A report released Monday by Sen. Claire McCaskill (D-MO) said five opioid manufacturers have paid more than $10 million to advocacy groups and doctors tied to them, many of whom amplified industry messages supporting the use of the opioids. The report said groups who received the donations aligned themselves with industry goals and issued guidance promoting opioids for chronic pain and lobbied against laws to curb their use. "These financial relationships were insidious, lacked transparency, and are one of many factors that have resulted in arguably the most deadly drug epidemic in American history," McCaskill said in a statement. Purdue Pharma, which on Saturday announced it would stop promoting opioids to doctors, was the biggest donor, giving $4.15 million to 12 groups from 2012 to 2017, the report said. Purdue said in a statement that it supported organizations interested in helping patients receive appropriate care. The report said Insys Therapeutics gave $3.15 million to various groups, ranking second in donations to the 14 groups examined. The report said the groups also received $1.07 million from Depomed, $465,142 from Johnson & Johnson, and $20,250 from Mylan NV.