Clay Siegall co-founded Seagen, the company previously known as Seattle Genetics that is now the largest biotech company in the Seattle area, and went on to become the highest-paid CEO in the state. Last May, he resigned as CEO after allegations of domestic violence.

(Gabriel Campanario / The Seattle Times)
Clay Siegall built Seattle biotech firm Seagen into a $1.6B giant. Then the cops came calling

Here’s a look at some of the most significant milestones in the history of Seagen and how they intersect with Siegall’s personal life.


Seattle Genetics is founded by Henry Perry Fell Jr. and Clay Siegall.


Seattle Genetics begins operations in Bothell.


Seattle Genetics begins publicly trading at $7 a share.


December 7: Seattle Genetics gets $12 million from Genentech as it starts clinical trials of a cancer therapy to treat lymphoma. The company’s shares close at $12.50.


Seattle Genetics’ drug to treat lymphoma, Adcetris (brentuximab vedotin), receives FDA approval.



May: Siegall divorces his first wife.

October: Siegall accused of using cocaine with banker Sage Kelly.

Siegall begins a relationship with the woman who would become his second wife.


Siegall buys a chateau-style mansion in Woodway for $8 million.

Seagen stock goes up more than 50% on the strength of Adcetris, its flagship drug for the treatment of Hodgkin’s lymphoma, a cancer of the lymphatic system that can spread to the lungs, liver or bone marrow.


Seattle Genetics acquires fellow Puget Sound area biotech Cascadian Therapeutics, a deal that brought breast cancer treatment expertise into its portfolio.


August: Siegall and his second wife are married.

September: Siegall’s second wife calls 911 on him for the first time.


Siegall becomes the highest-paid CEO in Washington, receiving $16.5 million.

Seagen receives billions in investment from Merck.

October: Seattle Genetics rebrands its corporate identity and becomes Seagen.


February: Siegall and his second wife file for divorce.

March: Siegall’s second wife calls 911 about Nordstrom items returned without her permission.

May: Siegall’s second wife calls 911 to get access to their home.

July: The couple gets back together and dismisses the divorce.


April 23: Siegall is arrested for allegedly pushing his second wife. 

May 5: Siegall takes a leave of absence. 

May: Seagen reports 27% sales increase over the same period in 2021.

May 16: Siegall resigns as CEO of Seagen. The 3,000-employee company appoints Chief Medical Officer Roger Dansey as interim CEO. Seagan’s stock closes at $142.54.