of indebtedness so distributed or such subscription rights applicable to one share of Common Stock. Such adjustment shall be made whenever any such distribution is made and shall become effective immediately after the record date mentioned above.

     d) Fundamental Transaction . If, at any time while this Warrant is outstanding, (i) the Company, directly or indirectly, in one or more related transactions effects any merger or consolidation of the Company with or into another Person, (ii) the Company, directly or indirectly, effects any sale, lease, license, assignment, transfer, conveyance or other disposition of all or substantially all of its assets in one or a series of related transactions, (iii) any, direct or indirect, purchase offer, tender offer or exchange offer (whether by the Company or another Person) is completed pursuant to which holders of Common Stock are permitted to sell, tender or exchange their shares for other securities, cash or property and has been accepted by the holders of 50% or more of the outstanding Common Stock, (iv) the Company, directly or indirectly, in one or more related transactions effects any reclassification, reorganization or recapitalization of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property, (v) the Company, directly or indirectly, in one or more related transactions consummates a stock or share purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization, spin-off or scheme of arrangement) with another Person whereby such other Person acquires more than 50% of the outstanding shares of Common Stock (not including any shares of Common Stock held by the other Person or other Persons making or party to, or associated or affiliated with the other Persons making or party to, such stock or share purchase agreement or other business combination) (each a “ Fundamental Transaction ”), then, upon any subsequent exercise of this Warrant, the Holder shall have the right to receive, for each Warrant Share that would have been issuable upon such exercise immediately prior to the occurrence of such Fundamental Transaction, at the option of the Holder (without regard to any limitation in Section 2(e) on the exercise of this Warrant), the number of shares of Common Stock of the successor or acquiring corporation or of the Company, if it is the surviving corporation, and any additional consideration (the “ Alternate Consideration ”) receivable as a result of such Fundamental Transaction by a holder of the number of shares of Common Stock for which this Warrant is exercisable immediately prior to such Fundamental Transaction (without regard to any limitation in Section 2(e) on the exercise of this Warrant). For purposes of any such exercise, the determination of the Exercise Price shall be appropriately adjusted to apply to such Alternate Consideration based on the amount of Alternate Consideration issuable in respect of one share of Common Stock in such Fundamental Transaction, and the Company shall apportion the Exercise Price among the Alternate Consideration in a reasonable manner reflecting the relative value of any different components of the Alternate Consideration. If holders of Common Stock are given any choice as to the securities, cash or property to be received in a Fundamental Transaction, then the Holder shall be given the same choice as to the Alternate Consideration it receives upon any exercise of this Warrant following such Fundamental Transaction. The Company shall cause any successor entity in a Fundamental Transaction in which the Company is not the survivor (the “ Successor Entity ”) to assume in writing all of the obligations of the Company under this Warrant and the other Transaction Documents in accordance with the provisions of this Section 3(d)

pursuant to written agreements in form and substance reasonably satisfactory to the Holder and approved by the Holder (without unreasonable delay) prior to such Fundamental Transaction and shall, at the option of the holder of this Warrant, deliver to the Holder in exchange for this Warrant a security of the Successor Entity evidenced by a written instrument substantially similar in form and substance to this Warrant which is exercisable for a corresponding number of shares of capital stock of such Successor Entity (or its parent entity) equivalent to the shares of Common Stock acquirable and receivable upon exercise of this Warrant (without regard to any limitations on the exercise of this Warrant) prior to such Fundamental Transaction, and with an exercise price which applies the exercise price hereunder to such shares of capital stock (but taking into account the relative value of the shares of Common Stock pursuant to such Fundamental Transaction and the value of such shares of capital stock, such number of shares of capital stock and such exercise price being for the purpose of protecting the economic value of this Warrant immediately prior to the consummation of such Fundamental Transaction), and which is reasonably satisfactory in form and substance to the Holder. Upon the occurrence of any such Fundamental Transaction, the Successor Entity shall succeed to, and be substituted for (so that from and after the date of such Fundamental Transaction, the provisions of this Warrant and the other Transaction Documents referring to the “Company” shall refer instead to the Successor Entity), and may exercise every right and power of the Company and shall assume all of the obligations of the Company under this Warrant and the other Transaction Documents with the same effect as if such Successor Entity had been named as the Company herein.

