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Active, not recruiting Phase 3 Interventional Results available

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

ClinicalTrials.gov ID: NCT03861273

Public ClinicalTrials.gov record NCT03861273. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 1, 2026, 7:41 PM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Official title

Phase 3, Open-label, Single-arm Study to Evaluate Efficacy and Safety of FIX Gene Transfer With PF-06838435 (rAAV-Spark100-hFIX-R338L) in Adult Male Participants With Moderately Severe to Severe Hemophilia B (FIX:C ≤2%) (BeneGene-2)

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

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).

Study identification

NCT ID
NCT03861273
Recruitment status
Active, not recruiting
Study type
Interventional
Phase
Phase 3
Lead sponsor
Pfizer
Industry
Enrollment
51 participants

Conditions and interventions

Conditions

Interventions

Biological

Eligibility (public fields only)

Age range
18 Years to 65 Years
Sex
Male
Healthy volunteers
Healthy volunteers not accepted

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Jul 28, 2019
Primary completion
Nov 15, 2022
Completion
Feb 24, 2031
Last update posted
May 31, 2026

2019 – 2031

United States locations

U.S. sites
17
U.S. states
5
U.S. cities
6
Facility City State ZIP Site status
UCSF IDS Pharmacy San Francisco California 94143
University of California, San Francisco - Clinical Research Center San Francisco California 94143
University of California, San Francisco - Outpatient Hematology Clinic San Francisco California 94143
The Regents of the University of California, San Francisco campus San Francisco California 94158
Hemophilia and Thrombosis Center at the University of Colorado Anschutz Medical Campus Aurora Colorado 80045
Regents of the University of Colorado University of Colorado Denver, Office of Grants and Contracts Aurora Colorado 80045
Indiana Hemophilia & Thrombosis Center, Inc. Indianapolis Indiana 46260
Indiana Hemophilia and Thrombosis Center, Inc Indianapolis Indiana 46260
Innovative Hematology, Inc. Indianapolis Indiana 46260
St. Vincent Hospital & Health Care Center, Inc. Indianapolis Indiana 46260
Madison Radiological Group Madison Mississippi 39110
Mississippi Center for Advanced Medicine Madison Mississippi 39110
The Trustees of the University of Pennsylvania, Office of Clinical Research- Legal Hamilton Pennsylvania 19104
Center for Human Phenomic Science Philadelphia Pennsylvania 19104
Investigational Drug Service Philadelphia Pennsylvania 19104
Penn Blood Disorder Center Philadelphia Pennsylvania 19104
The Trustees of the University of Pennsylvania, Office of Clinical Research- Legal Philadelphia Pennsylvania 19104

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

Non-U.S. locations

This page focuses on the U.S. directory. The official record also lists 50 non-U.S. sites.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT03861273, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted May 31, 2026 · Synced Sep 1, 2026

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Open the official record

The complete protocol, eligibility criteria, and contact information for NCT03861273 live on ClinicalTrials.gov.

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