Some people in Original Medicare could pay a smaller share of the bill for certain expensive drugs starting April 1, 2027. The Trump administration’s Centers for Medicare & Medicaid Services (CMS) finished a new drug-pricing rule called GLOBE on October 2, and it takes effect November 30, 2026. Who benefits depends on where a person lives, not on anything they sign up for.
The final rule in the Federal Register picks about 25 percent of people in Original Medicare Part B, using randomly selected ZIP Code Tabulation Areas, which are the Census Bureau’s statistical versions of ZIP codes. Everyone else keeps paying the usual coinsurance.
How the new Part B drug coinsurance would work
Part B covers drugs given in a doctor’s office or clinic, such as infusions and eye injections. After the yearly deductible, which is $283 in 2026, people in Original Medicare usually pay 20 percent of the cost of each covered item, and there is no yearly limit on that spending unless they have supplemental coverage.
Under GLOBE, drugmakers must pay larger rebates when a Part B drug’s price runs above what 19 other countries pay. For people in the chosen areas, the coinsurance is then figured on a lower amount. CMS illustrated that 94 percent of the model drugs would carry a coinsurance of between 2 and 12 percent, compared with the standard 20 percent.
That is an illustration based on past data, not a promise for every drug. The rule covers certain single-source drugs and biologics in seven categories, including cancer drugs, immune-system drugs and eye drugs, and each must have topped $100 million in Original Medicare Part B spending over a year. The list is limited to high-spend drugs.
Who is in, and who is left out
Inclusion is decided by the address Medicare has on file. CMS says it will post the list of selected areas on the GLOBE model website, and the rule says people in those areas do not have to enroll or take any action. The agency also will not send individual notices or offer an opt-out.
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People enrolled in a Medicare Advantage plan are not part of the group. Neither are people in a cost plan or a health care prepayment plan, or anyone whose primary coverage comes from a group plan such as an employer’s retiree plan. The rule counts only people for whom Original Medicare Part B pays first.
Supplemental coverage changes the picture, too. The rule notes that people with a Medigap or similar policy may not directly benefit from the lower coinsurance. All Original Medicare Part B enrollees, in the selected areas or not, may see somewhat lower premiums, CMS says. With no yearly cap on Original Medicare spending, a 20 percent share of an expensive infusion can add up fast over a course of treatment, which is why even a partial cut matters to households on long therapies.
What the rule says it could save, and why it started this way
The rule projects $177 million in total out-of-pocket savings for people in the model, along with $440 million in Medicare Part B net spending savings over a seven-year payment period. Those are CMS estimates, spread across years, not a per-person figure. The reduced coinsurance runs in performance years from April 1, 2027 through March 31, 2032.
The path to this rule has shifted. CMS first proposed GLOBE on December 23, 2025, with a start of October 1, 2026 and comments due February 23, 2026. The final version moved the beneficiary start to April 2027, with the model itself beginning January 1, 2027.
The White House has also said it has pricing agreements with 26 drugmakers covering 89 percent of the branded drug market. A trade-press report on the rule says companies with those deals are exempt from GLOBE, which could leave as few as four manufacturers directly covered.
A lawsuit could still block the rule
The drug industry’s trade group, the Pharmaceutical Research and Manufacturers of America (PhRMA), has sued to stop the model. Its general counsel, Jim Stansel, told Reuters that Congress gave CMS only limited authority to test payment models, according to Managed Healthcare Executive.
CMS Administrator Dr. Mehmet Oz has said the agency is taking action to pilot a new approach to lower costs. Unless a court blocks it, the rule takes effect November 30. If it were struck down, any coinsurance relief for people in the chosen areas would go away with it.
Because the rule applies drug by drug, anyone who gets Part B drugs such as infusions or eye injections can ask the doctor’s office which drug is being billed and what the coinsurance runs today. That gives a baseline to compare against if April 2027 brings a lower bill. Questions about the model can go to CMS at [email protected], the contact listed in the rule.
For now, a few things are settled and a few are not. The rule is final, the effective date is November 30, 2026, and the lower coinsurance is scheduled for April 1, 2027. What no one has published in the rule itself is the list of ZIP-based areas, and a court ruling could still change the timeline.
Wondering if Part B drug coinsurance will drop in 2027?
Whether a given household lands in a selected area will not be known until CMS posts the list, and even then the lower coinsurance applies only to certain drugs. People in Original Medicare with no supplemental policy still face a 20 percent share and no yearly limit on Part B spending in the meantime.
The Medicare Cost & Coverage Protection Kit covers the cost help that exists today, including the 51 state Medicare cost-help packs and the new Part D out-of-pocket cap. It also includes a medication and cost tracker, so Part B and Part D drug bills sit in one place while the GLOBE rule plays out.
Get the state cost-help packs and the drug cost tracker for Medicare bills →
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This article was produced with AI assistance and edited for accuracy against the sources linked above.
