Pfizer has received early U.S. antitrust clearance more than a week early for its proposed $7.3 billion Metsera acquisition, which has been called into question by Novo Nordisk's higher $8.5 billion offer.

Pfizer has filed a lawsuit against Metsera and Novo Nordisk, claiming Metsera violated its merger agreement by entertaining Novo's superior bid offer. Pfizer seeks a court order to prevent Metsera from terminating their agreement,

For Novo, it marks the boldest move yet for recently appointed CEO Maziar Mike Doustdar. In response to a slowdown in sales growth for its blockbuster obesity drug Wegovy, Doustdar has already announced plans to lay off about 9,000 employees worldwide and shutter the company’s cell therapy R&D work.

The move, announced Thursday, escalates the competition between the two pharmaceutical giants for a critical advantage in the highly lucrative weight-loss drug market.

From a more company-specific point of view, Pfizer has also agreed to buy Metsera. This will help the company deal with upcoming patent cliffs, in which older drugs lose their patent protections. The acquisition was necessitated by the fact that Pfizer's own drug pipeline was looking a little weak.