Etranacogene Dezaparvovec

HEMGENIX is an adeno-associated virus serotype 5 (AAV5) based gene therapy designed to deliver a copy of a gene encoding the Padua variant of human coagulation Factor IX (hFIX-Padua). Single intravenous infusion of HEMGENIX results in cell transduction and increase in circulating Factor IX activity in patients with Hemophilia B.

• HEMGENIX is indicated for treatment of adults with Hemophilia B (congenital Factor IX deficiency) who: Currently use Factor IX prophylaxis therapy, or Have current or historical life-threatening hemorrhage, or Have repeated, serious spontaneous bleeding episodes. HEMGENIX is an adeno-associated virus vector-based gene therapy indicated for the treatment of adults with Hemophilia B (congenital Factor IX deficiency) who: Currently use Factor IX prophylaxis therapy, or Have current or historical life-threatening hemorrhage, or Have repeated, serious spontaneous bleeding episodes.

• None. None.contraindicated

For single-use intravenous infusion only. ( 2 ) Perform baseline testing to select patients, including testing for Factor IX inhibitor presence and liver health tests. ( 2.1 ) The recommended dose of HEMGENIX is 2 × 10 13 genome copies (gc) per kg of body weight. ( 2.1 ) Administer HEMGENIX as an intravenous infusion after dilution with 0.9% normal saline at a constant infusion rate of 500 ml/hour (8 mL/min). ( 2.1 ) 2.1 Critical Administration-related Information For single-use intravenous infusion only. For patient selection: Perform Factor IX inhibitor titer testing. Do not administer HEMGENIX for patients with positive FIX inhibitors or a prior history for FIX inhibitors. Perform liver health assessments, including: Enzyme testing [alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and total bilirubin)], hepatic ultrasound and elastography. In case of radiological liver abnormalities and/or sustained liver enzyme elevations, consider a consultation with hepatologist to assess eligibility for HEMGENIX. Perform laboratory tests to evaluate active hepatitis B and C. Postpone HEMGENIX treatment until patient does not have active hepatitis B or C infection as active infection may reduce the efficacy of HEMGENIX and/or increase the risk of adverse reactions [see Warnings and Precautions (5.2) ] .

Infusion reactions: Monitor during administration and for at least 3 hours after end of infusion. If symptoms occur, slow or interrupt administration. Re-start administration at a slower infusion once resolved. ( 2.3 , 5.1 ) Hepatotoxicity: Monitor transaminase levels once per week for 3 months and thereafter monthly up to 1 year after HEMGENIX administration to mitigate the risk of potential hepatotoxicity. Consider corticosteroid treatment should elevations occur and as clinically indicated ( 5.2 ) Hepatocellular carcinogenicity: For patients with preexisting risk factors consider liver ultrasound and alpha-fetoprotein testing following administration. ( 5.4 ) Monitoring Laboratory tests: Monitor for Factor IX activity and Factor IX inhibitors. ( 5.5 ) 5.1 Hypersensitivity and Infusion-Related Reactions Moderate to severe hypersensitivity and infusion-related reactions have occurred with HEMGENIX treatment [see Adverse Reactions (6) ] . Anaphylaxis may occur with HEMGENIX treatment. Symptoms may include chest tightness, headaches, abdominal pain, lightheadedness, flu-like symptoms, shivering, flushing, rash, and hypertension. Monitor patients for signs or symptoms of hypersensitivity and infusion-related reaction throughout the infusion period and for at least 3 hours after end of infusion. Do not infuse the product faster than 500 mL/hour [see Adverse Reactions (6) ] . In the event of hypersensitivity or infusion reaction during administration, the infusion may be slowed or stopped. If the infusion is stopped, restart at a slower rate when the symptoms have resolved.

The most common adverse reactions (incidence ≥5%) were elevated ALT, headache, blood creatine kinase elevations, flu-like symptoms, infusion-related reactions, fatigue, malaise and elevated AST. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact CSL Behring at 1-866-915-6958 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety of HEMGENIX was evaluated in two clinical studies (study 1 enrolled 3 patients and study 2 enrolled 54 patients). Both studies enrolled adult male patients with moderately severe or severe Hemophilia B (N = 57), who received a single intravenous dose of 2 × 10 13 gc/kg body weight of HEMGENIX. Three patients in study 1 and 50 of 54 patients from study 2 completed the study-specific 5-year follow-up period. No serious adverse reactions were reported [see Clinical Studies (14) ] . The most common adverse reactions observed in ≥5% of patients post-dose are listed in Table 4: Table 4.

