RecruitingRare disease

Efficacy of efanesoctocog alfa in reducing synovitis in patients with congenital hemophilia A – a multicenter, randomized, open‑label phase 3 trial

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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on people born with a blood‑clotting disorder called Congenital hemophilia A, which can cause bleeding into joints and lead to inflammation of the joint lining known as synovitis. The medication being tested is a replacement factor called efanesoctocog alfa, given by intravenous injection to raise the blood’s clotting factor level.

The purpose of the study is to see whether giving a higher amount of this replacement therapy can reduce or eliminate the signs of synovitis over a year. Participants will receive regular infusions of the medicine, will have periodic checks of joint health using ultrasound imaging, and will be followed for about 12 months to record any bleeding events and any side effects.

Throughout the trial, safety will be monitored by recording any adverse events, and the amount of clotting factor in the blood will be measured to understand how long therapeutic levels are maintained. The study will collect information on how often bleeding occurs in joints and the overall number of bleeds, as well as whether the joint inflammation improves.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

Step 1
Baseline assessment
At the first visit, an ultrasound of the joints is performed to document the extent of synovitis.
Blood samples are taken to measure baseline factor viii activity and to confirm the diagnosis of congenital hemophilia a.
Step 2
Start of intensified replacement therapy
You receive efanesoctocog alfa by intravenous injection.
The prescribed amount is 35 iu/kg (35 international units for each kilogram of body weight).
The medication is supplied in vials of 250 iu, 500 iu, 1000 iu, 2000 iu, or 3000 iu; the appropriate vial strength is chosen based on your weight.
Step 3
Regular dosing visits
You continue to receive efanesoctocog alfa at the same dose of 35 iu/kg according to the schedule defined by the study protocol.
Each dose is administered as an intravenous injection.
Factor viii trough levels may be measured to ensure adequate protection.
Step 4
Periodic evaluations
At approximately month 3, month 6, and month 9, repeat ultrasounds are performed to assess changes in joint synovial thickness.
Blood tests are repeated to monitor factor viii activity and to record any bleeding episodes.
The information collected helps determine the proportion of joints showing a treatment response.
Step 5
Final assessment at 12 months
After 12 months of therapy, a final ultrasound is performed.
A treatment response is defined as a reduction or complete resolution of synovial hypertrophy in at least one affected joint.
Additional data on annualized bleeding rate, joint bleeding rate, and any treatment‑emergent adverse events are collected.
Step 6
Ongoing safety monitoring
Throughout the trial, any adverse events are recorded and evaluated.
Regular safety laboratory tests may be performed as required by the study protocol.

Who can join the trial?

6 criteria

Provide written informed consent before any study tests or procedures are done.
Be a male between 18 and 70 years old at the first screening visit.
Be able to understand the study information and follow the instructions given.
Have severe to moderate congenital hemophilia A (a bleeding disorder you are born with that affects clotting).
Have used regular preventive treatment with approved factor VIII medicines (standard, extended‑release, or high‑sustained versions) at the recommended dose for the past 6 months.
Have synovitis (inflammation and swelling of the joint lining) in the elbow, knee, or ankle, with a score of 1 or higher for joint lining thickening on a HEAD‑US ultrasound exam performed in a blinded (unbiased) manner.

Who cannot join the trial?

15 criteria

Having a fresh joint bleed (acute hemarthrosis) at the time of screening or within the past 4 weeks.
Taking blood‑thinning medicines (anticoagulant or antiplatelet drugs) at the time of screening.
Having any other bleeding disorder besides hemophilia A.
Expected to live less than 12 months at the time of screening.
Being allergic (hypersensitivity) to the study drug or any of its inactive ingredients.
Being of Asian ethnicity.
Having a close family relationship with the study doctor or working at the study site, sponsor, or contract research organization.
Having taken part in another interventional clinical trial within the past 3 months.
Any condition that the doctor believes makes participation unsafe, unlikely to follow the study plan, or not scientifically useful.
Being in legal custody (detained by a court or administrative order).
Having a current factor VIII inhibitor level of 0.6 BU/mL or higher.
Being currently treated with immune tolerance therapy.
Planning to increase regular factor VIII (FVIII) prophylaxis above the doses allowed in the study.
Having had radiosynovectomy (radiation treatment of a joint) or orthopedic surgery in the past 3 months, or planning such procedures in the next 12 months.
Having a history of blood clots (thrombosis), heart attack (myocardial infarction), other serious blood‑vessel disease, irregular heartbeat (atrial fibrillation), or a combination of risk factors that would raise heart‑related risk during treatment.

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Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Verified
Goethe University Frankfurt
Frankfurt, Germany
Verified
HZRM Haemophilie-Zentrum Rhein Main GmbH
Mörfelden-Walldorf, Germany
Verified
Justus-Liebig-Universitaet Giessen
Giessen, Germany

Trial locations

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Investigated drugs

efanesoctocog alfa is a medicine that replaces the missing clotting protein (factor VIII) in people with hemophilia A. It is given by injection into a vein and helps the blood form normal clots. In this trial the drug is used at higher‑than‑usual amounts, called intensified replacement therapy, to see if it can reduce swelling and joint damage (synovitis) in patients with congenital hemophilia A. The product is supplied as a powder that is mixed with a liquid right before it is injected.

Efanesoctocog Alfa

What is already known about the treatment

Efanesoctocog alfa - This medication is supplied as a powder that is mixed with a solvent to create a clear solution for intravenous injection. It is an approved orphan drug used to treat people with congenital hemophilia A and to help reduce joint inflammation (synovitis). It works by supplying a laboratory‑made version of the natural clotting protein factor VIII, allowing blood to clot normally and stop bleeding. It belongs to the class of recombinant coagulation factor VIII products, designed for a longer lasting effect.

Investigated diseases

Hemophilia A
Hemophilia A is a genetic condition in which the blood lacks enough clotting factor VIII, causing bleeding to take longer to stop. People with this condition may notice easy bruising, prolonged bleeding from cuts, or bleeding into muscles and joints. When bleeding occurs inside a joint, it can cause swelling and pain. Repeated joint bleeds can lead to thickening of the joint lining and reduced movement over time. The condition is present from birth and persists throughout life.
Synovitis
Synovitis is the inflammation of the thin tissue that lines the inside of a joint, called the synovium. The inflamed tissue becomes thickened and produces extra fluid, leading to joint swelling and discomfort. Early on, the joint may feel warm and stiff, especially after activity. If the inflammation continues, the synovium can become permanently thickened, limiting joint motion. Over time, chronic synovitis can contribute to joint damage and reduced function.