Medicare Part D does cover biologics, but with two important limits: the biologic has to be one you administer yourself (an injection or pill you take at home rather than an infusion in a clinic), and it has to appear on your specific plan’s formulary. When both conditions are met, your plan covers the drug, almost always on a specialty tier, and your out-of-pocket spending for all Part D drugs is capped at $2,100 for 2026.
Self-Administered or Clinic-Administered: Which Part Applies
The first question is not whether Medicare covers your biologic, but which part of Medicare. Part B covers drugs and biologics a healthcare professional gives you by infusion or injection in a physician’s office or hospital outpatient department, provided Medicare classifies the drug as “not usually self-administered.”1MedPAC. Part B Drugs Payment Systems Infusion-center cancer treatments and rheumatology infusions typically fall here, and you generally pay 20 percent of the Medicare-approved amount after the Part B deductible.
Part D takes over for biologics you handle on your own, including prefilled syringes and auto-injectors used at home for conditions like rheumatoid arthritis, psoriasis, or Crohn’s disease. Medicare.gov defines self-administered drugs as “medications that you would normally take on your own,” and confirms that when Part B doesn’t cover a self-administered drug, your Part D plan may.2Medicare.gov. How Medicare Covers Self-Administered Drugs Given in Hospital Outpatient Settings If the route of administration for your biologic is unclear, your prescriber’s office or the plan itself can confirm which part applies.
Where Biologics Sit on Part D Formularies
Every Part D plan maintains a formulary that sorts covered drugs into cost-sharing tiers. Biologics almost always land on the top rung, the specialty tier. CMS lets plan sponsors place any drug costing $670 or more per month on a specialty tier, and most biologics clear that threshold without difficulty.3MedPAC. Restructuring Medicare Part D for the Era of Specialty Drugs During the initial coverage phase, plans charge between 25 and 33 percent coinsurance on specialty-tier drugs, depending on the plan’s deductible structure.
Formularies vary from one plan to the next. A biologic on the specialty tier of one plan may not appear on another plan’s formulary at all. Checking the formulary before you enroll, and again during each year’s open enrollment, is the most useful step you can take. Plans publish searchable formularies on their own websites and on Medicare.gov.
Protected Classes That Keep Some Biologics on the Formulary
Federal rules require Part D plans to cover all or substantially all drugs in six protected classes: antidepressants, antipsychotics, anticonvulsants, immunosuppressants for transplant rejection, antiretrovirals, and antineoplastics.4Centers for Medicare & Medicaid Services. Medicare Advantage and Part D Drug Pricing Final Rule CMS-4180-F – Section: Part D Protected Classes Biologics used for cancers and transplant rejection fall within these classes, which means plans cannot simply drop them.
Protected status does not erase cost sharing. The plan can still put the drug on the specialty tier and charge the matching coinsurance. It also does not block all utilization controls. Plans may still impose prior authorization and step therapy for new prescriptions in five of the six classes; antiretrovirals are the exception, where neither tool is allowed.
What Your Biologic Will Cost in 2026
Part D cost sharing moves through phases, and biologic users typically clear them quickly.
Deductible
You pay the full cost of your drugs until you meet the annual deductible, which is capped at $615 in 2026.5Centers for Medicare & Medicaid Services. 2026 Medicare Advantage and Part D Rate Announcement Some plans set a lower deductible or waive it for certain tiers, but specialty-tier biologics rarely get a waiver. A single fill often meets the deductible in one trip to the pharmacy.
Initial Coverage
After the deductible, you typically pay 25 percent of the drug’s cost while the plan and the manufacturer cover the rest. On a biologic that lists for several thousand dollars a month, 25 percent is still a large bill, so this phase is short for most biologic users.
