X0306 4 2022-01-28 0 0001060736 Seagen Inc. SGEN 0001202335 GRYSKA DAVID W 21823 30TH DRIVE SE BOTHELL WA 98021 1 0 0 0 Common Stock 2022-01-28 4 M 0 850 20.06 A 47100 D Common Stock 2022-01-28 4 S 0 850 121.69 D 46250 D Common Stock 2022-01-28 4 M 0 2553 20.06 A 48803 D Common Stock 2022-01-28 4 S 0 2553 122.43 D 46250 D Common Stock 2022-01-28 4 M 0 883 20.06 A 47133 D Common Stock 2022-01-28 4 S 0 883 123.39 D 46250 D Common Stock 2022-01-28 4 M 0 214 20.06 A 46464 D Common Stock 2022-01-28 4 S 0 214 124.23 D 46250 D Non-Qualified Stock Option (right to buy) 20.06 2022-01-28 4 M 0 850 0.0 D 2022-05-17 Common Stock 850 12150 D Non-Qualified Stock Option (right to buy) 20.06 2022-01-28 4 M 0 2553 0.0 D 2022-05-17 Common Stock 2553 9597 D Non-Qualified Stock Option (right to buy) 20.06 2022-01-28 4 M 0 883 0.0 D 2022-05-17 Common Stock 883 8714 D Non-Qualified Stock Option (right to buy) 20.06 2022-01-28 4 M 0 214 0.0 D 2022-05-17 Common Stock 214 8500 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 $120.99 to $121.96. 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 $122.03 to $122.97. 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 $123.04 to $124.03. 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 $124.13 to $124.29. 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 were fully vested on 5/17/13. By: /s/ Jennifer Prosba For: David W. Gryska 2022-02-01