Medications
Filgrastim-aafi (Nivestym)
A biosimilar white-blood-cell growth factor (Nivestym) given as an injection under the skin or by IV infusion; it helps the body make neutrophils, the white blood cells that fight infection, to lower infection risk after chemotherapy and in other low-white-count conditions.
How Medicare covers it
Part D (prefilled syringes and vials used at home when the injection is self-given or given by a trained caregiver). Part B covers Nivestym when a clinician gives it in an office or clinic (Q5110 — see the Part B basis in this package). Part A during a covered inpatient stay.
| Coverage details | |
|---|---|
| Part B status | CMS Part B Spending by Drug HCPCS file (RY26, data through 2024) carries Q5110 (filgrastim-aafi, Nivestym): the clinician-administered path is Part B. Originator filgrastim (Neupogen) and the other biosimilars (filgrastim-sndz Zarxio, filgrastim-ayow Releuko, tbo-filgrastim) are distinct RxNorm ingredients and are explicitly NOT matched. |
| Medicare Advantage | Most Medicare Advantage plans that include drug coverage (MAPD plans) use the same formulary-and-tier system; the plan's own drug list decides coverage and copay — check the plan's formulary. |
| Medicare Supplement (Medigap) | Medicare Supplement (Medigap) plans sold today do not include prescription drug coverage; drug coverage comes from Part D or an MAPD plan. |
What it treats
Lowers the chance of infection (febrile neutropenia) in people with nonmyeloid cancers receiving chemotherapy that strongly lowers white blood cells. It is also used around bone marrow transplantation, to prepare blood for stem-cell (peripheral blood progenitor cell) collection, for severe chronic neutropenia, and to increase survival after exposure to high doses of radiation (Nivestym label).
What it is for, in depth
Filgrastim-aafi, sold as Nivestym, is a man-made growth factor that helps the body make neutrophils, the white blood cells that fight infection. It lowers the chance of infection, including febrile neutropenia, in people with nonmyeloid cancers who are getting chemotherapy that strongly lowers white blood cells. It is also used around bone marrow transplantation, to prepare blood for stem-cell collection, for severe chronic neutropenia, where white counts stay very low over time, and to increase survival after exposure to high doses of radiation. It is given as an injection under the skin or as an IV infusion, usually once a day. It comes in prefilled syringes of 300 mcg/0.5 mL and 480 mcg/0.8 mL, and in single-dose vials. Patients or caregivers can be trained to give the under-the-skin shots at home.
How it works
It is a granulocyte colony-stimulating factor (G-CSF) and a biosimilar of filgrastim (Neupogen). It stimulates the bone marrow to make more neutrophils, the white blood cells that fight bacterial infection, and helps them mature and work.
How it is taken
Given as an injection under the skin (subcutaneous) or as an IV infusion, usually once a day. For chemotherapy patients the usual starting dose is 5 mcg/kg/day, started at least 24 hours after chemotherapy and never within 24 hours before it, and continued daily until white counts recover. It comes in prefilled syringes (300 mcg/0.5 mL and 480 mcg/0.8 mL) and single-dose vials, and patients or caregivers can be trained to give the under-the-skin injections at home.
Common side effects
Bone pain is the most common side effect. Medullary bone pain, muscle aches, headache, nausea, fever, tiredness, rash, and pain or redness at the injection site also occur.
Serious warnings
Rare but serious risks include spleen rupture (which can be fatal — left upper belly or shoulder pain needs urgent care), acute respiratory distress syndrome (ARDS), serious allergic reactions including anaphylaxis, sickle cell crises in people with sickle cell disorders, kidney injury (glomerulonephritis), capillary leak syndrome, bleeding from inflamed lung tissue, aortitis (inflammation of the aorta), and, with long-term use in congenital neutropenia, myelodysplastic syndrome and acute myeloid leukemia. White blood cell counts are monitored during treatment.
Who should be careful
Do not use it after a serious allergic reaction to filgrastim or pegfilgrastim products. People with sickle cell disorders, breathing problems, kidney problems, or an enlarged spleen need extra monitoring. It is used in children for several indications, with dosing by weight. People who are pregnant or breastfeeding should discuss the published data with their doctor — studies have not established an association with major birth defects.
Major interactions
The label lists no major drug interaction table for filgrastim products. Timing matters most: do not give it in the 24 hours before or after cytotoxic chemotherapy, because dividing blood cells are sensitive to chemotherapy. Lithium release effects on neutrophils and other blood-growth factors are discussed on the label — the care team should know all medicines being taken.
