McKinsey & Company found opportunities to boost opioid manufacturers' sales amid the addiction crisis from 2004 to 2019, new documents published by the University of California at San Francisco and Johns Hopkins University show.

Why it matters: When one opioid fell out of favor with federal regulators, drugmakers created and marketed another, further stoking the crisis.

The more than 114,000 pages of documents show how McKinsey had a much broader role advising the companies than was previously documented, providing growth and turnaround plans to combat the loss of revenue from opioid lawsuits, advice on how to deal with regulators and strategies to boost sales while concern about the addictive properties of the painkillers grew.

Flashback: Nearly half a million people died from an opioid-related overdose from 1999 to 2019, according to the CDC, and the proliferation of prescription opioid addiction gave way to heroin then synthetic opioid use, which continued the upward trajectory of opioid deaths through 2019.

• Despite lawsuits, regulation and backlash during the height of the opioid epidemic, McKinsey continued to consult with leading opioid drugmakers Purdue Pharma, Endo Pharmaceuticals, Johnson & Johnson and Mallinckrodt, the new documents show.
• The new documents reveal "a sweeping and detailed depiction of a firm that became a trusted adviser to companies at the core of an epidemic that has claimed half a million American lives," the New York Times reported.

The other side: In 2019, McKinsey cut ties with opioid manufacturers, and in early 2021, the company reached a $573 million settlement agreement with 47 states, five territories and the District of Columbia, which called for the release of the internal documents.

• "As we have said before, we recognize the terrible consequences of the opioid epidemic and have acknowledged our role in serving opioid manufacturers," a McKinsey spokesperson said in a statement in response to the documents being published on Thursday.