With an eye on ADCs, Pfizer buys Seagen for $43B

March 13, 2023

Pfizer and Seagen have entered into a definitive merger agreement under which Pfizer will acquire the ADC technology pioneer for a total enterprise value of $43 billion. 

Together, Pfizer and Seagen will look to accelerate next-gen cancer breakthroughs by combining the power of Seagen’s antibody-drug conjugate (ADC) technology with Pfizer’s capabilities and expertise, according the Pfizer CEO, Albert Bourla.

"Oncology continues to be the largest growth driver in global medicine, and this acquisition will enhance Pfizer’s position in this important space and contribute meaningfully to the achievement of Pfizer’s near- and long-term financial goals," said Bourla.

ADCs, designed to preferentially kill cancer cells and limit off-target toxicities, are emerging as a powerful tool across a broad range of cancers. According to Pfizer, four of the twelve total FDA-approved and marketed ADCs use Seagen technology. This capability has positioned the Washington-based biotech as a prime takeover target.

Rumors about the Pfizer deal were first reported by the WSJ back in late Feb., but before that, talks of a potential $40 billion buyout by Merck circulated in July 2022. Merck had been tied to Seagen since 2020, when the drugmaker made a $1 billion equity investment. By August 2022, however, it was reported that the Merck buyout had stalled over price.

Pfizer and Seagen expect to complete the transaction in late 2023 or early 2024.