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7 Companies Owned by Pfizer

Pharmaceuticals and Biopharmaceuticals

Pfizer Inc. (PFE) is a global biopharmaceutical company engaged in the discovery, development, manufacture, and sale of medicines and vaccines. The company serves developed and emerging markets, developing biopharmaceutical products to treat a broad range of diseases. Its business spans the following therapeutic areas: internal medicine, oncology, hospital, vaccines, inflammation and immunology, and rare disease.

Pfizer posted net income attributable to common shareholders of $9.6 billion on revenue of $41.9 billion in its 2020 fiscal year (FY), which ended Dec. 31, 2020. The company’s market capitalization was $304.6 billion as of Dec. 4, 2021.

Pfizer traces its origins to 1849, when Charles Pfizer & Co. was founded by Charles Pfizer and Charles Erhart in Brooklyn, N.Y. The company expanded as a private company through the end of the 19th century and into the first part of the 20th century. It became a publicly traded company in 1942. In 1944, Pfizer succeeded in mass-producing penicillin, becoming the largest producer worldwide of what has been called the “miracle drug.”

More recently, the company has been at the forefront in the fight against COVID-19. In 2021, it became the first company to gain full approval from the U.S. Food and Drug Administration (FDA) for its vaccine against COVID-19 after receiving emergency use authorization (EUA) from the agency in December 2020.

Today, Pfizer is one of the biggest pharmaceutical companies in the world. Much of its expansion has been fueled by acquisitions over the past two decades. It acquired Warner-Lambert in 2000 to obtain full access to a blockbuster drug still under patent. Pharmaceutical companies spend significant amounts of money to develop novel drugs. Once patented, these drugs can enable companies to reap huge profits for years before generic drugmakers develop knockoffs of the original drug.

Pfizer’s acquisition strategy in the early 2000s was to acquire companies with patented drugs. Pfizer’s purchases of Warner-Lambert, and then of Pharmacia in 2003, are two examples. But as healthcare costs continued to soar, the market for cheaper generic drugs showed strong potential for growth. As a result, Pfizer began targeting generic drugmakers with attractive drug pipelines, including Hospira in 2015. More recently, the company has been bolstering its pipeline of cancer treatments by acquiring several oncology-focused drug companies.

We look in detail at seven of Pfizer’s major acquisitions below.


  • Type of business: pharmaceuticals
  • Acquisition price: $116 billion (completed)
  • Acquisition date: June 20, 2000 (completed)

Warner-Lambert originated in 1955 out of the combination of William R. Warner & Co. and Lambert Pharmacal Co. The company expanded throughout the rest of the 20th century, primarily through acquisitions—most notably the 1970 acquisition of Parke-Davis, which was the world’s largest drugmaker at one time.

In 1996, Warner-Lambert and Pfizer entered into a co-marketing agreement for Lipitor, a synthetic lipid-lowering agent and the highest-selling drug in the world. Lipitor was the main reason why Pfizer initially launched a hostile takeover bid for Warner-Lambert, which made Lipitor. Pfizer feared that its Lipitor agreement, under which it received half of the profits of sales of the drug, was at stake. Warner-Lambert initially rejected the takeover bid, but after months of court battles, it finally agreed in early February 2000 to be acquired by Pfizer. The deal closed in June 2000, making Pfizer the world’s second-largest and fastest-growing pharmaceutical company.


  • Type of business: pharmaceuticals
  • Acquisition price: $60 billion (completed)
  • Acquisition date: April 16, 2003 (completed)

Pharmacia was formed in April 2000 out of the merger between Pharmacia & Upjohn and Monsanto and its pharmaceutical unit, Searle. At the time of the merger, Searle had an agreement with Pfizer to co-promote Celebrex, a blockbuster arthritis drug that both companies had developed together. Celebrex is a nonsteroidal anti-inflammatory drug used to temporarily relieve pain and inflammation.

Pharmacia completed the planned spinoff of its agricultural subsidiary Monsanto in August 2002. During the month prior to that spinoff, in July 2002, Pfizer agreed to purchase Pharmacia for $60 billion. The deal was finalized in April 2003 and gave Pfizer full rights to Celebrex. The deal came during a time when pharmaceutical companies were struggling to develop new drugs, facing increasing competition from generic drugmakers, and pricing pressures from governments and private buyers. The acquisition also made Pfizer the top pharmaceutical company by revenue in every major market in the world.


