SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* SIGMA TAU FINANZIARIA SPA (Last) (First) (Middle) VIA SUDAFRICA, 20 (Street) ROME L6 00144 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol REGENERX BIOPHARMACEUTICALS INC [ RGRX.OB ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 01/05/2011
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/05/2011		P		925,926	A	$0.27	12,937,111	I(1)	Indirect(1)
Common Stock								984,615	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Common Stock Warrants (right to buy)	$0.38	01/05/2011		J(2)		1		07/07/2011	01/07/2016	Common Stock	370,370	(2)	1	I(1)	Indirect(1)
Common Stock Warrants (right to buy)	$4.06	01/05/2011		J(3)			1	(3)	03/16/2011	Common Stock	256,148	(3)	0	I(1)	Indirect(1)
Common Stock Warrants (right to buy)	$0.38	01/05/2011		J(3)		1		(3)	12/31/2011	Common Stock	256,148	(3)	1	I(1)	Indirect(1)
Common Stock Warrants (right to buy)	$2.75	01/05/2011		J(4)			1	(4)	12/21/2011	Common Stock	333,333	(4)	0	I(1)	Indirect(1)
Common Stock Warrants (right to buy)	$0.38	01/05/2011		J(4)		1		(4)	12/31/2011	Common Stock	333,333	(4)	2	I(1)	Indirect(1)

1. Name and Address of Reporting Person* SIGMA TAU FINANZIARIA SPA (Last) (First) (Middle) VIA SUDAFRICA, 20 (Street) ROME L6 00144 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* DEFIANTE FARMACEUTICA LDA (Last) (First) (Middle) 1 NEW YORK STREET (Street) NEW YORK NY 10005 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Securities directly owned by Defiante Farmaceutica S.A. ("Defiante"). Defiante is 58% directly owned by Sigma Tau Finanziaria S.p.A. ("Sigma Tau") and 42% directly owned by Sigma Tau's wholly-owned subsidiary, Sigma Tau International S.A.

2. The Warrant was issued by the Issuer to Defiante in consideration of Defiante's purchase of Common Stock.

3. The two reported transactions involved an amendment of an outstanding warrant, resulting in the deemed cancellation of the "old" warrant and the issuance of a replacement warrant. The warrant became exercisable on September 16, 2006.

4. The two reported transactions involved an amendment of an outstanding warrant, resulting in the deemed cancellation of the "old" warrant and the issuance of a replacement warrant. The warrant became exercisable on December 21, 2006.

Remarks:

Exhibit List Exhibit 99.1 - Joint Filer Information

	/s/ Fabio Amabile, Attorney-in-fact	01/07/2011
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
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