Biologic medicines

Last reviewed: June 2019

Biologic medicines are a form of treatment for Crohn’s and Colitis. In general, they are prescribed for people with moderate to severe Crohn's or Colitis when other treatments have not worked.

Deciding to take a biologic medicine can feel like a big step. But if you’re not well and other treatments aren’t working, they can make a huge difference to your quality of life. Whether you’ve been prescribed a biologic for Crohn’s or Colitis or you’re considering it as an option, this information is for you.

It looks at:

Download this information (PDF)

  • What is a biologic medicine?

    Biologic medicines are treatments for people with moderate to severe Crohn’s Disease or Ulcerative Colitis. They may be an option when other drugs such as immunosuppressants (azathioprinemercaptopurine, and methotrexate) or steroids haven’t been effective, or side effects have been hard to manage.

    Biologic medicines are produced by biological rather than chemical processes. Living organisms, such as living cells, produce the active substance which is made of proteins.

  • What biologic medicines are used to treat Crohn's and Colitis?

    There are five different biologic medicines available to treat moderate to severe Crohn’s Disease or Ulcerative Colitis. These are infliximabadalimumabgolimumabvedolizumab and ustekinumab.

    Not all drugs are available to treat both conditions - find out more in our individual drug treatment information

    Crohn's Disease

    Drug Adalimumab Infliximab Ustekinumab Vedolizumab
    Brand name











    Stelara Entyvio
    Available for  Adults and children over age 6 Adults and children over age 6 Adults Adults

    Infliximab is available to treat active fistulising Crohn’s Disease that hasn’t responded to treatment. Adalimumab has also been used successfully to treat fistulas in people with Crohn’s who also have active inflammation. Find out more in Living with a Fistula.

    Vedolizumab is a treatment option only when infliximab or adalimumab (anti-TNF drugs) haven’t been effective or there is a reason why you shouldn’t take these.

    Ustekinumab may be used where immunosuppressants or steroids haven’t worked, or an anti-TNF drug hasn’t been effective or has stopped working.

    Ulcerative Colitis

    Drug Adalimumab Infliximab Golimumab Usktekinumab Vedolizumab
    Brand name











    Simponi Stelera Entyvio
    Available for Adults and children over age 6 Adults and children over age 6 Adults Adults Adults

    Vedolizumab may be an option if other treatments such as steroids or immunosuppressants haven’t helped your condition. This and ustekinumab may also be an option if infliximab, adalimumab or golimumab (anti-TNF drugs) haven’t worked for you, have stopped working or side effects have been difficult to manage.

  • How do biologic medicines work?

    Gut inflammation in Crohn’s and Colitis is caused by over-activity of the immune system. Biologic medicines act to block some parts of this, reduce the inflammation and so improve symptoms.

    They work in different ways:

    Blocking the activity of cytokines (TNF-alpha or interleukins). Cytokines are specific proteins usually produced as a response to infection or injury. In Crohn’s and Colitis overproduction of these proteins is thought to be partly responsible for the inflammation in the gut.

    • Infliximab, adalimumab, golimumab – Anti-TNF. These drugs work by targeting a protein in the body called tumour necrosis factor-alpha (TNF-alpha). They bind to the TNF-alpha, this reduces the inflammation and helps to relieve symptoms. They are known as anti-TNF drugs.
    • Ustekinumab – Anti-interleukin. Ustekinumab targets the proteins interleukin-12 (IL-12) and interleukin-23 (IL-23) which contribute to ongoing inflammation in the gut. Ustekinumab binds to both these proteins and prevents them from working, helping to reduce inflammation and improve symptoms.

    Blocking white cells moving into the gut – Gut-selective integrin blocker. White blood cells are made by the immune system to fight infection, but in Crohn’s and Colitis, overproduction of these cells leads to gut inflammation.

    • Vedolizumab – Anti-integrin. This works by stopping the white blood cells from entering the lining of the gut and causing inflammation. The drug only targets the immune system of the gut and because the action is local, it may cause fewer immunosuppressive side effects.

    how biologics work

    This can mean that if one type of treatment hasn’t worked for you, trying a drug that works in a different way could be an option. The decision about which treatment to try next depends on several factors which you could discuss with your IBD team. 

  • What can I expect from treatment?

    Biologic medicines have all been shown to be effective in improving gut symptoms, bringing about and maintaining remission (preventing flares) in people with moderate to severe Crohn’s or Colitis. They can also reduce the need for hospitalisation or surgery. But they don’t work for everyone, and for some people, they stop working after some time.

    Because they suppress parts of the immune system, all biologics carry an increased risk of infections, which in rare cases can be serious. Find out more in our individual treatment information.

