DUBLIN—The two major pharma companies with prescription drug treatments for dry eye disease (DED)—Allergan plc (NYSE: AGN) and Shire plc (LSE: SHP, NASDAQ: SHPG)—are now involved in a lawsuit related to the marketing of their drugs, Restasis and Xiidra, respectively.

Shire, which received FDA approval for Xiidra in July 2016, filed the lawsuit in which it claims Allergan is violating antitrust laws, according to the court filing, in U.S. District Court in Newark, N.J.

In its suit, Shire said that “Allergan’s anticompetitive scheme” is denying patients covered by Medicare Part D prescription drug plans access to Xiidra, according to the court filing. “Through a combination of anticompetitive bundling and exclusive dealing arrangements, Allergan is coercing Part D plans representing over 70 percent of the Part D market for prescription DED medications to effectively exclude Xiidra from, or severely restrict Xiidra on, their formularies, while at the same time maintaining Restasis… on a ‘preferred’ formulary tier,” the lawsuit stated.

In addition, the lawsuit noted that Shire believes “Allergan’s scheme also has severely limited and will continue to limit the growth of the Part D market for DED medications. Restasis is approved to treat a limited subset of the DED population. Xiidra, on the other hand, is approved to treat all of the signs and symptoms of DED and, therefore, can be prescribed to treat a much larger population of DED patients.”

Shire is asking the court to permanently enjoin “the anticompetitive, predatory and/or exclusionary conduct of Allergan” and that Shire be awarded its costs for bringing this action, including reasonable attorneys’ fees, and “other and further relief as this court deems just and proper.”

Allergan disputes the claims in the lawsuit. “There is no merit to this lawsuit,” a spokesman said. He added, “Allergan operates in accordance with all CMS Medicare Part D policies and regulations. In our negotiations with Medicare Part D sponsors, we are competing on value and price, and competition in the chronic dry eye therapeutic market has driven pricing down for patients and payers in Medicare Part D and commercial plans.”