     e) Calculations . All calculations under this Section 3 shall be made to the nearest cent or the nearest 1/100th of a share, as the case may be. For purposes of this Section 3, the number of shares of Common Stock deemed to be issued and outstanding as of a given date shall be the sum of the number of shares of Common Stock (excluding treasury shares, if any) issued and outstanding.

     f) Voluntary Adjustment By Company . The Company may at any time during the term of this Warrant reduce the then current Exercise Price to any amount and for any period of time deemed appropriate by the Board of Directors of the Company.

     g) Notice to Holder .

     i.  Adjustment to Exercise Price . Whenever the Exercise Price is adjusted pursuant to any provision of this Section 3, the Company shall promptly mail to the Holder a notice setting forth the Exercise Price after such adjustment and setting forth a brief statement of the facts requiring such adjustment.

     ii.  Notice to Allow Exercise by Holder . If (A) the Company shall declare a dividend (or any other distribution in whatever form) on the Common Stock, (B) the Company shall declare a special nonrecurring cash dividend on or a redemption of the Common Stock, (C) the Company shall authorize the granting to all holders of the Common Stock rights or warrants to subscribe for or purchase any shares of capital stock of any class or of any rights, (D) the approval of any stockholders of the Company shall be required in connection with any reclassification of the Common Stock, any consolidation or merger to which the Company is a party, any sale or transfer of all or substantially all of the assets of the Company, or any compulsory share exchange whereby the Common Stock is converted into other securities, cash or property, or (E) the Company shall authorize the voluntary or involuntary dissolution, liquidation or winding up of the affairs of the Company, then, in each case, the Company shall cause to be mailed to the Holder at its last address as it shall appear upon the Warrant Register of the Company, at least 20 calendar days prior to the applicable record or effective date hereinafter specified, a notice stating (x) the date on which a record is to be taken for the purpose of such dividend, distribution, redemption, rights or warrants, or if a record is not to be taken, the date as of which the holders of the Common Stock of record to be entitled to such dividend, distributions, redemption, rights or warrants are to be determined or (y)

the date on which such reclassification, consolidation, merger, sale, transfer or share exchange is expected to become effective or close, and the date as of which it is expected that holders of the Common Stock of record shall be entitled to exchange their shares of the Common Stock for securities, cash or other property deliverable upon such reclassification, consolidation, merger, sale, transfer or share exchange; provided that the failure to mail such notice or any defect therein or in the mailing thereof shall not affect the validity of the corporate action required to be specified in such notice. To the extent that any notice provided hereunder constitutes, or contains, material, non-public information regarding the Company or any of its subsidiaries, the Company shall simultaneously file such notice with the Commission pursuant to a Current Report on Form 8-K. The Holder shall remain entitled to exercise this Warrant during the period commencing on the date of such notice to the effective date of the event triggering such notice except as may otherwise be expressly set forth herein.

      Section 4 . Transfer of Warrant .

     a) Transferability . This Warrant and all rights hereunder (including, without limitation, any registration rights) are transferable, in whole or in part, upon surrender of this Warrant at the principal office of the Company or its designated agent, together with a written assignment of this Warrant substantially in the form attached hereto duly executed by the Holder or its agent or attorney and funds sufficient to pay any transfer taxes payable upon the making of such transfer. Upon such surrender and, if required, such payment, the Company shall execute and deliver a new Warrant or Warrants in the name of the assignee or assignees, as applicable, and in the denomination or denominations specified in such instrument of assignment, and shall issue to the assignor a new Warrant evidencing the portion of this Warrant not so assigned, and this Warrant shall promptly be cancelled. The Warrant, if properly assigned in accordance herewith, may be exercised by a new holder for the purchase of Warrant Shares without having a new Warrant issued.

     b) New Warrants . This Warrant may be divided or combined with other Warrants upon presentation hereof at the aforesaid office of the Company, together with a written notice specifying the names and denominations in which new Warrants are to be issued, signed by the Holder or its agent or attorney. Subject to compliance with Section 4(a), as to any transfer which may be involved in such division or combination, the Company shall execute and deliver a new Warrant or Warrants in exchange for the Warrant or Warrants to be divided or combined in accordance with such notice. All Warrants issued on transfers or exchanges shall be dated the initial issuance date set forth on the first page of this Warrant and shall be identical with this Warrant except as to the number of Warrant Shares issuable pursuant thereto.

