Pfizer Inc. (NYSE: PFE) filed a second lawsuit against Metsera Inc., its controlling stockholders, and Novo Nordisk A/S (NYSE: NVO) in the U.S. District Court for the District of Delaware, the company announced.

The lawsuit alleges that Novo Nordisk's proposal to acquire Metsera violates federal antitrust laws, including Section 7 of the Clayton Act, Section 1 of the Sherman Act, and Section 2 of the Sherman Act. Pfizer claims the transaction would harm competition in GLP-1 drug markets.

The complaint names Metsera's controlling stockholders as co-defendants: Validae Health L.P., Population Health Partners GP LLC, ARCH Venture Fund XII L.P., and ARCH Venture Fund XIII L.P. Pfizer alleges these entities conspired with Metsera and Novo Nordisk in anticompetitive activities.

Pfizer seeks injunctive relief to prevent the proposed transaction from proceeding. The company stated it aims "to preserve and enhance competition in this important therapeutic area and to stop Novo Nordisk from illegally paying off Metsera and its controlling stockholders."

This represents Pfizer's second legal action regarding the Metsera acquisition. The pharmaceutical company previously filed a separate lawsuit in Delaware Court of Chancery against Metsera, its board of directors, and Novo Nordisk, along with a motion for a temporary restraining order to prevent Metsera from terminating their merger agreement.

The lawsuits center on competition in the GLP-1 drug market, which treats obesity, diabetes, and other metabolic conditions. Information is based on Pfizer's press release statement.