This bill amends Title XVIII of the Social Security Act, which governs Medicare, to establish a new rebate system for manufacturers of certain drugs and biological products. The core purpose is to ensure that the benefits of maximum fair price negotiation for these drugs are realized through a manufacturer rebate mechanism. This rebate is designed to bridge the gap between the higher average sales price (ASP) and the lower negotiated maximum fair price (MFP) for selected drugs. Under this new system, manufacturers of selected drugs subject to a maximum fair price negotiation agreement will be required to pay a quarterly rebate to the Secretary of Health and Human Services. The rebate amount is calculated by taking the difference between the ASP+6 payment amount and the MFP+6 payment amount , then multiplying this difference by the total units of the drug furnished under Medicare Part B. These collected rebates will be deposited into the Federal Supplementary Medical Insurance Trust Fund. A significant provision of the bill is its impact on beneficiary cost-sharing. For selected drugs for which a rebate is paid, the amount of beneficiary coinsurance will be based on the lower MFP+6 coinsurance amount , which is 20 percent of the MFP+6 payment amount, aiming to reduce out-of-pocket costs for Medicare beneficiaries. The bill also includes provisions for civil money penalties for manufacturers who fail to comply with these new rebate requirements and clarifies that manufacturers are not required to provide drugs at maximum fair prices except through this rebate system.