Rituximab (Rituxan) and Medicare

The short answer

Rituximab is an infusion, so Part B covers it. You pay 20%, and there is no yearly limit on that 20%. There is no pill, no home injection and no Part D version for rheumatology — so the $2,100 Part D cap you may have heard about does not apply to you at all.

The only things that cap it are a Medicare supplement policy, an Advantage plan’s yearly limit, Medicaid, or a charitable foundation.

Here the cheaper version really is much cheaper

There are three rituximab biosimilars on the market — Truxima, Ruxience and Riabni. Unlike infliximab, where switching saves almost nothing, the gap here is enormous. Medicare pays this much per 10 mg:

Because you pay 20% of whichever one you get, that difference lands directly on you. All three biosimilars are approved for rheumatoid arthritis and for GPA and MPA — the two forms of ANCA-associated vasculitis — in adults. So for most rheumatology patients this is a real conversation to have.

One thing to check rather than assume: make sure the product your plan prefers is approved for your condition. The adult labels line up today, but the biosimilars are approved for adults only, where the original also covers children. If you are on Medicare through a disability and were diagnosed young, that gap is worth raising.

What a year actually costs

These are your 20%, after the $283 Part B deductible.

Vasculitis induction doses depend on your height and weight, so that row is an estimate for an average-sized adult. If rheumatoid arthritis is re-treated more than once a year, the cost multiplies accordingly. The infusion visit is billed separately on top.

Why the bills feel so brutal

Someone on a monthly infusion pays a little every month. Rituximab is given two or three times a year, so the same annual cost arrives as a few very large bills.

A single 1,000 mg Rituxan infusion is about $1,470 to you. For rheumatoid arthritis you get two of those two weeks apart — roughly $2,900 inside a fortnight, and then nothing for months.

Two things follow from that. First, ask what product you are getting before the first infusion, not after the bill. Second, remember the Part B deductible resets every January — if the timing of the first infusion of the year is flexible at all, it is worth a conversation.

If you have vasculitis, read this part

Maintenance for GPA or MPA is often 500 mg every six months, indefinitely. That is around $1,470 a year on Rituxan, or around $320 on Ruxience — every year, with no cap, for as long as you stay on it.

Over ten years that difference is more than $11,000. It is the single largest lever you have on this medication, and it costs nothing to ask about.

A few other things specific to vasculitis care that affect timing rather than cost: your response to vaccines is blunted after an infusion, so vaccines are best timed beforehand; hepatitis B screening is required before starting; and preventive antibiotics are standard during induction. Your rheumatologist will handle all of it — it is worth knowing so the scheduling makes sense.

Approvals: none under Original Medicare

Original Medicare requires no prior authorization for rituximab given in a doctor’s office or infusion suite, and cannot require you to try something else first.

Medicare Advantage plans routinely require a biosimilar first. One national insurer’s 2026 policy lists Riabni, Ruxience and Truxima as the preferred products, with Rituxan available only if you have failed or cannot take one of them. Many plans grandfather you in if you have had a paid claim in the past year — so if you are switching plans, that is worth asking about specifically.

If a request is denied, appeal. Across Medicare Advantage in 2024, only about one denial in nine was appealed — and 81% of those appeals succeeded.

Things that surprise people

• The Rituxan copay card does not work if you have Medicare. Federal law prohibits it, and that includes Medicare Advantage and Medigap.
• Charitable foundations do work — Good Days, the HealthWell Foundation and the PAN Foundation among them. Their disease funds open and close through the year, so if one is closed, check again in a month. The manufacturer’s own foundation can also supply the drug free if your out-of-pocket costs exceed a share of your income.
• Rituximab infusions are long — often four to six hours — and you pay 20% of that infusion charge too.
• Hospital outpatient departments cost you more than a doctor’s office or an independent infusion suite for the identical medication, because of the facility fee.
• Truxima became the first interchangeable rituximab in 2026. That is a technical designation about pharmacy substitution; it does not change what your doctor can prescribe.

Free help, from someone who is not paid a commission

• Washington: SHIBA — insurance.wa.gov/shiba or 1-800-562-6900
• Any other state: SHIP — shiphelp.org
• Compare plans — medicare.gov/plan-compare
• Extra Help — ssa.gov/medicare/part-d-extra-help

Why isn’t my infusion covered by the $2,100 cap?

