CUSIP No. 686164302

CUSIP No. 686164302

CUSIP No. 686164302

Item 1.

(a) Name of Issuer

Orexigen Therapeutics, Inc. (the “ Issuer ”)

(b) Address of Issuer’s Principal Executive Offices

3344 N. Torrey Pines Ct., Suite 200

La Jolla, CA 92037

Item 2.

(a) Name of Person Filing

(b) Address of Principal Business Office or, if none, Residence

(c) Citizenship

This Schedule 13G is being filed on behalf of (i) Kevin Russell, an individual who is a citizen of the United States of America (“ Mr. Russell ”), (ii) Andrew Martin, an individual who is a citizen of the United States of America (“ Mr. Martin ”) and (iii) UBS O’Connor LLC, a Delaware limited liability company (“ O’Connor ” and together with Mr. Russell and Mr. Martin, collectively the “ Reporting Persons ”).

O’Connor serves as the investment manager to each of (1) Nineteen77 Global Multi-Strategy Alpha (Levered) Master Limited (“ GLEA XL ”) and (2) Nineteen77 Global Multi-Strategy Alpha Master Limited (“ GLEA ”, and together with GLEA XL, collectively, the “ O’Connor Funds ”). In such capacity, O’Connor exercises voting and investment power over the shares of Common Stock held for the account of each of GLEA XL and GLEA. O’Connor is a registered investment adviser under Section 203 of the Investment Advisers Act of 1940, as amended. Mr. Russell is the Chief Investment Officer of O’Connor and Mr. Martin is a Portfolio Manager for O’Connor, and each also exercises voting and investment power over the shares of Common Stock held for the account of the O’Connor Funds. As a result, each of O’Connor, Mr. Russell and Mr. Martin may be deemed to have beneficial ownership (as determined under Section 13(d) of the Securities Exchange Act of 1934, as amended) of the shares of Common Stock held for the account of the O’Connor Funds.

The Reporting Persons have entered into a Joint Filing Agreement, a copy of which is filed with this Schedule 13G as Exhibit 1 , pursuant to which the Reporting Persons have agreed to file this Schedule 13G jointly in accordance with the provisions of Rule 13d-1(k) of the Securities Exchange Act of 1934, as amended.

The principal business office of each of the Reporting Persons is One North Wacker Drive, 32 ^nd Floor, Chicago, Illinois 60606.

(d) Title of Class of Securities

Common stock, $0.001 par value per share, of the Issuer (the “ Common Stock ”).

(e) CUSIP Number

686164302

(a) and (b):

(i) As of the close of business on December 31, 2016, each of the Reporting Persons may have been deemed to have beneficial ownership of 1,618,951 shares of Common Stock issuable upon exercise of a warrant held by GLEA (the “ GLEA Warrant ”), and all such shares of Common Stock represented beneficial ownership of approximately 9.99% of the Common Stock, based on (1) 14,586,771 shares of Common Stock outstanding as of November 1, 2016, as reported in the Issuer’s Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2016 filed with the Securities and Exchange Commission (the “ SEC ”) on November 7, 2016, plus (2) 1,618,951 shares of Common Stock issuable upon exercise of the GLEA Warrant. The foregoing excludes: (I) 1,531,049 shares of Common Stock issuable upon exercise of the GLEA Warrant because the GLEA Warrant contains a blocker provision under which the holder thereof does not have the right to exercise the GLEA Warrant to the extent that such exercise would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the “ Exchange Act ”), of more than 9.99% of the Common Stock, (II) 183,333 shares of Common Stock issuable upon exercise of a warrant held by GLEA XL (the “ GLEA XL Warrant ”) because the GLEA XL Warrant contains a blocker provision under which the holder thereof does not have the right to exercise the GLEA XL Warrant to the extent that such exercise would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (III) 3,149,999 shares of Common Stock issuable upon conversion of a convertible note held by GLEA (“ GLEA Note 1 ”) because GLEA Note 1 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA Note 1 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (IV) 154,606 shares of Common Stock issuable upon conversion of a second convertible note held by GLEA (“ GLEA Note 2 ”) because GLEA Note 2 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA Note 2 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (V) 183,333 shares of Common Stock issuable upon conversion of a convertible note held by GLEA XL (“ GLEA XL Note 1 ”) because GLEA XL Note 1 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA XL Note 1 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, and (VI) 28,576 shares of Common Stock issuable upon conversion of a second convertible note held by GLEA XL (“ GLEA XL Note 2 ”) because GLEA XL Note 2 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA XL Note 2 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock. Without such blocker provisions, each of the Reporting Persons may have been deemed to have beneficial ownership of 6,849,847 shares of Common Stock.

