X0202 4/A 2006-03-10 2006-03-14 0 0001018952 KOS PHARMACEUTICALS INC KOSP 0001013702 KING RICHARD 2200 N. COMMERCE PKWY, SUITE 300 WESTON FL 33326 0 1 0 0 EVP, Commercial Operations Common Stock, $.01 par value 2006-03-10 4 S 0 5000 50 D 12908 D Stock Option (Right to Buy) 19.5 2006-03-10 4 M 0 5000 0 D 2013-01-22 Common Stock 5000 61000 D The sales reported in the original Form 4 filed on March 14, 2006 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 15, 2005. The adoption date of such trading plan was incorrectly stated as June 15, 2005 in the original Form 4. Includes 3,908 shares of Kos common stock acquired by the reporting person in transactions exempt under Section 16 of the Exchange Act under the Kos 401(k) Plan and the Employee Stock Purchase Plan. Part of an original grant of 80,000 options, exercisable in the following amounts on the following dates: 20,000 on January 23, 2004 20,000 on January 23, 2005 20,000 on January 23, 2006 20,000 on January 23, 2007 The number of options beneficially owned by the reporting person following the transaction reported on the original Form 4 filed on March 14, 2006 was incorrectly stated as 66,000. Juan F. Rodriguez, Attorney-in-Fact 2006-03-30