    Symptoms outside the gut

    Some biologic medicines (infliximabadalimumab) have been shown to be effective in improving symptoms outside the gut related to Crohn’s or Colitis. These are also known as extra intestinal manifestations (EIMs) and can include problems with:

    • Joints – pain (arthralgia), pain and swelling (arthritis). Find out more in Joints.
    • Skin – erythema nodosum, this is swollen fat under the skin causing red bumps and patches.
    • Eyes – uveitis, this is inflammation of the eyes that causes redness and soreness.

    My experience of having been on Humira, Remicade and Remsima are only positive, all can be life changing, and when they work it is like you no longer have IBD. Ensure you keep in contact with your IBD team and let them know how you are doing – remember they have lots of experience of IBD and are the best people to talk to.

    Living with Crohn's Colitis 

  • How do I take biologic medicines?

    All these drugs are taken either by injection under the skin or through a drip in the arm (IV infusion). You can’t take biologics by mouth because the digestive system would break down and destroy the drug.

    Drug Adalimumab Infliximab Golimumab Ustekinumab Vedolizumab
    How it is taken Injection under the skin Infusion through a drip in the arm (IV infusion) Injection under the skin  Infusion through a drip in the arm (IV infusion) followed by injection under the skin Infusion through a drip in the arm (IV infusion)
    How often Every 1 or 2 weeks Every 8 weeks Every 4 weeks Every 8 or 12 weeks Every 4 or 8 weeks
    Where Self-inject at home Hospital outpatients Self-inject at home Single, initial infusion in hospital outpatients. Allowed by self-injection at home Hospital outpatients
  • Making treatment choices

    The decision about your treatment should be made a after full discussion between you and your IBD team. You should consider the potential benefits, possible risks, and the goals of your treatment together.

    This will include how active the condition is, how the medicine doses are taken and the impact on other symptoms you may have such as joint or skin problems. You might like to think about whether a hospital infusion or an injection at home would work best for you; will you be able to arrange time off for infusions with your employer? Do you have a reliable fridge at home?

    The first biologic medicines that are often tried are infliximab or adalimumab. This is because they have been used for a long time and are shown to be effective. But, if they don’t work well for you, there may be other biologics you can try. 

  • Stopping or changing treatment?

    Treatment doesn’t work or stops working

    Treatment isn’t effective from the start

    Biologic medicines don’t work for everyone. Some people find that treatment doesn’t make them feel better. Your IBD team will monitor how treatment is working for you in the first three months.

    If your symptoms haven’t improved treatment will be stopped, and another approach tried. Some people may not respond to the way one biologic works, so switching to a biologic that acts in a different way can be helpful.

    Treatment loses effect over time

    Some people find treatment is effective to begin with, but this becomes less over time. This often happens because the immune system recognises the drug as a foreign substance and thinks it is harmful. It then produces proteins called antibodies against the biologic drug and these stop it from working as well.

    If this happens there may be a few options:

    • Increase the dose.

    • Add an immunosuppressant so that you would be taking a combination of medicines. There is evidence that this can reduce the levels of antibodies.

    • Change to a biologic that works in a different way.

    • Change to a different biologic that works in the same way.

    Side effects are severe or difficult to manage

    Treatment may be stopped if you experience side effects that are difficult to manage.

    Stable remission

    If you are in stable remission after one year of treatment, your IBD team may decide that you can stop taking your biologic. Stable remission means that your symptoms have gone away, and you haven’t had any flares in that time. You’ll continue to be monitored and if a relapse happens you should be able to start treatment again.

    If you’ve been taking the biologic together with an immunosuppressant such as azathioprine, your IBD team may suggest you continue treatment with the immunosuppressant alone. 

  • What is a biosimilar?

    It isn’t possible to produce an exact copy of a biological drug because they are complex medicines made from living cells.

    As you can see, aspirin is a small molecule so it’s easy to replicate compared to a complex biologic medicine. 

    aspirin and biologic drug graphic

    A biosimilar is a biological medicine which is highly similar to the original drug. The first brand produced is known as the “originator”, other brands of the same medicine are known as “biosimilars”.

    Infliximab and adalimumab have biosimilars. Both these medicines should always be prescribed by the brand name so there is no uncertainty about which one is being used.

    Infliximab: the originator product is Remicade. Biosimilar versions are Inflectra, Remsima and Flixiabi which became available from February 2015. Zessly is a biosimilar which became available in 2018.

    Adalimumab: the originator product is Humira. Biosimilar versions are Amgevita, Hulio, Imraldi and Hyrimoz. These became available in 2018.

    What are the advantages of biosimilar medicines?

    Biosimilars are much cheaper for the NHS to use than the originator medicine. The money saved can be reinvested in new drugs and treatments.

    What differences might there be?

    Biosimilars are thoroughly tested. They meet strict standards to show they are as safe, effective and have no clinically meaningful differences from the originator. Where NICE has recommended the use of a biological medicine, they state that the same guidance applies to the biosimilar.

