Amgen Completes $27.8B Horizon Acquisition Following FTC Challenge

Amgen HQ sign_iStock, JHVEPhoto

Pictured: Amgen headquarters/iStock, JHVEPhoto

Amgen has finally completed its $27.8 billion buy of Horizon Therapeutics. After a 10-month acquisition process was slowed down in court over antitrust concerns from the Federal Trade Commission, the California company proclaimed victory Friday with the completion of the deal. 

Dublin’s High Court was the final hurdle for the deal, as Horizon is based in Ireland, with most of its team in Chicago. On Thursday, the court gave its stamp of approval. The approving judge was satisfied that all criteria had been met for the takeover and there were no objections to the proposal, with 99.89% of shareholders voting in favor of the buy. 

The biggest obstacle to the deal came from the FTC. However, in September 2023, the agency gave clearance to Amgen to proceed with the acquisition—but with strings. Under a consent order agreement, Amgen is prohibited from bundling any of its products with Horizon’s Tepezza or Krystexxa, which the FTC contends would stifle competition. 

Amgen denied the claims and stated the objective of the acquisition was to expand its rare disease portfolio. To assuage the FTC’s concerns, Amgen signed an agreement prohibiting it from bundling any of its products with Tepezza or Krystexxa. 

The deal brings in seven products already approved in the U.S. along with a healthy pipeline of assets already in clinical trials. Demand for its key drugs—Tepezza, Krystexxa and Uplizna—increased second-quarter revenues for 2023 by 8% over the prior year to bring in $945 million, exceeding estimates. Tepezza is its biggest seller with $445.5 million in sales in the second quarter of this year.  

Amgen’s Horizon acquisition is the biggest to close this year. Pfizer continues to duke it out with the FTC over its massive $43 billion buy of Seattle-based Seagen. In July 2023, Pfizer announced the commission had requested additional information on the acquisition, which would further delay the deal. The transaction is expected to close by the end of the year, or in early 2024, subject to regulatory approval. The companies have also sought approval from the European Commission. 

This week, a coalition of pharma companies banded together to push back against the overhaul of antitrust guidelines. The 31-member group—which includes AbbVie, Amgen, Gilead, Merck and Novartis—is advocating for “pro-innovation” mergers and acquisitions in the pharma sector. 

Kate Goodwin is a freelance life science writer based in Des Moines, Iowa. She can be reached at and on LinkedIn.   

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