Tests CSL222 gene therapy in adolescent boys with severe hemophilia B
Tests a single gene therapy dose in adolescent boys with severe hemophilia B.
Plain-language title generated from the registry record
Registry title: 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
Key facts
- Where
- Ann Arbor, Atlanta, Gainesville, Memphis, Orange, and San Diego, United StatesSee the 6 sites
- Phase
- Phase 3
Where in United States
- University of Michigan Medical CenterAnn Arbor, United StatesTaking people
- Arthur M Blank Hospital - Children's Healthcare of AtlantaAtlanta, United StatesTaking people
- University of FloridaGainesville, United StatesTaking people
- St. Jude Children's Research HospitalMemphis, United StatesTaking people
- Center for Inherited Blood DisordersOrange, United StatesTaking people
- Rady Children's Hospital - San DiegoSan Diego, United StatesTaking people
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- CSL Behring
- Trial code
- NCT07080905EU 2023-505805-18-00
- Record updated
- 20 October 2026
- Original description
This is a phase 3, prospective, open-label, single-arm, single-dose, multicenter study investigating the efficacy, safety, and tolerability of CSL222 (AAV5-hFIXco-Padua) in adolescent male participants with severe or moderately severe hemophilia B.Read full original descriptionShow less
Phase 3, Open-label, Single-dose, Multicenter Study Investigating Efficacy, Safety, and Tolerability of CSL222 (Etranacogene Dezaparvovec) Administered to Adolescent Male Subjects (≥ 12 to < 18 Years of Age) With Severe or Moderately Severe Hemophilia B
This is a phase 3, prospective, open-label, single-arm, single-dose, multicenter study investigating the efficacy, safety, and tolerability of CSL222 (AAV5-hFIXco-Padua) in adolescent male participants with severe or moderately severe hemophilia B.
Inclusion: Key Inclusion Criteria for the Lead-in Period: Assigned male sex at birth; Aged ≥138 months (11 years and 6 months) to less than (<) 206 months (17 years and 2 months) at the time of informed consent / assent; Congenital hemophilia B with known severe or moderately severe FIX deficiency (less than or equal to [≤] 2% of normal circulating FIX) for which the participant has been on continuous FIX prophylaxis; On stable continuous FIX prophylaxis for at least 2 months before Screening; Minimum of 75 previous exposure days of treatment with FIX protein before Screening; Additional Key Inclusion Criteria for the Treatment Period:; Completed the Lead-in Period: minimum of 6 months (26 weeks) of lead-in data collected and eligibility has been confirmed; Aged ≥ 12 to < 18 years at the time of CSL222 treatment.
Exclusion: Any uncontrolled or untreated infection (human immunodeficiency virus, hepatitis C, etc) or any other significant concurrent, uncontrolled medical condition, as evaluated by the investigator, including, but not limited to renal, hepatic, cardiovascular, hematological, gastrointestinal, endocrine, pulmonary, neurological, cerebral, or psychiatric disease, alcoholism, drug dependency, or any other psychological disorder evaluated by the investigator to interfere with adherence to the Clinical Study Protocol procedures or with the degree of tolerance to CSL222; Any condition other than hemophilia B resulting in an increased bleeding tendency; Key Exclusion Criteria for the Lead-in Period: History of FIX inhibitors or positive FIX inhibitor test at Screening (based on central laboratory results); Screening laboratory values (based on central laboratory results):; Total bilirubin > 2 × the upper limit of normal (ULN); Alanine aminotransferase (ALT) > 2 × the ULN; Aspartate aminotransferase (AST) > 2 × the ULN; Alkaline phosphatase (ALP) > 2 × the ULN; Serum creatinine > 2 × the ULN; Hemoglobin < 8 g/dL; Thrombocytopenia, defined as a platelet count below 50 × 10\^9/L, at screening (based on central laboratory results); Additional Key Exclusion Criteria for the Treatment Period: Positive FIX inhibitor test at Visit L-Final (based on central laboratory results); Visit L-Final laboratory values (based on central laboratory results) of:; Total bilirubin > 2 × the ULN; ALT > 2 × the ULN; AST > 2 × the ULN; ALP > 2 × the ULN; Serum creatinine > 2 × the ULN; Hemoglobin < 8 g/dL; Thrombocytopenia, defined as a platelet count below 50 × 10\^9/L, at Visit L-Final (based on central laboratory results); AAV5 NAb titer > 1:900 as assessed at Visit LX (last visit before Visit L-Final).