Not yet recruitingPhase IIInterventional

A study to investigate whether novel vaccines can improve Crohn's disease by targeting a bacterium thought to contribute to the condition

This study is investigating two new vaccines for Crohn's disease. Researchers think a bacterium called Mycobacterium avium subspecies paratuberculosis (MAP) might play a role in Crohn's, and these vaccines are designed to target it. This is a Phase II clinical trial, meaning it's an early-stage study in humans. It aims to see how effective the vaccines are at improving Crohn's, check their safety, and understand how the immune system responds to them. Adults aged 18-50 with active Crohn's disease can take part. Participants will receive either the vaccine or a dummy treatment (placebo) and will be closely monitored for several months. The study hopes to find new treatment options for future patients.

At a glance

Status

Not yet recruiting

Phase

Phase II

Sponsor

HAV Vaccines Limited

Enrolment target

120

Start

01 Nov 2026

Estimated completion

31 Oct 2027

Crohn's disease

What is this study about?

This study, taking place in the UK, is exploring a new way to treat Crohn's disease. Researchers are testing two new vaccines that are designed to target a specific bacterium called Mycobacterium avium subspecies paratuberculosis, or MAP for short. Some scientists believe that this bacterium might play a role in Crohn's disease for some people. The idea is that by targeting this bacterium with a vaccine, it might help to reduce the symptoms and improve the condition.

This is a 'Phase II' study, which means it's an important step in researching new medicines. It's not yet a widely available treatment, but an early stage where scientists are carefully looking at how well the new vaccines work, if they are safe, and how a person's immune system reacts to them. The ultimate goal is to understand if this vaccine approach could become a helpful new treatment option for people living with Crohn's disease in the future.

The study involves giving participants two different vaccines (or dummy treatments) spread over several weeks. Scientists will then closely watch how the Crohn's disease changes, checking to see if participants experience an improvement in their symptoms or achieve remission. They will also be looking out for any side effects and monitoring the overall health of everyone taking part.

Key takeaways

Testing new vaccines for Crohn's disease, targeting a bacterium called MAP.
Early-stage (Phase II) study to check effectiveness, safety, and immune response.
Participants will receive either vaccine or a dummy treatment (placebo).
Close monitoring for side effects and Crohn's improvement over several months.
May not directly benefit, but could help find future treatments for Crohn's.
Takes place at Guy's Hospital, UK, from late 2026 to late 2028.

Who may be eligible?

This study is looking for adults aged between 18 and 50 years old who have a confirmed diagnosis of Crohn's disease. Your Crohn's disease should be mildly to moderately active, meaning you might have certain markers in your blood or stool, or active inflammation seen during a scope examination.

You would not be able to join if you are currently taking certain strong immune-suppressing medications for your Crohn's, or have taken them recently (within the last 3 months). This also applies to other research studies involving new medications or vaccines. You also can't have certain conditions that affect your immune system, like HIV, or have had certain recent treatments like blood products.

If you are a woman who could become pregnant, you would need to agree to use effective contraception throughout the study and have a negative pregnancy test to participate. All participants need to be able to follow the study's requirements and give their informed consent.

Quick self-check

Are you between 18 and 50 years old?
Do you have a confirmed diagnosis of Crohn's disease?
Is your Crohn's disease currently mildly to moderately active?
Are you able to attend clinic visits at Guy's Hospital in London?
Have you avoided certain strong Crohn's medications in the last 3 months?
Are you willing to use effective contraception if you are a woman of childbearing age?

This is a guide only — the research team will confirm whether you can take part.

What does participation involve?

If you decide to take part in this study, you will be randomly put into one of two groups: one group will receive the new vaccines, and the other will receive a 'placebo' (a dummy treatment that looks just like the real thing). Neither you nor the study doctors will know which treatment you are receiving – this is called 'double-blinded'.

The vaccine group will have two injections into the muscle: the first on Day 0 and the second about 8 weeks later (Day 56). The placebo group will receive similar dummy injections at the same times. You will have several visits to the clinic over roughly 4 to 5 months. These visits include an initial screening to check if you're suitable, the vaccination appointments, regular safety checks, and follow-up assessments. Your Crohn's disease activity will be looked at using standard assessments, and you'll be monitored for at least 112 days after your first vaccine.

Potential risks and benefits

You may or may not personally benefit directly from taking part in this study, as it's an early-stage investigation. However, the information gathered could be very valuable in developing new treatments for Crohn's disease for future patients. If you receive the vaccine, there's a chance your Crohn's symptoms might improve, but this isn't guaranteed. Like all medications, the investigational vaccines may cause side effects. These are generally expected to be mild to moderate and temporary, similar to what you might experience with other common vaccines, for example, pain, redness, or swelling at the injection site, headache, tiredness, fever, joint aches, or flu-like feelings. Study staff will closely monitor you for any side effects throughout your participation. You are free to withdraw from the study at any time without giving a reason.

Locations (1)

Guy's and St Thomas' Hospitals
London, England

Common questions

What is a Phase II study?

A Phase II study is an early stage of clinical research. It mainly looks at how well a new treatment works, its safety, and how the body reacts to it in a small group of people.

What is a 'placebo'?

A placebo is a dummy treatment. It looks exactly like the actual medication being tested but contains no active ingredients. It's used to compare against the real treatment.

What is Mycobacterium avium subspecies paratuberculosis (MAP)?

MAP is a type of bacterium that some researchers believe might contribute to Crohn's disease in certain people. This study's vaccines are designed to target it.

How long will I be in the study?

You will attend several clinic visits over approximately 4-5 months and be monitored for at least 112 days after your first vaccine.

Can I still take my regular Crohn's medication?

You cannot be taking certain strong immune-suppressing medications for Crohn's, or have taken them recently, to join this study. The research team will discuss your specific medications with you.

How to find out more

Jeremy Sanderson

gstt.gastroenterologyofficestaff@nhs.net +44 02071882499 Official trial record

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