Medicare Part D Formulary Changes in 2026
Medicare Part D Formulary Changes in 2026
Medicare Part D in 2026 Is Fundamentally Different. Here Is What Changed and What It Means for You.
5 minute read
If you have been on Medicare for a few years, you know that formularies change every January, costs shift, and keeping track of it all can feel like a second job. But 2026 is not a routine year for Medicare Part D. Three significant forces are reshaping what is covered and how much you pay: the first wave of Inflation Reduction Act drug price negotiations is now in effect, GLP-1 coverage rules have changed, and a wave of biosimilar launches is pushing plans to restructure their formularies in ways that directly affect patients taking some of the most common specialty medications. If your coverage has changed this year and you do not understand why, this is where to start.
IRA Drug Price Negotiations: The First Real-World Results
The Inflation Reduction Act authorized Medicare to directly negotiate drug prices with manufacturers for the first time in the program's history. The first ten negotiated drugs have Maximum Fair Prices that took effect January 1, 2026. These are the drugs in the first negotiation round:
Eliquis (apixaban), Jardiance (empagliflozin), Xarelto (rivaroxaban), Januvia (sitagliptin), Farxiga (dapagliflozin), Entresto (sacubitril/valsartan), Enbrel (etanercept), Imbruvica (ibrutinib), Stelara (ustekinumab), and Fiasp/NovoLog insulin products.¹
CMS published the Maximum Fair Prices for each of these drugs, and the reductions from list price are significant in some cases. For example, the negotiated price for Eliquis represents a substantial reduction from its previous list price.¹ However, whether you see those savings at the pharmacy counter depends on how your specific Part D plan has structured its formulary and cost-sharing around these negotiated prices.
An Oliver Wyman analysis from February 2026 noted that the translation of negotiated prices into actual patient cost-sharing varies considerably across plans, and that beneficiaries may need to compare plans carefully to find where negotiated price benefits flow through most directly.² The $2,000 annual out-of-pocket cap also applies in 2026, which means high-cost medication users will hit a ceiling on what they pay regardless of tier placement.
GLP-1 Coverage Is Expanding for Medicare Patients
For years, Medicare Part D plans were prohibited from covering weight management drugs. GLP-1 receptor agonists like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) were covered only when prescribed for type 2 diabetes, not for obesity or chronic weight management.
CMS took steps in 2025 to allow Medicare coverage of GLP-1 medications for obesity treatment, and 2026 is the first year many plans are implementing this expanded coverage.³ If you have been denied a GLP-1 for obesity or weight management under Medicare in prior years, the coverage landscape has changed. Not all plans have added GLP-1 obesity coverage, and those that have may require prior authorization documenting your BMI and any related comorbidities.
If your physician has prescribed a GLP-1 for obesity or chronic weight management and your plan denied it, check whether your plan has a 2026 coverage policy for these medications. The prior authorization criteria typically require documentation of a BMI meeting the Medicare criteria and in some cases documentation of a weight-related comorbidity.
Biosimilar Launches and Formulary Restructuring
Several major biologic medications lost their exclusivity periods and now face biosimilar competition that is directly reshaping Part D formularies. Ustekinumab (Stelara), adalimumab (Humira), and others now have biosimilar versions entering the Medicare market.
Part D plans have financial incentives to favor biosimilars because they typically carry lower net costs. As a result, you may find that a medication you were previously covered for is now on a higher cost-sharing tier, requires step therapy (trying the biosimilar first), or has been moved to a specialty tier with higher out-of-pocket requirements.
Oliver Wyman's February 2026 Part D analysis found that plan formulary restructuring around biosimilar availability is one of the primary drivers of cost-sharing changes for specialty drug users in 2026.² For patients who have been stable on reference biologics and find their cost-sharing has dramatically increased, the formulary exception and appeal process is available.
What This Means for You
If your Part D costs have changed significantly in 2026, there are several ways to respond.
Use the Medicare Plan Finder at Medicare.gov to compare your current plan's formulary and cost-sharing for your specific medications against alternative plans during any Special Enrollment Period you may qualify for.
If you are taking one of the ten negotiated drugs and your costs have not changed or have increased, check whether your plan has passed through the savings from the negotiated price or whether the savings are being captured elsewhere in the plan's design.
If a biosimilar is now required where you previously had your reference biologic covered without restrictions, ask your physician to document whether there is a clinical reason to continue the reference product. That documentation supports a formulary exception request.
If your GLP-1 was previously denied for obesity and you have not re-tried under the 2026 expanded coverage rules, check your plan's current coverage policy and work with your physician to submit a new prior authorization request with current criteria.
Ellen can help you understand your denial and build your appeal. Start here
Frequently Asked Questions
How do I find out if my drug has a negotiated Medicare price in 2026?
CMS publishes the Maximum Fair Prices for negotiated drugs on its Medicare Drug Price Negotiation Program page at CMS.gov. You can search for your medication by name to see if it is among the first ten negotiated drugs and what its Maximum Fair Price is for 2026.
The $2,000 out-of-pocket cap is new in 2026. How does it work?
Starting in 2026, once you have paid $2,000 in out-of-pocket costs for covered Part D drugs in a calendar year, you pay $0 for covered drugs for the rest of the year. This replaces the previous "catastrophic" coverage structure. The $2,000 counts toward your out-of-pocket total in the same way it always has: your deductible payments, copays, and coinsurance all count, but your premium does not.
My plan switched me to a biosimilar. Do I have any say in this?
Yes. You can request a formulary exception if your physician has a clinical reason for the specific medication you were on. You can also appeal a denial of that exception. Mid-year formulary changes for current members trigger specific transition supply protections, so if your plan changed its formulary during the year, you may be entitled to a temporary supply while your exception request is processed.
Sources: