UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

Omthera Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock, $.001 par value

(Title of Class of Securities)

68217A103

(CUSIP Number)

Louis S. Citron, Esq.

New Enterprise Associates

1954 Greenspring Drive, Suite 600

Timonium, MD 21093

(410) 842-4000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

July 18, 2013

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. o

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 68217A103

13D

Page 2 of 9 Pages

Schedule 13D

Item 1. Security and Issuer.

This statement relates to the common stock, $.001 par value (the “Common Stock”) of Omthera Pharmaceuticals, Inc. (the “Issuer”) having its principal executive office at 707 State Road, Princeton, NJ 08540.

Item 2. Identity and Background.

This statement is being filed by:

(a) New Enterprise Associates 13, L.P. (“NEA 13”, the “Fund” or the “Record Holder”);

(b) NEA Partners 13, L.P. (“NEA Partners 13” or the “GPLP”), which is the sole general partner of NEA 13; and NEA 13 GP, LTD (“NEA 13 LTD” and, together with the GPLP, the “Control Entities”), which is the sole general partner of NEA Partners 13; and

(c) Michael James Barrett (“Barrett”), Peter J. Barris (“Barris”), Forest Baskett (“Baskett”), Ryan D. Drant (“Drant”), Patrick J. Kerins (“Kerins”), Krishna S. Kolluri (“Kolluri”), David M. Mott (“Mott”), Scott D. Sandell (“Sandell”), Ravi Viswanathan (“Viswanathan”) and Harry R. Weller (“Weller”) (together, the “Directors”). The Directors are the directors of NEA 13 LTD.

The persons named in this Item 2 are referred to individually herein as a “Reporting Person” and collectively as the “Reporting Persons.”

The address of the principal business office of the Record Holder and each Control Entity is New Enterprise Associates, 1954 Greenspring Drive, Suite 600, Timonium, MD 21093. The address of the principal business office of each of Barrett, Barris, Drant, Kerins, Mott and Weller is New Enterprise Associates, 5425 Wisconsin Avenue, Suite 800, Chevy Chase, MD 20815. The address of the principal business office of Baskett, Kolluri, Sandell and Viswanathan is New Enterprise Associates, 2855 Sand Hill Road, Menlo Park, California 94025.

The principal business of the Fund is to invest in and assist growth-oriented businesses located principally in the United States. The principal business of NEA Partners 13 is to act as the sole general partner of NEA 13. The principal business of NEA 13 LTD is to act as the sole general partner of NEA Partners 13. The principal business of each of the Directors is to manage the Control Entities, the Fund and a number of affiliated partnerships with similar businesses.

During the five years prior to the date hereof, none of the Reporting Persons has been convicted in a criminal proceeding or has been a party to a civil proceeding ending in a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

The Fund and the GPLP are exempt limited partnerships organized under the laws of the Cayman Islands. NEA 13 LTD is an exempted company organized under the laws of the Cayman Islands. Each of the Directors is a United States citizen.

Item 3. Source and Amount of Funds or Other Consideration.

Not applicable.

CUSIP No. 68217A103

13D

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Item 4. Purpose of Transaction.

Not applicable.

Item 5. Interest in Securities of the Issuer.

Each of the Reporting Persons has ceased to beneficially own more than five percent of the Common Stock of the Issuer.

Item 6. Contracts, Arrangements, Undertakings or Relationships with Respect to Securities of the Issuer.

Not applicable.

Item 7. Material to be Filed as Exhibits.

Exhibit 1 – Agreement regarding filing of joint Schedule 13D.

Exhibit 2 – Power of Attorney regarding filings under the Securities Exchange Act of 1934, as amended.

CUSIP No. 68217A103

13D

Page 4 of 9 Pages

SIGNATURE

After reasonable inquiry and to the best of its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

EXECUTED this 23rd day of July, 2013.

NEW ENTERPRISE ASSOCIATES 13, L.P.

By:	NEA PARTNERS 13, L.P.

General Partner

By:

NEA 13 GP, LTD

General Partner

By: *

Peter J. Barris

Director

NEA PARTNERS 13, L.P.

By:	NEA 13 GP, LTD

General Partner

By: *

Peter J. Barris

Director

NEA 13 GP, LTD

By: *

Peter J. Barris

Director

Michael James Barrett

Peter J. Barris

Forest Baskett

Ryan D. Drant

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13D

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Patrick J. Kerins

Krishna S. Kolluri

David M. Mott

Scott D. Sandell

Ravi Viswanathan

Harry R. Weller


			*/s/ Louis S. Citron
			Louis S. Citron
			As attorney-in-fact

This Amendment No. 1 to Schedule 13D was executed by Louis S. Citron on behalf of the individuals listed above pursuant to a Power of Attorney a copy of which is attached as Exhibit 2.

