Zarxio (filgrastim-sndz) has been hard to find at pharmacies. Learn why there's a shortage in 2026 and what you can do to get your prescription filled.
You just finished a round of chemotherapy. Your doctor hands you a prescription for Zarxio to help your white blood cell count recover. You call your pharmacy — and they tell you it's out of stock. You try another pharmacy. Same answer. It's a frustrating, scary experience, especially when your immune system is already compromised.
If this sounds familiar, you're not alone. Thousands of patients across the country have struggled to find Zarxio (filgrastim-sndz) over the past few years. In this article, we'll explain what Zarxio is, why it's been so hard to find, and — most importantly — what you can do about it.
Zarxio is a biosimilar medication — essentially, a near-identical copy of the brand-name drug Neupogen (filgrastim). It's made by Sandoz, a division of Novartis, and was actually the first biosimilar ever approved in the United States back in 2015.
Zarxio belongs to a class of drugs called granulocyte colony-stimulating factors (G-CSFs). It works by telling your bone marrow to produce more white blood cells, specifically neutrophils — the cells your body uses to fight infections.
Doctors prescribe Zarxio most commonly to:
Because Zarxio is a biologic medication given by injection, it can't simply be made by any pharmaceutical company. Manufacturing is complex, which plays a big role in the supply problems we'll discuss next.
There's no single reason Zarxio is hard to find. Instead, it's a combination of factors that have created a perfect storm of supply issues.
Unlike a simple pill, Zarxio is a biologic medication made from living cells. The manufacturing process involves growing specific proteins in controlled environments, which takes time, precision, and specialized facilities. If anything goes wrong at any step — contamination, equipment failure, quality control issues — entire batches can be lost. You can't just flip a switch and make more overnight.
Only a handful of companies in the world produce filgrastim products. When one manufacturer experiences a disruption, the remaining suppliers can't always pick up the slack. This is different from common generic pills, where dozens of companies might produce the same drug.
Cancer treatment has become more accessible and more aggressive in recent years, which means more patients need supportive medications like Zarxio. Seasonal flu outbreaks and other infections can also increase demand unexpectedly. When demand spikes and supply is already tight, shortages get worse.
Even when Zarxio is being manufactured, it needs to be stored and shipped under refrigeration — a cold chain that adds complexity. Distribution bottlenecks, shipping delays, and inventory management issues at wholesalers and pharmacies all contribute to spotty availability. Some pharmacies may have it while the one down the street doesn't.
Finding Zarxio might take some extra effort, but there are practical steps you can take right now.
Medfinder helps you search for pharmacies that currently have Zarxio in stock near your location. Instead of calling pharmacy after pharmacy, you can check availability online in seconds. This is especially helpful during shortage periods when stock changes daily.
Large chain pharmacies (CVS, Walgreens, etc.) often get the most attention during shortages, so their stock runs out fastest. Independent pharmacies and specialty pharmacies that focus on oncology medications may have better availability. Your oncologist's office may also have a preferred specialty pharmacy they work with.
If Zarxio is truly unavailable, your doctor can prescribe a similar G-CSF medication. Options include Neupogen (the original filgrastim), Granix (tbo-filgrastim), or longer-acting options like Neulasta (pegfilgrastim) or its biosimilar Udenyca. Your doctor can help determine which alternative is right for your situation.
If your insurance requires Zarxio specifically but it's unavailable, call your insurance company and ask for a formulary exception. During active shortages, many insurance plans will approve coverage for alternative G-CSF products.
Sandoz, the manufacturer of Zarxio, offers patient support through their Sandoz One Source program. They may be able to help you locate available supply or connect you with a specialty pharmacy.
Being unable to find a critical medication like Zarxio is stressful — especially when you're already dealing with cancer treatment or another serious condition. The shortage is real, and it's caused by factors largely outside your control.
But you do have options. Use tools like Medfinder to find pharmacies with Zarxio in stock, explore alternatives with your doctor, and don't hesitate to reach out to your insurance company or Sandoz for help. The more proactive you are, the better your chances of getting the treatment you need on time.
For the latest updates on Zarxio availability, check our Zarxio shortage update for 2026.
You focus on staying healthy. We'll handle the rest.
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