  • Type of business: pharmaceuticals
  • Acquisition price: $68 billion (completed)
  • Acquisition date: Oct. 15, 2009 (completed)

Wyeth traces its origins to the establishment of John Wyeth and Brother in Philadelphia by John and Frank Wyeth in 1860. The company’s drug, Ovral, was the leading oral contraceptive in the United States in the late 1960s. It has since been discontinued.

In late January 2009, Pfizer announced that it agreed to purchase Wyeth in a deal valued at $68 billion. Part of the motivation for the Wyeth deal was to soften the blow from a loss in revenue to generic drugmakers that Pfizer expected when the patent for Lipitor ran out in a few years. It would also diversify Pfizer’s portfolio with vaccines and injectable biologic medicines through the addition of two key drugs: Prevnar, a vaccine for infants against pneumococcal disease; and Enbrel, an arthritis drug. Both of those therapeutic areas are considered less vulnerable to generic competition.

Pfizer completed the acquisition of Wyeth in October 2009 for an estimated $67 billion (final figure equaled $68 billion), following approval by U.S. and Canadian antitrust regulators.


  • Type of business: pharmaceuticals and medical devices
  • Acquisition price: $16 billion (completed)
  • Acquisition date: Sept. 3, 2015 (completed)

Hospira became a separate, publicly traded company in 2004 after being spun off by Abbott Laboratories (ABT). Over the next decade, the company became a leader in developing and manufacturing biosimilars, which are knockoffs of more expensive biotech drugs.

Acquiring Hospira’s biosimilars pipeline was one of the main reasons why Pfizer made the bid to purchase the smaller rival in 2015. Pfizer had spent years focusing on acquiring companies that manufactured costly biotech drugs and whose patents had yet to run out. But expectations at the time were that the global market for biosimilars would rise from a few billion dollars to $20 billion over five years. The key driver was a new focus on reducing healthcare costs by governments and healthcare plans. Hospira was also a leading provider of injectable drugs and infusion technologies. The global market for generic sterile injectables was estimated to be worth $70 billion by 2020.


  • Type of business: biopharmaceuticals
  • Acquisition price: $14.3 billion (completed)
  • Acquisition date: Sept. 28, 2016 (completed)

Medivation was founded in 2003 by David Hung, who then took his company public through a reverse merger with a shell company in 2004. A reverse merger occurs when a private company purchases enough shares to control a publicly traded company.

Medivation specialized in developing drugs for the treatment of cancer. The big prize for Pfizer in acquiring the company in 2016 was XTANDI, a drug for treating prostate cancer. XTANDI was already generating about $2 billion in annual sales for Medivation, and analysts were predicting that those sales had the potential to more than double.

The deal also came with a pipeline of other oncology treatments. Pfizer said that Medivation’s assets could potentially benefit from combinations with its own, helping the company to become a leader in the field of oncology.

Array BioPharma

  • Type of business: biopharmaceuticals
  • Acquisition price: $11.2 billion (completed)
  • Acquisition date: July 30, 2019 (completed)

Array BioPharma, a company focused on the discovery and development of targeted small molecule drugs to treat patients with cancer and other diseases, was founded in 1998. The biopharmaceutical company first began collaborating with Pfizer in 2017 on developing cancer drugs.

Two years later, Pfizer paid a high premium to acquire Array BioPharma for approximately $11 billion. The acquisition bolstered Pfizer’s expanding portfolio of cancer treatments, especially through the addition of BRAFTOVI and MEKTOVI. Both drugs are used to treat metastatic melanoma, a type of skin cancer, and other cancers.

Trillium Therapeutics

  • Type of business: biopharmaceuticals
  • Acquisition price: $2.2 billion (completed)
  • Acquisition date: Nov. 17, 2021 (completed)

Trillium Therapeutics, a clinical stage immuno-oncology company that develops therapies for the treatment of cancer, was first incorporated in March 2004 in Canada. In August 2021, Pfizer announced that it had agreed to purchase the Canada-based oncology company for nearly $2.3 billion, representing a 118% premium above the stock’s 60-day weighted average price. Pfizer closed the deal in November 2021 at an aggregate purchase price of $2.2 billion.

In addition to Trillium’s leading scientific talent, Pfizer said that the deal bolsters its pipeline of cancer treatments. Trillium is currently developing two biologics, the molecules TTI-622 and TTI-621, which Pfizer hopes will be able to be used to help treat blood, bone marrow, and lymph node cancers.

