President Trump claimed credit Thursday for cutting prices on popular weight-loss drugs by Eli Lilly and Novo Nordisk. Sorry to spoil the celebration, but market competition probably would achieve the same result. Consider the battle between Pfizer and Novo to buy Metsera, an obesity-drug startup.

President Donald Trump, joined by members of the pharmaceutical industry and administration officials, delivers remarks on lowering drug prices in the Oval Office on ThursdayPresident Donald Trump, joined by members of the pharmaceutical industry and administration officials, delivers remarks on lowering drug prices in the Oval Office on Thursday

Pfizer appeared to win the bidding war on Friday with an unfortunate assist from the Trump Federal Trade Commission. But the real story is pharma competition to grab a share of the weight-loss drug boom.

Novo Nordisk kicked off the weight-loss race in 2018 with its GLP-1 drug Ozempic. Lilly followed years later with its own GLP-1, which is marketed as Mounjaro for type 2 diabetes and Zepbound for obesity. Lilly’s drug was somewhat more effective than Novo’s in clinical trials and recently became the world’s best-selling medicine.

Lilly isn’t resting on its success. The drug maker plans to launch a weight-loss pill as soon as next year. It is also testing an experimental once-weekly medication that mimics the hormone amylin and carries fewer side effects than its GLP-1s. Lilly said Thursday that patients on the amylin agonist shed 20% of their weight in a mid-stage trial.

Meanwhile, other drug makers are seeking to break into the market. Trailing Novo and Lilly, Pfizer in September made a $4.9 billion bid to buy Metsera, which is testing several obesity drugs. Metsera’s experimental drugs seem to carry fewer side effects and don’t have to be injected as often as GLP-1s currently on the market, so the hope is that more patients might stick with them. About half of patients quit GLP-1s within a year and then often regain lost weight.

Novo and Pfizer engaged in several rounds of competing bids for the company. Pfizer appeared to prevail on Friday evening with an offer topping $10 billion. Metsera said it decided to accept Pfizer’s offer in part because of a recent call from the Trump FTC warning about potential regulatory risks of tying up with Novo.

FTC Bureau of Competition Director Daniel Guarnera last week sent a letter to Novo and Metsera warning that their deal appeared to be structured to circumvent the agency’s pre-merger review requirements. Mr. Guarnera said closing the deal could result in penalties, including unwinding the transaction and liability for the companies’ boards.

Was the FTC assisting Pfizer? Sure looks that way. Pfizer CEO Albert Bourla recently struck a high-profile deal with Mr. Trump to cut its drug prices in return for a three-year tariff exemption. Pfizer last week also sued to stop the Novo-Metsera acquisition, which it claimed is “one of the most cynical and anticompetitive mergers ever contemplated.”

Pfizer argued that Novo shouldn’t be allowed to buy a potential competitor, but Roche, Amgen, AstraZeneca, Viking Therapeutics and others are developing weight-loss rivals. There’s no guarantee that Metsera’s drugs will succeed in trials. Pfizer knows this since several drugs that it has acquired in recent years have flopped in trials.

The bidding war has nonetheless benefited Metsera investors and could encourage more venture investment in weight-loss therapies. If Mr. Trump wants to boost competition and lower prices, he’ll tell his antitrust cops and drug-price regulators to knock it off.