The state attorney general Maura Healey said Publicis Health created a public nuisance from 2010 to 2019 through its work for drugmakers on campaigns to persuade doctors to prescribe more opioids, including to patients who did not need them.
Purdue alone paid Publicis more than $50 million for its work, which continued even after Publicis proposed in 2016 that Purdue shut down its sales force to "fully embrace a deeper-held responsibility" the drugmaker owed the public, Healey said.
"They knew what they were doing was wrong, they made the opioid crisis worse, and they kept cashing Purdue's checks," Healey told reporters in a Zoom meeting. "What they did was wrong. It hurt people. It killed people."
A Publicis Health spokesman said there was no legal basis for the lawsuit, and that the statute of limitations had run out. He also said the company's work was "completely lawful," and limited to implementing Purdue's advertising plan and buying ad space.
The advertising agencies Leo Burnett and Saatchi & Saatchi are among Publicis' other businesses.
Healey's lawsuit filed in a state court in Boston seeks civil penalties and restitution to victims.
It followed agreements this year by the consulting firm McKinsey & Co to pay $641 million to resolve lawsuits by all 50 U.S. states, Washington, D.C., and five U.S. territories over its role in the opioid epidemic.
The U.S. Centers for Disease Control and Prevention has said nearly 500,000 people died from opioid overdoses from 1999 to 2019.
Purdue is operating in bankruptcy. In March, it proposed a restructuring plan that would steer profits to opioid victims, and require members of the Sackler family who own the company to contribute nearly $4.3 billion.
(Reporting by Jonathan Stempel in New York; Editing by Dan Grebler and Bill Berkrot)
By Jonathan Stempel