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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
NCT03861273 · View on ClinicalTrials.gov ↗
Study 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 Studied
Interventions
- BIOLOGICAL PF-06838435/ fidanacogene elaparvovec
Study Locations (20)
California
- UCSF IDS Pharmacy — San Francisco
- University of California, San Francisco - Clinical Research Center — San Francisco
- University of California, San Francisco - Outpatient Hematology Clinic — San Francisco
- The Regents of the University of California, San Francisco campus — San Francisco
Indiana
- Indiana Hemophilia & Thrombosis Center, Inc. — Indianapolis
- Indiana Hemophilia and Thrombosis Center, Inc — Indianapolis
- Innovative Hematology, Inc. — Indianapolis
- St. Vincent Hospital & Health Care Center, Inc. — Indianapolis
Pennsylvania
- Center for Human Phenomic Science — Philadelphia
- Investigational Drug Service — Philadelphia
- Penn Blood Disorder Center — Philadelphia
- The Trustees of the University of Pennsylvania, Office of Clinical Research- Legal — Philadelphia
Colorado
- Hemophilia and Thrombosis Center at the University of Colorado Anschutz Medical Campus — Aurora
- Regents of the University of Colorado University of Colorado Denver, Office of Grants and Contracts — Aurora
Mississippi
- Madison Radiological Group — Madison
- Mississippi Center for Advanced Medicine — Madison
New South Wales
- Royal Prince Alfred Hospital — Camperdown
South Australia
- Royal Adelaide Hospital — Adelaide
Victoria
- The Alfred Hospital — Melbourne
Trial Details
| Field | Value |
|---|---|
| Enrollment Target | 51 participants |
| Start Date | 2019-07-29 |
| Est. Completion | 2031-02-25 |
| Phase | Phase 3 |
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Full Details on ClinicalTrials.gov ↗What the Registry Record Tells You About NCT03861273
The ClinicalTrials.gov registry entry for NCT03861273 describes a study currently listed as active not recruiting. It is categorized as Phase 3, which is the standard way researchers label where a study sits along the investigational pathway from early safety work through later efficacy and post-marketing evaluation. The registered enrollment target is 51 participants, a figure that helps gauge the scale of data the investigators plan to collect. The listed sponsor is Pfizer, which has 769 total studies on file at ClinicalTrials.gov, and sponsors are the parties responsible for study design, oversight, and regulatory filings.
The record links to 1 condition, with Hemophilia B appearing as the primary indexed condition, and to 1 intervention — of which PF-06838435/ fidanacogene elaparvovec is the first listed. Interventions can include drugs, devices, procedures, behavioral programs, or observational arms, and each is tracked as a separate registry field so that downstream queries can filter accurately. When a trial lists multiple interventions, it usually reflects a multi-arm design or a comparison protocol rather than a single treatment being tested in isolation. The brief summary published in the registry is the clearest source of protocol intent and should be read before drawing conclusions from any sidebar tags.
Geographic footprint matters for practical reasons: NCT03861273 reports 20 study locations spanning 9 distinct geographic areas — top geographies include California, Indiana, Pennsylvania. A larger site network tends to correlate with broader recruitment capacity, but it does not imply anything about study quality, and site-level enrollment status can diverge from the overall registry status shown above. Every data point on this page comes from the public ClinicalTrials.gov dataset and is reproduced here for reference only; it is not a medical recommendation, an endorsement of the sponsor, or an invitation to enroll. Verify current status, eligibility criteria, and contact details directly at ClinicalTrials.gov, and discuss any participation decision with your own healthcare provider.
Frequently Asked Questions
What is clinical trial NCT03861273 about?
NCT03861273 is a clinical study titled "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". 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 cell...
What is the current status of trial NCT03861273?
This trial is currently active not recruiting. It is a Phase 3 study. The enrollment target is 51 participants. The study started on 2019-07-29. Estimated completion is 2031-02-25.
What conditions does trial NCT03861273 study?
This clinical trial studies the following conditions: Hemophilia B. These conditions were identified from the trial registry and reflect the primary focus areas of the research.
What interventions are being tested in trial NCT03861273?
The interventions under investigation include: PF-06838435/ fidanacogene elaparvovec (BIOLOGICAL). Each intervention is being evaluated for safety and efficacy as part of this clinical study.
Who is sponsoring clinical trial NCT03861273?
This trial is sponsored by Pfizer, which has 769 total clinical trials registered on ClinicalTrials.gov. The sponsor is responsible for the study's design, funding, and regulatory compliance.
Where is trial NCT03861273 being conducted?
This trial has 20 study locations across California, Colorado, Indiana, Mississippi, Pennsylvania. Contact the study sites directly through ClinicalTrials.gov for enrollment availability.
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