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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 · Status: ACTIVE_NOT_RECRUITING · Phase: PHASE3 · Type: INTERVENTIONAL · Enrollment: 51

Last updated 2026-05-11

Study results available
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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

Interventions

BIOLOGICAL

PF-06838435/ fidanacogene elaparvovec

Gene Therapy

Sponsors & Collaborators

Principal Investigators

  • Pfizer CT.gov Call Center · Pfizer

Study Design

Allocation
NA
Purpose
TREATMENT
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
18 Years
Max Age
65 Years
Sex
MALE
Healthy Volunteers
No

Timeline & Regulatory

Start
2019-07-29
Primary Completion
2022-11-16
Completion
2031-02-25
FDA Drug
Yes

Countries

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

Study Locations

More Related Trials

Entities

Companies

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT03861273 on ClinicalTrials.gov