How to Help Your Patients Find Releuko In Stock: A Provider's Guide

For oncology care teams, managing G-CSF therapy is an essential component of supporting patients through myelosuppressive chemotherapy. Releuko (filgrastim-ayow) is an effective filgrastim biosimilar, but its specialty distribution model, insurance formulary position, and cold-chain requirements create access challenges that many patients cannot navigate without provider support. This guide gives you practical, actionable steps to help your patients find and access Releuko when issues arise.

Understanding Why Patients Struggle to Find Releuko

Most patients are unfamiliar with how specialty biologics are distributed. When they're told to fill a Releuko prescription, they may instinctively go to their local retail pharmacy and be turned away — or given incorrect information about availability. As a provider, understanding the distribution landscape helps you set the right expectations and steer patients toward the right resources from day one.

Key barriers your patients face:

Retail pharmacies don't carry it: Releuko requires cold-chain storage (2–8°C) and is distributed through specialty distributors, not standard wholesale pharmacy networks.

Prior authorization delays: Most commercial insurers require PA for specialty biosimilars. Without proactive submission, patients may face 3–10 day delays.

Step therapy requirements: Many plans prefer Zarxio and require documentation of a Zarxio trial before approving Releuko.

No automatic substitution: A pharmacist cannot swap Releuko for another filgrastim product without a new prescription from the prescriber.

Step 1: Use Buy-and-Bill When Possible

The simplest way to ensure patients receive Releuko on schedule is to administer it in your clinic through the buy-and-bill model. Your clinic purchases Releuko directly from a specialty distributor (such as AmerisourceBergen Specialty Group, McKesson Specialty, or Cardinal Health Specialty), administers it, and bills the patient's insurer under HCPCS code Q5125 for Medicare Part B or the appropriate commercial billing code. This removes the patient from the pharmacy access equation entirely and allows you to control supply and timing.

Best practice: Order Releuko from your specialty distributor 5–7 business days before the patient's scheduled dose, particularly around holidays or high-volume periods when distributor supply may be stressed.

Step 2: Refer Patients to In-Network Specialty Pharmacies Early

For patients who self-administer Releuko at home (common in chronic neutropenia), provide a referral to an in-network specialty pharmacy at the time of prescribing — not after they've already struggled at a retail pharmacy. Recommended specialty pharmacies that handle oncology biologics include Accredo (Express Scripts), CVS Specialty, Walgreens Specialty, and Biologics by McKesson. Your clinic's patient navigation or prior authorization team can confirm which pharmacies are in-network for each patient's specific insurance plan.

Step 3: Submit Prior Authorization Before the First Cycle

Never wait until after chemotherapy begins to submit a PA for Releuko. Submit it when the treatment plan is finalized — ideally 7–10 days before the anticipated start of G-CSF therapy. Key documentation to include in your PA submission:

The patient's diagnosis and stage

The chemotherapy regimen and myelosuppressive risk category (high-risk = >20% febrile neutropenia risk)

Clinical rationale if choosing Releuko over the payer's preferred formulary product (Zarxio)

NCCN guideline references supporting G-CSF use for the specific regimen

Step 4: Have a Rapid-Switch Protocol Ready

When Releuko is unavailable — whether due to formulary denial, supply issues, or specialty pharmacy barriers — your team should be able to rapidly switch to an available filgrastim alternative without significant workflow disruption. Recommended approach:

Identify the best available alternative (Zarxio, Nivestym, or Neupogen) based on the patient's insurer and indication

Issue a new prescription for the specific alternative product

Contact the specialty pharmacy directly to expedite the fill and same-day or next-day delivery if available

Document the switch in the patient's chart and notify billing to adjust the claim codes accordingly

Step 5: Direct Patients to medfinder for Retail Pharmacy Searches

For patients managing their own access, recommend medfinder — a service that calls pharmacies near the patient to check availability. This is especially valuable for patients in areas with limited specialty pharmacy access or those managing chronic neutropenia with home-administered injections. medfinder texts results directly to the patient, eliminating the need for them to make dozens of phone calls. For a clinical overview of the broader shortage landscape, see our provider-focused Releuko shortage guide.

Documentation Best Practices

Whenever a product switch occurs due to availability, document the following in the patient's chart: (1) the original prescribed product and the reason for switching, (2) the alternative product dispensed and the date of the switch, (3) any clinical equivalence discussion with the patient, and (4) the updated billing codes used for the alternative product. This documentation protects you in the event of an audit and supports future PA requests.