RecruitingPHASE3INTERVENTIONAL

A Study to Investigate the Efficacy and Safety of Fitusiran Prophylaxis in Male Participants Aged 1 to Less Than 12 Years With Hemophilia A or B

This research study is looking at a new medicine called Fitusiran. It's for young boys, aged between 1 and 11 years old, who have severe haemophilia A or B. Haemophilia is a condition where blood doesn't clot properly, leading to bleeding problems. The main goals of this study are to find out how effective Fitusiran is at preventing bleeds and if it is safe for children. Some boys joining the study will be new to Fitusiran, meaning they haven't taken it before. Others have already been using Fitusiran in a previous study and will continue their treatment. The study also compares Fitusiran with standard treatments.

At a glance

Status

Recruiting

Phase

PHASE3

Sponsor

Sanofi

Enrolment target

Start

18 Dec 2025

Estimated completion

30 Dec 2031

Hemophilia

What is this study about?

This study is about a new way to help young boys who have severe haemophilia A or B. Haemophilia is a lifelong condition where your blood doesn't clot properly, which can lead to bleeding inside the body, especially in joints like knees and elbows. Boys with severe haemophilia need regular treatment to prevent these bleeds.

The new medicine being tested in this study is called Fitusiran. It's hoped that Fitusiran could offer a different way to prevent bleeds and improve the lives of children with haemophilia. The study is called a 'Phase 3' study, which means it's one of the final stages of testing, after earlier studies have shown it might be helpful and safe.

Researchers want to see if Fitusiran is effective at stopping bleeds and if it has any side effects when used regularly. They are comparing it to the usual treatments for haemophilia. By the end of this study, they hope to have a clearer picture of whether Fitusiran could become a new treatment option for young boys with this condition.

Key takeaways

Tests Fitusiran, a new medicine for severe haemophilia A or B.
For boys aged 1 to 11 years old.
Aims to prevent bleeds and check safety.
Some boys will be new to Fitusiran, others continuing from a previous study.
Participation involves regular clinic visits and close monitoring.
You can withdraw at any time.

Who may be eligible?

This study is for boys between 1 and 11 years old who have severe haemophilia A or B. You'd need to have a specific level of severity for your haemophilia. This study looks at two types of participants: those who have 'inhibitors' (which means their body can fight off some haemophilia treatments) and those who don't have inhibitors.

If your child has inhibitors, they would typically need certain medicines to help their blood clot or stop bleeds. If they don't have inhibitors, they would usually be on regular clotting factor treatments. Your doctor will be able to tell you if your child's haemophilia status matches what the study is looking for.

You also need to be able to have blood taken for tests. Importantly, a parent or legal guardian needs to agree for their child to take part, and the child (if old enough) will also be asked if they want to join.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Is your child a boy aged between 1 and 11 years old?
Does your child have severe haemophilia A or B?
Does your child currently receive treatment to prevent bleeds or manage them?
Does your child have good veins for blood tests?
Are you (as a parent/guardian) willing to provide consent?

Answer every question to see your result.

What does participation involve?

If your child is suitable for the study and you agree for them to take part, what happens next depends on whether they've taken Fitusiran before.

If your child has *never had Fitusiran*: First, they'll be checked to make sure they meet all the study requirements. Then, for about 24 weeks, they will continue with their usual haemophilia treatment (what doctors call 'standard of care'). After this period, they would start taking Fitusiran as part of the study for up to 160 weeks (about three years).

If your child has *already been taking Fitusiran* in a previous study (EFC15467): They won't need all the initial checks again. As long as they're still on treatment and you agree, they can simply continue taking Fitusiran in this new study for up to 60 weeks (just over a year). Throughout the study, there will be regular visits to the clinic for check-ups, blood tests, and to make sure the medicine is working and your child is well.

Potential risks and benefits

Taking part in any medical study has potential benefits and risks. For your child, a potential benefit could be access to a new medicine that might better prevent bleeds or reduce the need for other treatments. However, it's also possible Fitusiran may not work as expected or could cause side effects, some of which might be serious. The study doctors and nurses will monitor your child very closely to ensure their safety and well-being. Remember, you can decide to withdraw your child from the study at any time, for any reason, without it affecting their future medical care.

Locations (27)

The Luskin Orthopaedic Institute for Children- Site Number : 8400013
Verified postcode
Los Angeles, United States· Recruiting
The Center for Inherited Blood Disorders- Site Number : 8400009
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Orange, United States· Recruiting
Cure 4 The Kids Foundation- Site Number : 8400001
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Las Vegas, United States· Recruiting
Hackensack Meridian Health - Hackensack University Medical Center- Site Number : 8400008
Verified postcode
Hackensack, United States· Recruiting
Investigational Site Number : 0560002
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Brussels, Belgium· Recruiting
Investigational Site Number : 0560001
Verified postcode
Brussels, Belgium· Recruiting
Hospital das Clinicas da Faculdade de Medicina de Ribeirao Preto- Site Number : 0760003
Verified postcode
Ribeirão Preto, Brazil· Recruiting
Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo- Site Number : 0760004
Verified postcode
São Paulo, Brazil· Recruiting
Investigational Site Number : 1240003
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Montreal, Canada· Recruiting
Investigational Site Number : 3560004
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Bengaluru, India· Recruiting
Investigational Site Number : 3560002
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Mumbai, India· Recruiting
Investigational Site Number : 3560001
Verified postcode
Pune, India· Recruiting

Common questions

What is haemophilia?

Haemophilia is a condition where your blood doesn't clot properly, which can lead to longer bleeds or bleeds inside the body, especially in joints like knees.

What is Fitusiran?

Fitusiran is a new investigational medicine being tested to help prevent bleeding in people with haemophilia.

Which age group is this study for?

This study is for boys aged 1 year up to their 12th birthday (1 to 11 years old).

Do I have to stop my child's current treatment?

If your child hasn't had Fitusiran before, they'll stay on their usual treatment for 24 weeks before starting Fitusiran. If they're already on Fitusiran from another study, they'll continue it.

Can girls take part in this study?

No, this specific study is only open to boys.

How to find out more

Trial Transparency email recommended (Toll free for US & Canada)

contact-us@sanofi.com 800-633-1610 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.