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One-Time gene therapy aims to stop bleeding in severe hemophilia

NCT ID NCT04370054

Disease control Sponsor: Pfizer Source: ClinicalTrials.gov ↗

What the study statuses mean

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Recruitment status, easiest to join first

Recruiting now
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing This study
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Jun 27, 2026 · Last updated Aug 20, 2026 · Updated 2 times

Summary

This study tests a one-time gene therapy (PF-07055480) in 77 adult men with moderately severe to severe hemophilia A. The goal is to see if the treatment can reduce or prevent bleeding episodes compared to their usual factor VIII infusions. Participants receive a single IV dose and are followed for 5 years.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

77 people

The number who actually took part.

Started

Aug 2020

Expected to finish

Oct 2026

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 to 64 years

Sex

Male participants only

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Main inclusion Criteria * Males who have been followed on routine Factor VIII prophylaxis therapy during the lead-in study (C0371004) and have \> = 150 documented exposure days to a Factor VIII protein product * Moderately severe to severe hemophilia A (Factor VIII activity \< =1%) * Suspension of FVIII prophylaxis therapy post study drug infusion Main exclusion Criteria * Anti-AAV6 neutralizing antibodies * History of inhibitor to Factor VIII * Laboratory values at screening visit that are abnormal or outside acceptable study limits * Significant and/or unstable liver disease, biliary disease, significant liver fibrosis * Conditions associated with increased thromboembolic risk such as inherited or acquired thrombophilia, or a history of thrombotic events * Planned surgical procedure requiring Factor VIII surgical prophylactic factor treatment 12 months from screening visit * Active hepatitis B or C * Serological evidence of human immunodeficiency virus HIV-1 or HIV-2 with Cluster of Differentiation 4 positive (CD4+) cell count ≤200 mm3 and/or viral load \>20 copies/mL

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Conditions

The condition(s) this trial relates to.

hemophilia A

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Hemophilia A

Contacts and locations

Locations

  • Access Sourcecorp Deliverex (off-site storage)

    San Jose, California, 95131, United States

  • Adana Acibadem Hospital

    Adana, 01130, Turkey (Türkiye)

  • Azienda Ospedaliero Universitaria Careggi SODc Malattie Emorragiche e della Coagulazione

    Florence, 50134, Italy

  • Clinical and Translational Research Unit (CTRU)

    Palo Alto, California, 94304, United States

  • Dip. di Medicina Clinica e Chirurgia, Università degli Studi di Napoli Federico II - UOC di Medicina

    Naples, 80131, Italy

  • Ege University Medical Faculty

    Izmir, 35100, Turkey (Türkiye)

  • Ege University Medical Faculty, Pediatric Hematology

    Izmir, 35100, Turkey (Türkiye)

  • Gaziantep University Sahinbey Research and Training Hospital

    Gaziantep, 27310, Turkey (Türkiye)

  • General Hospital of Athens "Hippokration"

    Athens, 11527, Greece

  • General Hospital of Athens ''Laiko''

    Athens, Attikí, 115 27, Greece

  • Guy's and St. Thomas' NHS Foundation Trust

    London, SE1 7EH, United Kingdom

  • H.U. Rio Hortega

    Valladolid, 47012, Spain

  • Hamilton Health Sciences Corporation

    Hamilton, Ontario, L8L 8E7, Canada

  • Hopital Necker

    Paris, 75015, France

  • Hospital Universitari Vall d'Hebron

    Barcelona, 08035, Spain

  • Imaging Clinic at Stanford Medicine Outpatient Center in Redwood City

    Redwood City, California, 94063, United States

  • Juravinski Hospital - Hamilton Health Sciences

    Hamilton, Ontario, L8V 1C3, Canada

  • King Faisal Specialist Hospital & Research Center

    Riyadh, Saudi Arabia

  • Klinikum der Johann Wolfgang Goethe-Universitaet, Medizinische Klinik II

    Frankfurt am Main, 60590, Germany

  • Kyung Hee University Hospital at Gangdong

    Seoul, 05278, South Korea

  • Lucile Packard Childrens Hospital

    Palo Alto, California, 94304, United States

  • McMaster University Medical Centre - Hamilton Health Sciences

    Hamilton, Ontario, L8N 3Z5, Canada

  • NOW Physical Therapy

    Mountain View, California, 94040, United States

  • Nagoya University Hospital - Transfusion Medicine

    Nagoya, Aichi-ken, 466-8560, Japan

  • National Taiwan University Hospital

    Taipei, 10002, Taiwan

  • Regents of The University of California

    Oakland, California, 94607, United States

  • Saitama Medical University Hospital

    Iruma-gun, Saitama, 350-0495, Japan

  • Skåne University Hospital

    Malmö, Skåne County, 205 02, Sweden

  • Stanford Health Care

    Stanford, California, 94305, United States

  • Stanford Health Care (hospital and IDS pharmacy)

    Stanford, California, 94305, United States

  • The Alfred Hospital

    Melbourne, Victoria, 3004, Australia

  • The Board of Trustees of the Leland Stanford Junior University

    Redwood City, California, 94063, United States

  • UCSF IDS Pharmacy

    San Francisco, California, 94143, United States

  • UCSF Outpatient Radiology

    San Francisco, California, 94143, United States

  • UCSF Outpatient Radiology (alternate location)

    San Francisco, California, 94143, United States

  • UCSF Outpatient Radiology.

    San Francisco, California, 94115, United States

  • UCSF lnvestigational Drug Service

    San Francisco, California, 94143, United States

  • Universidade Estadual de Campina

    Campina, 13083-970, Brazil

  • University of California, San Francisco - Clinical Research Center

    San Francisco, California, 94143, United States

  • University of California, San Francisco - Moffitt/Long Inpatient Hematology

    San Francisco, California, 94143, United States

  • University of California, San Francisco - Outpatient Hematology Clinic

    San Francisco, California, 94143, United States

  • University of Washington Medical Center - Translational Research Unit (TRU)

    Seattle, Washington, 98195, United States

  • Università degli studi di Roma "La Sapienza"- Policlinico Umberto I

    Roma, RM, 00161, Italy

  • Vivantes Klinikum im Friedrichshain

    Berlin, 10249, Germany

  • Washington Institute for Coagulation

    Seattle, Washington, 98101, United States

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