Under the Securities Exchange Act of 1934
(Amendment No. 1)*

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

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

(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 Rule 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).

* See Note 1 on Appendix 1.

2

* See Note 3 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

3

* See Note 4 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

4

* See Note 5 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

5

* See Note 6 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

6

* See Note 7 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

7

* See Note 8 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

8

* See Note 9 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

9

* See Note 10 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

10

* See Note 11 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

11

* See Note 12 on Appendix 1.

** Includes shares owned by Sutter Hill Ventures, A California Limited Partnership.  See Appendix 1.

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13

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Signatures

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.

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APPENDIX 1 TO SCHEDULE 13D — HORIZON PHARMA, INC.

All warrants mentioned below are exercisable within 60 days after 9/25/12.

Note 1:  Includes 458,902 shares of common stock issuable upon exercise of warrants.

Note 2: Includes individual shares (and shares of common stock issuable upon exercise of warrants) plus all shares (and shares of common stock issuable upon exercise of warrants) held by Sutter Hill Ventures, A California Limited Partnership of which the reporting person is a Managing Director of the General Partner.  The reporting person disclaims beneficial ownership of the partnership’s shares except as to the reporting person’s pecuniary interest therein.

Note 3:  Comprised of 49,679 shares (including 8,390 shares of common stock issuable upon exercise of warrants) held in The Anderson Living Trust of which the reporting person is the trustee, 78,604 shares (including 14,362 shares of common stock issuable upon exercise of warrants) held by Anvest, L.P. of which the reporting person is the trustee of a trust which is the General Partner and 17,500 shares (including 3,500 shares of common stock issuable upon exercise of a warrant) held by Starfish Holdings, LP of which the reporting person is the trustee of a trust which is the General Partner.  The reporting person disclaims beneficial ownership of the living trust’s and the partnerships’ shares except as to the reporting person’s pecuniary interest therein.

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Note 4:  Comprised of 53,342 shares (including 9,046 shares of common stock issuable upon exercise of warrants) held in The Baker Revocable Trust of which the reporting person is a trustee, 15,385 shares held by a Roth IRA for the benefit of the reporting person and 148,975 shares (including 30,178 shares of common stock issuable upon exercise of warrants) held by Saunders Holdings, L.P. of which the reporting person is a trustee of a trust which is the General Partner. The reporting person disclaims beneficial ownership of the revocable trust’s and the partnership’s shares except as to the reporting person’s pecuniary interest therein.

Note 5: Comprised of 76,182 shares (including 16,748 shares of common stock issuable upon exercise of warrants) held in The William H. Younger, Jr. Revocable Trust of which the reporting person is the trustee, 30,590 shares held by a retirement trust for the benefit of the reporting person and 147,503 shares (including 31,403 shares of common stock issuable upon exercise of  warrants) held by Yovest, L.P. of which the reporting person is the trustee of a trust which is the General Partner.  The reporting person disclaims beneficial ownership of the revocable trust’s and the partnership’s shares except as to the reporting person’s pecuniary interest therein.

Note 6: Comprised of 247,740 shares (including 26,128 shares of common stock issuable upon exercise of warrants) held in The Coxe Revocable Trust of which the reporting person is a trustee, 194,276 shares (including 40,137 shares of common stock issuable upon exercise of warrants) held by a retirement trust for the benefit of the reporting person and 12,159 shares held by Rooster Partners, L.P. of which the reporting person is a trustee of a trust which is the General Partner.  The reporting person disclaims beneficial ownership of the revocable trust’s and the partnership’s shares except as to the reporting person’s pecuniary interest therein.

Note 7: Comprised of 874 shares held in the individual name, 22,747 shares (including 4,428 shares of common stock issuable upon exercise of warrants) held in The Gaither Revocable Trust of which the reporting person is the trustee and 21,054 shares (including 4,417 shares of common stock issuable upon exercise of warrants) held by Tallack Partners, L.P. of which the reporting person is the trustee of a trust which is the General Partner.  The reporting person disclaims beneficial ownership of the revocable trust’s and the partnership’s shares except as to the reporting person’s pecuniary interest therein.

Note 8: Comprised of 32,313 shares (including 9,776 shares of common stock issuable upon exercise of warrants) held in The White Revocable Trust of which the reporting person is a trustee, 11,250 shares (including 2,250 shares of common stock issuable upon exercise of a warrant) held by a retirement trust for the benefit of the reporting person, 2,353 shares (including 294 shares of common stock issuable upon exercise of warrants) held by Sierra Trust of which the reporting person is the trustee and 21,873 shares held by RoseTime Partners L.P. of which the reporting person is a trustee of a trust which is the General Partner. The reporting person disclaims beneficial ownership of the revocable trust’s, the trust’s and the partnership’s shares except as to the reporting person’s pecuniary interest therein.

Note 9: Comprised of 121,597 shares (including 21,685 shares of common stock issuable upon exercise of warrants) held in the Jeffrey W. and Christina R. Bird Trust of which the reporting person is a trustee, 6,250 shares (including 1,250 shares of common stock issuable upon exercise of a warrant) held by a Roth IRA for the benefit of the reporting person and 8,750 shares (including 1,750 shares of common stock issuable upon exercise of a warrant) held by NestEgg Holdings, LP of which the reporting person is a trustee of a trust which is the General Partner.  The reporting person disclaims beneficial ownership of the trust’s and the partnership’s shares except as to the reporting person’s pecuniary interest therein.

Note 10: Comprised of 4,982 shares (including 297 shares of common stock issuable upon exercise of warrants) held in The David and Robin Sweet Living Trust of which the reporting person is a trustee, 14,629 shares (including 3,060 shares of common stock issuable upon exercise of a warrant) held by a retirement trust for the benefit of the reporting person and 9,044 shares (including 1,809 shares of common stock issuable upon exercise of a warrant) held by a Roth IRA for the benefit of the reporting person.  The reporting person disclaims beneficial ownership of the living trust’s shares except as to the reporting person’s pecuniary interest therein.

Note 11: Comprised of 6,441 shares (including 1,179 shares of common stock issuable upon exercise of warrants) held in the Sheehan 2003 Trust of which the reporting person is a trustee.  The reporting person disclaims beneficial ownership of the trust’s shares except as to the reporting person’s pecuniary interest therein.

Note 12: Comprised of 3,016 shares (including 530 shares of common stock issuable upon exercise of warrants) held in the Speiser Trust Agreement of which the reporting person is a trustee and 1,384 shares (including 277 shares of common stock issuable upon exercise of a warrant) held by a retirement trust for the benefit of the reporting person.  The reporting person disclaims beneficial ownership of the trust agreement’s shares except as to the reporting person’s pecuniary interest therein.

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