UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No.6 and Amendment No.8)* QUESTCOR PHARMACEUTICALS INC. - ------------------------------------------------------------------------------- (Name of Issuer) Common Stock - ------------------------------------------------------------------------------- (Title of Class of Securities) 232808105 - ------------------------------------------------------------------------------- (CUSIP Number) Joseph J. Giunta, Esq. Skadden, Arps, Slate, Meagher & Flom LLP 300 South Grand Avenue Los Angeles, CA 90071 (213) 687-5000 - ------------------------------------------------------------------------------- (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) January 12, 2004 - ------------------------------------------------------------------------------- (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 ss.240.13d-1(e), 240.13d-1(f) or 240.13d-(1)(g), check the following box |_|. *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).SCHEDULE 13D - ------------------------------------------------------------------------------- CUSIP No. 232808105 - ------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS Claudio Cavazza - ------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X| (b) |_| - ------------------------------------------------------------------------------- 3 SEC USE ONLY - ------------------------------------------------------------------------------- 4 SOURCE OF FUNDS - ------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) |_| - ------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION Italy - ------------------------------------------------------------------------------- 7 SOLE VOTING POWER NUMBER OF 0 SHARES ------------------------------------------------------ BENEFICIALLY 8 SHARED VOTING POWER OWNED BY 14,631,375 EACH ------------------------------------------------------ REPORTING 9 SOLE DISPOSITIVE POWER PERSON WITH 1,756,781 ------------------------------------------------------ 10 SHARED DISPOSITIVE POWER 10,668,712 - ------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 14,631,375 - ------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - ------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 31.53% - ------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON IN - ------------------------------------------------------------------------------- SCHEDULE 13D - ------------------------------------------------------------------------------- CUSIP No. 232808105 - ------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS Paolo Cavazza - ------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X| (b) |_| - ------------------------------------------------------------------------------- 3 SEC USE ONLY - ------------------------------------------------------------------------------- 4 SOURCE OF FUNDS - ------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) |_| - ------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION Italy - ------------------------------------------------------------------------------- 7 SOLE VOTING POWER NUMBER OF 0 SHARES ------------------------------------------------------ BENEFICIALLY 8 SHARED VOTING POWER OWNED BY 14,631,375 EACH ------------------------------------------------------ REPORTING 9 SOLE DISPOSITIVE POWER PERSON WITH 1,756,782 ------------------------------------------------------ 10 SHARED DISPOSITIVE POWER 11,117,812 - ------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 14,631,375 - ------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - ------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 31.53% - ------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON IN - ------------------------------------------------------------------------------- SCHEDULE 13D - ------------------------------------------------------------------------------- CUSIP No. 232808105 - ------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS Sigma-Tau Finanziaria SpA - ------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X| (b) |_| - ------------------------------------------------------------------------------- 3 SEC USE ONLY - ------------------------------------------------------------------------------- 4 SOURCE OF FUNDS - ------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) |_| - ------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION Italy - ------------------------------------------------------------------------------- 7 SOLE VOTING POWER NUMBER OF 0 SHARES ------------------------------------------------------ BENEFICIALLY 8 SHARED VOTING POWER OWNED BY 14,631,375 EACH ------------------------------------------------------ REPORTING 9 SOLE DISPOSITIVE POWER PERSON WITH 0 ------------------------------------------------------ 10 SHARED DISPOSITIVE POWER 10,668,712 - ------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 14,631,375 - ------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - ------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 31.53% - ------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON CO - ------------------------------------------------------------------------------- SCHEDULE 13D - ------------------------------------------------------------------------------- CUSIP No. 232808105 - ------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS Sigma-Tau International S.A. - ------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X| (b) |_| - ------------------------------------------------------------------------------- 