X0201 4 2003-07-29 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 ROME L6 00144 ITALY 0 0 1 0 0001168857 DEFIANTE FARMACEUTICA LDA RUA DOS FERREIROS, 260 FUNCHAL MADEIRA S1 9000-082 PORTUGAL 0 0 1 0 0001164803 CAVAZZA CLAUDIO VIA SUDAFRICA, 20 ROME L6 00144 ITALY 0 0 1 0 0001163608 CAVAZZA PAOLO VIA TESSERETE, 10 LUGANO V8 SWITZERLAND 0 0 1 0 0001232942 APTAFIN S P A VIA QUIRINO MAJORANA NO. 171 ROME L6 00152 ITALY 0 0 1 0 Common Stock, no par value per share 2003-07-29 2003-07-29 4 S 0 10000 0.8409 D 16431375 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. Maurizio Terenzi, Attorney-in-fact for Sigma-Tau International S.A. 2003-07-31 Maurizio Terenzi, Attorney-in-fact for Sigma-Tau Finanziari S.p.A. 2003-07-31 Maurizio Terenzi, Attorney-in-fact for Defiante Farmaceutica L.D.A. 2003-07-31 Maurizio Terenzi, Attorney-in-fact for Claudio Cavazza 2003-07-31 Maurizio Terenzi, Attorney-in-fact for Paolo Cavazza 2003-07-31 Maurizio Terenzi, Attorney-in-fact for Aptafin S.p.A. 2003-07-31