A new lawsuit accuses Amgen Inc. of hampering competition and maintaining monopoly prices for its blockbuster prescription drug Enbrel, which is used to treat adults with rheumatoid arthritis.

Glasser and Glasser, Hagens Berman Sobol Shapiro and Lowey Dannenberg filed the class action lawsuit Tuesday on behalf of two nonprofit corporations doing business under the name CareFirst BlueCross BlueShield.