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Study on the Safety and Immune Response of Meningococcal B Vaccines in Adults with Asplenia: Bexsero, Trumenba, and a Drug Combination

Verified siteRegistered drugNo 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 the effectiveness and safety of three different vaccine strategies for preventing infections caused by the bacteria *Neisseria meningitidis* group B in patients with *asplenia*. *Asplenia* is a condition where a person does not have a functioning spleen, which is an organ that helps fight infections. The vaccines being studied are *Bexsero* and *Trumenba*, both of which are designed to protect against *meningococcal* group B infections. *Bexsero* contains several components produced using recombinant DNA technology, which means they are made by combining DNA from different sources to create a new set of genes. *Trumenba* includes proteins from two subfamilies of the *Neisseria meningitidis* group B bacteria.

The purpose of the study is to assess how well these vaccines work in generating an immune response in adults with *asplenia*. Participants will receive the vaccines as injections into the muscle. The study will last for several months, with the main evaluation occurring one month after the completion of the vaccine series. During this time, researchers will monitor the participants to see how their immune systems respond to the vaccines and to ensure their safety.

Participants in the study will be adults who have been without a functioning spleen for at least two weeks. The study will help determine the best vaccination strategy for protecting people with *asplenia* from *meningococcal* group B infections, which can be serious and life-threatening. The results of this study could provide valuable information for improving the health and safety of individuals with this condition.

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 visit and consent

    Upon joining the study, participants must provide written consent to participate in the trial.

    Eligibility is confirmed, ensuring participants are between 18 and 75 years old, have asplenia, and meet other criteria such as effective contraception for women of childbearing age.

  2. Step 2

    Vaccination phase

    Participants receive one of three meningococcal B vaccine strategies. The vaccines used are Bexsero and Trumenba, both administered as a suspension for injection.

    The vaccines are given intramuscularly.

  3. Step 3

    Follow-up and monitoring

    Participants are monitored for immunogenicity and safety of the vaccine strategies.

    The primary objective is to assess the immune response one month after completing the vaccination schedule, which is at month 7 for all participants.

  4. Step 4

    Long-term follow-up

    Participants are followed for a total of 4 years from the initial visit to monitor long-term effects and safety.

Who can join the trial?

7 criteria

  • Must be a male or female between 18 and 75 years old.
  • Must be an asplenic patient, meaning they do not have a spleen, for at least 2 weeks. This should be confirmed by the presence of Howell Jolly bodies in a blood test. Howell Jolly bodies are small remnants of red blood cells that can be seen under a microscope.
  • The removal of the spleen, known as a splenectomy, must be confirmed by a doctor's report or an ultrasound if it was done during regular check-ups.
  • Women who can have children must use effective birth control during the first 9 months of the study.
  • Participants must agree to the study and sign a consent form before any procedures begin.
  • Participants must have social security coverage or an equivalent.
  • Participants will be monitored for 4 years from the start of the study.

Who cannot join the trial?

4 criteria

  • Individuals who do not have a spleen, a condition known as asplenia, are not eligible to participate. The spleen is an organ that helps fight infections.
  • Participants must be within the specified age range for the study. If you are outside this age range, you cannot join the trial.
  • Both males and females can participate, but if you do not meet other specific criteria, you may be excluded.
  • If you belong to a vulnerable population, which means you might need special protection or care, you may not be eligible to participate.
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Investigated drugs

SPLEMENGO is a vaccine being tested to see how well it works in protecting against meningococcal B infections. This vaccine is being studied in people who do not have a spleen, as they are at higher risk for infections. The trial aims to understand how the immune system responds to this vaccine and to ensure it is safe for use in these patients.

What is already known about the treatment

Meningococcal B Vaccine – This vaccine is administered via injection to help protect against infections caused by meningococcal group B bacteria. It is currently being studied in clinical trials to evaluate its effectiveness and safety, particularly in individuals with asplenia, a condition where the spleen is absent or not functioning properly. The vaccine works by stimulating the immune system to produce antibodies that can recognize and fight the bacteria. It is classified as a vaccine under immunological agents.

Investigated diseases

Asplenia – Asplenia is a condition where the spleen is absent or nonfunctional. The spleen plays a crucial role in filtering blood and fighting infections. Without a functioning spleen, individuals are more susceptible to infections, particularly from certain bacteria. The condition can be congenital, meaning present at birth, or acquired due to surgical removal or disease. People with asplenia may experience increased vulnerability to infections and may require vaccinations and other preventive measures. The progression of asplenia involves ongoing management to prevent infections and maintain health.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-513649-35-00Protocol codeP170938JEstimated enrolment84 patientsSponsorAssistance Publique Hopitaux De Paris

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