4 2003-06-12 0 0000891288 QUESTCOR PHARMACEUTICALS INC QSC 0001170881 SIGMA TAU INTERNATIONAL SA 0 0 1 0 0001092601 SIGMA TAU FINANZIARIA SPA 0 0 1 0 0001164803 CAVAZZA CLAUDIO 0 0 1 0 0001163608 CAVAZZA PAOLO 0 0 1 0 0001168857 DEFIANTE FARMACEUTICA LDA 0 0 1 0 0001232942 APTAFIN S P A 0 0 1 0 Common Stock, no par value per share 2003-06-12 2003-06-12 4 S 0 10000 1.15 D 16441375 D Shares solely owned by Sigma-Tau International S.A. (f/k/a Sigma-Tau Finance Holding S.A.). Sigma-Tau Finanziaria S.p.A. owns 100% of the capital stock of Sigma-Tau International 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. Antonio Nicolai, Attorney-in-fact for Mauro Bove, Director, on behalf of Sigma-Tau International S.A. 2003-06-16 Antonio Nicolai, Attorney-in-fact for Mario Artali, Managing Director, on behalf of Sigma-Tau Finanziari S.p.A. 2003-06-16 Antonio Nicolai, Attorney-in-fact for Claudio Cavazza 2003-06-16 Antonio Nicolai, Attorney-in-fact for Paolo Cavazza 2003-06-16 Antonio Nicolai, Attorney-in-fact for Raffele Sanguigni, Director, on behalf of Defiante Farmaceutica L.D.A. 2003-06-16 Antonio Nicolai, Attorney-in-fact for Piero Belletti, Managing Director, on behalf of Aptafin S.p.A. 2003-06-16