UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A UNDER THE SECURITIES EXCHANGE ACT OF 1934 (AMENDMENT NO. 2)* Idenix Pharmaceuticals, Inc. -------------------------------------------------------------------------------- (Name of Issuer) Common Stock -------------------------------------------------------------------------------- (Title of Class of Securities) 45166R 20 4 -------------------------------------------------------------------------------- (CUSIP Number) Robert E. Pelzer, Esq. Morton A. Pierce, Esq. Novartis Pharma AG Dewey Ballantine LLP Lichtstrasse 35 1301 Avenue of the Americas CH-4002, Basel Switzerland New York, New York 10019 41-61-324-1111 (212) 259-8000 (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) -------------------------------------------------------------------------------- October 31, 2005 -------------------------------------------------------------------------------- (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 Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box [ ]. 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 information required on this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Exchange Act") or otherwise subject to the liabilities of that section of the Exchange Act but shall be subject to all other provisions of the Exchange Act (however, see the Notes). Page 1 of 10 ======== -------- --------------------------------------------------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON (entities only)* NOVARTIS AG -------- --------------------------------------------------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [ ] (b) [ ] -------- --------------------------------------------------------------------------------------------------------------------------- 3 SEC USE ONLY -------- --------------------------------------------------------------------------------------------------------------------------- 4 SOURCE OF FUNDS* AF -------- --------------------------------------------------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ] -------- --------------------------------------------------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION SWITZERLAND -------- --------------------------------------------------------------------------------------------------------------------------- 7 SOLE VOTING POWER NUMBER OF 0 SHARES BENEFICIALLY --------- ----------------------------------------------------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH REPORTING 31,295,870 PERSON --------- ----------------------------------------------------------------------------------------------- WITH 9 SOLE DISPOSITIVE POWER 0 --------- ----------------------------------------------------------------------------------------------- 10 SHARED DISPOSITIVE POWER 31,295,870 -------------------------- --------------------------------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 31,295,870 -------------------------- --------------------------------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES* [ ] -------------------------- --------------------------------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 56.26% -------------------------- --------------------------------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON* CO -------------------------- --------------------------------------------------------------------------------------------------------- *SEE INSTRUCTIONS Page 2 of 10 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON (entities only)* NOVARTIS PHARMA AG -------- --------------------------------------------------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [ ] (b) [ ] -------- --------------------------------------------------------------------------------------------------------------------------- 3 SEC USE ONLY -------- --------------------------------------------------------------------------------------------------------------------------- 4 SOURCE OF FUNDS* WC -------- --------------------------------------------------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) [ ] -------- --------------------------------------------------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION SWITZERLAND -------------------------- --------- ----------------------------------------------------------------------------------------------- 7 SOLE VOTING POWER NUMBER OF 0 SHARES BENEFICIALLY --------- ----------------------------------------------------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH REPORTING 31,295,870 PERSON WITH --------- ----------------------------------------------------------------------------------------------- 9 SOLE DISPOSITIVE POWER 0 ----------------------------------- ----------------------------------------------------------------------------------------------- 10 SHARED DISPOSITIVE POWER 31,295,870 ----------------------------------- ----------------------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 31,295,870 -------------------------- --------------------------------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES* [ ] -------------------------- --------------------------------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 56.26% -------------------------- --------------------------------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON* CO -------------------------- --------------------------------------------------------------------------------------------------------- *SEE INSTRUCTIONS Page 3 of 10 ITEM 1. SECURITY AND ISSUER This Amendment No. 2 to Schedule 13D (this "Amendment") amends the initial statement on Schedule 13D filed with the Securities and Exchange Commission on July 27, 2004 and amended on September 7, 2005 (the "Original Schedule 13D") relating to Common Stock (the "Common Stock"), par value $0.001 per share of Idenix Pharmaceuticals, Inc., a Delaware corporation (the "Company"). The address of the Company's principal executive offices is 60 Hampshire Street, Cambridge, Massachusetts 02139. Except as otherwise described herein, the information contained in the Original Schedule 13D remains in effect. Capitalized terms used but not defined in this Amendment shall have the respective meanings set forth with respect thereto in the Original Schedule 13D. ITEM 2. IDENTITY AND BACKGROUND No change except as described below. (a) - (c) and (f) The name, business address, present principal occupation or employment and citizenship of the executive officers and members of the Board of Directors of each of the Reporting Persons is set forth on Schedule I hereto and is incorporated herein by reference. (d) and (e) Neither the Reporting Persons nor, to the best knowledge of each of them, any of the persons listed on Schedule I hereto with respect to each such Reporting Person during the last five years, (i) has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or (ii) was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to 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. ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION No change except as described below. On October 31, 2005, Novartis Pharma acquired 3,939,131 shares of Common Stock for $20.61 per share or an aggregate of $81,185,489.91 in a registered public offering by the Company pursuant to Novartis Pharma's stock subscription rights. The source of funds for this acquisition was Novartis Pharma's working capital. ITEM 4. PURPOSE OF TRANSACTION No change. Page 4 of 10 ITEM 5. INTEREST IN SECURITIES OF THE ISSUER No change except as described below. (a) and (b) Novartis is the beneficial owner of 31,295,870 shares of Common Stock representing 56.26% of the outstanding shares of Common Stock, all of which shares are owned directly by Novartis Pharma. Novartis has shared power to vote or direct the vote and shared power to dispose or to direct the disposition of all shares of Common Stock beneficially owned by it. Novartis Pharma is the record and beneficial owner of 31,295,870 shares of Common Stock, representing 56.26% of the outstanding shares of Common Stock. Novartis Pharma has shared power to vote or direct the vote and shared power to dispose or to direct the disposition of all shares of Common Stock beneficially owned by it. To the best knowledge of each of the Reporting Persons, none of the persons listed on Schedule I hereto with respect to such Reporting Person is the beneficial owner of any shares of Common Stock. (c) Except for the transactions described in Item 3 neither the Reporting Persons nor, to the best knowledge of each of the Reporting Persons, any of the persons listed on Schedule I has engaged in any transaction in the Common Stock in the past 60 days. ITEM 6. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO SECURITIES OF THE ISSUER No change. ITEM 7. MATERIAL TO BE FILED AS EXHIBITS No change. Page 5 of 10 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. Date: November 2, 2005 NOVARTIS AG By: /s/ Peter Kornicker -------------------------------- Name: Peter Kornicker Title: Authorized Signatory By: /s/ Thomas Huggenberger -------------------------------- Name: Thomas Huggenberger Title: Authorized Signatory NOVARTIS PHARMA AG By: /s/ Matthias Runge --------------------------------- Name: Matthias Runge Title: Head of Legal Ophtha and Oncology Europe By: /s/ Joseph E. Mamie --------------------------------- Name: Joseph E. Mamie Title: Head Operational Treasury Page 6 of 10 SCHEDULE I DIRECTORS AND EXECUTIVE OFFICERS OF NOVARTIS AND NOVARTIS PHARMA DIRECTORS AND EXECUTIVE OFFICERS OF NOVARTIS The name, address, citizenship and present principal occupation or employment of each of the directors and executive officers of Novartis are set forth below. Unless otherwise indicated below, each occupation set forth opposite an individual's name refers to employment with Novartis. ---------------------------------------------------------------------------------------------------------------------- Name, Function and Business Address Citizenship Principal Occupation ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Daniel Vasella Switzerland Chairman of the Board of Directors, Chairman of the Board of Directors, Chief Executive Officer Chief Executive Officer c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Prof. Dr. Helmut Sihler Austria Retired Vice Chairman of the Board of Directors c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Hans-Jorg Rudloff Germany Chairman of the Executive Committee of Vice Chairman of the Board Barclays Capital c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Birgit Breuel Germany Consultant Director c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Prof. Dr. Peter Burckhardt Switzerland Head of Medical Service at the Director University Hospital of Lausanne c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Prof. Dr. Srikant Datar India Senior Associate Dean for Executive Director Education at Harvard Business School c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Page 7 of 10 ----------------------------------------------------- --------------------- ------------------------------------------ Name, Function and Business Address Citizenship Principal Occupation ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ William W. George USA Senior Lecturer at Harvard Business Director School c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Alexandre F. Jetzer Switzerland Consultant Director c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Pierre Landoldt Switzerland President of the Sandoz family foundation Director c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Dr. Ulrich Lehner Germany President and Chief Executive Officer of Director Henkel KGaA c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Dr. Wendelin Wiedeking Germany Chairman and Chief Executive Officer of Director Porsche AG c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Prof. Dr. Rolf M. Zinkernagel Switzerland Professor and Director of the Institute Director of Experimental Immunology at the c/o Novartis AG University of Zurich Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Dr. Raymund Breu Switzerland Chief Financial Officer c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Dr. Urs Barlocher Switzerland Head of Legal and General Affairs c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Juergen Brokatzky-Geiger Germany Head of Human Resources c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Page 8 of 10 ----------------------------------------------------- --------------------- ------------------------------------------ Name, Function and Business Address Citizenship Principal Occupation ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Paul Choffat Switzerland Head of Novartis Consumer Health c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Thomas Ebeling Germany Head of Novartis Pharma c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Prof. Marc C. Fishman, Md. USA Head of Pharmaceuticals Research c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ DIRECTORS AND EXECUTIVE OFFICERS OF NOVARTIS PHARMA The name, address, citizenship and present principal occupation or employment of each of the directors and executive officers of Novartis Pharma are set forth below. Unless otherwise indicated below, each occupation set forth opposite an individual's name refers to employment with Novartis Pharma. ----------------------------------------------------- --------------------- ------------------------------------------ Name, Function and Business Address Citizenship Principal Occupation ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Daniel Vasella Switzerland Chairman of the Board of Directors and Chairman of the Board of Directors Chief Executive Officer of Novartis AG Chief Executive Officer c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ ----------------------------------------------------- --------------------- ------------------------------------------ Dr. Raymund Breu Switzerland Member of the Board of Directors Director c/o Novartis AG Lichstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ Thomas Ebeling Germany Member of the Board of Directors, Head Director of Management Head of Management c/o Novartis AG Lichtstrasse 35 CH-4002 Basel, Switzerland ----------------------------------------------------- --------------------- ------------------------------------------ Page 9 of 10