RecruitingPhase IIIInterventional

A study of JNJ-78934804 in participants with moderately to severely active Crohn's disease

Crohn’s disease is a long-term condition that causes painful inflammation and ulcers in the gut. While existing medicines help many people, they often stop working over time. This Phase III clinical trial looks at whether a new medicine called JNJ-78934804 can help adults with moderate to severe Crohn’s disease. JNJ-78934804 brings together two treatments (guselkumab and golimumab) into a single injection under the skin. Each drug blocks a different protein linked to inflammation. Researchers are comparing this combination to guselkumab alone to see which works better to reduce symptoms and heal the gut. Participants will take part for up to three years, receiving regular injections and health checks. Taking part is completely voluntary. The study medication and health tests are free, and travel costs are reimbursed.

At a glance

Status

Recruiting

Phase

Phase III

Sponsor

Janssen-Cilag International NV

Enrolment target

460

Start

28 May 2026

Estimated completion

12 Jul 2027

Crohn’s disease

What is this study about?

Crohn’s disease causes chronic inflammation in parts of the digestive system, leading to distressing symptoms like severe tummy pain, frequent diarrhoea, weight loss, and extreme tiredness. Although advanced treatments have improved life for many people, the body can sometimes stop responding to a drug over time. When multiple treatments fail, finding a new way to bring inflammation under control can be very difficult.

This study explores a new approach by combining two medicines into a single treatment, known as JNJ-78934804. It contains guselkumab and golimumab. Both are 'targeted' therapies that block different inflammatory proteins in the immune system. Researchers hope that blocking two pathways at the same time will provide stronger, longer-lasting relief than targeting just one.

The main aim of this Phase III trial is to compare how well this combination treatment works against guselkumab on its own after 48 weeks. If successful, this trial could provide a valuable new treatment option for people living with difficult-to-treat Crohn’s disease, helping to heal the bowel lining and improve daily quality of life.

Key takeaways

Tests a two-in-one injection (guselkumab plus golimumab) for moderate to severe Crohn’s disease.
Aimed at adults whose previous Crohn’s treatments have stopped working or caused intolerable side effects.
Compares the combination drug against a single drug over a period of up to three years.
Includes regular hospital visits, health monitoring, and camera tests of the bowel.
Participation is voluntary, study costs are covered, and travel expenses are reimbursed.

Who may be eligible?

This study is open to adults aged 18 and older who have been diagnosed with moderate to severe Crohn’s disease for at least 12 weeks. To be eligible, you should currently have active symptoms, such as frequent loose stools or daily abdominal pain, along with visible inflammation seen during a bowel examination. You must also have tried standard approved treatments that either did not work well enough, stopped working, or caused difficult side effects.

You will not be able to join the study if you have a different bowel condition, such as ulcerative colitis. People who currently have a stoma bag, severe bowel narrowing that needs surgery, short bowel syndrome, or an active infection or abscess are also unable to take part. The study doctors will carry out full health checks and a camera test of the bowel to ensure the trial is safe for you.

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.

I am aged 18 or older.
I have had a confirmed diagnosis of Crohn’s disease for at least 12 weeks.
I currently have active symptoms, such as daily tummy pain or frequent loose stools.
Previous standard Crohn’s medications have stopped working, failed to help, or caused bad side effects.
I do not have a stoma bag, short bowel syndrome, or an active untreated infection.

Answer every question to see your result.

What does participation involve?

If you decide to join, your participation will last for up to three years. The study begins with a screening period of up to six weeks to check that the trial is right for you. You will then be placed into one of two treatment groups by chance (like flipping a coin). One group receives the combination injection (JNJ-78934804), while the other receives guselkumab alone. Injections are given under the skin at weeks 0, 4, and 8, and then once every four weeks.

Neither you nor your doctor can choose your group. However, if your Crohn’s does not improve by week 16, a safety plan allows you to receive the combination treatment. Throughout the trial, you will attend regular clinic visits for blood tests, heart checks (ECGs), and camera examinations of your bowel (colonoscopies). After the main 48-week phase, you may continue in a long-term treatment extension, followed by a final 12-week safety check.

Potential risks and benefits

Taking part may help improve your Crohn’s symptoms and heal your gut, but this cannot be guaranteed because the combination is still being tested. You will also receive close medical attention and thorough health monitoring throughout the trial. However, there are potential side effects. These medicines calm parts of your immune system, which can increase your risk of infections or cause allergic reactions. Other risks include injection site soreness, changes in liver function, and discomfort or rare complications (such as bleeding or a small tear) from bowel camera tests. Your safety is monitored closely at every visit, and you are free to leave the trial at any time without your normal medical care being affected.

Locations (12)

Fairfield General Hospital
Approximate
Bury, England
Ulster Hospital
Approximate
Belfast, Northern Ireland
Kings College Hospital
Approximate
London, England
St George's Hospital
Approximate
London, England
Royal Devon & Exeter Foundation Hospital
City only
Exeter, England
University Hospital Birmingham
Unverified
Birmingham, England
Ninewells Hospital
Unverified
Dundee, Scotland
University Hospital of Wales
Unverified
Cardiff, England
Chelsea & Westminster Hospital
Unverified
London, England
Glasgow Royal Infirmary
Unverified
Glasgow, Scotland
Royal Victoria Infirmary
Unverified
Newcastle upon Tyne, England
John Radcliffe Hospital
Unverified
Oxford, England

Common questions

What is JNJ-78934804?

It is an experimental injection that combines two active medicines, guselkumab and golimumab, designed to block two different causes of gut inflammation at once.

Will I have to pay to take part?

No. The study treatment, doctor visits, and medical tests are provided free of charge, and reasonable travel and parking expenses will be reimbursed.

Can I choose which treatment I receive?

No. A computer assigns you to either the combination medicine or guselkumab by chance to ensure the study results are fair and unbiased.

What happens if my Crohn's symptoms get worse?

The study has built-in rescue rules. If your symptoms do not improve by week 16, you can be switched to the combination treatment to help get your disease under control.

Can I leave the study early?

Yes. Joining is completely voluntary. You can withdraw at any point, for any reason, and your regular NHS doctors will continue to look after you.

How to find out more

Janssen UK Registry

JanssenUKRegistryQueries@its.jnj.com - Official trial record

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