HEMGENIX has surpassed 100 commercial treatments worldwide for adults with hemophilia B as CSL expands access following supply restoration and ongoing clinical progress.
Written By: Rishabh Sonawane, BPharm
Reviewed By: Pharmacally Editorial Team
HEMGENIX® (etranacogene dezaparvovec-drlb) has surpassed 100 commercial treatments worldwide, reflecting continued expansion of access to the one-time gene therapy for adults with hemophilia B. CSL reported the milestone several months after reestablishing limited product supply, following manufacturing measures implemented to maintain quality standards.
Since restoring limited availability in April 2026, HEMGENIX has been administered to 22 people across commercial practice and clinical trial settings. These treatments include the first commercial administration of HEMGENIX in Canada and the first adolescent to receive the therapy in a global clinical trial for hemophilia B. While these pediatric data represent an important research milestone, HEMGENIX remains approved only for adult patients, with adolescent use currently being evaluated exclusively in clinical studies.
One-Time Gene Therapy for Hemophilia B
HEMGENIX is an adeno-associated virus serotype 5 (AAV5)-based gene therapy that delivers a functional copy of the Factor IX Padua gene variant to liver cells. The Padua variant produces a Factor IX protein with substantially higher clotting activity than the naturally occurring protein, enabling sustained therapeutic Factor IX expression after a single intravenous infusion and reducing the need for routine prophylactic Factor IX replacement therapy.
Hemophilia B is a rare inherited bleeding disorder caused by mutations in the F9 gene, resulting in inadequate Factor IX activity. Patients with moderate to severe disease remain at risk of spontaneous bleeding, recurrent joint hemorrhage, chronic arthropathy, and reduced quality of life. Although regular Factor IX prophylaxis has significantly improved outcomes, lifelong replacement therapy remains burdensome, making durable gene therapy an important treatment option for eligible adults.
Supply Recovery Supports Broader Patient Access
CSL previously reported temporary HEMGENIX supply limitations while implementing measures to ensure consistent product quality. According to the latest update, the company continues to actively manage available supply to support physicians and eligible patients throughout treatment planning, clinical evaluation, laboratory testing, and other readiness assessments before infusion.
The company said it remains focused on enabling healthcare providers and patients to continue shared decision-making while commercial availability gradually expands. Continued treatment across established and newly activated centers suggests that access is steadily increasing as supply recovers.
Safety Considerations
HEMGENIX is indicated for adults with hemophilia B who currently receive Factor IX prophylaxis, have experienced current or historical life-threatening hemorrhage, or have repeated serious spontaneous bleeding episodes.
Before treatment, patients undergo evaluation for Factor IX inhibitors, liver health, and hepatitis B and C infection. Depending on regional clinical practice and institutional protocols, additional eligibility assessments may also be performed before treatment. Patients are monitored during infusion and for at least three hours afterward because infusion-related reactions, including anaphylaxis, may occur.
Liver enzyme elevations remain an important safety consideration and require routine monitoring for up to one year following treatment. Corticosteroids may be used to manage increased liver enzymes when necessary. Because HEMGENIX targets liver cells, long-term follow-up for potential hepatic malignancy may continue for up to five years. The most commonly reported adverse events include elevated liver enzymes, headache, increased creatine kinase, flu-like symptoms, infusion-related reactions, fatigue, nausea, and malaise.
Path Forward
CSL said it will continue providing regular updates to healthcare professionals and patient organizations as HEMGENIX availability expands. With more than 100 commercial treatments now completed worldwide and additional experience accumulating across commercial practice and clinical studies, the company continues to support broader access to one-time gene therapy for eligible adults with hemophilia B while maintaining established manufacturing and quality standards.
Reference
About the Writer
Rishabha Sonawane, B.Pharm (LinkedIn) is healthcare writer with a strong interest in medical writing, regulatory affairs, clinical research, and AI-driven drug discovery. He has completed specialized training from the NIH and ICMR in clinical pharmacology, clinical research, and scientific writing. Passionate about evidence-based healthcare communication, he focuses on translating complex scientific research into clear, accurate, and engaging medical content.