Sec Form 4 Filing - SOFINNOVA CAPITAL VI FCPR @ Omthera Pharmaceuticals, Inc. - 2013-04-16

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person SOFINNOVA CAPITAL VI FCPR 2. Issuer Name and Ticker or Trading Symbol Omthera Pharmaceuticals, Inc. [ OMTH] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 17, RUE DE SERENE 3. Date of Earliest Transaction (MM/DD/YY) 04/16/2013 (Street) PARIS, I075008 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 5,745,044 ( 1 ) A $ 0 5,745,044 D ( 2 ) Common Stock 04/16/2013 C 156,250 ( 3 ) A $ 0.01 5,901,294 D ( 2 ) Common Stock 04/16/2013 S( 4 ) 196 D $ 8 5,901,098 D ( 2 ) Common Stock 04/16/2013 C 633,219 ( 5 ) A $ 8 6,534,317 D ( 2 ) Common Stock 04/16/2013 P 625,000 A $ 8 7,159,317 D ( 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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 4,350,000 ( 6 ) ( 6 ) Common Stock 3,117,609 ( 6 ) 0 D ( 2 ) Series B Convertible Preferred Stock ( 6 ) 04/16/2013 C 3,666,061 ( 6 ) ( 6 ) Common Stock 2,627,435 ( 6 ) 0 D ( 2 ) Warrant (right to buy) $ 0.01 04/16/2013 C 156,250 04/16/2013 02/15/2023 Common Stock 156,250 $ 0 0 D ( 2 ) Secured Convertible Promissory Note $ 8 04/16/2013 C 633,219 04/16/2013 02/15/2014( 7 ) Common Stock 633,219 ( 8 ) 0 D ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other SOFINNOVA CAPITAL VI FCPR 17, RUE DE SERENE PARIS, I075008 X Sofinnova Partners SAS 17, RUE DE SERENE PARIS, I075008 X Signatures /s/Christian S. Schade, Attorney-in-Fact 04/18/2013 Signature of Reporting Person Date /s/Christian S. Schade, Attorney-in-Fact 04/18/2013 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents the total number of shares received upon conversion of 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 )Sofinnova Partners SAS is the managing company of Sofinnova Capital VI FCPR and disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any. ( 3 )Represents the total number of shares received upon conversion of the reporting person's warrant. ( 4 )Effective upon the closing of the Issuer's initial public offering ("IPO") of its Common Stock, the reporting person's warrant automatically converted into 156,250 shares of Common Stock. The reporting person 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 the reporting person the remaining 156,054 shares. ( 5 )Represents the total number of shares received upon conversion of the Secured Convertible Promissory Note issued to the reporting person. ( 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 the number of shares of Common Stock shown in column 7. 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 the reporting person 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 the number of shares of Common Stock shown in column 7.

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).

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