X0202 4 2006-05-26 0 0000707511 REGENERX BIOPHARMACEUTICALS INC RGN 0001163608 CAVAZZA PAOLO VIA TESSERETE 10 LUGANO V8 00000 SWITZERLAND 0 0 1 0 Common Stock 2006-05-26 4 P 0 125000 2.80 A 1222652 I I Common Stock 10914694 I I Common Stock 984615 I I Securities directly owned by Chaumiere Consultadoria e Servicos S.A. (?Chaumiere?), which is an indirect wholly-owned subsidiary of Aptafin S.p.A. (?Aptafin?). Aptafin is owned by Paolo Cavazza and members of his family. 307,692 of these shares were acquired on June 22, 2005 pursuant to a purchase agreement with the Issuer that provides that Defiante (as defined below) may not dispose of the shares for a five-year period (the ?Holding Period?), that the Issuer, rather than Defiante, has all voting rights in respect of the shares during the Holding Period, and that the Issuer shall have the right to repurchase the shares within 30 days of the expiration of the Holding Period at a price of $5.00 per share, provided that the Issuer may only repurchase an amount of shares that would leave Defiante, when combined with all of its affiliates, with no less than 30.1% of the Issuer?s shares of Common Stock. Securities directly owned by Defiante Farmaceutica, L.D.A. (?Defiante?). Defiante is 58% directly owned by Sigma Tau Finanziaria S.p.A. (?Sigma Tau?) and 42% directly owned by Sigma Tau?s wholly-owned subsidiary, Sigma Tau International S.A. Paolo Cavazza directly and indirectly owns 40% of Sigma Tau. Securities directly owned by Sigma Tau. /s/ Maurizio Terenzi, Attorney-in-fact 2006-05-30