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Factor IX deficiency – Trials in Disease

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Clinical Trials for Factor IX Deficiency (Hemophilia B)

Factor IX deficiency, also known as Hemophilia B, is a genetic bleeding disorder where blood does not clot properly due to insufficient levels of clotting factor IX. Currently, 12 clinical trials are investigating new treatments including gene therapies and novel preventive medications for children and adults with this condition. (Also known as: Hemophilia B, Christmas disease)

Clinical trial locations

Long-term Safety Study of Etranacogene Dezaparvovec in Adult Men with Hemophilia B

This trial focuses on monitoring adult men who have previously received a gene therapy treatment called Etranacogene Dezaparvovec (CSL222) for Hemophilia B. The study aims to track the long-term safety and effectiveness of this treatment over an extended period, potentially until 2035.

Who can participate: Adult males with Hemophilia B who have already received CSL222 treatment in previous studies (CSL222_2001 or CSL222_3001) and have either completed those studies or it has been at least 5 years since they received the treatment. Participants must provide written consent and be willing to follow all study requirements.

Who cannot participate: Females are not eligible. Those who have not participated in the previous CSL222 studies or do not have Hemophilia B cannot join.

Study focus: The research evaluates how well the gene therapy continues to work over time by monitoring bleeding episodes, Factor IX activity levels in the blood, and quality of life. Regular check-ups will track participants’ health and any potential side effects from the treatment.

Treatment being studied: Etranacogene Dezaparvovec is a gene therapy that was administered in earlier studies. It uses a specially designed virus to deliver a healthy version of the Factor IX gene to the liver, helping the body produce the clotting protein essential for proper blood clotting.

Study on Long-Term Safety and Effects of Marstacimab for Patients with Severe Hemophilia A or B, With or Without Inhibitors

This trial studies the long-term safety and effectiveness of Marstacimab, a preventive treatment given as an injection under the skin for people with severe forms of the condition. The study accepts patients with or without inhibitors, which are substances that can make traditional treatments less effective.

Who can participate: Males aged 1 to 74 years with severe Hemophilia A or moderately severe to severe Hemophilia B who have successfully completed previous studies (B7841005 or B7841008). Participants must be willing to attend all visits, follow the treatment plan, and complete required tests. Written consent from participants or their legal guardians is required.

Who cannot participate: Females cannot participate. Patients with Factor VIII activity of 1% or more, or Factor IX activity of more than 2%, are not eligible. Those outside the age range of 1 to less than 75 years cannot join.

Study focus: The study monitors participants over several years to assess how safe and well-tolerated Marstacimab is when used long-term. It tracks the number of bleeding episodes, any side effects including injection site reactions, changes in vital signs, laboratory test results, and joint health over time.

Treatment being studied: Marstacimab is a medication administered through subcutaneous injection (under the skin) using either a pre-filled pen or syringe. It works by helping the blood clot more effectively to reduce bleeding episodes.

Study on Marstacimab for Children with Severe Hemophilia A or B, With or Without Inhibitors

This study evaluates how well Marstacimab works in reducing bleeding episodes in children and teenagers under 18 years old. The trial compares the new treatment with the standard treatment participants have been receiving to see which approach is more effective.

Who can participate: Males under 18 years of age with severe Hemophilia A or moderately severe to severe Hemophilia B, with or without inhibitors. Participants must meet minimum body weight requirements (specific to age groups) and have documented treatment history from the past year. For children with inhibitors, at least 26 weeks of treatment records are required. For those without inhibitors, at least 52 weeks of treatment history with documented bleeding episodes, or 26 weeks of preventive treatment, is needed.

Who cannot participate: Females and males 18 years or older cannot participate. Those who do not meet the specific weight, age, and treatment history requirements are not eligible.

Study focus: The trial lasts about 48 weeks and examines whether Marstacimab can reduce bleeding episodes compared to previous treatments. It also assesses the impact on joint health and quality of life using age-appropriate questionnaires. Safety is closely monitored throughout, including any side effects or injection site reactions.

Treatment being studied: Marstacimab is given as a regular injection under the skin using a pre-filled pen device. It helps blood clot more effectively to prevent bleeding episodes.