Article Sources
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  1. U.S. Securities and Exchange Commission. “Pfizer Inc.: Form 10-K For the Fiscal Year Ended December 31, 2020,” Pages 1–2 (Pages 10–11 of PDF).

  2. U.S. Securities and Exchange Commission. “Pfizer Inc.: Form 10-K For the Fiscal Year Ended December 31, 2020,” Page 51 (Page 61 of PDF).

  3. Pfizer. “Company Timeline: A Legacy of Innovation.”

  4. U.S. Food and Drug Administration. “FDA Approves First COVID-19 Vaccine.”

  5. The Wall Street Journal. “Pfizer Completes Stormy Takeover of Warner-Lambert for $116 Billion.”

  6. U.S. Food and Drug Administration. “Lipitor®,” Page 1.

  7. Pfizer. “2000: Pfizer Joins Forces with Warner-Lambert.”

  8. The New York Times. “Pfizer Gets Its Deal to Buy Warner-Lambert for $90.2 Billion.”

  9. CNN Money. “It’s Official: Pfizer Buys Pharmacia.”

  10. U.S. Food and Drug Administration. “Celebrex (celecoxib) Information.”

  11. Pfizer. “2003: Pfizer and Pharmacia Merger.”

  12. The Wall Street Journal. “Pfizer to Buy Pharmacia for $60 Billion in Stock.”

  13. U.S. Securities and Exchange Commission. “Pfizer Inc.: Form 10-K for the Fiscal Year Ended December 31, 2009,” Page 1 (Page 3 of PDF).

  14. Encyclopedia of Cancer and Society, Volume 1, via Google Books. “Wyeth,” Page 1039.

  15. U.S. Food and Drug Administration. “Drugs@FDA: FDA-Approved Drugs: Ovral.”

  16. U.S. Food and Drug Administration. “Prevnar.”

  17. U.S. Food and Drug Administration. “Enbrel® (etanercept) Label,” Page 2.

  18. Reuters. “Pfizer to Buy Wyeth for $68 Billion.”

  19. Reuters. “Pfizer Completes $67 Billion Deal for Rival Wyeth.”

  20. U.S. Securities and Exchange Commission. “Pfizer Inc.: Form 10-K for the Fiscal Year Ended December 31, 2015,” Page 1 (Page 4 of PDF).

  21. The Wall Street Journal. “Hospira Begins Trading as Part of the S&P 500.”

  22. The Wall Street Journal. “Pfizer to Buy Hospira for $16 Billion.”

  23. Pfizer, via Internet Archive. “Pfizer Completes Acquisition of Hospira.”

  24. U.S. Securities and Exchange Commission. “Pfizer Inc.: Form 10-K for the Fiscal Year Ended December 31, 2016,” Page 1 (Page 5 of PDF).

  25. Reuters. “Exclusive: Medivation Succumbs to Pressure to Explore Sale — Sources.”

  26. U.S. Food and Drug Administration. “XTANDI® (enzalutamide) Capsules,” Page 2.

  27. The Wall Street Journal. “Pfizer to Buy Medivation for $14 Billion.”

  28. Pfizer. “Pfizer Completes Acquisition of Medivation.”

  29. U.S. Securities and Exchange Commission. “Pfizer Inc.: Form 10-K for the Fiscal Year Ended December 31, 2019,” Page 1 (Page 6 of PDF).

  30. The Denver Post. “Boulder’s Array BioPharma to Be Acquired by Pfizer.”

  31. S&P Global Market Intelligence. “Pfizer Ends M&A Silence with $11.4B Array Buy, Bulking Up Oncology Pipeline.”

  32. Pfizer. “Pfizer Completes Acquisition of Array BioPharma.”

  33. Reuters. “Pfizer Makes $10.6 Billion Cancer Bet in Cash Deal for Array BioPharma.”

  34. U.S. Food and Drug Administration. “MEKTOVI® (binimetinib) Tablets,” Page 2.

  35. U.S. Food and Drug Administration. “BRAFTOVI™ (encorafenib) Capsules,” Page 2.

  36. Pfizer. “Pfizer Completes Acquisition of Trillium Therapeutics.”

  37. U.S. Securities and Exchange Commission. “Form 20-F/A: Trillium Therapeutics Inc.,” Page F-6.

  38. Pfizer. “Pfizer to Acquire Trillium Therapeutics Inc.

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