X0306 4 2019-02-15 0 0001060736 SEATTLE GENETICS INC /WA SGEN 0001741836 DANSEY ROGER D 21823 30TH DRIVE SE BOTHELL WA 98021 0 1 0 0 See Remarks Common Stock 2019-02-15 4 A 0 5768 0.00 A 83009 D These shares represent restricted stock units and will be settled in common stock upon vesting. Shares shall vest at a rate of 25% on each anniversary of the vesting commencement date of February 1, 2019 until all shares are fully vested four years from the vesting commencement date. Amount of securities beneficially owned following reported transactions includes restricted stock units subject to vesting and 359 shares acquired under the Amended and Restated 2000 Employee Stock Purchase Plan on January 31, 2019. Chief Medical Officer 6150 - Other Research By: /s/ Jean Liu For: Roger Dansey 2019-02-20