X0202 4 2005-04-13 0 0000891288 QUESTCOR PHARMACEUTICALS INC QSC 0001170881 SIGMA TAU INTERNATIONAL SA 18 AVENUE DE LA PORTE NEUVE LUXEMBOURG N4 L-2227 LUXEMBOURG 0 0 1 0 0001092601 SIGMA TAU FINANZIARIA SPA VIA SUDAFRICA 20 00144 ROME ITALY 0 0 1 0 0001168857 DEFIANTE FARMACEUTICA LDA RUA DOS FERREIROS,260 FUNCHAL MADEIRA S1 9000-082 PORTUGAL 0 0 1 0 0001232942 APTAFIN S P A VIALE SHAKESPEARE 47 ROME L6 00144 ITALY 0 0 1 0 0001164803 CAVAZZA CLAUDIO VIA SUDAFRICA 20 ROME ITALY L6 00000 ITALY 0 0 1 0 0001163608 CAVAZZA PAOLO VIA TESSERETE, 10 LUGANO V8 V8 SWITZERLAND 0 0 1 0 Common Stock, no par value per share 8643397 D Common Stock, no par value per share 1756781 I Shares directly held by Claudio Cavazza. Common Stock, no par value per share 1756782 I Shares directly held by Paolo Cavazza. Common Stock, no par value per share 759493 I Shares directly held by Defiante Farmaceutica L.d.A. Common Stock, no par value per share 549100 I Shares directly held by Aptafin S.p.A. Common Stock, no par value per share 1265822 I Shares underlying the 8% Convertible Debenture held by Defiante Farmaceutica L.d.A. Common Stock, no par value per share 2005-04-13 4 P 0 100000 0.65 A 100000 I Shares directly held by Chaumiere - Consultadoria & Servicos SDC Unipessoal LDA. 8% Convertible Debenture 1.58 2005-04-15 Common Stock, no par value per share 1265822 2000000 I The 8% Convertible Debenture is directly held by Defiante Farmaceutica L.d.A. Sigma-Tau Finanziaria S.p.A. owns 100% of the capital stock of Sigma-Tau International S.A. (f/k/a Sigma-Tau Finance Holding S.A.) and 58% of the capital stock of Defiante Farmaceutica L.d.A. Sigma-Tau International S.A. owns 42% of the capital stock of Defiante Farmaceutica L.d.A. Claudio Cavazza owns, directly and indirectly, 60% of Sigma-Tau Finanziaria S.p.A. and Paolo Cavazza owns, directly and indirectly, 40% of Sigma-Tau Finanziaria S.p.A. Paolo Cavazza also owns, directly and indirectly, 100% of Aptafin S.p.A. Aptafin S.p.A. owns, directly and indirectly, 100% of Chaumiere - Consultadoria & Servicos SDC Unipessoal LDA. Defiante Farmaceutica L.d.A., the holder of the 8% Convertible Debenture, may convert all or any portion of the debenture into Common Stock, no par value per share, at any time prior to the maturity date of April 15, 2005. Maurizio Terenzi, Attorney-in-fact for Sigma-Tau International S.A. 2005-04-15 Maurizio Terenzi, Attorney-in-fact for Sigma-Tau Finanziaria S.p.A. 2005-04-15 Maurizio Terenzi, Attorney-in-fact for Defiante Farmaceutica L.D.A. 2005-04-15 Maurizio Terenzi, Attorney-in-fact for Aptafin S.p.A. 2005-04-15 Maurizio Terenzi, Attorney-in-fact for Chaumiere - Consultadoria & Servicos SDC Unipessoal LDA 2005-04-15 Maurizio Terenzi, Attorney-in-fact for Claudio Cavazza 2005-04-15 Maurizio Terenzi, Attorney-in-fact for Paolo Cavazza 2005-04-15