X0407 4 2023-04-01 0 0001060736 Seagen Inc. SGEN 0001361966 HIMES VAUGHN B 21823 30TH DRIVE SE BOTHELL WA 98021 0 1 0 0 Chief Technical Officer 0 Common Stock 2023-04-01 4 A 0 1214 0.00 A 68471 D Common Stock 119471 I by Trust These restricted stock units will be settled in common stock upon vesting. The restricted stock units shall vest 37.5% on the 18 month anniversary of the grant date, 31.25% on the 24 month anniversary of the grant date, and 31.25% on the 30 month anniversary of the grant date. Amount of securities beneficially owned following reported transactions includes restricted stock units subject to vesting. By: /s/ Jennifer Prosba For: Vaughn B. Himes 2023-04-04