British speciality pharmaceutical firm Indivior (LON: INDV) has said that it will appeal the US court ruling that Indian generic drug maker Dr Reddy's (NSE: DREDDY) had not breached its patents, Reuters reported on Friday.

As a consequence of the ruling, Indivior faces potentially losing market space to a rival to the company's Suboxone Film opioid addiction treatment. The company now has no way to stop Dr Reddy's from manufacturing and marketing a generic alternative to Suboxone Film in the United States.

The company's previous average market share of Suboxone Film in the United States was 61% in 2016 and it accounted for 80% of Indivior's total revenues last year.

Indivior said in a statement that while it could not quantify the exact financial impact of generic alternatives to Suboxone Film on revenues, it: "could potentially result in a rapid and material loss of market share for Suboxone Film in the US."

According to Reuters, the company suggested that if pharmacies were to replace Suboxone Film with a generic rival without direct consultation with each patient, it could result in the British firm's treatment losing as much as 80% of its market share "within a matter of months".