Amgen Lays Off 350 Employees Following $27.8B Horizon Acquisition

Pictured: Amgen's office in Tampa, Florida/iStock,

Pictured: Amgen’s office in Tampa, Florida/iStock,

JHVEPhoto/Getty Images

In its most recent round of layoffs this year, the California-based biopharma company is letting go of 350 former Horizon Therapeutics staff whose roles overlap with existing positions at Amgen.

Pictured: Amgen’s office in Florida/iStock, JHVEPhoto

Amgen is letting go of 350 employees following its $27.8 billion acquisition of Horizon Therapeutics, according to several media reports on Tuesday.

The layoffs will affect Horizon roles that overlap with existing teams at Amgen, a company spokesperson told BioSpace in an email. The employees will be informed of their termination this week and the separations will start taking effect on Dec. 30 and continue throughout 2024.

“We do not take these decisions lightly, and we appreciate the contributions of those employees being impacted. We will treat them with respect and offer support through the process,” the spokesperson said.

More than 80% of Horizon’s staff will be absorbed into Amgen roles “reflecting the knowledge and capabilities we need to continue serving patients suffering from rare diseases,” according to the spokesperson. At the end of 2022, Horizon had more than 2,100 employees, according to an SEC filing.

There have been other Amgen layoffs this year. The first came in January 2023, when the company set in motion organizational changes to “better manage against industry headwinds,” a company spokesperson told BioSpace at the time. Three hundred employees lost their jobs in that job-cutting round.

Amgen followed this up by terminating 450 employees in March and letting go four more staffers from its San Francisco campus in July.

Tuesday’s layoffs come weeks after Amgen finally closed its acquisition of Horizon. The buyout was first announced in December 2022 and was quickly met with antitrust and political pushback. In January 2023, Sen. Elizabeth Warren (D-MA) wrote to the Federal Trade Commission (FTC), urging it to “carefully scrutinize” biopharma mergers that could potentially “threaten competition, reduce innovation, or increase costs” of medicines.

Warren specifically named Amgen and Horizon in her letter, saying that the acquisition “presents numerous antitrust and price gouging concerns.”

The FTC soon filed a lawsuit seeking to block the deal from closing. Specifically, the agency raised concerns of “cross-market bundles or bundled rebates,” a negotiation strategy that allegedly takes advantage of Amgen’s products to secure better formulary placements for Horizon’s treatments.

Amgen and Horizon called these concerns “entirely speculative” in a statement and launched their own countersuit in July 2023. The companies questioned the constitutionality of the FTC’s efforts, particularly as the watchdog was seeking to hold hearings in an administrative court.

A month later, the FTC said that it was temporarily withdrawing its lawsuit and the agency formally cleared Amgen’s Horizon acquisition in September 2023. Under the consent order, Amgen cannot bundle any of its products with Horizon’s thyroid eye disease treatment Tepezza (teprotumumab-trbw) or chronic refractory gout medicine Krystexxa (pegloticase).

Amgen is also prohibited from offering product rebates or contract terms to better position either Horizon drug, or to disadvantage any competing products.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. He can be reached at or

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. Reach out to him on LinkedIn or email him at or