The suit, the first time since 2009 that the FTC has tried to block a drug company merger, reflects Chair Lina Khan's strong interest in antitrust action. In announcing the suit, the agency said that by fighting monopoly powers it aimed to tame prices and improve patients' access to cheaper products.

The FTC's action is a "shot across the bow for the pharmaceutical industry," said Robin Feldman, a professor and drug industry expert at the University of California College of the Law-San Francisco. David Balto, a former FTC official and attorney who fought the 2019 Bristol-Myers Squibb-Celgene and 2020 AbbVie-Allergan mergers, said FTC's action was long overdue.

The Horizon-Amgen merger would "cost consumers in higher prices, less choice, and innovation," he said. "The merger would have given Amgen even more tools to exploit consumers and harm competition."

The FTC also announced an expansion of a yearlong investigation of the PBMs, saying it was looking at two giant drug-purchasing companies, Ascent Health Services and Zinc Health Services. Critics claim the PBMs set up these companies to conceal profits.

When Amgen announced its purchase of Horizon in December — the biggest biopharma transaction in 2022 — it showed particular interest in Horizon's drugs for thyroid eye disease (Tepezza) and severe gout (Krystexxa), for which the company was charging up to $350,000 and $650,000, respectively, for a year of treatment. The complaint said the merger would disadvantage biotech rivals that have similar products in advanced clinical testing.

Amgen could promote the Horizon drugs through "cross-market bundling," the FTC said. That means requiring PBMs to promote some of Amgen's less popular drugs — the Horizon products, in this case — in exchange for Amgen offering the PBMs large rebates for its blockbusters. Amgen has nine drugs that each earned more than $1 billion last year, according to the complaint, the most popular being Enbrel, which treats rheumatoid arthritis and other diseases.

The three biggest PBMs negotiate prices and access to 80% of prescription drugs in the U.S., giving them enormous bargaining power. Their ability to influence which drugs Americans can get, and at what price, enables the PBMs to obtain billions in rebates from drug manufacturers.

"The prospect that Amgen could leverage its portfolio of blockbuster drugs to gain advantages over potential rivals is not hypothetical," the FTC complaint states. "Amgen has deployed this very strategy to extract favorable terms from payers to protect sales of Amgen's struggling drugs."

The complaint noted that biotech Regeneron last year sued Amgen, alleging that the latter's rebating strategy harmed Regeneron's ability to sell its competing cholesterol drug, Praluent. Amgen's Repatha generated $1.3 billion in global revenue in 2022.

It "may be effectively impossible" for smaller rivals to "match the value of bundled rebates that Amgen would be able to offer" as it leverages placement of the Horizon drugs on health plan formularies, the complaint states.

Business analysts were skeptical that the FTC action would succeed. Until now the commission and the Department of Justice have shied away from challenging pharmaceutical mergers, a precedent that will be hard to overcome.

Research on the impact of mergers has shown that they often benefit shareholders by increasing stock prices, but hurt innovation in drug development by trimming research projects and staffing.

Waves of consolidation shrank the field of leading pharma companies from 60 to 10 from 1995 to 2015. Most of the mergers in recent years have involved "big fish buying up lots of little fish," such as biotech companies with promising drugs, Feldman said.

The giant Amgen-Horizon merger is an obvious exception, and therefore a good opportunity for the FTC to demonstrate a "theory of harm" around drug industry bundling maneuvers with PBMs, said Aaron Glick, a mergers analyst with Cowen & Co.

But that doesn't mean the FTC will win.

Amgen may or may not engage in anti-competitive practices, but "a separate question is, how does this lawsuit fit under current antitrust laws and precedent?" Glick said. "The way the law is set up today, it seems unlikely it will hold up in court."

The FTC's argument about Amgen's behavior with Horizon products is hypothetical. The Regeneron suit against Amgen, as well as other, successful lawsuits, suggests that rules are in place to suppress this kind of anti-competitive behavior when it occurs, Glick said.

The judge presiding over the case in U.S. District Court in Illinois is John Kness, who was appointed by then-President Donald Trump and is a former member of the Federalist Society, whose membership tends to be skeptical of antitrust efforts. The case is likely to be settled by Dec. 12, the deadline for the merger to go through under current terms.

Amgen sought to undercut the government's case by agreeing not to bundle Horizon products in future negotiations with pharmacy benefit managers. That promise, while hard to enforce, might get a sympathetic hearing in court, Glick said.

Related: FTC to examine business practices of several large PBMs

Still, even a loss would enable the FTC to shed light on a problem in the industry and what it sees as a deficiency in antitrust laws that it wants Congress to correct, he said.

The day after suing to stop the merger, the FTC announced it was pushing further into an investigation of pharmacy benefit managers that it began last June. The agency demanded information from Ascent and Zinc, the two so-called rebate aggregators — drug purchasing organizations set up by PBMs Express Scripts and CVS Caremark.

At a May 10 hearing, Eli Lilly & Co. CEO Dave Ricks said that most of the $8 billion in rebate checks his company paid last year went to rebate aggregators, rather than to the PBMs directly. A "big chunk" of the $8 billion went overseas, he said. Ascent is based in Switzerland, while Emisar Pharma Services, an aggregator established by PBM OptumRx, is headquartered in Ireland. Zinc Health Services is registered in the U.S.

Critics say the aggregators enable PBMs to obscure the size and destination of rebates and other fees they charge as intermediaries in the drug business.

The PBMs say their efforts reduce prices at the pharmaceutical counter. Testimony in Congress and in FTC hearings over the past year indicate that, at least in some instances, they actually increase them.

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