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13D

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EXHIBIT 1

AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13D need be filed with respect to the ownership by each of the undersigned of shares of stock of Omthera Pharmaceuticals, Inc.

EXECUTED this 23rd day of July, 2013.

NEW ENTERPRISE ASSOCIATES 13, L.P.

By:	NEA PARTNERS 13, L.P.

General Partner

By:

NEA 13 GP, LTD

General Partner

By: *

Peter J. Barris

Director

NEA PARTNERS 13, L.P.

By:	NEA 13 GP, LTD

General Partner

By: *

Peter J. Barris

Director

NEA 13 GP, LTD

By: *

Peter J. Barris

Director

Michael James Barrett

Peter J. Barris

Forest Baskett

Ryan D. Drant

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13D

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Patrick J. Kerins

Krishna S. Kolluri

David M. Mott

Scott D. Sandell

Ravi Viswanathan

Harry R. Weller


			*/s/ Louis S. Citron
			Louis S. Citron
			As attorney-in-fact

This Agreement relating to Amendment No. 1 to Schedule 13D was executed by Louis S. Citron on behalf of the individuals listed above pursuant to a Power of Attorney a copy of which is attached hereto as Exhibit 2.

CUSIP No. 68217A103

13D

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EXHIBIT 2

KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby constitutes and appoints Charles W. Newhall III, Louis S. Citron, Eugene A. Trainor III, Timothy Schaller and Shawn Conway, and each of them, with full power to act without the others, his true and lawful attorney-in-fact, with full power of substitution, to sign any and all instruments, certificates and documents that may be necessary, desirable or appropriate to be executed on behalf of himself as an individual or in his capacity as a direct or indirect general partner, director, officer or manager of any partnership, corporation or limited liability company, pursuant to section 13 or 16 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and any and all regulations promulgated thereunder, and to file the same, with all exhibits thereto, and any other documents in connection therewith, with the Securities and Exchange Commission, and with any other entity when and if such is mandated by the Exchange Act or by the Financial Industry Regulatory Authority, granting unto said attorney-in-fact full power and authority to do and perform each and every act and thing necessary, desirable or appropriate, fully to all intents and purposes as he might or could do in person, thereby ratifying and confirming all that said attorney-in-fact, or his substitutes, may lawfully do or cause to be done by virtue hereof.

IN WITNESS WHEREOF, this Power of Attorney has been signed as of the 4th day of May, 2009.

/s/ M. James Barrett

M. James Barrett

/s/ Peter J. Barris

Peter J. Barris

/s/ Forest Baskett

Forest Baskett

/s/ Rohini Chakravarthy

Rohini Chakravarthy

/s/ Patrick Chung

Patrick Chung

/s/ Ryan Drant

Ryan Drant

/s/ Shawn Conway

Shawn Conway

/s/ Anthony A. Florence

Anthony A. Florence

/s/ Robert Garland

Robert Garland

/s/ Paul Hsiao

Paul Hsiao

/s/ Vladimir Jacimovic

Vladimir Jacimovic

/s/ Patrick J. Kerins

Patrick J. Kerins

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13D

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/s/ Suzanne King

Suzanne King

/s/ Krishna S. Kolluri

Krishna S. Kolluri

/s/ C. Richard Kramlich

C. Richard Kramlich

/s/ Charles M. Linehan

Charles M. Linehan

/s/ Edward Mathers

Edward Mathers

/s/ David M. Mott

David M. Mott

/s/ John M. Nehra

John M. Nehra

/s/ Charles W. Newhall III

Charles W. Newhall III

/s/ Jason R. Nunn

Jason R. Nunn

/s/ Mark W. Perry

Mark W. Perry

/s/ Jon Sakoda

Jon Sakoda

/s/ Scott D. Sandell

Scott D. Sandell

/s/ Peter W. Sonsini

Peter W. Sonsini

/s/ A. Brooke Seawell

A. Brooke Seawell

/s/ Eugene A. Trainor III

Eugene A. Trainor III

/s/ Ravi Viswanathan

Ravi Viswanathan

/s/ Paul E. Walker

Paul E. Walker

/s/ Harry Weller

Harry Weller

Omthera Pharmaceuticals, Inc. SC 13D/A