Publicis Health had called Attorney General Maura Healey's lawsuit an unprecedented attempt to sue an advertising agency over a manufacturer's marketing of its products. It called her allegations conclusory and said she mischaracterized documents.
But Suffolk County Superior Court Judge Brian Davis said Healey brought "non-speculative" claims under the state's public nuisance law and consumer protection statute that could move forward.
He pointed to allegations in Healey's complaint, filed in May, that he said showed Publicis "played an integral part in developing marketing strategies" to boost opioid sales from 2010 to 2019.
Davis said those marketing campaigns were designed to get doctors "to use more OxyContin, prescribe higher doses and prescribe it for longer periods of time for patients."
Healey said she was pleased Davis "rejected Publicis' attempt to skirt responsibility for its marketing campaigns."
Publicis said in a statement its work was "completely lawful" and that nothing it did was deceptive. Its lawyer, David Anders of Wachtell, Lipton, Rosen & Katz, argued that Purdue, not Publicis, dictated the content of its marketing.
"No advertiser has ever been held responsible in these circumstances," he said.
More than 3,300 lawsuits have been filed by largely state and local governments seeking to hold drug companies responsible for an epidemic the U.S. government says led to nearly 500,000 overdose deaths from 1999 to 2019.
A bankruptcy judge in August approved a settlement by Purdue and its wealthy Sackler family owners of the claims against them that the company values at more than $10 billion.
Consulting company McKinsey & Co separately agreed to pay $641 million to resolve claims by various states that it helped Purdue and other drugmakers design marketing plans and boost painkiller sales.
(Reporting by Nate Raymond in Boston; Editing by Richard Chang)
By Nate Raymond
