Sept 1 (Reuters) – The U.S. Federal Trade Commission (FTC) has allowed Amgen (AMGN.O) to continue its $27.8 billion acquisition of Horizon Therapeutics (HZNP.O), while preventing the drugmaker from using anticompetitive tactics to extend the market dominance of two Horizon drugs.

The agreement, announced on Friday, ends months of uncertainty over the deal since the FTC in May filed a lawsuit over concerns that Amgen would leverage its drugs to secure favorable insurance coverage terms for Horizon’s thyroid eye disease treatment Tepezza and gout drug Krystexxa.

Under the FTC settlement, Amgen is prohibited from bundling any of its products with Tepezza or Krystexxa, and from using any product rebate or contract term to exclude or disadvantage products that would compete with those drugs.

It also prevents Amgen from buying any competitors to the two Horizon drugs without the FTC’s permission.

“While the companies do not have drugs that directly compete with one another, Commission staff focused on the deal rationale and assessed how the acquisition would change the combined firm’s power and incentive to thwart competition,” FTC Chair Lina Khan said in a statement.

Amgen in a statement said it had consistently stated in the past that it had no reason, or ability, to bundle the two Horizon drugs with any of its products.

“This narrow assurance, formalized in the consent order with the FTC, will have no impact on Amgen’s business,” the drugmaker said.

However, the settlement could become a hurdle for future deals in the sector, analysts said.

Wells Fargo analyst Mohit Bansal said he believed that the FTC is now scrutinizing bigger deals more, and added that he expected drugmakers would want to stay under the radar with smaller acquisitions.

The FTC filed the lawsuit on May 16 in a rare move to block a large pharmaceutical deal, but suspended its challenge in late August, enabling the agency to consider whether it should settle the case.

The lawsuit had raised concerns over increased oversight on mergers and acquisitions in a sector that often turns to consolidation to power future growth as patents on older treatments expire.

Consolidation in the industry has given companies the power to engage in exclusionary practices that can cause prices for essential medications to surge, the FTC said.

“The bundling and exclusionary rebating practices at issue in this matter highlight deeper concerns about how pharmaceutical companies and pharmacy benefit managers may work together to deprive Americans of access to affordable drugs,” said Khan.

The companies expect the deal to close early in the fourth quarter.

Horizon’s shares rose 2.5% in morning trading. Shares of Seagen (SGEN.O), which is in the process of being acquired by Pfizer (PFE.N), rose 1.5%.

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