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* Seghezzi Graziano (Last) (First) (Middle) C/O SOFINNOVA PARTNERS 17, RUE DE SERENE (Street) PARIS I0 75008 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Omthera Pharmaceuticals, Inc. [ OMTH ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 04/16/2013
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person 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	04/16/2013		C		0(1)	A	$0	0	I	See footnote(2)
Common Stock	04/16/2013		C		0(3)	A	$0.01	0	I	See footnote(2)
Common Stock	04/16/2013		S(4)		0(4)	D	$8	0	I	See footnote(2)
Common Stock	04/16/2013		C		0(5)	A	$8	0	I	See footnote(2)
Common Stock	04/16/2013		P		0	A	$8	0	I	See footnote(2)

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
Series A Convertible Preferred Stock	(6)	04/16/2013		C			0	(6)	(6)	Common Stock	0	(6)	0	I	See footnote(2)
Series B Convertible Preferred Stock	(6)	04/16/2013		C			0	(6)	(6)	Common Stock	0	(6)	0	I	See footnote(2)
Warrant (right to buy)	$0.01	04/16/2013		C			0	04/16/2013	02/15/2023	Common Stock	0	$0	0	I	See footnote(2)
Secured Convertible Promissory Note	$8	04/16/2013		C			0	04/16/2013	02/15/2014(7)	Common Stock	0	(8)	0	I	See footnote(2)

Explanation of Responses:

1. Sofinnova Capital VI FCPR ("Sofinnova") received a total of 5,745,044 shares of Common Stock upon conversion of its shares of the Issuer's Series A Convertible Preferred Stock (the "Series A Shares") and Series B Convertible Preferred Stock (the "Series B Shares" and together with the Series A Shares, the "Preferred Shares").

2. The Common Stock, Preferred Shares, warrant and Secured Convertible Promissory Note are held directly by Sofinnova. The reporting person is a partner of Sofinnova Partners SAS, which is the managing company of Sofinnova. The reporting person disclaims beneficial ownership of these securities, except to the extent of his pecuniary interest, if any, therein, and the filing of this report is not an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.

3. Sofinnova received 156,250 shares of Common Stock upon conversion of its warrant.

4. Effective upon the closing of the Issuer's initial public offering ("IPO") of its Common Stock, Sofinnova's warrant automatically converted into 156,250 shares of Common Stock. Sofinnova paid the exercise price of $0.01 per share of the warrant on a cashless basis, resulting in the Issuer's withholding of 196 of the warrant shares to pay the exercise price and issuing to Sofinnova the remaining 156,054 shares.

5. Sofinnova received 633,219 shares of Common Stock upon conversion of the Secured Convertible Promissory Note issued to Sofinnova.

6. Effective upon the closing of the Issuer's IPO of its Common Stock, each Preferred Share automatically converted at a ratio of 1.3953-to-1 into 5,745,044 shares of Common Stock. The Preferred Shares had no expiration date.

7. This is the maturity date of the Secured Convertible Promissory Note.

8. The Secured Convertible Promissory Note was issued to Sofinnova in exchange for $5,000,000. Effective upon the closing of the Issuer's IPO of its Common Stock, the Secured Convertible Promissory Note automatically converted into 633,219 shares of Common Stock.

	/s/Christian S. Schade, Attorney-in-Fact	04/18/2013
	** 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).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.