The Medicare Part B drug test that starts in 2027, and who is in it

On September 30, CMS finalized a model it calls GLOBE, short for Global Benchmark for Efficient Drug Pricing. It was published in the Federal Register on October 2. It concerns Medicare Part B, which pays for drugs a clinician gives you in an office or clinic — infusions and some injections, for example — and not for the prescriptions you pick up at a pharmacy, which fall under Part D.

The short version: for certain drugs, in certain places, what Medicare pays and what the patient owes would be tied to what other wealthy countries pay. It is a test, it is mandatory for the areas chosen, and it does not start for patients until April 2027.

What a patient would notice

In Original Medicare, Part B generally leaves the patient with 20% coinsurance on a covered drug given in a clinic. That share is a percentage of the price, which is why a very expensive drug can mean a very large bill. The GLOBE model ties the coinsurance for the drugs it covers to the international benchmark rather than to the full U.S. price. CMS gave an illustration in which coinsurance falls to 10%, so that a patient owing $20 on a $100 allowed amount would owe $10. That example shows how the mechanism works. It is not a promise about any particular drug.

Providers are paid less to offset the lower coinsurance, since Medicare’s payment is the allowed amount minus the patient’s share. The patient-facing change is therefore the coinsurance line, not what the clinic bills.

Why it is narrower than the proposal

The final rule is smaller than what CMS first proposed. The start was pushed from October 2026 to 2027, the covered drugs were limited to specific categories with more than $100 million in annual Part B spending, and several kinds of drugs were excluded. Estimates of the savings fell sharply as a result, though the figures reported for the old and new versions are not directly comparable, so this piece does not quote them.

GLOBE is a test in about a quarter of Original Medicare, not a change for everyone. Whether you are in it depends on where you live, not on what you chose.

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Part B and Part D are different systems

It helps to keep the two apart, because news about drug prices usually blurs them. Part D covers drugs you take yourself and pick up at a pharmacy, and it has the annual out-of-pocket cap and the negotiated prices covered in the piece on the next round of Medicare drug discounts. Part B covers drugs administered by a clinician, usually where you are treated, and it works on the 20 percent coinsurance described above. GLOBE concerns Part B only. It is a separate effort from the negotiation program and does not change the Part D rules.

Because it is built as a test, CMS chose the areas at random. That is deliberate: a test needs a comparison group. Two people with the same plan and the same drug can have different coinsurance depending on the ZIP code each lives in. The model does not look at income, diagnosis or the plan a person would prefer, and neither a patient nor a doctor can opt into it or out of it.

The timeline

The proposal would have started the model on October 1, 2026. The final rule moved the start to January 1, 2027, when drug manufacturers may begin submitting their international prices voluntarily. The part patients feel starts on April 1, 2027, with the lower coinsurance, and the performance years run through March 31, 2032. The rule’s own effective date, reported as November 30, 2026, is when it becomes part of the regulations, and is a different date from the day a patient sees any change.

The lawsuit

The model rests on CMS’s authority to test payment approaches. PhRMA argues in its complaint that the statute does not let the agency tie Medicare drug rebates to prices in other countries, and asks the court to declare the rule unlawful and postpone its effective date. The effective date reported for the final rule is November 30, 2026. A court can narrow, delay or block a rule, so the April 2027 start is the plan, not a guarantee. The outcome of the case will decide whether that happens on schedule.

What this does not touch

Part D premiums, the $2,400 out-of-pocket cap on prescriptions and the Part B premium are all separate from this model. Nothing about GLOBE changes what is on a Medicare Advantage plan’s benefit page. If a person is in Original Medicare, lives in a selected area and is given a covered drug, the coinsurance line is what changes.

What to watch

• You are affected only if you have Original Medicare, live in a selected area, and are given a covered Part B drug. Medicare Advantage members are not included.
• Nothing changes for patients before April 1, 2027, even if the rule takes effect earlier.
• Ask the clinic or infusion center about coinsurance before a course of treatment starts. That is the number the model is designed to change.
• Follow the court case. A ruling could change the start date or the model itself.
• Part D prescriptions you fill at a pharmacy are a separate system and are unaffected.

Whether the model survives, and what it saves, will take years to show. The thing to know now is narrow: who is in it, what it touches, and when it starts.