Releuko Shortage Update: What Patients Need to Know in 2026

If you rely on Releuko (filgrastim-ayow) to manage chemotherapy-induced neutropenia or another form of low white blood cell count, staying on schedule matters enormously. Even a short gap in therapy can increase your risk of infection during an already vulnerable time. This article covers the current state of Releuko availability in 2026, what's driving access challenges, and what you can do to protect your treatment.

Is Releuko in a Shortage in 2026?

As of 2026, Releuko is not listed as an active national shortage on the FDA's Drug Shortage Database. However, this doesn't tell the full story. Releuko is a specialty oncology injectable that is primarily distributed through specialty pharmacies and oncology clinic buy-and-bill programs — not through retail pharmacy channels. Many patients who are prescribed Releuko experience real difficulty locating it, even when national supply is technically adequate.

The key point: a drug can be technically "not in shortage" while still being very difficult to access for individual patients depending on their location, insurance plan, and the type of pharmacy they use.

What Makes Releuko Hard to Access Even Without a Formal Shortage?

Several structural factors affect Releuko availability:

Specialty distribution only: Releuko is distributed through specialty pharmaceutical channels, not the standard retail pharmacy wholesale network. Most retail pharmacies do not carry it.

Cold-chain requirements: Releuko must be kept refrigerated at 2–8°C and can only be held at room temperature for 24 hours. This limits which pharmacies can handle it.

Insurance formulary restrictions: Many insurers list Zarxio as the preferred filgrastim biosimilar and require step therapy — meaning you must try Zarxio first. This can delay access to Releuko even when it's the prescribed option.

No automatic substitution: A pharmacist cannot swap in another filgrastim product without a new prescription. If a pharmacy is out of Releuko, you're effectively stuck until your oncologist writes a new script.

Prior authorization delays: Most insurers require prior authorization for specialty biologics. PA approvals can take days, creating gaps in therapy for newly prescribed patients.

The History of Filgrastim Supply: Should Patients Be Concerned?

Filgrastim products — including Neupogen, Zarxio, and Nivestym — have a long track record of supply stability. Releuko, as the newest filgrastim biosimilar (approved February 2022), has had relatively stable supply since its U.S. launch in Q3 2022. Amneal Pharmaceuticals and Kashiv Biosciences manufacture it domestically, which helps insulate it from some of the international supply chain risks that affect other injectable biologics.

Broader filgrastim products have appeared on the FDA shortage list at various times historically — particularly the injectable forms of generic filgrastim — but there is no current indication of a manufacturing problem with Releuko or its active supply chain as of 2026.

What Should Patients Do Right Now?

Even without a formal shortage, proactive steps can prevent treatment gaps:

Confirm your supply 5–7 days before you need your next dose. Don't wait until the day before your chemotherapy cycle to check on availability.

Verify your prior authorization is active. PA approvals can expire. Call your insurer or have your oncology team check before each chemotherapy cycle.

Know your specialist pharmacy. Establish a relationship with a specialty pharmacy that reliably carries Releuko so you're not scrambling each cycle.

Ask your oncologist about alternatives. Know in advance whether Zarxio or Nivestym are acceptable alternatives for your treatment plan, so a switch can happen quickly if needed.

Use medfinder. medfinder calls pharmacies near you to find which ones have Releuko in stock, saving you the time and stress of calling multiple pharmacies yourself.

How to Monitor Releuko Availability Going Forward

Bookmark the FDA Drug Shortage Database and check it monthly. Search for both "Releuko" and "filgrastim-ayow." If a shortage is declared, the database will list the reason, affected products, and estimated resupply timelines. For more background on why Releuko can be difficult to find, read our article on why Releuko is so hard to find.