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

Verified siteInvestigationalNo placebo
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What is this trial about?

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

This clinical trial is focused on studying a treatment for Hemophilia B, a genetic disorder that affects the blood's ability to clot properly. The study will use a treatment called REGV131-LNP1265, which is a new type of therapy involving a method known as CRISPR/Cas9. This method is designed to help the body produce a protein called clotting factor IX, which is essential for blood clotting. The treatment is given as a solution through an intravenous (IV) infusion, meaning it is delivered directly into the bloodstream.

The purpose of the study is to evaluate the safety and effectiveness of REGV131-LNP1265 in helping the body make clotting factor IX in adults with Hemophilia B. The study is divided into two parts. In the first part, participants will receive a single dose of the treatment to assess its safety and how well it helps the body produce clotting factor IX. In the second part, participants will receive the recommended dose to further evaluate its effectiveness in reducing bleeding events over time.

Participants in the study will be monitored for any side effects and changes in their ability to produce clotting factor IX. The study will also track the rate of bleeding events and the need for additional clotting factor treatments. The trial is expected to last several years, allowing researchers to gather comprehensive data on the long-term effects and benefits of the treatment. This study aims to provide valuable insights into a potential new therapy for managing Hemophilia B.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial administration

    The study begins with a single intravenous (IV) infusion of the medication REGV131-LNP1265. This medication is a solution designed to help the body produce clotting factor IX, which is important for blood clotting.

    The infusion is administered to evaluate its safety and how well it is tolerated. This step is crucial for determining the appropriate dose for further study.

  2. Step 2

    Monitoring and assessment

    After the infusion, the functional activity of clotting factor IX is measured at day 29. This involves a chromogenic substrate assay, a test that helps assess how well the treatment is working.

    Participants are monitored for any adverse events, which are any unwanted effects that occur after the treatment. This monitoring continues for up to 104 weeks.

  3. Step 3

    Follow-up and evaluation

    The study includes a follow-up period where the change in clotting factor IX activity is assessed at week 26. This helps determine the effectiveness of the treatment over time.

    The annualized bleeding rate (ABR) is evaluated over 52 weeks to understand the impact of the treatment on bleeding events.

  4. Step 4

    Long-term observation

    Participants continue to be observed for up to 104 weeks to monitor the long-term effects of the treatment. This includes checking for the presence of antibodies that might affect the treatment's effectiveness.

    The study also looks at the use of any additional clotting factor IX therapy and whether participants remain free of spontaneous bleeding events during this period.

Who can join the trial?

5 criteria

  • Must be a male at birth and at least 18 years old.
  • Must have a confirmed diagnosis of severe or moderately severe hemophilia B. This means having a history of low levels of a blood clotting protein called FIX (Factor IX), specifically 2% or less of normal levels.
  • Must currently be taking FIX prophylaxis, which is a regular treatment to prevent bleeding, and have previous experience with FIX therapy.
  • Must have participated in the initial phase of this study or a related study for at least 6 months to collect data on bleeding events while on FIX prophylaxis.
  • Other specific criteria defined in the study protocol may also apply.

Who cannot join the trial?

4 criteria

  • Participants who do not have Hemophilia B cannot join the study. Hemophilia B is a condition where blood doesn't clot properly due to a lack of a specific protein called Factor IX.
  • Females are not eligible to participate in this study.
  • Individuals who are not within the specified age range for the study cannot participate. The study is open to certain age groups only.
  • Participants who are considered part of a vulnerable population are not eligible. A vulnerable population includes groups who may have limited ability to protect their own interests.
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Investigated drugs

REGV131-LNP1265 is a gene therapy treatment being studied for its potential to help people with Hemophilia B. This therapy uses a technology called CRISPR/CAS9 to insert a specific gene into the body. The goal is to help the body produce more of a protein called Factor IX, which is important for blood clotting. By increasing the levels of this protein, the therapy aims to reduce bleeding episodes in people with Hemophilia B. The study is looking at how safe and well-tolerated this treatment is, as well as how effective it is in improving blood clotting.

What is already known about the treatment

REGV131-LNP1265 – This medication is administered intravenously and is currently being studied in clinical trials for its potential use in treating Hemophilia B. It is a CRISPR/Cas9-based gene therapy designed to insert the coagulation factor IX gene into patients' cells, aiming to improve blood clotting function. The main therapeutic indication is to enhance clotting factor IX activity in individuals with Hemophilia B, potentially reducing bleeding episodes. As a gene therapy, it represents a novel approach in the pharmacological classification of genetic treatments, focusing on altering the genetic makeup to address the underlying cause of the disease.

Investigated diseases

Hemophilia B – Hemophilia B is a genetic disorder characterized by a deficiency of clotting factor IX, which is essential for blood clotting. This condition leads to prolonged bleeding after injuries, surgeries, or even spontaneously without any apparent cause. Individuals with Hemophilia B may experience frequent nosebleeds, easy bruising, and joint bleeds, which can cause pain and swelling. The severity of symptoms can vary, with some individuals experiencing mild symptoms and others having more severe bleeding episodes. Over time, repeated bleeding into joints can lead to joint damage and mobility issues. Hemophilia B is typically inherited, but in some cases, it can occur due to a spontaneous genetic mutation.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2023-507260-40-00Protocol codeR131L1265-HEMB-2318Estimated enrolment118 patientsSponsorRegeneron Pharmaceuticals Inc.

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