British drugmaker Indivior Plc launched a copycat version of its blockbuster opioid addiction drug Suboxone in the United States, just one day after the U.S. Supreme Court cleared the way for its rivals to market generic versions.

Rejecting arguments from Indivior, Chief Justice John Roberts left in force a ruling, set to take effect Tuesday, that lets Dr. Reddy’s put the generic drug on market.

Indivior argued that Dr. Reddy’s should wait until the high court considers whether to hear an appeal in the case.

Indivior has spent over two years fighting multiple legal battles and patent disputes in the United States with companies including Dr. Reddy’s, Teva and Mylan to block them from launching generics.

The drugmaker has said it faces potentially severe losses in market share to copycats in the immediate future.

Suboxone accounted for almost all of the company’s $1 billion in sales last year, and the company said on Feb. 14 that it’s unable to provide financial guidance for 2019 “given uncertainties surrounding how the U.S. market for both Suboxone Film and generic alternatives will ultimately develop.”

The United States accounts for 80 percent of Indivior’s revenue. Indivior ended 2018 with a 53 percent share of the Suboxone film market in the United States, compared to 56 percent in 2017 and 61 percent in 2016.

The appeals court case is Indivior Inc. v. Dr. Reddy’s Laboratories SA 18-2167, U.S. Court of Appeals for the Federal Circuit (Washington).

The company’s authorized generic is being marketed and distributed by Sandoz Inc.