Study on the Effectiveness of Concizumab for Children Under 12 with Hemophilia A or B, With or Without Inhibitors

This clinical trial studies how well Concizumab prevents bleeding episodes in young children compared to their previous treatment. The medication is administered as an injection under the skin using a special pen-injector device.

Who can participate: Males under 12 years old with severe Hemophilia A or moderate/severe Hemophilia B, with or without inhibitors, who have not used Concizumab before. Participants must have documented treatment history: at least 26 weeks of records for those with inhibitors, or at least 52 weeks with documented bleeding episodes (or 26 weeks of preventive treatment) for those without inhibitors. Informed consent from parents or guardians is required.

Who cannot participate: Females and males 12 years or older are not eligible.

Study focus: The study, expected to conclude by November 2029, monitors the number of bleeding episodes participants experience and compares this to their previous treatment. Researchers also track any side effects such as injection site reactions, antibodies against Concizumab, and overall health status through regular assessments.

Treatment being studied: Concizumab is given as regular injections under the skin. It works by inhibiting a protein called tissue factor pathway inhibitor (TFPI), which helps regulate blood clotting and can reduce bleeding episodes.

Study on the Safety and Effectiveness of REGV131 and LNP1265 for Adults with Hemophilia B

This trial tests a new gene therapy treatment called REGV131-LNP1265 that uses CRISPR/Cas9 technology. The treatment is designed to help the body produce more Factor IX protein by inserting a functional gene into liver cells. It is given as a single intravenous infusion.

Who can participate: Males aged 18 years or older with confirmed severe or moderately severe Hemophilia B (Factor IX levels of 2% or less). Participants must be currently taking regular preventive Factor IX therapy and have previous experience with such treatment. Those who participated in the initial phase of the study or a related study for at least 6 months to collect baseline bleeding data are eligible.

Who cannot participate: Females cannot participate. Those without Hemophilia B or outside the specified age range are not eligible. Vulnerable populations are also excluded.

Study focus: The trial is divided into two parts. The first part assesses the safety and how well a single dose helps produce Factor IX. The second part evaluates the recommended dose’s effectiveness in reducing bleeding events over time. Participants will be monitored for several years for side effects, changes in Factor IX production, bleeding rates, and the need for additional treatments.

Treatment being studied: REGV131-LNP1265 is a CRISPR/Cas9-based gene therapy delivered through a single IV infusion. It aims to insert the clotting factor IX gene into patients’ liver cells to enable the body to produce its own clotting protein.

Study of Etranacogene Dezaparvovec (CSL222) in Adolescent Males with Severe or Moderately Severe Hemophilia B

This study investigates whether a one-time gene therapy treatment can work as well as regular preventive injections in adolescent males. The therapy uses a modified virus to deliver a working copy of the Factor IX gene to the liver.

Who can participate: Males born male, between 12 and under 18 years old at treatment time, with severe or moderately severe Hemophilia B (2% or less Factor IX activity). Participants must be on regular preventive Factor IX treatment, have received Factor IX on at least 75 separate days, been on stable treatment for at least 2 months before screening, and completed a lead-in observation period of at least 6 months. Consent must be provided, and participants must agree to use condoms during sexual activity until the treatment is no longer present in semen.

Who cannot participate: Those under 12 or 18 years or older, with mild Hemophilia B, previous gene therapy, active hepatitis C or B infections, detectable HIV, history of Factor IX inhibitors, allergies to study drug components, significant liver, kidney, or heart disease, or who participated in another trial within 30 days cannot join.

Study focus: The study tracks bleeding episodes, Factor IX protein levels, whether regular treatments are still needed, side effects, and quality of life impacts over 18 months following a 6-month lead-in period. This research aims to determine if one-time gene therapy can replace regular injections.

Treatment being studied: Etranacogene dezaparvovec (CSL222, also known as Hemgenix) is a gene therapy given as a single intravenous infusion containing a modified virus with a functional Factor IX gene copy.

Study on Joint Health in Hemophilia A and B Patients Using Efmoroctocog Alfa or Eftrenonacog Alfa

This trial studies how two clotting factor replacement treatments affect joint health over an 18-month period. The treatments, efmoroctocog alfa (for Hemophilia A) and eftrenonacog alfa (for Hemophilia B), are given as injections and used to prevent bleeding episodes.

