(Reuters) -The U.S. Federal Commerce Fee is anticipated to file a lawsuit as early as Tuesday to dam Amgen Inc (NASDAQ:)’s $27.8 billion deal to purchase Horizon Therapeutics (NASDAQ:) PLC, an individual accustomed to the matter advised Reuters.

Amgen struck a deal final yr to purchase Horizon to strengthen its uncommon illnesses medication portfolio. The corporate has stated it hopes to finish the acquisition within the first half of this yr.

Amgen stated on Monday it wasn’t conscious of any determination made by the company. “We are going to present any applicable updates when we’ve got extra info,” the corporate stated in an announcement.

U.S. Senator Elizabeth Warren, an outspoken critic of company consolidation, wrote to the FTC earlier this yr expressing her issues about pharmaceutical offers together with the Amgen buy of Horizon.

The Democratic Senator stated each Amgen and Horizon Therapeutics “have engaged in brazen value will increase,” together with on Amgen’s Enbrel for arthritis and Horizon’s Krystexxa, a gout medicine.

Amgen stated it disagreed with Warren’s evaluation of the deal.

It’s uncommon for the company to sue to cease a pharmaceutical deal. Lately, the company has normally recognized illnesses the place the merging firms made therapies, and required one of many two medicines to be divested.

The deal would give Amgen two fast-growing medication, the thyroid eye illness remedy Tepezza and Krystexxa. Amgen hopes they will act as a bulwark in opposition to competitors for its blockbuster arthritis drug Enbrel.

Gross sales of Amgen’s Enbrel tumbled 33% year-over-year within the first quarter of 2023 to $579 million.

Each Tepezza and Krystexxa have an orphan drug designation, a standing granted by the U.S. Meals and Drug Administration to encourage improvement of medicine for uncommon circumstances.

Orphan standing additionally means they might seemingly not be among the many medication for which the U.S. authorities’s Medicare program can negotiate decrease drug costs beneath the Biden Administration’s Inflation Discount Act.

    Tepezza, Horizon’s largest promoting drug, noticed gross sales rise 18% to $1.97 billion in 2022 from a yr earlier, however gross sales within the newest quarter fell 19% to $405 million.

    Horizon’s Krystexxa introduced in gross sales of $716 million final yr. They’re forecast to succeed in $1.58 billion by 2028.