3 SEC USE ONLY - ------------------------------------------------------------------------------- 4 SOURCE OF FUNDS - ------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) |_| - ------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION Luxembourg - ------------------------------------------------------------------------------- 7 SOLE VOTING POWER NUMBER OF 0 SHARES ------------------------------------------------------ BENEFICIALLY 8 SHARED VOTING POWER OWNED BY 14,631,375 EACH ------------------------------------------------------ REPORTING 9 SOLE DISPOSITIVE POWER PERSON WITH 0 ------------------------------------------------------ 10 SHARED DISPOSITIVE POWER 10,668,712 - ------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 14,631,375 - ------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - ------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 31.53% - ------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON CO - ------------------------------------------------------------------------------- SCHEDULE 13D - ------------------------------------------------------------------------------- CUSIP No. 232808105 - ------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS Defiante Farmaceutica L.D.A. - ------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X| (b) |_| - ------------------------------------------------------------------------------- 3 SEC USE ONLY - ------------------------------------------------------------------------------- 4 SOURCE OF FUNDS - ------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) |_| - ------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION Portugal - ------------------------------------------------------------------------------- 7 SOLE VOTING POWER NUMBER OF 0 SHARES ------------------------------------------------------ BENEFICIALLY 8 SHARED VOTING POWER OWNED BY 14,631,375 EACH REPORTING ------------------------------------------------------ PERSON WITH 9 SOLE DISPOSITIVE POWER 0 ------------------------------------------------------ 10 SHARED DISPOSITIVE POWER 2,025,315 - ------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 14,631,375 - ------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - ------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 31.53% - ------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON CO - ------------------------------------------------------------------------------- SCHEDULE 13D - ------------------------------------------------------------------------------- CUSIP No. 232808105 - ------------------------------------------------------------------------------- 1 NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS Aptafin S.p.A. - ------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X| (b) |_| - ------------------------------------------------------------------------------- 3 SEC USE ONLY - ------------------------------------------------------------------------------- 4 SOURCE OF FUNDS - ------------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) |_| - ------------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION Italy - ------------------------------------------------------------------------------- 7 SOLE VOTING POWER NUMBER OF 0 SHARES ------------------------------------------------------ BENEFICIALLY 8 SHARED VOTING POWER OWNED BY 14,631,375 EACH ------------------------------------------------------ REPORTING 9 SOLE DISPOSITIVE POWER PERSON WITH 0 ------------------------------------------------------ 10 SHARED DISPOSITIVE POWER 11,117,812 - ------------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 14,631,375 - ------------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES |_| - ------------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 31.53% - ------------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON CO - ------------------------------------------------------------------------------- Amendment No. 6 and Amendment No. 8 to Statement on Schedule 13D This Amendment No. 6 (the "Amendment No. 6") amends the Statement on Schedule 13D filed with the Securities and Exchange Commission ("SEC") on March 25, 2002 (the "Sigma/Defiante Schedule 13D"), as amended, relating to shares of the common stock, no par value (the "Common Stock"), of Questcor Pharmaceuticals Inc., a California corporation ("Questcor"). This Amendment No. 8 (the "Amendment No. 8" and, together with the Amendment No. 6, this "Statement") amends the Statement on Schedule 13D, filed with the SEC on August 7, 2001 (the "Cavazza/Sigma Schedule 13D" and, together with the Sigma/Defiante Schedule 13D, the "Schedule 13Ds"), as amended, relating to the shares of Common Stock. Pursuant to Rule 13d-2 of Regulation 13D-G promulgated under the Securities Exchange Act of 1934, as amended (the "Act"), this Amendment No. 6 is being filed on behalf of Sigma-Tau Finanziaria SpA, an Italian corporation ("Sigma Tau") and Defiante Farmaceutica L.D.A., a Portuguese corporation ("Defiante") (formerly known as Defiante Farmaceutica Unipessoal L.D.A.), and this Amendment No. 8 is being filed on behalf of Sigma-Tau International S.A., a Luxembourg corporation ("Sigma Tau International") (formerly known as Sigma-Tau Finance Holding S.A.), Aptafin S.p.A., an Italian corporation ("Aptafin"), Mr. Claudio Cavazza ("Mr. C. Cavazza") and Mr. Paolo Cavazza ("Mr. P. Cavazza" and, together with Mr. C. Cavazza, Sigma Tau International, Aptafin, Defiante and Sigma Tau, the "Reporting