A Study to Evaluate the Efficacy and Safety of Factor IX Gene Therapy With PF-06838435 in Adult Males With Moderately Severe to Severe Hemophilia B (BENEGENE-2)

Pfizer

Status and phase

Active, not recruiting

Phase 3

Conditions

Hemophilia B

Treatments

Biological: PF-06838435/ fidanacogene elaparvovec

Study type

Interventional

Funder types

Industry

Identifiers

NCT03861273

2022-502844-11-00 (Other Identifier)

C0371002

Details and patient eligibility

About

This study will evaluate the efficacy and safety of PF-06838435 (a gene therapy drug) in adult male participants with moderately severe to severe hemophilia B (participants that have a Factor IX circulating activity of 2% or less). The gene therapy is designed to introduce genetic material into cells to compensate for missing or non-functioning Factor IX. Eligible study participants will have completed a minimum 6 months of routine Factor IX prophylaxis therapy during the lead in study (C0371004). Participants will be dosed once (intravenously) and will be evaluated over the course of 6 years. The main objective of the study will evaluate the annualized bleeding rate [ABR] for participants treated with gene therapy versus standard of care (SOC) therapy (FIX prophylaxis replacement regimen).

Enrollment

51 patients

Sex

Male

Ages

18 to 65 years old

Volunteers

No Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria

Males who completed 6 months of Factor IX prophylaxis therapy during the lead-in study (C0371004) prior to providing consent at the screening visit for this study.
Documented moderately severe to severe hemophilia B (Factor IX activity < =2%)
Previous experience with FIX therapy (=>50 documented exposure days to a FIX protein product)
Suspension of prophylaxis therapy for hemophilia B after administration of the study drug
Laboratory values (hemoglobin, platelets and creatinine) within study specified limits
Agree to contraception until components of the drug are eliminated from their body
Capable of giving signed informed consent

Exclusion Criteria

Anti-AAVRh74var neutralizing antibodies (nAb) titer above the established threshold (ie, positive for nAb).
History of inhibitor to Factor IX or inhibitor detected during screening. Clinical signs or symptoms of decreased response to Factor IX
Hypersensitivity to Factor IX replacement product or IV immunoglobulin administration
History of chronic infection or other chronic disease
Any conditions associated with increased thromboembolic risk
Concurrent clinically significant major disease or condition unsuitable for participation and/or may interfere with the interpretation of study results
Laboratory values at screening visit that are abnormal or outside acceptable study limits
Current unstable liver or biliary disease
Currently on antiviral therapy for hepatitis B or C
Planned surgical procedure requiring Factor IX surgical prophylactic factor treatment 15 months from screening visit
Use of restricted therapies (e.g., blood products, acetylsalicylic acid [aspirin] or ibuprofen, other investigational therapy, and by-passing agents)
Previously dosed in a gene therapy research trial at any time or in an interventional clinical study within 12 weeks of screening visit
Active hepatitis B or C; hepatitis B surface antigen, hepatitis B virus deoxyribonucleic acid positivity, or hepatitis C virus ribonucleic acid positivity
Significant liver disease
Serological evidence of HIV1 or HIV2 infection with either CD4+ cell count <=200 mm3 and/or a viral load >20 copies/mL
Study and sponsor staff involved in the conduct of the study and their families
Unable to comply with study procedures
Sensitivity to heparin or heparin induced thrombocytopenia
Sensitivity to any of the study interventions, or components thereof, or drug or other allergy