Pfizer’s Seagen Takeover Plan Faces Further Antitrust Scrutiny

Pfizer Inc.’s proposed $43 billion takeover of Seagen Inc. will undergo an in-depth antitrust review by the Federal Trade Commission.

Seagen disclosed in a regulatory filing that both companies received a so-called second request seeking additional information on the deal from the antitrust agency. In June, the companies withdrew their filing and submitted it again to give the FTC more time to conduct their initial review.

The request is normal in major deals, though it could signal potential antitrust difficulties. It may lengthen the review period by months or years, depending on its complexity. The companies still expect ...