X0202 4/A 2006-05-02 2006-05-05 0 0000765258 IMCLONE SYSTEMS INC IMCL 0001361754 Denner Alexander J C/O VIKING GLOBAL PERFORMANCE LLC 55 RAILROAD AVENUE GREENWICH CT 06830 1 0 0 0 0001132625 VIKING GLOBAL PERFORMANCE LLC C/O VIKING GLOBAL PERFORMANCE LLC 55 RAILROAD AVENUE GREENWICH CT 06830 1 0 0 0 Stock Option (Right to Buy) 35.48 2006-05-02 4 A 0 3315 0 D 2006-07-18 2016-05-01 Common Stock 3315 23315 D Stock Option (Right to Buy) 35.48 2006-05-02 4 A 0 5000 0 D 2006-10-18 2016-05-01 Common Stock 5000 28315 D The options reported in this Form 4 are owned directly by Mr. Denner. The fifth and sixth line items from the Form 4 originally filed on May 5, 2006 are hereby amended to reflect the correct date the Stock Options (Right to Buy) are exercisable. The fifth line item from the Form 4 originally filed on May 5, 2006 is hereby amended to reflect the correct expiration date of the Stock Option (Right to Buy). In addition to being a Director to the Company, Alexander J. Denner ("Mr. Denner") also serves as a portfolio manager for Viking Global Performance LLC ("VGP") which acts as (i) the general partner of Viking Global Equities LP, a Delaware limited partnership ("VGE"), and (ii) investment manager to VGE III Portfolio Ltd., a Cayman Islands company ("VGE III"). As general partner and investment manager, respectively, VGP has the power to dispose of and vote the shares of Common Stock directly owned by VGE and VGE III. O. Andreas Halvorsen and David C. Ott are the managing members of VGP. /s/ Alexander J. Denner 2006-05-08 /s/ O. Andreas Halvorsen 2006-05-08