From 2017 to 2022, the companies marked up prices at their pharmacies by hundreds or thousands of percent, netting them $7.3 billion in revenue.

Optum RX, CVS Caremark and Express Scripts are marking up drugs that treat cancer and multiple sclerosis by more than 1,000-percent.

Pharmacy benefit managers, which serve as the middlemen between drug makers, insurers and pharmacies, reaped $7.3 billion in revenue from marking up the prices of dozens of specialty generic drugs between 2017 and 2022,