No dose adjustment is required in geriatric, hepatic, or renal impaired patients. ( 8.5 , 8.6 , 8.7 ) 8.1 Pregnancy Risk Summary HEMGENIX is not intended for administration in women. No adverse effects on mating rate and fertility indices or fetal weights were observed in healthy naïve female mice mated with healthy male mice that were intravenously administered a predecessor of HEMGENIX product 6 days prior to mating. Vector DNA was not detected in the uterus, placenta, or fetus. In the United States general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. 8.2 Lactation Risk Summary HEMGENIX is not intended for administration in women. 8.3 Females and Males of Reproductive Potential Risk Summary No clinical studies have been performed to evaluate the effects of HEMGENIX on fertility in humans. Twenty days after intravenous administration of a predecessor of HEMGENIX product in healthy male mice, vector DNA was detected in all reproductive tissues examined (epididymis, seminal vesicles, testes, and sperm). However, no differences were observed in mating rates and fertility indices in healthy naïve female mice following mating with the dosed males. 8.4 Pediatric Use The safety and efficacy of HEMGENIX in pediatric patients have not been established.

Metabolism

Vector Biodistribution (within the body) and Vector Shedding (excretion/secretion) Nonclinical data Biodistribution of HEMGENIX was evaluated after intravenous administration in healthy male mice and non-human primates (NHPs). The highest levels of vector DNA were detected in the liver and adrenal glands in both species.

1. 1Alanine Aminotransferase Increased1632%
2. 2Headache1530%
3. 3Fatigue1122%
4. 4Immunosuppression714%
5. 5Pain714%
6. 6Hepatic Enzyme Increased612%
7. 7Aspartate Aminotransferase Increased510%
8. 8Coagulation Factor Ix Level Decreased510%
9. 9Nausea510%
10. 10Contusion48.0%
11. 11Limb Injury48.0%
12. 12Liver Function Test Increased48.0%
13. 13Malaise48.0%
14. 14Pyrexia48.0%
15. 15Back Pain36.0%

The 6 most recently updated of 6 ClinicalTrials.gov registrations naming Etranacogene Dezaparvovec as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Phase 3, Open-label, Single-dose Study of CSL222 in Adolescent Male Subjects (≥ 12 to < 18 Years of Age) With Severe or Moderately Severe Hemophilia B
  Recruiting · Phase 3 · Interventional · 20 enrolled · CSL Behring
  NCT07080905updated 2026-06-04
• HOPE-B: Trial of AMT-061 in Severe or Moderately Severe Hemophilia B Patients
  Completed · Phase 3 · Interventional · 67 enrolled · CSL Behring
  NCT03569891updated 2026-03-27
• Efficacy and Safety of CSL222 (Etranacogene Dezaparvovec) Gene Therapy in Adults With Hemophilia B With Pretreatment Adeno-associated Virus Serotype 5 (AAV5) Neutralizing Antibodies (Nabs)
  Recruiting · Phase 3 · Interventional · 35 enrolled · CSL Behring
  NCT06003387updated 2026-03-17
• An Observational Cohort Study to Characterize the Effectiveness and Safety of HEMGENIX® in Patients With Hemophilia B
  Recruiting · Observational · 500 enrolled · CSL Behring
  NCT06008938updated 2026-02-19
• ATHN Transcends: A Natural History Study of Non-Neoplastic Hematologic Disorders
  Recruiting · Observational · 3,000 enrolled · American Thrombosis and Hemostasis Network
  NCT04398628updated 2026-01-12
• Long-term Follow-up Study of Male Adults With Hemophilia B Previously Treated With Etranacogene Dezaparvovec (CSL222)
  Enrolling by invitation · Observational · 56 enrolled · CSL Behring
  NCT05962398updated 2025-07-18

Frequently asked questions

How does Etranacogene Dezaparvovec work?

HEMGENIX is an adeno-associated virus serotype 5 (AAV5) based gene therapy designed to deliver a copy of a gene encoding the Padua variant of human coagulation Factor IX (hFIX-Padua). Single intravenous infusion of HEMGENIX results in cell transduction and increase in circulating Factor IX activity in patients with Hemophilia B.

What is Etranacogene Dezaparvovec used for?

According to FDA labeling, Etranacogene Dezaparvovec carries indications including: HEMGENIX is indicated for treatment of adults with Hemophilia B (congenital Factor IX deficiency) who: Currently use Factor IX prophylaxis therapy, or Have current or historical life-threatening hemorrhage, or Have repeated, serious spontaneous bleeding episodes. HEMGENIX is an adeno-associated virus vector-based gene therapy indicated for the treatment of adults with Hemophilia B (congenital Factor IX deficiency) who: Currently use Factor IX prophylaxis therapy, or Have current or historical life-threatening hemorrhage, or Have repeated, serious spontaneous bleeding episodes.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Etranacogene Dezaparvovec?

Etranacogene Dezaparvovec is classified as Blood coagulation factors, Gene Editing or Modification.

What are the brand names for Etranacogene Dezaparvovec?

Etranacogene Dezaparvovec is marketed under brand names including Hemgenix.

What are the contraindications for Etranacogene Dezaparvovec?

Etranacogene Dezaparvovec labeling lists contraindications including: None. None.. Always consult the full prescribing information and a clinician.