Clinical trial Recruiting at 13 sites Phase 4 Interventional Ages 12 and up

Weekly efanesoctocog alfa for hemophilia A with joint synovial hypertrophy

Official title: Prospective Interventional Study of Effectiveness of Efanesoctocog Alfa Prophylaxis on Synovial Hypertrophy in Patients With Hemophilia A

Run by Sanofi · NCT06941870 · Data updated 2026-11-12

This trial tests whether taking efanesoctocog alfa once a week for 12 months can reduce synovial hypertrophy in people aged 12 and older with moderate to severe hemophilia A.

More Factor VIII Deficiency trials

Quick facts

PhasePhase 4
Study typeInterventional
Ages12 Years and up
SexAll
Enrollment35 (estimated)
SponsorSanofi
Industry-sponsored
Locations19 sites (Los Angeles, California and 18 other locations)
StatusRecruiting
StartedSeptember 23, 2025
Main results expectedOctober 25, 2027
Study endsOctober 25, 2027
Registry record updatedNovember 9, 2026
Trial IDNCT06941870 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates are people aged 12 or older with moderate to severe hemophilia A (≤5% FVIII activity) who have at least one joint with synovial hypertrophy (HEAD‑US synovitis score 1 or 2) and no planned major orthopedic procedures for that joint.

Probably not a fit

People without synovial hypertrophy, with mild hemophilia A, or those who recently had or plan major orthopedic joint surgery are unlikely to benefit from this specific intervention.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This Phase 4, multi-center interventional trial gives participants weekly prophylaxis with efanesoctocog alfa for approximately 12 months and monitors changes in synovial hypertrophy in affected joints. Eligible joints are identified by a HEAD‑US synovitis score of 1 or 2 at baseline, and joints with planned major orthopedic procedures are excluded. The study uses serial imaging and clinical follow-up to document any changes in synovial thickness and related joint health over the treatment period. Sites are in Los Angeles, Indianapolis, and Iowa City, and the sponsor is Sanofi.

Why it matters

Potential benefit: If successful, weekly efanesoctocog alfa could shrink hypertrophic synovium and help preserve joint health and function in people with hemophilia A.

How similar studies have gone: Efanesoctocog alfa has demonstrated substantial reductions in bleeding rates and improved factor troughs in earlier trials, but direct evidence that it reverses established synovial hypertrophy is limited.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Participant is diagnosed with moderate to severe hemophilia A (defined as less than or equal to (≤)5 percent (%) of endogenous FVIII clotting activity) at the time of consent/assent.
* Participant is more than or equal to (≥)12 years old at the time of consent/assent.
* Participant has existing synovial hypertrophy, defined as at least 1 eligible\* joint by the HEAD-US score (Synovitis score: 1 or 2) at the time of consent/assent.
* Participant has at least 1 eligible\* joint without planned future major orthopedic procedures (example, arthroscopic synovectomy, radioisotopic or chemical synoviorthesis), or major orthopedic procedures in the past 3 months prior to the screening visit (Visit 1).

  \*An eligible joint is a joint with existing synovial hypertrophy, as defined by a HEAD-US synovitis score of 1 or 2, considering hypertrophic synovium as an indication of the presence of synovitis
* Participant has received prophylactic treatment with hemophilia prophylaxis prescriptions in the last 12 months prior to the baseline visit (Visit 2).
* Participant is capable of understanding the written Informed Consent Form (ICF)/assent form, provides a signed and witnessed written ICF/assent form, and agrees to comply with the protocol requirements.
* If male, no contraceptive measures are required for this study.
* If female, is not pregnant or breastfeeding, and one of the following conditions applies:
* Is a women of nonchildbearing potential (WONCBP)
* Is a WOCBP and agrees to use a highly effective contraceptive method, with a failure rate of less than (\<)1 percent during the study treatment period (at least until the Week 52/ End of Treatment \[EoT\] visit).
* A WOCBP must have a negative serum pregnancy test at the screening visit (Visit 1)

Exclusion Criteria:

* Participants are excluded from the study if any of the following criteria apply:
* Has other associated clotting disorders at the time of consent/assent.
* Is already under efanesoctocog alfa treatment.
* Has a current diagnosis of an factor VIII (FVIII) inhibitor, defined as inhibitor titer ≥0.60 BU/mL.
* Has ITI within the last 2 years prior to the baseline visit (Visit 2).
* Has been enrolled in a concurrent clinical interventional study or exposed to other investigational drug(s) within 3 months prior to screening for this study.
* Is currently in an institution because of regulatory or legal order (that is, is a prisoner or a patient who is legally institutionalized).
* Is not suitable for participation, whatever the reason, as judged by the investigator, including medical or clinical conditions, or patients potentially at risk of noncompliance to study procedures.
* Is an employee or family member of the investigator or site personnel.
* Is involved in a specific situation during study implementation or the course of the study that may raise ethics considerations.
* Has hypersensitivity to efanesoctocog alfa or its components or any of its excipients that, in the opinion of the investigator, contraindicates participation in the study.

