An advertising company that state prosecutors say falsely promoted the drug OxyContin as safe will pay $350 million in the first ever settlement targeting a marketing firm involved in the opioid crisis.

The settlement, which New York Attorney General Letitia James announced Thursday, will be paid by Publicis Health, part of the French media conglomerate Publicis Groupe SA. The company worked with Purdue Pharma from 2010 to 2019 to develop marketing campaigns and materials, including brochures promoting opioids, James said.

“No amount of money can compensate for lives lost and addiction suffered,” James said in a statement, “but with this agreement, Publicis will cease their illegal behavior and pay $350 million to help our communities rebuild.”

Publicis carried out Purdue Pharma’s “Evolve to Excellence” scheme, which targeted doctors who prescribed the most OxyContin. The campaign flooded them with sales calls and messages encouraging them to increase patients’ dosages, an investigation by a coalition of attorneys general found.

That campaign was developed for Purdue by McKinsey & Co., a consulting firm. McKinsey has already agreed to pay nearly $1 billion in a series of settlements for its role in the opioid crisis. The attorneys general argued that the advertising company should also be held accountable for its role in promoting the misleading messages as a form of consumer fraud.

Between 1999 and 2021, nearly 645,000 Americans died from an overdose involving any opioid, including prescription and illicit opioids, according to the Centers for Disease Control and Prevention. State attorneys general have mounted an aggressive campaign to exact financial penalties on companies they say are responsible for sparking the epidemic.

The latest settlement, negotiated by a group co-led by James and Phil Weiser, the attorney general of Colorado, requires that Publicis pay the $350 million within 60 days to states across the country to help address the opioid crisis. The agreement also prohibits Publicis from accepting any future contracts related to the marketing or sale of opioids, and requires it to disclose hundreds of thousands of internal documents detailing its work in opioid promotion.

In a statement on Thursday, Publicis Health said the settlement was “in no way an admission of wrongdoing or liability.” It said its marketing work for opioid manufacturers had primarily been done by a smaller advertising agency, Rosetta, that it owned but shut 10 years ago.

Publicis defended its work as “at all times fully compliant with the law.”

The New York attorney general’s office disputed that claim.

The company added that the attorneys general had recognized Publicis Health’s “good faith and responsible corporate citizenship” in reaching a settlement after three years of negotiations.

Since litigation began years ago, more than $50 billion in settlement funds has started to flow to thousands of state and local governments from companies that touted, produced and distributed opioid painkillers that have left millions addicted or dead, according to a tracking project by KFF Health News, a nonprofit news outlet.

New York state alone has won more than $2.6 billion in settlement funds, which it has begun using for treatment and harm-reduction efforts such as needle exchanges. It will receive an additional $19 million from Publicis as part of this latest agreement, James said.

The largest remaining sticking point in the opioid settlement saga is the fate of Purdue and the billionaire Sackler family that controlled the company.

The Supreme Court is weighing a bankruptcy settlement for Purdue Pharma that would funnel up to $6 billion into addressing the opioid epidemic in exchange for shielding members of the family from related lawsuits.