X0306 4 2019-08-30 0 0001060736 SEATTLE GENETICS INC /WA SGEN 0001361966 HIMES VAUGHN B 21823 30TH DRIVE SE BOTHELL WA 98021 0 1 0 0 See Remarks Common Stock 2019-08-30 4 A 0 18013 0.00 A 193210 D Common Stock 2019-08-30 4 M 0 8000 12.00 A 201210 D Common Stock 2019-08-30 4 S 0 7287 72.82 D 193923 D Common Stock 2019-08-30 4 S 0 713 73.24 D 193210 D Common Stock 2019-09-03 4 S 0 1814 70.7992 D 191396 D Common Stock 2019-09-03 4 S 0 3878 70.7994 D 187518 D Incentive Stock Option (right to buy) 72.64 2019-08-30 4 A 0 1333 0.00 A 2029-08-30 Common Stock 1333 1333 D Non-Qualified Stock Option (right to buy) 12.00 2019-08-30 4 M 0 8000 0.00 D 2020-08-27 Common Stock 8000 12498 D Non-Qualified Stock Option (right to buy) 72.64 2019-08-30 4 A 0 41453 0.00 A 2029-08-30 Common Stock 41453 41453 D These shares represent restricted stock units and will be settled in common stock upon vesting. Amount of securities beneficially owned following reported transactions includes restricted stock units subject to vesting. Shares shall vest at a rate of 25% on each anniversary of the grant date until all shares are fully vested four years from the grant date. 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 $72.10 to $73.09. 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 $73.17 to $73.44. 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. Shares sold pursuant to a 10b5-1 arrangement to satisfy tax obligations arising out of the vesting of previously granted restricted stock units. Options vested at a rate of 25% on 8/27/11 and monthly thereafter until all the shares were fully vested on 8/27/14. Options shall vest at a rate of 25% one year from grant date and monthly thereafter until all shares are fully vested four years from grant date. Chief Technical Officer 5250 - TOPS Administration By:/s/ Jean Liu For: Vaughn B. Himes 2019-09-04