Do ‘biologics’ (medications that target specific parts of the immune system) help manage Crohn’s disease?

Key messages

• For making symptoms go away (remission), ustekinumab works slightly better than placebo (sham treatment). Adalimumab plus immune system drugs, guselkumab and upadacitinib probably work slightly better than placebo, while vedolizumab and natalizumab probably work only a little better than placebo.

• For stopping symptoms coming back (preventing active disease) within one to two years of remission, adalimumab probably works slightly better than placebo.

• In the short term (about one year), compared to placebo, upadacitinib, ustekinumab and vedolizumab probably lead to fewer people stopping treatment due to unwanted effects. We can’t be sure about unwanted effects of biologics in the long term based on the existing evidence.

What is Crohn's disease?

Crohn's disease is a life-long (chronic) inflammatory disease that can affect any part of the gut. Common symptoms include bloody poo (stool or faeces), diarrhoea, stomach ache, fever, weight loss, fatigue and others. When someone is experiencing symptoms of Crohn's, they are said to have 'active' disease, and when their symptoms are under control, then they are said to be 'in remission'. We don't know what exactly causes Crohn's, but it could be related to a combination of genes, immune system malfunction, 'bad' gut bacteria and environmental reasons. There is no known cure, but the symptoms are usually managed with medications, such as steroids, immune system medications and, if necessary, surgery.

What are biologics?

At the turn of the century, a new category of medications called biologics, or advanced treatments, became available and started being widely used for the treatment of Crohn's. These are new and different treatments that target parts of the immune system more specifically than the older treatments, and they are thought to be better and have fewer unwanted effects. They can be delivered through a vein (intravenous), under the skin or sometimes orally.

What did we want to find out?

We wanted to find out whether all the biologics (medications that target specific parts of the immune system) or advanced treatments that are being used (or have been tested) can treat Crohn's, whether they have unwanted effects and how they compare to each other. The things we looked for were whether a medication can make symptoms go away, improve symptoms or make the gut look healed during a colonoscopy (examination inside the colon), as well as whether these medications have unwanted effects in the short term (up to one to two years) and long term (longer than two years).

What did we do?

We searched for studies that compared biologics with any other medical treatment or a placebo (a sham treatment) for adults with Crohn’s disease. People in the studies could be men or women. They could have had Crohn’s disease for any length of time and have used any medication for their Crohn’s disease. We summarised the findings and assessed how confident we could be in the results, based on how the studies were designed and carried out.

What did we find?

We included 94 studies with 27,476 people, with about equal numbers of men and women. Most people were around 30 to 40 years old, but they ranged from older adolescents to people in their sixties. Severity in the induction studies was moderate to severe. In the maintenance studies, some people were in remission and some had responded to previous therapy and still had some symptoms. Most induction studies followed people for three to six months and maintenance studies for about one year.

Main results

• There were 66 induction studies, involving 20,653 people, and 22 maintenance studies, involving 6823 people.

• For making symptoms go away (remission), ustekinumab works slightly better than placebo (sham treatment). Adalimumab plus immune system drugs, guselkumab and upadacitinib probably work slightly better than placebo, while vedolizumab and natalizumab probably work only a little better than placebo. Risankizumab, BI695501 (a medication that resembles adalimumab), a combination of infliximab with immune system medications, and filgotinib may also work, but we are less certain about them.

• We are uncertain whether other medications work or not, compared to placebo.

• For stopping symptoms coming back (preventing active disease) within one to two years of remission, adalimumab probably works slightly better than placebo.

• In the short term (about one year), compared to placebo, upadacitinib, ustekinumab and vedolizumab probably lead to fewer people stopping treatment due to unwanted effects. Other medications like risankizumab, certolizumab and filgotinib could be similar to placebo too, but we're less certain about them.

• We can’t be sure about unwanted effects of biologics in the long term based on the existing evidence.

What are the limitations of the evidence?

The included studies had people with very different characteristics between them, such as mixes of people who have or have not used biologics or advanced treatments before, people with more or less serious disease, and people using or not using other treatments at the same time. When these characteristics of people are not similar across the studies, it can make it difficult to be sure of the results.

The information we have is mainly around clinical symptoms, and information from colonoscopies or microscope examination was limited. There were also some issues with the way the included studies were carried out and the quality of the methods they used.

How up to date is this review?

This review is up to date to June 2025.