Aug 8 (Reuters) - The U.S. Justice Department has joined several whistleblower lawsuits against Indivior Plc and Reckitt Benckiser Group PLC, alleging that the drugmakers improperly marketed the opioid addiction treatment Suboxone.
The Justice Department in filings last week in federal court in Abingdon, Virginia, said it was intervening in four separate whistleblower lawsuits related to the Britain-based companies' marketing of Suboxone and the related drug Subutex.
The action came after Indivior, which was spun out of Reckitt in 2014, said last month it was in "advanced discussions" with the Justice Department to resolve an investigation dating back to 2013 related to its marketing practices.
Indivior said it has set aside $438 million to cover legal matters, most of which relates to the investigation. Reckitt has separately reserved 303 million pounds ($390 million) in connection with the investigation.
"We have been cooperating with the DOJ in its investigation for several years, and we remain in advanced discussions about a possible resolution that would render any suit by the department unnecessary," Indivior said in a statement.
Reckitt spokeswoman Patty O'Hayer said on Wednesday that the company "will be presenting our case to the DOJ in the appropriate channels to defend the actions that we believe that we have taken."
The Justice Department declined to comment.
The lawsuits were filed under the False Claims Act, which allows whistleblowers to sue companies on the government's behalf. The government may intervene in the cases, which is typically a major boost for them.
Among the complaints unsealed on Aug. 2 was one filed by former Reckitt employee Ann Marie Williams.
Her 2013 lawsuit alleged the companies marketed unapproved dosages and uses of Suboxone and Subutex and claimed Reckitt made misleading claims to the U.S. Food and Drug Administration to obtain approval for a dissolvable film version of Suboxone.
The lawsuit claimed that as a period of marketing exclusivity granted by the FDA for the tablet form of Suboxone was coming to an end, Reckitt sought U.S. approval of a new patent-protected dissolvable strip version of the drug, which it claimed would be safer and less susceptible to abuse.
But the lawsuit alleges that the film version was inferior to the tablets as it could be more easily diverted for improper purposes and posed an increased risk to children who could accidentally put it in their mouths.
The companies marketed the Suboxone film as "safer" for patients and children than tablets, the lawsuit said. The case is U.S. ex rel. Williams v. Reckitt Benckiser Inc, et al, U.S. District Court, Western District of Virginia, No. 13-cv-00036. (Reporting by Nate Raymond in Boston Editing by Bill Berkrot)