Key takeaways

  • Medicare covers immunotherapy costs under different parts, though you may have some out-of-pocket expenses depending on your coverage.
  • Each part of Medicare (A, B, C, D) covers a specific portion of immunotherapy treatment and has varying costs. You must meet your plan’s deductible before it begins paying for treatment.
  • The cost and coverage for immunotherapy vary based on the type of medication, where you receive it, and your specific Medicare plan.

Each part of Medicare covers a different portion of immunotherapy treatment, but you can expect some out-of-pocket expenses.

Your coverage may vary depending on where you receive the medication and what type of medication it is.

Part A is hospital insurance. It covers inpatient immunotherapy during a hospital stay and limited stays in skilled nursing facilities.

Here are the basic costs for Part A in 2025:

  • $285 or $518 monthly premium, if you have one
  • $1,676 deductible for each benefit period
  • 20% of all Medicare-approved costs during your stay
  • $0 coinsurance for days 1 to 60 of treatment after you pay your deductible
  • $419 coinsurance per day for days 61 to 90 of treatment
  • $838 coinsurance per day for days 91 to 150 of treatment while using your 60 lifetime reserve days
  • 100% of the treatment costs for days 151+

Part B is medical insurance. It covers visits to outpatient centers like doctor’s offices or freestanding clinics. When you’re receiving cancer treatments, Part B will cover a variety of therapies, including:

Here are the basic costs for Part B in 2025:

  • $185+ monthly premium, if you have one
  • $257 deductible
  • 20% of all Medicare-approved costs during your treatment
  • any copayment or coinsurance fees

Part C, or Medicare Advantage, bundles hospital and medical insurance with prescription drug coverage (Part D).

Costs vary depending on the plan and provider you choose. Each plan has a different premium, deductible, copayment, and coinsurance amount. That said, according to the Centers for Medicaid & Medicare (CMS), the average monthly premium for Part C plans is around $17.00 in 2025.

Staying within your plan’s “network” of healthcare professionals, pharmacies, and other providers ensures you receive the maximum coverage at the lowest out-of-pocket cost.

Once you pay your plan’s out-of-pocket maximum, your plan will cover 100% of all Medicare-approved costs.

Part D covers prescription drugs that you take outside of a healthcare facility. Like Part C, Part D plans are private and have different premiums, deductibles, and copayments or coinsurance amounts. The national base beneficiary premium is $36.78 in 2025.

In addition, the amount of coverage each plan provides per drug depends on its formulary and tier system. A formulary is a list of medications the plan covers. Those medications are then divided into groups or tiers, typically based on cost.

Part D costs and coverage for individual immunotherapy drugs can vary based on the medication.

Let’s look at the cost of Keytruda as an example.

In 2025, a single 200-milligram (mg) dose costs $11,564.16 without insurance and is administered every 3 weeks. A 400-mg dose costs $23,138.32 without insurance and is administered every 6 weeks.

According to a 2022 analysis of commercial and Medicare claims for 200-mg Keytruda in 2020:

  • About 80% of people with Original Medicare without supplemental Medigap insurance paid $1,200 to $2,100 per 200-mg infusion.
  • 38% of people with a Part C plan had no out-of-pocket costs. About 80% paid $0.01 to $925 per 200-mg infusion.
What is Medigap?

Medigap can help cover some costs associated with parts A and B, such as premiums, deductibles, and copays. You can only enroll in Medigap if you have an Original Medicare plan.

You can’t enroll in Medigap if you have a Part C plan.

Immunotherapy is covered under the various parts of Medicare. You’ll need to meet your plan’s deductible and then pay some coinsurance or copayment costs.

Talk with your plan provider to get a better understanding of how much coverage you’ll receive before you start your treatment.