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

NCT ID: NCT03861273

Last Updated: 2025-09-30

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: PHASE3
• Total Enrollment: 51 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-07-29
• Study Completion Date: 2031-02-25

Brief Summary

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).

Conditions

Hemophilia B

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

PF-06838435/ fidanacogene elaparvovec

Group Type: EXPERIMENTAL

PF-06838435/ fidanacogene elaparvovec

Intervention Type: BIOLOGICAL

Gene Therapy

Interventions

PF-06838435/ fidanacogene elaparvovec

Gene Therapy

Intervention Type: BIOLOGICAL

Eligibility 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: No

Sponsors

Pfizer

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Pfizer CT.gov Call Center

Role: STUDY_DIRECTOR

Pfizer

Locations

University of California, San Francisco - Clinical Research Center

San Francisco, California, United States

University of California, San Francisco - Outpatient Hematology Clinic

San Francisco, California, United States

Hemophilia and Thrombosis Center at the University of Colorado Anschutz Medical Campus

Aurora, Colorado, United States

Indiana Hemophilia & Thrombosis Center, Inc.

Indianapolis, Indiana, United States

Indiana Hemophilia and Thrombosis Center, Inc

Indianapolis, Indiana, United States

St. Vincent Hospital & Health Care Center, Inc.

Indianapolis, Indiana, United States

Madison Radiological Group

Madison, Mississippi, United States

Mississippi Center for Advanced Medicine

Madison, Mississippi, United States

Center for Human Phenomic Science CHPS

Philadelphia, Pennsylvania, United States

Center for Human Phenomic Science

Philadelphia, Pennsylvania, United States

Investigational Drug Service

Philadelphia, Pennsylvania, United States

Penn Blood Disorder Center

Philadelphia, Pennsylvania, United States

Royal Prince Alfred Hospital

Camperdown, New South Wales, Australia

Royal Adelaide Hospital

Adelaide, South Australia, Australia

The Alfred Hospital

Melbourne, Victoria, Australia

Fiona Stanley Hospital

Murdoch, Western Australia, Australia

Royal Brisbane and Women's Hospital

Herston, , Australia

Centro Estadual de Hemoterapia e Hematologia Marcos Daniel Santos - Hemoes

Vitória, Espírito Santo, Brazil

Centro de Hematologia e Hemoterapia - Hemocentro de Campinas - UNICAMP

Campinas, São Paulo, Brazil

Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo

São Paulo, São Paulo, Brazil

Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti- HEMORIO

Rio de Janeiro, , Brazil

McMaster University Medical Centre - Hamilton Health Sciences

Hamilton, Ontario, Canada

Juravinski Hospital - Hamilton Health Sciences

Hamilton, Ontario, Canada

St. Michael's Hospital

Toronto, Ontario, Canada

Hopital Cardiologique Louis Pradel - CRTH

Bron, , France

Hopital Necker

Paris, , France

Vivantes Klinikum Friedrichshain

Berlin, , Germany

Vivantes Klinikum im Friedrichshain

Berlin, , Germany

Universitaetsklinikum Bonn

Bonn, , Germany

Universitätsklinikum Bonn, Anstalt des öffentlichen Rechts

Bonn, , Germany

Universitätsklinikum Bonn

Bonn, , Germany

General Hospital of Athens "LAIKO", 2nd Regional Blood Transfusion Center

Athens, , Greece

Azienda Ospedaliero Universitaria Careggi

Florence, , Italy

Azienda Ospedaliera Universitaria Federico II

Naples, , Italy

Sapporo Tokushukai Hospital

Sapporo, Hokkaido, Japan

Nara Medical University Hospital

Kashihara, Nara, Japan

Saitama Medical University Hospital

Iruma-gun, Saitama, Japan

National Center for Child Health and Development

Setagaya-ku, Tokyo, Japan

King Abdulaziz Medical City-Ministry of national guard

Riyadh, Kingdom of Saudi Arabia, Saudi Arabia

King Faisal Specialist Hospital and Research Centre

Riyadh, , Saudi Arabia

Kyung Hee University Hospital at Gangdong

Seoul, , South Korea

Hospital Universitario Virgen de la Arrixaca

El Palmar, Murcia, Spain

Hospital Universitari Vall d´Hebrón

Barcelona, , Spain

Skåne University Hospital, Department of Hematology, Oncology and Radiation Physics

Malmo, , Sweden

ApoEx AB

Malmo, , Sweden

Changhua Christian Hospital

Changhua, , Taiwan

Kaohsiung Medical University Chung-Ho Memorial Hospital

Kaohsiung City, , Taiwan

Chung Shan Medical University Hospital

Taichung, , Taiwan

Chung Shan Medical University

Taichung, , Taiwan

Taichung Veterans General Hospital

Taichung, , Taiwan

National Taiwan University Hospital

Taipei, , Taiwan

Acibadem Adana Hospital

Adana, , Turkey (Türkiye)

Gaziantep University Sahinbey Training and Research Hospital

Gaziantep, , Turkey (Türkiye)

Istanbul University Oncology Institute

Istanbul, , Turkey (Türkiye)

Ege University Medical Faculty Hospital

Izmir, , Turkey (Türkiye)

Newcastle upon Tyne Hospitals NHS FT

Newcastle upon Tyne, TYNE & WEAR, United Kingdom

Newcastle upon Tyne Hospitals NHS FT

Newcastle upon Tyne, TYNE & WEAR, United Kingdom

Glasgow Royal Infirmary

Glasgow, , United Kingdom

Guy's and St. Thomas' NHS Foundation Trust

London, , United Kingdom

Newcastle upon Tyne Hospitals NHS Foundation Trust

Newcastle upon Tyne, , United Kingdom

Countries

United States; Australia; Brazil; Canada; France; Germany; Greece; Italy; Japan; Saudi Arabia; South Korea; Spain; Sweden; Taiwan; Turkey (Türkiye); United Kingdom

References

Wojciechowski J, Gaitonde P, Hughes JH, Ravva P. Population Modeling of Factor IX Activity Following Administration of Fidanacogene Elaparvovec Gene Therapy in Participants with Hemophilia B. Clin Pharmacokinet. 2025 Oct;64(10):1531-1548. doi: 10.1007/s40262-025-01535-y. Epub 2025 Aug 1.

Reference Type: DERIVED

PMID: 40750723 (View on PubMed)

Cuker A, Kavakli K, Frenzel L, Wang JD, Astermark J, Cerqueira MH, Iorio A, Katsarou-Fasouli O, Klamroth R, Shapiro AD, Hermans C, Ishiguro A, Leavitt AD, Oldenburg JB, Ozelo MC, Teitel J, Biondo F, Fang A, Fuiman J, McKay J, Sun P, Rasko JEJ, Rupon J; BENEGENE-2 Trial Investigators. Gene Therapy with Fidanacogene Elaparvovec in Adults with Hemophilia B. N Engl J Med. 2024 Sep 26;391(12):1108-1118. doi: 10.1056/NEJMoa2302982.

Reference Type: DERIVED

PMID: 39321362 (View on PubMed)

Provided Documents

Document Type: Study Protocol

View Document

Document Type: Statistical Analysis Plan

View Document

Related Links

https://pmiform.com/clinical-trial-info-request?StudyID=C0371002

To obtain contact information for a study center near you, click here.

Other Identifiers

2022-502844-11-00

Identifier Type: REGISTRY

Identifier Source: secondary_id

C0371002

Identifier Type: -

Identifier Source: org_study_id