BOSTON (REUTERS) - John Kapoor, the founder of Insys Therapeutics, on Thursday (Jan 23) was sentenced to 66 months in prison for his role in a bribery and fraud scheme that contributed to the US opioid crisis.

Kapoor, 76, is now the highest-ranking pharmaceutical executive to be sentenced in a case linked to the opioid crisis.

During a hearing that lasted nearly two hours, US prosecutors asked US District Court Judge Allison D Burroughs to sentence Kapoor to 15 years in prison. Some victims also asked her to give Kapoor a maximum penalty.

Burroughs said her lesser sentence took into account his central role in the crime, his many good works as a philanthropist and his age.

Nevertheless, Kapoor is due to serve significantly more time in prison than other former senior Insys executives convicted in the bribery and fraud scheme.

On Wednesday, former Insys chief executive Michael Babich, 43, was sentenced to 30 months in prison.

Last year, a federal jury in Boston found Kapoor guilty of racketeering conspiracy in a scheme that involved bribing doctors to prescribe the company's fentanyl-based painkiller, Subsys. The scheme also defrauded insurers into paying for the drug.

Assistant US Attorney Nathaniel Yeager described Kapoor as the linchpin of the scheme.

"It was a top-down conspiracy run by John Kapoor," Yeager told the judge.

Kapoor, who served as the Chandler, Arizona-based drugmaker's chairman and later chief executive, apologised to the victims who were present in the courtroom.

"I am heartbroken by the words of the patients," Kapoor said.

"I sincerely apologise to them."

From 1999 to 2017, some 400,000 people died from overdoses involving an opioid, including prescription and illicit drugs, according to the US Centres for Disease Control and Prevention.