     c) Warrant Register . The Company shall register this Warrant, upon records to be maintained by the Company for that purpose (the “ Warrant Register ”), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

     d) Representation by the Holder . The Holder, by the acceptance hereof, represents and warrants that it is acquiring this Warrant and, upon any exercise hereof, will acquire the Warrant Shares issuable upon such exercise, for its own account and not with a view to or for distributing or reselling such Warrant Shares or any part thereof in violation of the 1933 Act or any applicable state securities law, except pursuant to sales registered or exempted under the 1933 Act.

      Section 5 . Miscellaneous .

     a) No Rights as Stockholder Until Exercise . This Warrant does not entitle the Holder to any voting rights, dividends or other rights as a stockholder of the Company prior to the exercise hereof as set forth in Section 2(d)(i).

     b) Loss, Theft, Destruction or Mutilation of Warrant . The Company covenants that upon receipt by the Company of evidence reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Warrant or any stock certificate relating to the Warrant Shares, and in case of loss, theft or destruction, of indemnity or security reasonably satisfactory to it (which, in the case of the Warrant, shall not include the posting of any bond), and upon surrender and cancellation of such Warrant or stock certificate, if mutilated, the Company will make and deliver a new Warrant or stock certificate of like tenor and dated as of such cancellation, in lieu of such Warrant or stock certificate.

     c) Saturdays, Sundays, Holidays, etc . If the last or appointed day for the taking of any action or the expiration of any right required or granted herein shall not be a Business Day, then, such action may be taken or such right may be exercised on the next succeeding Business Day.

     d) Authorized Shares .

          The Company covenants that, during the period the Warrant is outstanding, it will reserve from its authorized and unissued Common Stock a sufficient number of shares to provide for the issuance of the Warrant Shares upon the exercise of any purchase rights under this Warrant. The Company further covenants that its issuance of this Warrant shall constitute full authority to its officers who are charged with the duty of executing stock certificates to execute and issue the necessary certificates for the Warrant Shares upon the exercise of the purchase rights under this Warrant. The Company will take all such reasonable action as may be necessary to assure that such Warrant Shares may be issued as provided herein without violation of any applicable law or regulation, or of any requirements of the Trading Market upon which the Common Stock may be listed. The Company covenants that all Warrant Shares which may be issued upon the exercise of the purchase rights represented by this Warrant will, upon exercise of the purchase rights represented by this Warrant and payment for such Warrant Shares in accordance herewith, be duly authorized, validly issued, fully paid and nonassessable and free from all taxes, liens and charges created by the Company in respect of the issue thereof (other than taxes in respect of any transfer occurring contemporaneously with such issue).

     Except and to the extent as waived or consented to by the Holder, the Company shall not by any action, including, without limitation, amending 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 of this Warrant, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as may be necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without limiting the generality of the foregoing, the Company will (i) not increase the par value of any Warrant Shares above the amount payable therefor upon such exercise immediately prior to such increase in par value, (ii) take all such action as may be necessary or appropriate in order that the Company may validly and legally issue fully paid and nonassessable Warrant Shares upon the exercise of this Warrant and (iii) use commercially reasonable efforts to obtain all such authorizations, exemptions or consents from any public regulatory body having jurisdiction thereof, as may be, necessary to enable the Company to perform its obligations under this Warrant.

     Before taking any action which would result in an adjustment in the number of Warrant Shares for which this Warrant is exercisable or in the Exercise Price, the Company shall obtain all such authorizations or exemptions thereof, or consents thereto, as may be necessary from any public regulatory body or bodies having jurisdiction thereof.

     e) Governing Law . This Warrant and all rights, obligations and liabilities hereunder shall be governed by the laws of the Commonwealth of Virginia.

     f) Restrictions . The Holder acknowledges that the Warrant Shares acquired upon the exercise of this Warrant, if not registered, and the Holder does not utilize cashless exercise, will have restrictions upon resale imposed by state and federal securities laws.