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Where it's running

  • University of California Davis Medical Center-Site Number: 8400005
    Sacramento, California, United States
    Recruiting
  • Indiana Hemophilia and Thrombosis Center- Site Number : 8400006
    Indianapolis, Indiana, United States
    Recruiting
  • University of Iowa- Site Number : 8400004
    Iowa City, Iowa, United States
    Recruiting
  • Oregon Health and Science University-Site Number: 8400002
    Portland, Oregon, United States
    Recruiting
  • Washington Center for Bleeding Disorders- Site Number : 8400008
    Seattle, Washington, United States
    Recruiting
  • Investigational Site Number : 1240002
    Calgary, Alberta, Canada
    Recruiting
Show 13 more locations
  • Investigational Site Number : 1240001
    St. John's, Newfoundland and Labrador, Canada
    Recruiting
  • Investigational Site Number : 1240003
    Hamilton, Ontario, Canada
    Recruiting
  • Investigational Site Number : 3920003
    Kawasaki, Kanagawa, Japan
    Recruiting
  • Investigational Site Number : 3920001
    Saitama, Japan
    Recruiting
  • Investigational Site Number: 1580003
    Kaohsiung City, Taiwan
    Recruiting
  • Investigational Site Number: 1580001
    Taichung, Taiwan
    Recruiting
  • Investigational Site Number: 1580002
    Taipei, Taiwan
    Recruiting
  • Orthopedic Institute for Children- Site Number : 8400009
    Los Angeles, California, United States
    Completed
  • The Ohio State University Wexner Medical Center - CarePoint East- Site Number : 8400001
    Columbus, Ohio, United States
    Completed
  • Investigational Site Number : 0360001
    Murdoch, Western Australia, Australia
    Completed
  • Investigational Site Number : 1240004
    Hamilton, Ontario, Canada
    Completed
  • Investigational Site Number : 3920002
    Hiroshima, Japan
    Completed
  • Investigational Site Number : 3920004
    Tokyo, Japan
    Completed

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

  • Long-term observation of non-cancer blood disorders

    This study is tracking people with blood disorders like hemophilia and thrombosis for at least 15 years to see how their conditions change over time and gather useful information for doctors and researchers.

    Recruiting at 74 sites American Thrombosis and Hemostasis Network · Phoenix, Arizona and 75 other locations · NCT04398628

  • Registry for managing hemophilia in children across Europe

    This study is collecting information about children with hemophilia A or B to see how different factors affect their bleeding patterns and treatment outcomes across Europe.

    Recruiting at 33 sites PedNet Haemophilia Research Foundation · Graz and 38 other locations · NCT02979119

  • Using Hemlibra to treat mild hemophilia A

    This study is testing if Hemlibra can safely help men with mild hemophilia A manage their condition and improve their joint health and quality of life.

    Recruiting Phase 4 Indiana Hemophilia &Thrombosis Center, Inc. · Indianapolis, Indiana · NCT04567511

  • Hemophilia A: comparing long-acting FVIII replacement vs non-FVIII therapy in kids

    This study tests whether children with moderate to severe Hemophilia A on long-acting FVIII or non-FVIII therapies form clots differently and develop small joint bleeds or early joint changes.

    Recruiting University of Texas Southwestern Medical Center · Dallas, Texas · NCT07692217

  • Mother-and-child hemophilia A program

    See if following pregnant people with a severe hemophilia A genotype and their children from pregnancy through early childhood can identify factors linked to maternal bleeding and the child’s development of anti‑FVIII antibodies.

    Recruiting University of Washington · Seattle, Washington · NCT07414511

  • Surgical Use of Efanoctocog alfa in Hemophilia A Patients

    This observational study looks at how efanesoctocog alfa (Altuvoct) is used around surgery in people with hemophilia A to see if it helps control bleeding.

    Recruiting Hospices Civils de Lyon · Bron · NCT07723560

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.