The reported settlement was the first of its kind to address the addiction crisis across the country that kills 130 Americans a day.

The Wall Street Journal reported that Purdue and its owners have agreed to pay US$270 million (RM1.1 billion). The CNBC network confirmed a settlement has been reached.

The state’s attorney general announced a news conference scheduled later in the day to announce a “development in the state’s lawsuit against the nation’s leading manufacturers of opioid pain medication.”

Purdue is facing hundreds of lawsuits in the US over claims that OxyContin causes addiction. The Oklahoma lawsuit was the first to go to trial, which was scheduled to begin later this week.

The Oklahoma Supreme Court on Monday rejected an appeal by opioid manufacturers to delay the trial. Purdue was the only one to reportedly settle.

The state’s attorney general, Mike Hunter, last month said his office had obtained confidential documents showing Purdue launched a “disinformation campaign” to cover up the epidemic.

“These documents are damning evidence showing Purdue executives were more interested in spreading propaganda than stopping the death toll from rising and fixing the problem they created,” Hunter said in a statement.

In a February statement, Purdue said OxyContin was a federally-approved drug developed through a “robust set of clinical trials.”

“Purdue recognizes the opioid addiction crisis is a significant public health challenge,” the company said. “We are proud of the actions we have taken to ensure opioids are prescribed appropriately.”

Overdoses from prescription painkillers and heroin – a last-resort drug for opioid addicts – exploded over the last 20 years, according to the National Institute on Drug Abuse.

Almost 400,000 people have died from an overdose involving prescription or illicit opioids, according to the Centers for Disease Control and Prevention (CDC).

Pop icon Prince and rocker Tom Petty were among the most high profile victims of the epidemic.