Because the $2,100 cap only applies to Part D, and an infusion is paid by Part B. The cap Congress created covers drugs you pick up and take yourself. A medication a nurse or doctor gives you is paid under Part B instead, where you owe 20% of the cost every time and there is no annual ceiling at all.

It is the same Medicare, often the same drug, and frequently the same disease. The rulebook is chosen by who puts the medicine in you. Almost everything written about the cap leaves this out, so people on infusions read that their costs are now limited, and then the bills keep coming.

A worked example. If Medicare’s approved amount for a year of your infusions is $18,000, you owe about $3,600 — this year, next year, and every year you stay on it. The $2,100 cap does not apply to any of it.

Four things do put a ceiling on Part B costs:

• A Medicare supplement (Medigap) policy, which pays the 20% for you. This is the main one, and the window to buy one closes six months after you enroll in Part B in most states.
• A Medicare Advantage plan’s yearly out-of-pocket maximum, which applies to everything the plan covers — though it comes with prior authorization attached.
• QMB, a Medicare Savings Program that eliminates the 20% entirely. This is the one people are not told about — and note that Extra Help, which people are told about, does nothing for a Part B drug.
• Full Medicaid, or retiree coverage that pays after Medicare.

Related

• Medicare and your medication
• Why your medication needs permission first
• Infliximab and Medicare — where switching to a biosimilar saves you almost nothing
• Tocilizumab and Medicare
• Where you get infused changes the bill — the same infusion costs more at a hospital, and the bill nobody warns you about

Where these figures come from

1. Medicare payment limits per 10 mg, CMS Part B ASP pricing file effective July 1 – September 30, 2026: Rituxan (J9312) $73.278; Truxima (Q5115) $34.563; Riabni (Q5123) $18.533; Ruxience (Q5119) $16.160.
2. Rituxan prescribing information — FDA. Rheumatoid arthritis: two 1,000 mg infusions two weeks apart, repeated every 24 weeks or based on clinical evaluation but not sooner than every 16 weeks. GPA and MPA induction: 375 mg/m² weekly for 4 weeks with glucocorticoids; follow-up treatment: two 500 mg infusions two weeks apart, then 500 mg every 6 months.
3. Part B annual deductible $283 and 20% coinsurance with no annual limit for 2026 — CMS, “2026 Medicare Parts A & B Premiums and Deductibles”; Social Security Act §1833(a). Vasculitis induction figures assume a body surface area of 1.8 m².
4. Rituximab biosimilar indications — product labels via DailyMed and the manufacturers. Truxima, Ruxience and Riabni each carry rheumatoid arthritis and GPA/MPA in adults; Rituxan additionally carries GPA/MPA from age 2. Rituxan Hycela, the subcutaneous form, is expressly not indicated for non-malignant conditions.
5. Truxima interchangeability, July 2026 — reported by industry legal press; not confirmed on an FDA-hosted page at the time of writing. A further rituximab biosimilar was approved in August 2026 with no brand name or price published yet.
6. No prior authorization program in Original Medicare covers physician-administered drugs — CMS, Prior Authorization and Pre-Claim Review Initiatives. Step therapy permitted for Medicare Advantage Part B drugs — 42 CFR §422.136; the preferred-product example is taken from a national insurer’s published 2026 Part B step therapy program.
7. Medicare Advantage appeal rates and outcomes for 2024 (11.5% of denials appealed, 80.7% overturned) — KFF analysis of CMS data, 2026.
8. Medicare Part B spending 2024: Rituxan $437 million across 22,261 beneficiaries; Truxima $127 million across 15,052; Riabni $92 million across 8,580; Ruxience $81 million across 15,510 — CMS Medicare Part B drug spending dashboard.
9. Copay assistance is prohibited for federal healthcare program beneficiaries — federal Anti-Kickback Statute, 42 U.S.C. §1320a-7b; Genentech Rituxan financial support terms.

About this page

Written and reviewed by Alison Bays, MD, MPH, board-certified rheumatologist. Figures are current for 2026 and were last checked in August 2026.

This is educational information, not advice — not medical, legal, financial or insurance advice, and not a substitute for talking to your doctor or your plan. Nothing is sold here. No insurance is sold here, no plan is recommended, and neither this page nor its author is paid by any insurance company, plan, pharmaceutical manufacturer or broker. This page is not affiliated with, endorsed by, or connected to Medicare, the Centers for Medicare & Medicaid Services, or any government agency.

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