X0306 4 2022-04-07 0 0001060736 Seagen Inc. SGEN 0001167496 SIEGALL CLAY B 21823 30TH DRIVE SE BOTHELL WA 98021 1 1 0 0 President and CEO Common Stock 2022-04-07 4 M 0 1649 26.10 A 669594 D Common Stock 2022-04-07 4 S 0 1649 151.42 D 667945 D Common Stock 2022-04-07 4 M 0 2100 26.10 A 670045 D Common Stock 2022-04-07 4 S 0 2100 152.59 D 667945 D Common Stock 2022-04-07 4 M 0 4692 26.10 A 672637 D Common Stock 2022-04-07 4 S 0 4692 153.38 D 667945 D Common Stock 2022-04-07 4 M 0 2400 26.10 A 670345 D Common Stock 2022-04-07 4 S 0 2400 154.36 D 667945 D Common Stock 2022-04-07 4 M 0 3828 26.10 A 671773 D Common Stock 2022-04-07 4 S 0 3828 155.83 D 667945 D Common Stock 2022-04-07 4 M 0 1900 26.10 A 669845 D Common Stock 2022-04-07 4 S 0 1900 156.48 D 667945 D Common Stock 2022-04-07 4 M 0 474 26.10 A 668419 D Common Stock 2022-04-07 4 S 0 474 157.23 D 667945 D Non-Qualified Stock Option (right to buy) 26.10 2022-04-07 4 M 0 1649 0.00 D 2022-08-20 Common Stock 1649 83566 D Non-Qualified Stock Option (right to buy) 26.10 2022-04-07 4 M 0 2100 0.00 D 2022-08-20 Common Stock 2100 81466 D Non-Qualified Stock Option (right to buy) 26.10 2022-04-07 4 M 0 4692 0.00 D 2022-08-20 Common Stock 4692 76774 D Non-Qualified Stock Option (right to buy) 26.10 2022-04-07 4 M 0 2400 0.00 D 2022-08-20 Common Stock 2400 74374 D Non-Qualified Stock Option (right to buy) 26.10 2022-04-07 4 M 0 3828 0.00 D 2022-08-20 Common Stock 3828 70546 D Non-Qualified Stock Option (right to buy) 26.10 2022-04-07 4 M 0 1900 0.00 D 2022-08-20 Common Stock 1900 68646 D Non-Qualified Stock Option (right to buy) 26.10 2022-04-07 4 M 0 474 0.00 D 2022-08-20 Common Stock 474 68172 D Amount of securities beneficially owned following reported transactions includes restricted stock units subject to vesting. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan. Reflects sales of common stock executed in multiple transactions at prices ranging from $150.90 to $151.86. The price reported reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the sales were effected. Reflects sales of common stock executed in multiple transactions at prices ranging from $151.98 to $152.92. The price reported reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the sales were effected. Reflects sales of common stock executed in multiple transactions at prices ranging from $153.00 to $153.94. The price reported reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the sales were effected. Reflects sales of common stock executed in multiple transactions at prices ranging from $154.03 to $154.97. The price reported reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the sales were effected. Reflects sales of common stock executed in multiple transactions at prices ranging from $155.14 to $156.13. The price reported reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the sales were effected. Reflects sales of common stock executed in multiple transactions at prices ranging from $156.15 to $157.10. The price reported reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the sales were effected. Reflects sales of common stock executed in multiple transactions at prices ranging from $157.17 to $157.28. The price reported reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the sales were effected. Options vested at a rate of 25% on 8/20/13 and monthly thereafter until all the options were fully vested on 8/20/16. By: /s/ Jennifer Prosba For: Clay B. Siegall 2022-04-08