(ii) As of the close of business on December 31, 2017, each of the Reporting Persons may have been deemed to have beneficial ownership of 2,079,808 shares of Common Stock issuable upon exercise of the GLEA Warrant, and all such shares of Common Stock represented beneficial ownership of approximately 9.99% of the Common Stock, based on (1) 16,603,831 shares of Common Stock outstanding as of November 10, 2017, as reported in the Issuer’s Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2017 filed with the SEC on November 14, 2017, plus (2) 2,135,268 shares of Common Stock issued at the closing of the exchange transactions as disclosed by in the Issuer’s Current Report on Form 8-K filed with the SEC on December 1, 2017, and (3) 2,079,808 shares of Common Stock issuable upon exercise of the GLEA Warrant. The foregoing excludes: (I) 1,070,192 shares of Common Stock issuable upon exercise of the GLEA Warrant because the GLEA Warrant contains a blocker provision under which the holder thereof does not have the right to exercise the GLEA Warrant to the extent that such exercise would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (II) 183,333 shares of Common Stock issuable upon exercise of the GLEA XL Warrant because the GLEA XL Warrant contains a blocker provision under which the holder thereof does not have the right to exercise the GLEA XL Warrant to the extent that such exercise would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (III) 3,023,999 shares of Common Stock issuable upon conversion of GLEA Note 1 because GLEA Note 1 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA Note 1 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (IV) 77,303 shares of Common Stock issuable upon conversion of GLEA Note 2 because GLEA Note 2 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA Note 2 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (V) 422,000 shares of Common Stock issuable upon conversion of a third convertible note held by GLEA (“ GLEA Note 3 ”) because GLEA Note 3 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA Note 3 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (VI) 175,999 shares of Common Stock issuable upon conversion of GLEA XL Note 1 because GLEA XL Note 1 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA XL Note 1 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, (VII) 14,288 shares of Common Stock issuable upon conversion of GLEA XL Note 2 because GLEA XL Note 2 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA XL Note 2 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock, and (VIII) 78,000 shares of Common Stock issuable upon conversion of a third convertible note held by GLEA XL (“ GLEA XL Note 3 ”) because GLEA XL Note 3 is subject to a blocker provision under which the holder thereof does not have the right to convert GLEA XL Note 3 to the extent that such conversion would result in beneficial ownership by the holder thereof, together with any persons whose beneficial ownership of the Common Stock would be aggregated with such holder’s for purposes of Section 13(d) of the Exchange Act, of more than 9.99% of the Common Stock. Without such blocker provisions, each of the Reporting Persons may have been deemed to have beneficial ownership of 7,124,922 shares of Common Stock.

(c)

Number of shares as to which each Reporting Person has:

(1) Sole power to vote or to direct the vote: 0.

(2) Shared power to vote or to direct the vote: 2,079,808.

(3) Sole power to dispose or to direct the disposition of 0.

(4) Shared power to dispose or to direct the disposition of 2,079,808.

Not applicable.

Not applicable.

The information set forth in Item 2 is hereby incorporated herein by reference.

Not applicable.

Not applicable.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: February 13, 2018

Exhibit 1

JOINT FILING AGREEMENT

The undersigned acknowledge and agree that the foregoing statement on Schedule 13G is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13G may be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained herein and therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

Date: February 13, 2018

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