    However, there are likely to be some small differences including:

    • Injection device: Injection devices for all the different products vary. If you have changed brand, this is likely to be different from the one you have been used to using. You will receive full training until you are confident to use the new one.
    • Homecare delivery service: If you change to a different product, you are likely to have this delivered by a different homecare delivery service.
    • Side effects: Because the formulations are not the same, some people who switch products may experience new injection site reactions. Your IBD team can help you with tips to reduce these.

    Some people may be sensitive to latex, which is used as a needle cover in some of some types of biosimilars, or citrate which is sometimes included as one of the ingredients.

    Some types of adalimumab are available without citrate or latex, and you can ask to try one of these. 

  • Questions you may have about biosimilar medicines

    How will my hospital tell me if it wants to use a new biosimilar medicine?
    Your IBD team will contact you by letter.

    Do I have to change to the biosimilar or can I stay on the originator product?
    Talk to your IBD team about any concerns you have. Each hospital should have alternative versions of adalimumab or infliximab but you can say if you are happy with your medication and don’t want to change brand. 

    What are my rights when it comes to changing to a new medicine?
    Switching to any new medicine should involve a discussion between you and your IBD team. This should consider your needs, preferences and values as well as all the available clinical evidence.

    Can I change back if I don’t feel as well on the biosimilar?
    Your IBD team will discuss any problems you’re experiencing with you and together you can agree the best way forward. A new side effect may be a good reason to change back. But if you feel your condition is not as well controlled on the biosimilar, it could be that you are losing response to the medication and a completely different biologic could be tried.

    I was moved from Remicade to a biosimilar in February 2015, when the patent expired. I have found the biosimilar to be no more different in effect from infliximab: I have had no side effects and it is just as an effective a treatment for me.


    Living with Colitis 

  • Starting treatment with a biologic medicine

    It can feel daunting starting a new medicine. You’ve probably never had to inject yourself before or you might be worried about taking time off to go for an infusion. But it’s all done with the aim of getting you better, and you’ll probably find you get used to it faster than you thought.

    Our Helpline takes many calls on these issues so you’re not alone. We can’t advise but it may help to talk through your worries. We can also provide you with more information about the individual biologics.

  • Help and support from Crohn's & Colitis UK
    We offer more than 50 publications on many aspects of Crohn’s DiseaseUlcerative Colitis and other forms of Inflammatory Bowel Disease. You may be interested in our comprehensive booklets on each disease, as well as the following publications:

    • Living With Crohn's or Colitis
    • Fatigue
    • Taking Medicines
    • Managing Bowel Incontinence
    • Living With a Stoma

    Health professionals can order some publications in bulk by using our online ordering system. If you would like a printed copy of a booklet or information sheet, please contact our helpline.

    Our helpline is a confidential service providing information and support to anyone affected by Crohn's or Colitis. Our team can:
    • help you understand more about Crohn's or Colitis, diagnosis and treatment options
    • provide information to help you to live well with your condition
    • help you understand and access disability benefits
    • be there to listen if you need someone to talk to
    • help you to find support from others living with the condition

    Call us on 0300 222 5700 
    Use our LiveChat 

    Crohn’s & Colitis UK Forum

    This closed-group community on Facebook is for everyone affected by Crohn's or Colitis. You can share your experiences and receive support from others.

    Crohn’s & Colitis UK Patient Panels

    IBD Patient Panels, which are supported by Crohn’s & Colitis UK, are groups of people with Crohn's or Colitis who use their perspective as a patient to work with their IBD healthcare team to help improve their hospital services. For more information on patient panels, please contact our Patient Engagement Team.

    Crohn’s & Colitis UK Local Networks

    Our Local Networks of volunteers across the UK organise events and provide opportunities to get to know other people in an informal setting, as well as to get involved with educational, awareness-raising and fundraising activities. You may find just being with other people and realising that you are not alone can be reassuring. Families and relatives may also find it useful to meet other people with Crohn's or Colitis. All events are open to members of Crohn’s & Colitis UK


This page has been saved in your personal space. Go to “My Page” to view all saved pages.

Helpline service


We know it can be difficult to live with, or support someone living with these conditions. But you’re not alone. We provide up-to-date, evidence-based information and can support you to live well with Crohn’s or Colitis.

Our helpline team can provide information on a range of subjects including:

  • Managing Symptoms
  • Disability benefits
  • Medication
  • Diet
  • Test and diagnosis
  • Wellbeing
  • Employment
  • Help to find support from others living with the condition

Please contact us via telephone, email or LiveChat - 9am to 5pm, Monday to Friday (except English bank holidays).

If you need specific medical advice about your condition, your GP or IBD team will be best placed to help.