Actively Recruiting
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
Led by CSL Behring · Updated on 2026-05-11
20
Participants Needed
11
Research Sites
430 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
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.
CONDITIONS
Official 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
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Assigned male sex at birth
- Age between 11 years and 6 months (138 months) and less than 17 years and 2 months (206 months) at consent
- Diagnosed with congenital hemophilia B with severe or moderately severe factor IX deficiency (≤ 2% of normal)
- On stable continuous factor IX prophylaxis for at least 2 months before screening
- At least 75 prior exposure days to factor IX protein before screening
- Completed a minimum of 6 months (26 weeks) lead-in period with collected data
- Age between 12 and less than 18 years at time of CSL222 treatment
You will not qualify if you...
- History of factor IX inhibitors or positive factor IX inhibitor test at screening
- Laboratory abnormalities at screening: total bilirubin > 2 times upper limit of normal (ULN), ALT > 2× ULN, AST > 2× ULN, ALP > 2× ULN, serum creatinine > 2× ULN, hemoglobin < 8 g/dL
- Any bleeding disorder other than hemophilia B
- Thrombocytopenia with platelet count < 50 × 10^9/L at screening
- Uncontrolled or untreated infections (e.g., HIV, hepatitis C) or other significant uncontrolled medical conditions including renal, hepatic, cardiovascular, hematological, gastrointestinal, endocrine, pulmonary, neurological, cerebral, or psychiatric diseases
- Alcoholism, drug dependency, or psychological disorders affecting study adherence or tolerance to CSL222
- Positive factor IX inhibitor test at final lead-in visit
- AAV5 neutralizing antibody titer > 1:900 before final lead-in visit
- Laboratory abnormalities at final lead-in visit similar to screening criteria
- Thrombocytopenia with platelet count < 50 × 10^9/L at final lead-in visit
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Trial Site Locations
Total: 11 locations
1
Center for Inherited Blood Disorders
Orange, California, United States, 92868
Actively Recruiting
2
University of Florida
Gainesville, Florida, United States, 32611
Actively Recruiting
3
Arthur M. Blank Hospital - Children's Healthcare of Atlanta
Atlanta, Georgia, United States, 30329
Actively Recruiting
4
University of Michigan Medical Center
Ann Arbor, Michigan, United States, 48109
Actively Recruiting
5
St. Jude Children's Research Hospital
Memphis, Tennessee, United States, 38105
Actively Recruiting
6
Medical University Vienna
Vienna, Austria, 1090
Actively Recruiting
7
UZ Leuven - Centrum voor Moleculaire en Vasculaire Biologie
Leuven, Belgium, 3000
Actively Recruiting
8
Chaim Sheba Medical Center
Ramat Gan, Israel, 5262000
Actively Recruiting
9
La Paz University Hospital
Madrid, Spain, 28046
Actively Recruiting
10
St Thomas Hospital
London, United Kingdom, SE1 7EH
Actively Recruiting
11
John Radcliffe Hospital - Oxford University Hospitals NHS
Oxford, United Kingdom, OX3 9DU
Actively Recruiting
Research Team
T
Trial Registration Coordinator
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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