     g) Nonwaiver and Expenses . No course of dealing or any delay or failure to exercise any right hereunder on the part of Holder shall operate as a waiver of such right or otherwise prejudice Holder’s rights, powers or remedies. Without limiting any other provision of this Warrant or the Purchase Agreement, if the Company willfully and knowingly fails to comply with any provision of this Warrant, which results in any material damages to the Holder, the Company shall pay to Holder such amounts as shall be sufficient to cover any costs and expenses including, but not limited to, reasonable attorneys’ fees, including those of appellate proceedings, incurred by Holder in collecting any amounts due pursuant hereto or in otherwise enforcing any of its rights, powers or remedies hereunder.

     h) Notices . Any notice, request or other document required or permitted to be given or delivered to the Holder by the Company shall be delivered in accordance with the notice provisions of the Purchase Agreement.

     i) Limitation of Liability . No provision hereof, in the absence of any affirmative action by Holder to exercise this Warrant to purchase Warrant Shares, and no enumeration herein of the rights or privileges of Holder, shall give rise to any liability of Holder for the purchase price of any Common Stock or as a stockholder of the Company, whether such liability is asserted by the Company or by creditors of the Company.

     j) Remedies . The Holder, in addition to being entitled to exercise all rights granted by law, including recovery of damages, will be entitled to specific performance of its rights under this Warrant. The Company agrees that monetary damages would not be adequate compensation for any loss incurred by reason of a breach by it of the provisions of this Warrant and hereby agrees to waive and not to assert the defense in any action for specific performance that a remedy at law would be adequate.

     k) Successors and Assigns . Subject to applicable securities laws, this Warrant and the rights and obligations evidenced hereby shall inure to the benefit of and be binding upon the successors and permitted assigns of the Company and the successors and permitted assigns of Holder. The provisions of this Warrant are intended to be for the benefit of any Holder from time to time of this Warrant and shall be enforceable by the Holder or holder of Warrant Shares.

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

     m) Headings . The headings used in this Warrant are for the convenience of reference only and shall not, for any purpose, be deemed a part of this Warrant.

********************

(Signature Pages Follow)

     IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its officer thereunto duly authorized as of the date first above indicated.

NOTICE OF EXERCISE

TO: REGENERX BIOPHARMACEUTICALS, INC.

          (1) The undersigned hereby elects to purchase ________ Warrant Shares of the Company pursuant to the terms of the attached Warrant (only if exercised in full), and tenders herewith payment of the exercise price in full, together with all applicable transfer taxes, if any.

          (2) Payment shall take the form of (check applicable box):

o in lawful money of the United States; or

o the cancellation of such number of Warrant Shares as is necessary, in accordance with the formula set forth in subsection 2(c), to exercise this Warrant with respect to the maximum number of Warrant Shares purchasable pursuant to the cashless exercise procedure set forth in subsection 2(c).

          (3) Please issue a certificate or certificates representing said Warrant Shares in the name of the undersigned or in such other name as is specified below:

 

The Warrant Shares shall be delivered to the following DWAC Account Number or by physical delivery of a certificate to:

 

 

 

[SIGNATURE OF HOLDER]

Name of Investing Entity:

 

Signature of Authorized Signatory of Investing Entity :

 

Name of Authorized Signatory:

 

Title of Authorized Signatory:

 

Date:

 

ASSIGNMENT FORM

(To assign the foregoing warrant, execute
this form and supply required information.
Do not use this form to exercise the warrant.)

          FOR VALUE RECEIVED, [____] all of or [_______] shares of the foregoing Warrant and all rights evidenced thereby are hereby assigned to

___________________________ whose address is

____________________________________________.

____________________________________________

Dated: ______________, _______

Holder’s Signature:
Holder’s Address:

_____________
________________

Signature Guaranteed: __________________________

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 whatsoever, and must be guaranteed by a bank or trust company. Officers of corporations and those acting in a fiduciary or other representative capacity should file proper evidence of authority to assign the foregoing Warrant.

Exhibit 4.2

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

January 7, 2011

Void After January 7, 2016

     THIS CERTIFIES THAT, for value received, [NAME OF INVESTOR], 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 ________ 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 of even date herewith (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 the fifth (5 ^th ) anniversary of the date hereof.

