The title of CMS’s May 26 proposed rule, “Misclassification of Drugs, Program Administration and Program Integrity Updates Under the MDRP,” buries the lede. Amid twenty Medicaid Drug Rebate Program-related proposals—some consequential, others mechanical—lies one that would require manufacturers to follow-the-pill and aggregate independent discounts when determining Best Price, reversing thirty years’ experience with the critical government pricing metric. There is truly something for everyone in the 59-page proposed rule. But it is the government’s position that discounts to independent entities must be stacked that strikes us as the most aggressive and impactful of the bunch (see number 8, below).The proposed rule (88 Fed. Reg. 34,238 (May 26, 2023)) presents for comment a great variety of ideas to modify the MDRP, and in no discernible order. It appears that CMS has been keeping a list for the last three years of items it hadn’t had time to get around to, until now. We summarize each of the proposals below for your review, including those that would punish drug misclassification; expand the definition of “manufacturer” to include all affiliated entities; establish an MFP-like “survey” on high cost Medicaid drugs; and impose limitations on AMP and Best Price restatements.Interesting too is what is not included in the grab bag: there is no “crack drug” AMP fix, for which the industry has been waiting for years.Comments on the proposed rule (PR) aredue on July 25. This Client Alert is designed to give in-house counsel, government pricing specialists, and market access personnel an at-a-glance overview and initial insight into the PR. As always, we at King & Spalding stand ready to help you understand the proposals, evaluate their i