EXHIBIT 10.1 [LETTERHEAD OF ICOS CORPORATION] June 11, 1999 Mr. Paul N. Clark 595 Crabtree Lane Lake Forest, IL 60045 Dear Paul: On behalf of ICOS Corporation (the "Company"), I am very pleased to extend to you an offer to join the Company as...Employment Agreement • August 13th, 1999 • Icos Corp / De • Pharmaceutical preparations • Washington
