Mylan skyrockets after securing a merger with Pfizer's off-patent drug unit

• Shares of Mylan surged more than 20% in early trading on Monday after the EpiPen maker agreed to merge with Pfizer's off-patient drug unit.
• Pfizer shareholders will own 57% of the new company, and the remainder will be owned by shareholders of Mylan, according to a statement from the companies.
• The new drugmaker will be rebranded and renamed, and is expected to generate between $19 billion and $20 billion in annual sales.
• Watch Mylan trade live.

Mylan, the drugmaker behind the life-saving EpiPen, has agreed to merge with Pfizer's off-patient drug unit in a deal that will create a new pharmaceutical company with as much as $20 billion in annual sales.

News of the deal sent shares of Mylan soaring more than 20% in early trading on Monday. Meanwhile, Pfizer slid by about 2%. Pfizer's off-patient drug business operates under the brand Upjohn, and sells well-known medicines such as Lipitor and Viagra.

Pfizer shareholders will own 57% of the new company, and shareholders of Mylan will own he remaining 43%. The boards of both firms unanimously approved the deal, according to a statement from the companies.

"We are creating a new champion for global health," Dr. Albert Bourla, Pfizer's chief executive officer, said in a statement. "By bringing Mylan's growth assets to Upjohn's growth markets, we will create a financially strong company with true global reach."

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The new company will be rebranded and renamed, and Heather Bresch - the chief executive officer of Mylan - is expected to retire after the deal closes in mid-2020. Michael Goettler, the current group president of Upjohn, will serve as CEO of the new company.

Some of the new company's major product lines included Mylan's EpiPen, and Upjohn's Viagra and Lipitor.

This move marks Pfizer second billion-dollar deal this year. In mid-June, the company agreed to purchase Array BioPharma, a biotechnology firm that specializes in cancer drugs, for $11 billion.

Mylan's stock has taken a hit this year as the company continues to grapple with shortages of EpiPen, its life-saving, anti-allergy treatment.

Shares of Mylan were down 33% year-to-date through Friday.