Long-term Safety and Efficacy Study and Dose-Escalation Substudy of PF 06838435 in Individuals With Hemophilia B

Running, not enrolling · Phase 2

Conditions studied: Hemophilia B

In brief

Long-term safety and efficacy follow-up for participants with Hemophilia B who were previously treated in the C0371005 (formerly SPK-9001-101) study, and a dose-escalation sub-study evaluating safety, tolerability, and kinetics of a higher dose with long-term safety and efficacy follow-up. Participants in the substudy do not need to have participated in C0371005.

Key facts

Study ID

NCT03307980

Run by

Pfizer

People needed

21

Starts

2017-06-22

Expected to finish

2029-10-25

Last updated by the study team

2026-05-12

Who can join

Age: 18 and older, up to 65. Sex: male. Healthy volunteers: not accepted.

You may qualify if…

• Able to provide informed consent and comply with requirements of the study
• Males age 18 to 65 years with confirmed diagnosis of hemophilia B (≤2 IU/dL or ≤2% endogenous factor IX)
• Received ≥50 exposure days to factor IX products
• No measurable factor IX inhibitor as assessed by the central laboratory and have no prior history of inhibitors to factor IX protein
• Agree to refrain from donating sperm and either abstain from intercourse or use reliable barrier contraception until 3 consecutive semen samples are negative for vector sequences

You may not qualify if…

• Evidence of active hepatitis B or C
• Currently on antiviral therapy for hepatitis B or C
• Have significant underlying liver disease
• Serological evidence* of HIV-1 or HIV-2 with CD4 counts ≤200/mm3 (* participants who are HIV+ and stable with CD4 count >200/mm3 and undetectable viral load are eligible to enroll)
• Neutralizing antibody titers to the capsid portion of PF-06838435 above the established threshold
• Sensitivity to heparin or heparin induced thrombocytopenia; sensitivity to any of the study interventions, or components thereof, or drug or other allergy
• Previously dosed in a gene therapy research trial at any time or in an interventional clinical study within 3 months of screening visit
• Any concurrent clinically significant major disease or condition
• Unable or unwilling to comply with the study procedures

Where it is running

• UC Davis Comprehensive Cancer Center — Sacramento, California, United States
• UC Davis Ellison Ambulatory Care Clinic — Sacramento, California, United States
• UC Davis Medical Center department of Radiology — Sacramento, California, United States
• UC Davis Medical Center — Sacramento, California, United States
• UC Davis Midtown Cancer Center — Sacramento, California, United States
• UC DavisHealth Main Hospital — Sacramento, California, United States
• LA Center for Bleeding and Clotting Disorders - Metairie — Metairie, Louisiana, United States
• Tulane Lakeside Hospital — Metairie, Louisiana, United States
• LA Center for Bleeding and Clotting Disorders — New Orleans, Louisiana, United States
• Tulane University Clinical Translational Unit — New Orleans, Louisiana, United States
• Tulane University Hospitals and Clinic — New Orleans, Louisiana, United States
• Tulane University School of Medicine — New Orleans, Louisiana, United States
• University Medical Center New Orleans — New Orleans, Louisiana, United States
• Louisiana Center for Advanced Medicine — Slidell, Louisiana, United States
• Mississippi Center for Advanced Medicine — Madison, Mississippi, United States
• Weill Cornell Medicine - New York Presbyterian Hospital — New York, New York, United States
• The Children's Hospital of Philadelphia — Philadelphia, Pennsylvania, United States
• Royal Prince Alfred Hospital — Camperdown, New South Wales, Australia
• McMaster University Medical Centre - Hamilton Health Sciences — Hamilton, Ontario, Canada
• McMaster University — Hamilton, Ontario, Canada
• The Research Institute of the McGill University Health Centre — Montreal, Quebec, Canada
• McGill University Health Center - Research Institute — Montreal, Quebec, Canada
• Istanbul Universitesi Onkoloji Enstitusu Çocuk Hematoloji Onkoloji Bilim Dali — Istanbul, Turkey (Türkiye)
• Istanbul University Clinical Trials Excellence Center — Istanbul, Turkey (Türkiye)
• Ege Universitesi Tip Fakultesi Cocuk Sagligi ve Hastaliklari Anabilim Dali — Izmir, Turkey (Türkiye)

Full record on ClinicalTrials.gov

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