Why it is in its tier
Filgrastim-aafi is most often placed on Tier 5. In Medicare Part D, Tier 1 is the lowest-cost tier, often $0-$15, and each higher tier usually means a higher copay or coinsurance. Tier 5 is the specialty tier and carries the highest percentage coinsurance, so a Tier 5 placement means the highest cost-share level. In the CMS formulary data, 2446 plans list this drug, a listing share of 44.51%. Of those listing plans, 96.73% place it on Tier 5, a clear majority, and the tier counts show 2366 plans at that tier. Its specialty placement and high cost level are visible in the data: the CMS dashboard average spending was $3673.6885436 per beneficiary in 2024. That is a CMS program average, not a patient's copay.
Sources
- NIVESTYM- filgrastim-aafi injection, solution — DailyMed
- MedlinePlus — National Library of Medicine
- MedlinePlus — Filgrastim Injection
What official patient guides say
This MedlinePlus page covers filgrastim injection generally, for several filgrastim products including Nivestym; the packaged product here is filgrastim-aafi, the Nivestym biosimilar, so the guidance below is the page's general filgrastim guidance as it applies to that product. Filgrastim comes as a solution in vials and prefilled syringes, injected under the skin or into a vein, usually 1 to 2 times a day, with treatment length depending on the condition and how your body responds. It may be given by a nurse or other healthcare provider, or you or a caregiver may be shown how to inject it under the skin at home. Use it exactly as directed, do not shake the vial or syringe, look at the solution before injecting and do not use it if it has particles or looks foamy, cloudy, or discolored, and use each vial or syringe only once, disposing of used needles, syringes, and vials in a puncture-resistant container. If you inject at home and forget a dose, the page directs you to talk to your doctor about what to do. Store it in the refrigerator in its original container, out of the reach of children; if accidentally frozen once, let it thaw in the refrigerator, but dispose of a vial or syringe frozen a second time, and Nivestym may be kept at room temperature for up to 24 hours away from direct sunlight.
Part D formulary coverage
| Formulary summary | |
|---|---|
| Most common tier | 5 |
| Plans listing this drug | 2446 |
| Total Part D plans | 5495 |
| Share of plans listing it | 44.51 |
| Formularies listing it | 170 |
| Tier | Plans |
|---|---|
| Tier 1 | 75 plans |
| Tier 4 | 5 plans |
| Tier 5 | 2366 plans |
Source: CMS Prescription Drug Plan Formulary, Pharmacy Network, and Pricing Information Files — Monthly file 2026-10-15 (plan year 2027), file 2027_20261008.zip (data.cms.gov dataset ed1496ea-23e7-41f1-9292-172fa842ccfb): basic drugs formulary file + plan information file, both dated 20261031 inside the zip; downloaded and aggregated 2026-10-30. Medication RxCUI sets resolved through the NLM RxNav (RxNorm) API.
What you pay
| With Medicare Part D | |
|---|---|
| Most common tier | Tier 5 |
| Typical coinsurance | 25.0% of the price |
| Based on | 2328 plans that cover this drug · 2027 plan year |
A tier is not a price; what you pay depends on your plan, pharmacy, and benefit stage; Extra Help or Medicaid can lower it further.
Sources: CMS Plan Benefit Package + formulary data; CMS NADAC · Checked 2026-11-07
Similar medications
Other medications in the same FDA pharmacologic class (Leukocyte Growth Factor):
Read next
Part D spending averages (2024)
| Brand name | Generic name | Total claims 2024 | Total spending 2024 | Total beneficiaries 2024 | Rank by beneficiaries 2024 |
|---|---|---|---|---|---|
| Nivestym* | Filgrastim-Aafi | 13262 | 1.54368e+07 | 4202 | 1260 |
Source: CMS Medicare Part D Spending by Drug (Drug Spending Dashboard), release RY26 P04 V10, data through 2024 (DSD_PTD_RY26_P04_V10_DY24_BGM.csv), downloaded 2026-10-30
Companies covering this drug
2,446 plans from 258 companies list this drug on a formulary for 2027. Search by company or plan name, or filter by tier. Cost sharing is the plan's published amount for this drug's tier in the initial coverage stage (1-month retail supply), where the plan publishes it; a blank means the plan does not publish it.
| Company | Plan | Tier | Copay | Coinsurance |
|---|
A tier is not a price; what you pay depends on your plan, pharmacy, and benefit stage; Extra Help or Medicaid can lower it further.
Coverage and costs change. Drug lists (formularies), tiers, and copays can change during the year and differ by plan. Always check with your insurance company or plan directly to confirm what is covered and what you will pay.
Care and Living Guide is not connected with or endorsed by the U.S. government or the federal Medicare program. For official information visit Medicare.gov or call 1-800-MEDICARE.