Persons"). Item 3. Source and Amount of Funds or Other Consideration. ------------------------------------------------- Item 3 of the Schedule 13Ds are hereby amended to add the following, which more specifically describes the transaction reported by the Reporting Persons on January 13, 2004: The 759,493 shares of Common Stock purchased by Defiante were purchased from Questcor in a private placement on January 12, 2004. Questcor sold the shares to Defiante in exchange for total consideration of $489,113.51, consisting of $435,949.00 in cash and the surrender of 759,493 warrants held by Defiante (which were valued at $53,164.51 upon surrender). Defiante used its working capital to provide the cash portion of the consideration. Item 4. Purpose of the Transaction. -------------------------- Item 4 of the Schedule 13Ds are hereby amended to add the following: The Reporting Persons originally acquired the shares reported herein to gain an equity investment interest in Questcor. The Reporting Persons acquired the shares described in Item 3 above upon their determination that the purchase price for the shares provided for an attractive investment. The Reporting Persons intend to evaluate on an ongoing basis Questcor's financial condition, business operations and prospects. Based on such evaluations and prevailing market conditions, the Reporting Persons will determine whether to acquire or sell shares of Common Stock, subject to compliance with Section 16(b) of the Act and the rules promulgated thereunder. None of the Reporting Parties has any present plans or proposals which relate to or would result in any transaction, change or event specified in clauses (a) through (j) of Item 4 of Schedule 13D. Item 5. Interest in Securities of Questcor. ---------------------------------- Item 5(b) of the Schedule 13Ds are hereby amended as follows: Aptafin ------- The number of shares of Common Stock as to which Aptafin has the sole power to vote or direct the vote is zero. The number of shares of Common Stock as to which Aptafin shares the power to vote or direct the vote is 14,631,375. The number of shares of Common Stock as to which Aptafin has the sole power to dispose or direct the disposition is zero. The number of shares of Common Stock as to which Aptafin shares the power to dispose or direct the disposition is 11,117,812. Item 7. Material to be Filed as Exhibits. -------------------------------- EXHIBIT 1 - Joint Filing Agreement dated January 13, 2004 by and between the Reporting Persons(1). EXHIBIT 2 - Power of Attorney dated April 8, 2003 by and between the Reporting Persons(2). ________________ (1) Incorporated by reference to Exhibit 1 of Amendment No. 5 and Amendment No. 7 to the Statement on Schedule 13D, filed with the SEC on January 13, 2004, relating to the shares of Common Stock. (2) Incorporated by reference to Exhibit 1 of Form 4, filed with the SEC on May 9, 2003, relating to the shares of Common Stock. Signatures ---------- After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement with respect to Claudio Cavazza is true, complete and correct. Dated: January 15, 2004 CLAUDIO CAVAZZA By: /s/ MAURIZIO TERENZI ------------------------------ Maurizio Terenzi, Attorney-in- fact for Claudio Cavazza After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement with respect to Paolo Cavazza is true, complete and correct. Dated: January 15, 2004 PAOLO CAVAZZA By: /s/ MAURIZIO TERENZI ------------------------------ Maurizio Terenzi, Attorney-in- fact for Paolo Cavazza After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement with respect to Sigma-Tau Finanziaria SpA is true, complete and correct. Dated: January 15, 2004 SIGMA-TAU FINANZIARIA SPA By: /s/ MAURIZIO TERENZI ------------------------------ Maurizio Terenzi, Attorney-in- fact for Sigma-Tau Finanziari SpA After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement with respect to Sigma-Tau International S.A. is true, complete and correct. Dated: January 15, 2004 SIGMA-TAU INTERNATIONAL S.A. By: /s/ MAURIZIO TERENZI ------------------------------ Maurizio Terenzi, Attorney-in-fact for Sigma-Tau International S.A. After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement with respect to Defiante Farmaceutica L.D.A. is true, complete and correct. Dated: January 15, 2004 DEFIANTE FARMACEUTICA L.D.A. By: /s/ MAURIZIO TERENZI ---------------------------------- Maurizio Terenzi, Attorney-in-fact for Defiante Farmaceutica L.D.A. After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement with respect to Aptafin S.p.A. is true, complete and correct. Dated: January 15, 2004 APTAFIN S.P.A. By: /s/ MAURIZIO TERENZI ---------------------------------- Maurizio Terenzi, Attorney-in-fact for Aptafin S.p.A. The original statement shall be signed by each person on whose behalf the statement is filed or his authorized representative. If the statement is signed on behalf of a person by his authorized representative (other than an executive officer or general partner of the filing person), evidence of the representative's authority to sign on behalf of such person shall be filed with the statement: provided, however, that a power of attorney for this purpose which is already on file with the Commission may be incorporated by reference. The name and any title of each person who signs the statement shall be typed or printed beneath his signature. Attention: Intentional misstatements or omissions of fact constitute Federal criminal violations (See 18 U.S.C. 1001)