BOSTON (Reuters) – A lawyer for Insys Therapeutics Inc’s one-time billionaire founder on Monday rejected claims that her client directed a scheme to bribe doctors to prescribe an addictive fentanyl spray and denied the product was related to the U.S. opioid crisis.

John Kapoor, the company’s former chairman, and four colleagues are the first painkiller manufacturer executives to face trial over conduct authorities say contributed to an opioid abuse epidemic that has killed tens of thousands of Americans.

Assistant U.S. Attorney David Lazarus told jurors that Insys paid doctors to participate in speaker programs ostensibly meant to educate medical professionals about its medication, Subsys, but that were actually poorly attended sham events.

But at the start of the 75-year-old’s trial in Boston federal court, defense lawyer Beth Wilkinson called those charges “patently false.”

Prosecutors have alleged that from 2012 to 2015, Kapoor and four co-defendants conspired to illegally pay doctors millions of dollars to prescribe Subsys, an under-the-tongue fentanyl spray approved only for managing severe pain in cancer patients.

Fentanyl is an opioid 100 times stronger than morphine.

Kapoor’s co-defendants include former Insys executives and managers Michael Gurry, Richard Simon, Sunrise Lee and Joseph Rowan.

Wilkinson acknowledged Insys paid doctors. But she said Kapoor’s goal was to legally compensate them for acting as speakers at educational events.

She called Kapoor, who served as Insys chief executive from 2015 to 2017, a visionary who developed Subsys after watching his wife suffer from breast cancer.

The product had no role in the drug crisis, Wilkinson argued, saying Subsys made up a tiny fraction of all prescription opioids.

“It is certainly not part of the opioid crisis,” she said in her opening statement.

A record 47,600 Americans died of opioid-related overdoses in 2017, according to the U.S. Centers for Disease Control and Prevention

Lazarus told jurors Kapoor’s scheme led doctors to write medically unnecessary prescriptions for Subsys to patients, many of whom did not have cancer.

“John Kapoor and his co-defendants paid doctors to abandon their medical duties,” he said.

Lazarus said Kapoor also helped defraud insurers into paying for the expensive drug.

Two top former executives – Michael Babich, Insys’ CEO from 2011 to 2015, and Alec Burlakoff, its ex-vice president of sales – will to testify against Kapoor after pleading guilty, Lazarus told jurors.

Insys in August said it would pay at least $150 million to resolve a Justice Department probe related to its marketing of Subsys.