          (c) “ Exercise Price ” shall mean $0.38 per share, subject to adjustment pursuant to Section 5 below.

          (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 the fifth (5 ^th ) anniversary of the date hereof.

          (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.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

     IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its duly authorized officer as of January 7, 2011.

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:

EXHIBIT 4.3

REGENERX BIOPHARMACEUTICALS, INC.

OMNIBUS WARRANT AMENDMENT AGREEMENT

      This Omnibus Warrant Amendment Agreement (the “ Amendment ”) is made effective as of January 5, 2011, by and among RegeneRx Biopharmaceuticals, Inc ., a Delaware corporation (the “ Company ”), Defiante Farmaceutica S.A. ( “ Defiante ”), Taufin International S.A. (“ Taufin ”), as successor in interest to Inverlochy-Consultadoria e Servicos (S.U.) LDA (“ Inverlochy ”), and Sinaf S.A. (“ Sinaf ”), as successor in interest to Chaumiere-Consultadoria e Servicos SDC Unipessoal LDA (“ Chaumiere ”). Defiante, Taufin and Sinaf are referred to collectively herein as the “ Holders ”.

Recitals

      Whereas, the Company previously issued to Defiante (i) that certain warrant to purchase 256,148 shares of common stock of the Company, dated as of March 16, 2006 (the “ March 2006 Defiante Warrant ”); and (ii) that certain warrant to purchase 333,333 shares of common stock of the Company, dated as of December 21, 2006 (the “ December 2006 Defiante Warrant ”);

      Whereas, the Company previously issued to Inverlochy, as predecessor of Taufin, (i) that certain warrant to purchase 22,601 shares of common stock of the Company, dated as of March 16, 2006 (the “ March 2006 Inverlochy Warrant ”); (ii) that certain warrant to purchase 333,333 shares of common stock of the Company, dated as of December 21, 2006 (the “ December 2006 Inverlochy Warrant ”); (iii) that certain warrant to purchase 500,000 shares of common stock of the Company, dated as of February 22, 2008 (the “ February 2008 Inverlochy Warrant ”); and (iv) that certain warrant to purchase 372,552 shares of common stock of the Company, dated as of December 18, 2008 (the “ December 2008 Inverlochy Warrant ”);

      Whereas, the Company previously issued to Chaumiere, as predecessor of Sinaf, (i) that certain warrant to purchase 22,601 shares of common stock of the Company, dated as of March 16, 2006 (the “ March 2006 Chaumiere Warrant ,” and together with the March 2006 Defiante Warrant and the March 2006 Inverlochy Warrant, the “ March 2006 Warrants ”); (ii) that certain warrant to purchase 333,333 shares of common stock of the Company, dated as of December 21, 2006 (the “ December 2006 Chaumiere Warrant ,” and together with the December 2006 Defiante Warrant and the December 2006 Inverlochy Warrant, the “ December 2006 Warrants ”); (iii) that certain warrant to purchase 500,000 shares of common stock of the Company, dated as of February 22, 2008 (the “ February 2008 Chaumiere Warrant ,” and together with the February 2008 Inverlochy Warrant, the “ February 2008 Warrants ”); and (iv) that certain warrant to purchase 372,552 shares of common stock of the Company, dated as of December 18, 2008 (the “ December 2008 Chaumiere Warrant ,” and together with the December 2008 Inverlochy Warrant, the “ December 2008 Warrants ”; the March 2006 Warrants, December 2006 Warrants, February 2008 Warrants and December 2008 Warrants are referred to collectively as the “ Warrants ”);

      Whereas, each of the March 2006 Warrants carries an Exercise Price (as such term is defined therein) of $4.06 per share and an Expiration Date (as such term is defined therein) of March 15, 2011;

      Whereas, each of the December 2006 Warrants carries an Exercise Price (as such term is defined therein) of $2.75 per share and an Expiration Date (as such term is defined therein) of December 20, 2011;

      Whereas, each of the February 2008 Warrants carries an Exercise Price (as such term is defined therein) of $1.60 per share and an Expiration Date (as such term is defined therein) of December 31, 2010;

      Whereas, each of the December 2008 Warrants carries an Exercise Price (as such term is defined therein) of $1.74 per share and an Expiration Date (as such term is defined therein) of December 31, 2011; and

      Whereas, the Company and the Holders wish to (a) reduce the Exercise Price of each of the Warrants to $0.38 per share and (b) extend the Expiration Date of each of the March 2006 Warrants, December 2006 Warrants and February 2008 Warrants to December 31, 2011.

