Millions of Medicare beneficiaries who take expensive prescription drugs will no longer face a costly middle phase of coverage when buying their medications starting in calendar year 2027. The Centers for Medicare and Medicaid Services has finalized rules that remove the Part D coverage gap, long known as the “donut hole,” so that out-of-pocket spending counts directly toward the annual cap without an intermediate stage where enrollees shouldered a share of brand-name drug costs. The structural change, rooted in the Inflation Reduction Act, shifts financial risk toward drug manufacturers and Part D plan sponsors, raising hard questions about how insurers will design their formularies in response.
Why the 2027 Coverage Gap Removal Changes the Math for Beneficiaries
Under the old benefit design, Part D enrollees hit a coverage gap after their total drug costs passed an initial threshold. Inside that gap, beneficiaries paid roughly a quarter of brand-name drug prices out of pocket before reaching catastrophic coverage. The gap created a zone where patients often skipped doses or abandoned prescriptions because costs spiked. According to a CMS fact sheet on the Contract Year 2027 final rule, the agency is codifying redesign changes for 2027 and beyond that explicitly eliminate the coverage gap phase. Once the gap disappears, every dollar a beneficiary spends on covered drugs after the deductible will count toward the annual out-of-pocket maximum without interruption.
The practical effect is that enrollees taking high-cost specialty medications or multiple brand-name drugs will reach the spending cap faster. That matters because the Inflation Reduction Act established a hard annual out-of-pocket limit for Part D, replacing the old catastrophic phase structure where beneficiaries still owed a percentage of costs even after heavy spending. Beneficiaries who previously stalled in the gap, unable to afford their prescriptions, should see a cleaner path to full coverage each year. For people with chronic conditions such as cancer, rheumatoid arthritis, or multiple sclerosis-where single prescriptions can run into thousands of dollars per month-the redesign can mean the difference between continuous therapy and dangerous interruptions.
Lower and more predictable out-of-pocket liability also has behavioral implications. When patients know their spending will move steadily toward a cap, instead of spiking unpredictably in the middle of the year, they are less likely to ration pills or delay refills to save money. That, in turn, can improve adherence and may reduce downstream medical costs from avoidable hospitalizations or complications. The new structure essentially turns what used to be a jagged spending curve into a smoother, more transparent progression.
How CMS and Manufacturers Split the New Cost Burden
The gap’s removal does not erase its costs. Instead, those costs shift. According to CMS, the Manufacturer Discount Program replaced the Coverage Gap Discount Program on Jan. 1, 2025, requiring drugmakers to provide discounts across a broader range of the benefit. The Congressional Research Service, in its analysis of Part D (R40611), describes how manufacturer discount obligations expanded beginning in 2025 as part of the phased Inflation Reduction Act rollout. Where manufacturers once focused their discounts within the donut hole, they now shoulder responsibility earlier and more consistently as beneficiaries move through the benefit.
A timing distinction is worth tracking here. CMS materials on the 2027 rate announcement tie Part D payment methodology to Inflation Reduction Act benefit changes taking effect for calendar year 2027, while the Manufacturer Discount Program itself launched in 2025. The two timelines are not contradictory but reflect a staggered rollout: manufacturer discounts started earlier, while the formal elimination of the coverage gap phase and related plan payment recalculations take hold in 2027. CMS finalized these 2027 payment policies in a broader package that also addresses Medicare Advantage rates and plan accountability standards, outlined in a separate CMS announcement on payment policies.
The hypothesis that Part D sponsors will tighten formularies to offset their increased exposure is grounded in straightforward economics. When plans bear more risk in the initial coverage phase and manufacturers owe larger discounts, sponsors have an incentive to steer enrollees toward lower-cost therapies and to manage utilization more aggressively. That can show up as stricter prior authorization requirements, more step-therapy protocols that require trying cheaper drugs first, or narrower preferred drug lists where only certain brands receive the most favorable cost sharing.
At the same time, CMS has signaled that it will scrutinize plan behavior to ensure access is not unduly restricted. The 2027 rules sit alongside broader oversight initiatives aimed at transparency, marketing practices, and network adequacy. Plans that respond to the new financial pressures by erecting barriers to medically necessary drugs could draw regulatory attention, especially if beneficiary complaints or appeals spike.
Manufacturers, for their part, must weigh how deeper discount obligations interact with ongoing federal drug price negotiations and other Inflation Reduction Act provisions. Some companies may adjust launch prices, rebate strategies, or patient assistance programs to maintain revenue targets. Others may lean into outcomes-based contracts with plans, where the net price of a drug is tied to how well it performs for enrolled patients.
For beneficiaries, the bottom line is that the disappearance of the donut hole in 2027 simplifies a notoriously confusing benefit and caps personal exposure more clearly. Yet the behind-the-scenes rebalancing of who pays-taxpayers, plans, and manufacturers-will continue to evolve. How that balance ultimately affects premiums, plan choice, and real-world access to cutting-edge therapies is likely to remain a central policy debate well beyond the first year of the new design.
