Metsera, a US firm specialising in obesity treatments, has been the subject of escalating offers from US pharma giant Pfizer and Novo Nordisk, which makes the weight-loss drug Wegovy and the antidiabetic medication Ozempic.

In a press release Friday, Metsera said Pfizer had made an improved offer to acquire it for up to US$86.25 per share, in a deal worth around US$10 billion.

Metsera said its board “unanimously recommends that… stockholders approve the adoption of the amended Pfizer merger agreement and approve the merger.”

It added that it expected to close the deal “promptly” after a shareholder meeting on Nov 13.

Pfizer’s latest offer would double its valuation compared to an initial deal the companies struck in September, which triggered a counteroffer from Novo Nordisk that spiralled into a price war.

The Danish firm said Saturday that it “does not intend to make an increased offer to acquire Metsera.”

The company “will continue to assess opportunities for business development and acquisitions that… further its strategic objectives,” it said.

The Novo Nordisk sale had drawn scrutiny over potential antitrust implications.

Metsera said the US Federal Trade Commission had called it to discuss “potential risks from proceeding with the proposed Novo Nordisk structure under US antitrust laws.”

The call strengthened the board’s conclusion that the Novo Nordisk deal “presents unacceptably high legal and regulatory risks… compared to the proposed merger with Pfizer.”

Novo Nordisk said it believed that its prospective deal was “compliant with antitrust laws.”

The World Health Organization says more than one billion people worldwide lived with obesity, and more than 800 million lived with diabetes as of 2022.