(Adds details on Suboxone market share decline, DoJ talks)
July 31 (Reuters) - Drugmaker Indivior Plc reported a 14% rise in quarterly profit on Wednesday, as its best-selling opioid addiction drug Suboxone lost market share to generic rivals at a slower pace than the company's previous modelling had expected.
The maker of drugs that treat opioid addiction posted a pretax profit of $89 million in the second quarter ended June 30 from $78 million a year earlier.
The company's shares were seen up 10%, according to premarket indicators.
Revenue fell nearly 20% to $215 million in the quarter due to the expected decline in market share for Suboxone, but Indivior reaffirmed that it expects 2019 revenue to be between $670 million and $720 million.
The company said U.S. net revenue declined 12% primarily due to Suboxone share loss to generic competitors, "albeit at a lower rate than suggested by historical industry analogues".
Indivior, which gets 80% of its sales from the United States, had gained from the government's stepped up efforts to combat an opioid overdose epidemic that led to nearly 50,000 deaths in 2017.
However, worries of declining prospects for its blockbuster drug Suboxone with the arrival of cheaper alternatives and a $3 billion fine from the U.S. Department of Justice for illegally marketing Suboxone, pummelled shares down 85% over the last 12 months.
Indivior said on Wednesday it believes that it has "strong defences" to the U.S. government's charges and will "vigorously" defend itself. (Reporting by Justin George Varghese in Bengaluru; Editing by Shounak Dasgupta)