Pfizer Completes Acquisition of Seagen

Pfizer Completes Acquisition of Seagen

NEW YORK, December 14, 2023 Pfizer Inc. (NYSE: PFE) today announced the successful completion of its acquisition of Seagen Inc. (NASDAQ: SGEN), a global biotechnology company that discovers, develops and commercializes transformative cancer medicines. Pfizer completed its acquisition of all outstanding common stock of Seagen for $229 in cash per share, for a total enterprise value of approximately $43 billion.

Cancer remains a leading cause of death, and one in three people in the U.S. will receive a cancer diagnosis in their lifetime. With one of the largest investments in Pfizer s history, we are going all in on cancer with the goal of delivering breakthroughs that drastically improve the lives of people with cancer, said Dr. Albert Bourla, Pfizer Chairman and Chief Executive Officer. With Seagen s proprietary, world-leading Antibody-Drug Conjugate (ADC) technology, together with the scale and strength of Pfizer s capabilities and expertise, we are poised to change the cancer treatment paradigm. We believe Oncology will be a significant growth driver for Pfizer and contribute meaningfully to the achievement of our near- and long-term financial goals.

Seagen is a world-leader in ADC technology, a transformative modality that is emerging as a powerful tool across a broad range of cancers designed to preferentially kill cancer cells and limit off-target toxicities. With the addition of Seagen s four in-line medicines, ADCETRIS (brentuximab vedotin), PADCEV (enfortumab vedotin), TIVDAK (tisotumab vedotin) and TUKYSA (tucatinib), Pfizer s industry-leading Oncology portfolio now includes over 25 approved medicines and biosimilars across more than 40 indications, including nine medicines that are either blockbuster or have the potential to be blockbuster.

With the addition of Seagen, Pfizer s Oncology pipeline has doubled in size with 60 programs spanning multiple modalities, including ADCs, small molecules, bispecifics and other immunotherapies. Moving forward, Pfizer will leverage its leading protein engineering and medicinal chemistry capabilities to advance Seagen s ADC technology, unlocking potential novel combinations and next-generation biologics.

This is a great day for Pfizer, and, more importantly, for people living with cancer, as we bring together the game-changing science and top talent of Seagen and Pfizer to form a leading

Oncology organization, said Chris Boshoff, Chief Oncology Officer and Executive Vice President, Pfizer. Driven by science and a passion for improving and extending patients lives, together, we will work with urgency towards our common purpose to deliver transformative cancer medicines and bring new hope to people living with cancer everywhere.

As previously disclosed, to address U.S. Federal Trade Commission concerns, Pfizer has chosen to irrevocably donate the rights of royalties from sales of Bavencio (avelumab) in the U.S. to the American Association for Cancer Research (AACR). This unrestricted donation will support AACR in its mission to prevent and cure cancer through research, education, communication, collaboration, science policy, and funding for cancer research.

Guggenheim Securities, LLC served as Pfizer s financial advisor and Wachtell, Lipton, Rosen & Katz and Arnold & Porter Kaye Scholer LLP served as Pfizer s legal advisors. Centerview Partners LLC served as Seagen s financial advisor and Sullivan & Cromwell LLP served as Seagen s legal advisor. MTS Health Partners also provided financial advice to Seagen.

Prescribing Information for Legacy Seagen Medicines

Please see full Prescribing Information for ADCETRIS (brentuximab vedotin).

Please see full Prescribing Information for PADCEV (enfortumab vedotin).

Please see full Prescribing Information for TIVDAK (tisotumab vedotin).

Please see full Prescribing Information for TUKYSA (tucatinib).

About Pfizer Oncology

At Pfizer Oncology, we are at the forefront of a new era in cancer care. Our industry-leading portfolio and extensive pipeline includes game-changing mechanisms of action to attack cancer from multiple angles, including antibody-drug conjugates (ADCs), small molecules, bispecifics and other immunotherapies. We are focused on delivering transformative therapies in some of the world s most common cancers, including breast cancer, genitourinary cancer and hematologic malignancies, as well as melanoma, gastrointestinal, gynecological and thoracic cancers, which includes lung cancer. Driven by science, we are committed to accelerating breakthroughs to extend and improve patients lives.

About Pfizer: Breakthroughs That Change Patients Lives

Disclosure Notice : The information contained in this press release is as of December 14, 2023. Pfizer assumes no obligation to update forward-looking statements contained in this release as the result of new information or future events or developments.

A further description of risks and uncertainties can be found in Pfizer s Annual Report on Form 10-K for the fiscal year ended December 31, 2022 and in its subsequent reports on Form 10-Q, including in the sections thereof captioned Risk Factors and Forward-Looking Information and Factors That May Affect Future Results , as well as in its subsequent reports on Form 8-K, all of which are filed with the U.S. Securities and Exchange Commission and available at www.sec.gov and www.pfizer.com.

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