Pharmaceutical giant Pfizer has sued rival Johnson & Johnson over claims the company forced health care providers and insurers into exclusionary contracts aimed at blocking a competing autoimmune medication Pfizer recently introduced into the market.

Pfizer filed its lawsuit Wednesday in the U.S. District Court for the Eastern District of Pennsylvania, alleging J&J engaged in monopolistic conduct and violated the Sherman Antitrust Act. The lawsuit, which, according to the docket, has been assigned to Judge J. Curtis Joyner, was filed by Cozen O’Connor attorney Robert Fiebach.