Who can participate: Patients aged 6 years or older with Hemophilia A or B who have at least 6 months of documented treatment history including prescriptions and bleeding episodes. Participants must have been previously treated with approved recombinant or plasma-derived Factor VIII or IX concentrates for at least 6 months. Those joining must have started or will start preventive treatment with rFVIIIFc or rFIXFc. Signed consent is required (from legally authorized representatives for minors, with child’s assent per local regulations).

Who cannot participate: Those without Hemophilia A or B, or outside the specified age ranges (some sub-studies may have specific age criteria) cannot participate.

Study focus: The trial uses ultrasound imaging to evaluate joint health throughout the 18-month treatment period. It monitors bleeding episodes, overall well-being, and any changes in joint condition. Some participants may receive a placebo for comparison. Regular check-ups track joint health and treatment effectiveness.

Treatments being studied: Efmoroctocog alfa is a recombinant fusion protein acting like Factor VIII for Hemophilia A patients, while eftrenonacog alfa is similar but acts like Factor IX for Hemophilia B patients. Both are given as injections to prevent bleeding and protect joint health.

Study on the Safety and Effectiveness of Etranacogene Dezaparvovec Gene Therapy for Adults with Severe or Moderately Severe Hemophilia B and AAV5 Antibodies

This study evaluates whether gene therapy with CSL222 (Etranacogene Dezaparvovec) can effectively treat adults with severe or moderately severe Hemophilia B who have specific antibodies (AAV5 neutralizing antibodies) before treatment. The therapy is delivered as a single intravenous infusion.

Who can participate: Adults (at least 18 years old) with congenital Hemophilia B with severe or moderately severe Factor IX deficiency (2% or less). Participants must have two consecutive positive AAV5 antibody test results, more than 150 days of previous Factor IX replacement therapy, been on stable treatment for at least 2 months before screening, be able to accurately complete an electronic diary, and agree to use barrier contraception for 1 year after treatment. Written informed consent is required.

Who cannot participate: Those without Hemophilia B, outside the specified age range, or who are part of vulnerable populations are not eligible.

Study focus: After a lead-in period of at least 6 months maintaining current Factor IX therapy, participants receive a single dose of gene therapy. The study monitors bleeding episodes compared to previous standard care, side effects, liver function changes, and overall effectiveness for up to 18 months. Regular assessments include blood tests, liver ultrasounds, and monitoring for new or resolved joint issues.

Treatment being studied: CSL222 (Etranacogene Dezaparvovec) is a single-dose gene therapy infusion that delivers a functional Factor IX gene copy using an adeno-associated virus vector, aiming to reduce bleeding episodes by enabling the body to produce its own clotting protein.

Study on How Concizumab Works for Patients with Hemophilia A or B Without Inhibitors

This trial compares regular preventive treatment with Concizumab to on-demand treatment (treatment only when bleeding occurs) to see which approach better prevents bleeding episodes in people without inhibitors. The medication is given as injections under the skin.

Who can participate: Males aged 12 years or older weighing more than 25 kg with severe Hemophilia A (Factor VIII less than 1%) or moderate/severe Hemophilia B (Factor IX 2% or less) without inhibitors. Participants must have records of using coagulation factor products in the last 24 weeks. Informed consent is required.

Who cannot participate: Females, those with inhibitors, or those considered part of vulnerable populations cannot participate.

Study focus: The trial, expected to conclude by June 2026, randomly assigns participants to either regular Concizumab treatment or on-demand treatment. It monitors bleeding episodes, injection site reactions, hypersensitivity reactions, and overall health through regular blood tests and assessments. The treatment lasts at least 32 weeks with ongoing monitoring.

Treatment being studied: Concizumab is administered as a subcutaneous injection (under the skin) using the PDS290 pen-injector device. It works by inhibiting tissue factor pathway inhibitor (TFPI), which helps maintain normal clotting function and prevent bleeding episodes.

Study on Long-Term Safety and Efficacy of Etranacogene Dezaparvovec for Adults with Severe or Moderately Severe Hemophilia B

This long-term follow-up study monitors adults who previously received AAV5-hFIX gene therapy for 6 to 10 years after treatment to assess its ongoing safety and effectiveness. The treatment was designed to help the body produce Factor IX protein.

