Bothell-based Seagen may be acquired by pharma giant Merck in a deal valued at $40 billion, The Wall Street Journal reported Wednesday. 

Talks started in late June, and the acquisition could happen within the next few weeks, according to The Journal. Seagen, previously known as Seattle Genetics, is Washington’s largest biotechnology company.

Reached by The Seattle Times, Seagen declined to comment on the possible acquisition. There is no guarantee the two companies will reach a deal. But if they do, it could be the year’s largest health care acquisition. The possible acquisition value also falls just below Elon Musk’s Twitter bid of $44 billion.

The talks come after the resignation of Seagen’s longstanding CEO Clay Siegall in May amid allegations of domestic violence at his Edmonds-area home. The company’s Chief Medical Officer Roger Dansey is serving as interim CEO while the board of directors searches for a replacement.

Siegall was arrested in late April, days before the company’s earnings call with investors, after reports that he allegedly pushed his wife, who has since filed a protection order against him. Charges have not yet been filed.

New Jersey-based Merck has a market value of $236 billion, well above Seagen’s valuation of $33 billion. The acquisition could draw antitrust scrutiny from the Federal Trade Commission.

Seagen, which develops and commercializes cancer drugs, saw its shares rise after news of the possible bid. The acquisition could expand Merck’s portfolio of cancer drugs.

Merck and Seagen have existing collaborations, including development of a breast cancer treatment. Merck agreed to pay Seagen $600 million and bought 5 million shares for $1 billion for a joint breast cancer-treatment agreement.