A report Monday from United States Sen. Claire McCaskill said Phoenix-based Insys Therapeutics is one of five opioid manufacturers that paid more than $10 million to advocacy groups and doctors tied to them, and as a result, play a significant role in contributing to the opioid epidemic.

Joe McGrath is with Insys Therapeutics. He said Insys contributions were for cancer patients with breakthrough pain, a condition he said is undertreated in the U.S.

“You have to understand that breakthrough cancer pain is excruciating and debilitating," McGarth said. "People with breakthrough cancer pain have said they want to die rather than continue living with that kind of pain. It is so intense."

McGrath noted Insys has been cooperating with McCaskill since 2016, including providing briefings to the Senator by company executives, sharing documents and financial data that comply with ongoing investigations into Insys across several states.

“We believe that our charitable contributions are patient focused. With regard to the US Pain Foundation specifically, our donation was directed to a disease state fund for cancer patients with breakthrough pain,” McGrath said.

According to the company’s statement, in the second half of 2017, Insys’s charitable contributions to these foundations decreased by approximately 77 percent. The amount paid to physician speakers was also reduced by 82 percent.

McCaskill’s request was sent last year to Purdue Pharma, Insys Therapeutics, Janssen Pharmaceuticals, owned by Johnson & Johnson, Mylan, and Depomed.