      Now, Therefore, in consideration of the mutual agreements, covenants and considerations contained herein, and for other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereto hereby agree as follows:

      1.  The Company and the Holders hereby agree that the definition of “Exercise Price” in each March 2006 Warrant is hereby amended and restated to read in its entirety as follows:

““ Exercise Price ” is equal to $0.38, subject to adjustment.”

      2.  The Company and the Holders hereby agree that the definition of “Expiration Date” in each March 2006 Warrant is hereby amended and restated to read in its entirety as follows:

““ Expiration Date ” means December 31, 2011.”

      3.  The Company and the Holders hereby agree that the first paragraph of each December 2006 Warrant is hereby amended and restated to read in its entirety as follows:

“RegeneRx Biopharmaceuticals, Inc., a Delaware corporation (the “Company”), hereby certifies that, for value received, the Holder or its permitted registered assigns is entitled to purchase from the Company shares of common stock, $0.001 par value (the “Common Stock”), of the Company (each such share, a “Warrant Share” and all such shares, the “Warrant Shares”) at an exercise price per share equal to $0.38 (as adjusted from time to time as provided in Section 9 herein, the “Exercise Price”), at any time and from time to time from and after the Original Issue Date and through and including 5:30 P.M., New

York City time, on December 31, 2011 (the “Expiration Date”), and subject to the following terms and conditions:”

      4.  The Company and the Holders hereby agree that the definition of “Exercise Period” in each February 2008 Warrant is hereby amended and restated to read in its entirety as follows:

““ Exercise Period ” shall mean the period commencing with the date hereof and ending at 5:30 p.m. New York City time on December 31, 2011, unless sooner terminated as provided below.”

      5.  The Company and the Holders hereby agree that the definition of “Exercise Price” in each February 2008 Warrant is hereby amended and restated to read in its entirety as follows:

““ Exercise Price ” shall mean $0.38 per share, subject to adjustment pursuant to Section 5 below.”

      6.  The Company and the Holders hereby agree that the definition of “Expiration Date” in each February 2008 Warrant is hereby amended and restated to read in its entirety as follows:

““ Expiration Date ” shall mean 5:30 p.m. New York City time on December 31, 2011.”

      7.  The Company and the Holders hereby agree that the definition of “Exercise Price” in each December 2008 Warrant is hereby amended and restated to read in its entirety as follows:

““ Exercise Price ” shall mean $0.38 per share, subject to adjustment pursuant to Section 5 below.”

      8.  All provisions of the Warrants, except as modified by this Amendment, shall remain in full force and effect and are reaffirmed. Other than as stated in this Amendment, this Amendment shall not operate as a waiver of any condition or obligation imposed on the parties under the Warrants.

      9.  In the event of any conflict, inconsistency, or incongruity between any provision of this Amendment and any provision of the Warrants, the provisions of this Amendment shall govern and control.

      10.  This Amendment shall be governed by and construed in accordance with the laws of the State of Delaware, excluding that body of law relating to conflict of laws.

      11.  This Amendment may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

[SIGNATURE PAGE FOLLOWS]

      In Witness Whereof, the undersigned have executed this Omnibus Warrant Amendment Agreement with an effective date of January 5, 2011.

COMPANY:				HOLDERS:
RegeneRx Biopharmaceuticals, Inc.				Defiante Farmaceutica S.A.
By:		/s/ J.J. Finkelstein		Signature:		/s/ Paulo Viegas
		J.J. Finkelstein President and Chief Executive Officer				Print Name: Paulo Viegas Title: CEO
				Taufin International S.A.
				Signature:		/s/ Nicola Wullschleger
						Print Name: Nicola Wullschleger
						Title: attorney-in-fact
				Sinaf S.A.
				Signature:		/s/ Nicola Wullschleger
						Print Name: Nicola Wullschleger
						Title: attorney-in-fact

SIGNATURE PAGE
TO
OMNIBUS AMENDMENT AGREEMENT