Pfizer has announced that it has filed a lawsuit against Metsera, its Board of Directors and Novo Nordisk.
The lawsuit has been filed in the Delaware Court of Chancery.
The suit claims that Metsera violated its merger agreement by deeming Novo Nordisk's $8.5bn offer for the US obesity drug developer a "superior proposal".
The Danish drugmaker's offer had aimed to overturn a previously agreed deal between Pfizer and Metsera’s board that was valued at up to $7.3bn.
The suit alleges that Novo Nordisk's bid is "an illegal attempt by a company with a dominant market position to suppress competition and uses an unprecedented structure designed to deliberately evade antitrust review."
Pfizer has also asked the Delaware court to issue a temporary restraining order preventing Metsera from terminating the agreement.
On Friday, Pfizer confirmed that its deal had been cleared by the US Federal Trade Commission, nearly a week earlier than expected.
All regulatory approvals in respect of Pfizer’s acquisition of Metsera have been obtained and Pfizer has said it is ready to complete the transaction shortly following the Metsera stockholder meeting on November 13th.
Pfizer, which currently lacks a weight-loss therapy, is seeking entry into the rapidly expanding obesity market, projected to reach $150bn by the early 2030s.
The company has struggled to advance its own candidates and aims to counter declining COVID-related revenue and upcoming patent losses.
Novo Nordisk, the maker of Wegovy and Ozempic, is looking to recover market share lost to Eli Lilly, whose Zepbound and Mounjaro have delivered stronger clinical outcomes.
Metsera’s pipeline includes investigational GLP-1 and amylin-based therapies that analysts estimate could achieve peak sales of around $5bn.
Pfizer has said it “is taking this action to enforce and preserve its rights under the merger agreement."
"Metsera’s and its Directors’ actions, as well as those of Novo Nordisk, are in clear violation of their respective contractual and legal obligations."
"We are confident in the merits of our case and look forward to presenting it to the Court.”