Who can participate: Adult males with congenital Hemophilia B who completed the previous study CT-AMT-060-01 and can provide informed consent.

Who cannot participate: Females, those without severe or moderately severe Hemophilia B, or those considered vulnerable populations are not eligible.

Study focus: The study monitors long-term safety by tracking side effects, liver health through ultrasounds and blood tests, antibody development, Factor IX activity levels, bleeding event frequency, need for additional treatments, joint health, and quality of life through questionnaires. The study is expected to conclude by May 31, 2026.

Treatment being studied: AAV5-hFIX (Hemgenix, etranacogene dezaparvovec) was previously administered as a single intravenous infusion. This gene therapy uses a viral vector to deliver a modified Factor IX gene to liver cells, aiming to enable long-term Factor IX production and reduce bleeding episodes.

Study on the Efficacy and Safety of Fidanacogene Elaparvovec Gene Therapy in Adult Males with Moderate to Severe Hemophilia B

This study evaluates a gene therapy called fidanacogene elaparvovec (PF-06838435) that involves a single infusion delivering a modified gene to help the body produce Factor IX. The trial will continue for several years to gather comprehensive data on long-term effects.

Who can participate: Males aged 18 to 65 years with moderately severe to severe Hemophilia B (Factor IX levels 2% or less). Participants must have completed at least 6 months of data collection while on regular preventive Factor IX therapy, have used Factor IX products for at least 50 days, agree to stop regular preventive treatment after receiving the study drug (though Factor IX can still be used as needed), have acceptable lab results (hemoglobin at least 11 g/dL, platelets at least 100,000 cells/µL, creatinine 2.0 mg/dL or less), and agree to contraception requirements including not donating sperm and using condoms during sexual activity.

Who cannot participate: Those with other serious medical conditions, history of allergic reactions to similar treatments, recent experimental treatment for Hemophilia B, other bleeding disorders, active infections requiring treatment, history of drug or alcohol abuse, conditions affecting study participation understanding, or involvement in other clinical trials simultaneously cannot join.

Study focus: After a 6-month pre-treatment period maintaining usual Factor IX therapy, participants receive a single gene therapy infusion. The study monitors bleeding event rates, Factor IX activity levels, health status, and any side effects or adverse reactions for up to 6 years. Regular follow-up visits include laboratory tests and health evaluations.

Treatment being studied: Fidanacogene elaparvovec (PF-06838435) is a one-time gene therapy infusion that delivers a working copy of the Factor IX gene to help the body produce clotting protein on its own, potentially reducing the need for regular Factor IX injections.

Summary

These 12 clinical trials represent a diverse range of research approaches for treating Factor IX deficiency, with studies conducted across multiple European countries. A notable concentration of trials is taking place in Germany, France, Italy, and Spain, reflecting these countries’ strong research infrastructure for rare bleeding disorders.

Several trials focus on innovative gene therapies, including Etranacogene Dezaparvovec (CSL222/Hemgenix), which appears in multiple studies examining both initial treatment and long-term safety across different age groups from adolescents to adults. Another gene therapy approach uses REGV131-LNP1265 with CRISPR/Cas9 technology, representing cutting-edge genetic editing techniques.

Other studies investigate novel preventive medications like Marstacimab and Concizumab, both administered as subcutaneous injections and tested in various age groups from young children to adults. These trials include patients with and without inhibitors, addressing the needs of different patient populations.

The research also examines traditional replacement therapies such as efmoroctocog alfa and eftrenonacog alfa, focusing on their impact on joint health over time. Several trials specifically target pediatric populations, including children under 12 and adolescents, filling an important gap in treatment options for younger patients.

Many of these studies include long-term follow-up periods extending from 18 months to 10 years, reflecting the importance of understanding the lasting effects and safety of these treatments. The trials evaluate various outcomes including bleeding episode frequency, quality of life, Factor IX activity levels, and joint health, providing comprehensive assessment of treatment effectiveness beyond just bleeding control.

Ongoing Clinical Trials on Factor IX deficiency

  • Study on the Effectiveness of Concizumab for Children Under 12 with Hemophilia A or B, With or Without Inhibitors

    Recruiting

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    Investigated diseases:
    Investigated drugs:
    Bulgaria France Greece Italy Lithuania Norway +4

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