Hemgenix Shortage Update: What Patients Need to Know in 2026

In March 2026, CSL Behring released a formal letter to the hemophilia B community confirming a temporary global stockout of Hemgenix (etranacogene dezaparvovec-drlb). For patients who have been planning to receive this one-time gene therapy — including those actively in the insurance authorization process or waiting to schedule their infusion — this news was alarming.

Here is the most current information available, along with practical guidance for patients navigating this disruption.

What CSL Behring Said About the 2026 Stockout

CSL Behring was explicit in its March 2026 communication that the global stockout is:

Not related to safety or effectiveness. Hemgenix remains FDA-approved and clinically proven. No new safety concerns have been identified.

Due to manufacturing complexity. Gene therapy production requires extraordinary precision, specialized bioreactors, and multi-stage quality testing. Even small deviations can delay batch releases.

Temporary in nature. CSL Behring stated it is working with regulatory authorities on strategies to ensure stable ongoing supply and remains fully committed to making Hemgenix available.

Why Gene Therapies Are Uniquely Vulnerable to Stockouts

Unlike conventional drugs produced in massive quantities, gene therapies like Hemgenix are manufactured in much smaller volumes for rare patient populations. Hemophilia B affects approximately 1 in 40,000 people — about 7,250 patients in the U.S. — so production batches are small and highly customized. Each patient receives a weight-specific kit (such as the 126–130 kg kit), meaning the drug cannot simply be repackaged or redirected from inventory.

The manufacturing process also involves growing viral vectors (AAV5) in regulated cleanrooms, extensive sterility testing, and regulatory batch-release testing by both FDA and EMA before any product can be shipped. A single failed batch can create a supply gap that takes months to resolve.

Hemgenix Shortage History: Is This the First Time?

Hemgenix was first approved in November 2022 as the world's first gene therapy for hemophilia B. Since its commercial launch, supply has been inherently limited by the complexity of manufacturing and the controlled distribution network (only certified hemophilia treatment centers can administer it). The 2026 global stockout represents the first confirmed large-scale supply disruption since commercial launch.

The broader gene therapy space has seen similar challenges. Pfizer's Beqvez (the second gene therapy for hemophilia B, approved April 2024) was discontinued entirely in February 2025 due to low commercial uptake — a different kind of access failure, but one that leaves Hemgenix as the only gene therapy option for hemophilia B going into 2026.

How This Stockout Affects Patients Waiting for Hemgenix

If you were in any of the following situations when the stockout was announced, here's what it means for you:

In the insurance prior authorization process: Continue — having your authorization approved before supply returns positions you to receive treatment quickly.

Completing pre-treatment eligibility tests: Continue — pre-screening results are time-limited, so track expiration dates and plan retesting if needed.

Had a treatment date scheduled: Contact your hemophilia treatment center immediately. Your center has direct communication with CSL Behring and can provide your specific situation update.

Just beginning to explore Hemgenix: Start the process now. Pre-screening and insurance paperwork take weeks and should run parallel to the supply recovery timeline.

What Patients Should Do Right Now

Call HEMGENIX Connect: 1-833-436-0021, M–F 8AM–8PM ET. Your Case Manager is the best source of real-time information on supply status and treatment timelines.

Keep your hematologist informed: Your treating physician at a certified HTC will receive communications from CSL Behring with specific supply updates for their region.

Do not stop your current Factor IX therapy: Maintain your prophylaxis regimen. If you face coverage or access issues with your current therapy, your Case Manager can help.

Discuss bridge therapy options: If your current Factor IX regimen is not adequately controlling bleeds, ask your hematologist about extended half-life options like Alprolix or Idelvion as a bridge.

Use medfinder to check regional availability: medfinder contacts treatment centers near you to find out which ones currently have Hemgenix in stock, so you don't have to make dozens of calls yourself.

For additional context on why Hemgenix supply is so limited, read Why Is Hemgenix So Hard to Find? And visit medfinder.com to locate centers with available supply near you.