The $2,100 Cap
Once your out-of-pocket spending on covered Part D drugs reaches $2,100 for the year in 2026, you pay nothing more for those drugs for the rest of the calendar year.5Centers for Medicare & Medicaid Services. 2026 Medicare Advantage and Part D Rate Announcement The old coverage gap, often called the donut hole, was eliminated starting in 2025 under the Inflation Reduction Act’s Part D redesign.6Centers for Medicare & Medicaid Services. Final CY 2025 Part D Redesign Program Instructions Fact Sheet
Spreading the Cost Across the Year
A $2,100 cap still hurts if you hit it in January. The Medicare Prescription Payment Plan lets you spread out-of-pocket costs into capped monthly installments instead of paying at the pharmacy counter. Every Part D plan has to offer it, with no interest and no fee, and CMS has codified the program’s rules for 2026 and beyond.7Centers for Medicare & Medicaid Services. Medicare Prescription Payment Plan If you take a high-cost biologic, enrolling at the start of the plan year avoids a large January bill.
Biosimilars Worth Asking About
Biosimilars are biologics that are highly similar to an already-approved reference biologic, with no clinically meaningful differences in safety or effectiveness. They often carry a lower list price. A 2025 review by the HHS Office of Inspector General found that 96 percent of standalone Part D plans covered at least one biosimilar to Humira, and 99 percent of those formularies placed Humira and its biosimilars on the same cost-sharing tier.8HHS Office of Inspector General. Most Medicare Part D Plans Formularies Included Humira Biosimilars for 2025 Same-tier placement means your copay may not change much today, but wider competition is expected to pull prices down over time.
Not every reference biologic has a biosimilar yet, and plans differ on which ones they include. Ask your prescriber whether a biosimilar exists for your medication and check your plan’s formulary for its tier placement.
Prior Authorization and Step Therapy
Part D plans routinely require prior authorization for biologics. Your doctor contacts the plan and documents that the drug is medically necessary before the pharmacy can fill the prescription.
Step therapy goes further. The plan may require you to try one or more lower-cost drugs first and show they didn’t work before it will cover the biologic your doctor originally prescribed. Avalere Health has reported that for conditions such as psoriatic arthritis and multiple sclerosis, Part D plans sometimes require up to two alternative drugs, beyond what the FDA label calls for.9Avalere Health Advisory. Part D Prior Authorization Policies May Include Step Therapy
If your doctor believes a required step-therapy drug would be harmful or ineffective for you, they can request an exception. Plans must decide standard requests within 72 hours, or within 24 hours when your doctor asks for an expedited decision because a delay could endanger your health.10Centers for Medicare & Medicaid Services. Coverage Determinations
When the Plan Says No
If your biologic isn’t on the formulary, or sits on a tier you can’t afford, you can request a coverage exception. A formulary exception asks the plan to cover a drug it doesn’t normally list. A tiering exception asks the plan to charge you the lower cost sharing of a preferred tier.11Centers for Medicare & Medicaid Services. Exceptions Your prescriber must submit a supporting statement explaining why the specific biologic is medically necessary for you.
If the plan denies the exception, you can appeal. The process has five levels, starting with a redetermination by the plan itself and moving on to an Independent Review Entity, an Administrative Law Judge, the Medicare Appeals Council, and ultimately federal court.12Medicare. Appeals in a Medicare Drug Plan Most disputes end at the first two levels. If coverage problems continue past the appeals window, switching plans during annual open enrollment is always an option.
Programs That Lower What You Pay
Extra Help, also called the Low-Income Subsidy, reduces or eliminates Part D premiums, deductibles, and copayments for people with limited income and resources. For 2026, the income limit is $23,940 for an individual or $32,460 for a married couple, with resource limits of $18,090 and $36,100.13Medicare. Help with Drug Costs Those thresholds correspond roughly to 150 percent of the federal poverty level. Partial assistance is available above the full-benefit cutoff, so applying is worthwhile even if your income is somewhat higher.
Many biologic manufacturers run patient assistance programs that supply free or discounted medication to people who qualify, with rules that vary by company. Nonprofit organizations also offer copayment assistance for specialty drugs. Your prescriber’s office, a hospital social worker, or a State Health Insurance Assistance Program counselor can help match you to a program.