Collegium Pharmaceutical Inc said on Tuesday its abuse-deterrent painkiller won full marketing approval from U.S. health regulators.

The drug, Xtampza ER, won a tentative approval in November, but full approval was contingent on the outcome of a lawsuit filed by Purdue Pharma against Collegium.

Purdue Pharma, which has also developed abuse-deterrent versions of the commonly prescribed and often-abused painkiller Oxycontin, claimed that Xtampza infringed some of its patents.

However, the District Court of Massachusetts in February ruled in favor of Collegium.

Xtampza ER is a long-acting oral opioid painkiller meant to be taken after a meal for maximum effect.