Clay Siegall, the founding CEO of Seagen and its leader for 24 years, is on a leave of absence following an accusation of domestic violence, the company said in a statement Monday.
Seagen’s board began an investigation after an “alleged incident of domestic violence” that occurred recently at Siegall’s home. Siegall denied the allegation and told Seagen he’s going through a divorce. The company has hired a law firm and formed a committee of independent directors to investigate the incident.
In the meantime, Seagen named current chief medical officer Roger Dansey, a former Merck & Co. executive, as its interim CEO pending the investigation's outcome.
“We have high standards for employee conduct, we condemn domestic violence in all its forms, and we are treating these allegations with the utmost seriousness,” said Nancy Simonian, the chair of Seagen’s corporate governance committee, in the company's statement. “At this time, the facts are still uncertain, and our decisions will be guided by the outcome of our investigation.”
Seagen didn’t provide any more details about the incident or how long the investigation might take. In an email, a spokesperson said the board’s priority is to conduct a “thorough investigation” and determine “what is in the best interest of the company and its employees."
“The board and its independent counsel will take the time needed to conduct a thorough, deliberate investigation,” the spokesperson said. “It’s unclear how long this will take, but our intent is to move expeditiously.”

Siegall, a former National Institutes of Health researcher and Bristol Myers Squibb executive, has led Seagen since he cofounded it in 1998 as Seattle Genetics. The company is a pioneering developer of a class of cancer medicines known as antibody drug conjugates, which chemically link a targeting antibody to a tumor-killing toxin.
Seagen was once a small startup that had trouble getting investor support to develop its medicines, which are meant to specifically target tumors while sparing healthy tissue. But over the years its research has helped validate ADCs, which have recently become the focus of industry investment and dealmaking. The company won Food and Drug Administration approval of its first drug, a lymphoma treatment called Adcetris, in 2011, and since secured regulatory clearance of three more cancer medicines.
In the process, Seagen has grown considerably, becoming the largest biotech in the Pacific Northwest. It now has more than 28,000 employees and a market capitalization of over $22 billion, making it one of biotech’s biggest companies — worth more than companies like Alnylam Pharmaceuticals and Incyte. Yet the biotech isn't consistently profitable and still faces long-term questions about its growth.
Like many drugmakers recently, Seagen’s stock price has fallen significantly during the sector’s recent downturn. Competitive pressures are weighing on its future, too. Though the company beat Wall Street forecasts in reporting $383 million in sales this quarter, it reiterated lower financial guidance for 2022 because of competition to its breast cancer drug Tukysa. Shares have lost nearly 40% of their value since they peaked at over $200 apiece in late 2020.
Seagen is counting on upcoming clinical trial readouts, like from a study of its drug Padcev in first-line bladder cancer, to boost investors’ outlook. That effort, at least in the short term, will be led by CMO Dansey, who joined the company in 2018 from Merck and led the registration efforts for the pharma’s top-selling immunotherapy Keytruda in multiple tumor types.
“Seagen is an extraordinary company, and I am deeply committed to continuing our standards of excellence in developing and commercializing transformative medicines,” Dansey said in a statement. “Our strong leadership team is dedicated to working with our exceptional employees around the globe on addressing the unmet needs of cancer patients.”
Seagen shares dipped nearly 3% in premarket trading Monday.