Key Takeaways
- GLOBE launches January 1, 2027 and runs through March 31, 2032, covering single-source Part B drugs with more than $100 million in annual Medicare spend in randomly selected areas that hold about 25% of original Medicare beneficiaries.
- Manufacturers owe rebates when their prices exceed the lowest net price across 19 reference countries, and patient coinsurance falls starting April 1, 2027.
- All 17 large drugmakers in the first tariff phase signed most-favored-nation and manufacturing agreements by August 31, which secures a 0% tariff rate through January 20, 2029.
- An analysis of the secret deals suggests they could cut the anticipated savings from most-favored-nation pricing by as much as 80%.
Washington has spent a year announcing deals that promise lower drug prices. On September 30 it turned one of them into a rule. CMS finalized the mandatory GLOBE model, a five-year test that links what Medicare recovers on certain Part B drugs to what 19 wealthy countries pay. The harder question is how much of the headline savings will survive, because the agreements drugmakers signed to avoid tariffs were never published in full.
What GLOBE Actually Does
According to AJMC's summary of the final model, GLOBE starts on January 1, 2027 and ends March 31, 2032. It applies to single-source drugs and sole-source biologicals whose annual original Medicare spending exceeds $100 million, across oncology, rheumatology, immunology, ophthalmology and endocrinology. Participation is mandatory for manufacturers, and the model operates in randomly selected areas covering roughly 25% of beneficiaries who have original Medicare as their primary coverage.
The mechanism is a rebate. When a manufacturer's price exceeds the international net price drawn from 19 reference countries, including Canada, Germany, Japan and the United Kingdom, it pays the difference back to the Medicare trust fund. Patients benefit through lower coinsurance starting April 1, 2027. Biosimilars and their reference biologicals, orphan-only drugs, plasma-derived products and certain cell and gene therapies are exempt, so the model reaches the large, established Part B franchises.
The Deals Behind the Rule
GLOBE is one half of a pair. A companion model for Part D, called GUARD, applies the same additional-rebate logic to pharmacy-benefit drugs. Both sit on top of agreements the administration struck privately with manufacturers. Managed Healthcare Executive reports that tariffs on patented drugs reached 100% on September 29, with a 0% rate for companies that hold both a U.S. manufacturing plan and a most-favored-nation pricing agreement through January 20, 2029. All 17 large companies named in the first phase, a group that includes Pfizer, Merck, Novartis and Eli Lilly, had signed by August 31.
Those terms were not made public, and that is where the savings story gets complicated. An analysis summarized by STAT's Pharmalot concluded that the secretive arrangements may undermine most-favored-nation pricing, potentially reducing anticipated savings by as much as 80%. Separately, Drug Discovery Trends reported that more than 350 branded medications faced price increases on January 1, 2026, including from companies that had signed deals. One health policy researcher quoted there said the agreements "nibble around the margins" of what patients pay.
Net Price Is Now the Number That Matters
For life sciences teams, the practical lesson is that the list price is no longer the figure that determines revenue or patient cost. A rebate keyed to an international benchmark, layered on a confidential deal and a tariff schedule, makes net price the variable that every stakeholder needs and few can see. Manufacturers will model scenarios. Plan sponsors and pharmacy benefit teams will ask how rebates, coinsurance and utilization management interact. Health systems and physician practices will need to explain to patients why their out-of-pocket cost changed in some counties and not in others.
The randomized geography adds a second layer of complexity. Because only about a quarter of beneficiaries are in scope, two patients on the same infused therapy can face different coinsurance depending on where they live. That creates a measurable natural experiment, and it also creates a communication problem for every organization that touches the patient.
A Playbook for Sponsors, Plans and Providers
- Model net, not list. Build launch and lifecycle forecasts around net price scenarios that include GLOBE rebates, tariff status and any signed agreement terms.
- Map your exposure by geography. Identify which of your Part B products meet the $100 million threshold and which beneficiary areas fall inside the randomized sample.
- Ask for pharmacy benefit transparency. Plan sponsors should ask their pharmacy benefit partners how rebates, formulary design and AI-driven utilization tools translate into net spend under the new rules.
- Prepare patient-facing explanations. Coinsurance changes begin April 1, 2027, so primary care and navigation teams need plain-language scripts before the first bill arrives.
- Watch downstream spend. Lower Part B prices may shift where cost lands, so health plans should track post-acute and readmission utilization alongside drug spend.
- Document your evidence. Keep real-world outcomes data current, because it will anchor any argument about value as international benchmarks reset prices.
GLOBE gives CMS a five-year test of whether international benchmarks can lower what Medicare pays. Whether it delivers will depend on the figures that remain undisclosed, which is why the organizations that build their own view of net price now will be best placed to respond when the first rebate statements arrive.
