Medicare's drug program could have saved up to $3.6 billion in 2020 by mirroring the pricing strategy of entrepreneur and Shark Tank judge Mark Cuban's online pharmacy, according to a new study. Cuban's Cost Plus Drug Co. offers a selection of generic drugs at the cost of manufacturing them plus a flat 15% markup. The direct-to-consumer pharmacy does not accept insurance. The study's authors suggest that Medicare is overpaying for many generic drugs and could save billions a year if it purchased them directly from Cuban's online pharmacy. "The lower prices from a direct-to-consumer model highlight inefficiencies in the existing generic pharmaceutical distribution and reimbursement system, which includes wholesalers, pharmacy benefit managers, pharmacies, and insurers," wrote researchers at Brigham and Women's Hospital and Harvard Medical School in a brief published ... in the journal Annals of Internal Medicine. Cuban and his pharmacy did not fund or have any involvement in the study. Cost Plus Drug Co. says it engages in price negotiations with drugmakers. Medicare's drug program, Part D, however, prohibits the government from directly negotiating pharmaceutical prices. Researchers compared 2020 Medicare spending for a total of 89 drugs ... to their prices at Cost Plus Drug Co. in February. They estimate that Medicare overpaid for 77 generic drugs, spending $8.1 billion compared with $4.5 billion if the federal agency had purchased at the same prices as Cost Plus Drug Co. charges.