X0306 4 2018-03-20 0 0001060736 SEATTLE GENETICS INC /WA SGEN 0001361966 HIMES VAUGHN B 21823 30TH DRIVE SE BOTHELL WA 98021 0 1 0 0 Chief Technical Officer Non-qualified Stock Option (Right to buy) 34.20 2018-03-20 4 A 0 8333 0.00 A 2026-05-09 Common Stock 8333 8333 D On May 9, 2016, the reporting person was granted an option to purchase 8,333 options of common stock. The performance criteria for this grant were met as of March 20, 2018 and the option shall vest in four (4) equal tranches on the first, second, third and fourth anniversaries of March 20, 2018 subject to continuous service with the Company as of each vesting date. /s/ Jean Liu 2018-03-22