Tremfya (Guselkumab)

Tremfya (also referred to by its generic name, Guselkumab) is a biologic medication that is used to treat severe psoriasis and active psoriatic arthritis.

How does Tremfya work?

Tremfya blocks the activity of interleukin 23 (IL-23), a chemical ‘messenger’ in the immune system that signals other cells to cause inflammation. In people with psoriasis or psoriatic arthritis, the immune system is overactive and creates too much inflammation, which leads to the development of psoriasis and/or psoriatic arthritis symptoms. By blocking IL-23, Tremfya aims to prevent some of that inflammation from occurring, leading to an improvement in psoriasis and/or psoriatic arthritis symptoms for some people who take it.

Who is Tremfya for?

Tremfya is for adults with severe psoriasis who have not had a good response from, or cannot take or tolerate other systemic treatments including ciclosporin, methotrexate or PUVA. You will usually need to have tried these treatments before you can be offered Tremfya. If you have tried these treatments but they did not work, Tremfya might be an option for you.

Tremfya can also be prescribed to treat adults with active psoriatic arthritis if other disease modifying anti-rheumatic drugs (DMARDs) have not worked successfully, or cause unwanted side effects. The National Institute for Health and Care Excellence (NICE) has approved Tremfya to be used for people with psoriatic arthritis with 3 or more tender joints and 3 or more swollen joints, who also have moderate to severe psoriasis and have had 2 conventional DMARDs and at least 1 biologic.

Conventional DMARDs include systemic treatments such as methotrexate, sulfasalazine or leflunomide. Biologic treatments include Adalimumab, Etanercept, Infliximab, Simponi (Golimumab), Taltz (Ixekizumab).

How is Tremfya used?

Individuals take Tremfya at home by giving themselves an injection under the skin via a pre-filled syringe. Most people will be trained by a nurse to give the injection to themselves. The second dose is taken four weeks after the first, but after that Tremfya is usually taken every eight weeks.

People taking Tremfya will have regular blood tests every three to six months - usually carried out by Dermatology Nurses, Rheumatology Nurses or by their own GP - to monitor for infections or other possible effects of the treatment. People taking Tremfya are more at risk of infections and so should be vaccinated against pneumonia and have an annual flu vaccination. However, not all vaccinations are safe in people taking Tremfya; ‘live’ vaccinations should be avoided. Check with a doctor or nurse before having any vaccinations or taking other medication if you are not sure. Tremfya can be prescribed on its own, or alongside methotrexate.

Who should not take Tremfya?

  • People with active infections should not start Tremfya. You will be tested to check for infections before starting treatment.
  • In most cases, pregnant women should not be treated with Tremfya and women should not breastfeed during treatment with Tremfya. Women should not fall pregnant for twelve weeks after treatment has stopped.

What are the side effects of Tremfya?

As with all medications, some side effects are possible when taking Tremfya. It is important to remember that not every person taking a medication will get all, or even any, of the possible side effects listed. Many side effects of Tremfya are mild and do not cause most people to stop taking it. Tremfya is a new treatment and, as such, this side effect data comes from clinical trials, but will be updated as more ‘real-world’ experience with the treatment is collected.

The most common side effects of Tremfya are upper respiratory tract infections, headache, joint pain, diarrhoea, stomach flu (also known as gastroenteritis), fungal skin infections, herpes simplex infections (such as cold sores) and injection site reactions (such as redness or burning of the skin where the treatment is injected). Because Tremfya works by suppressing part of the activity in the immune system, it can make people taking it more prone to infections than they usually would be. If a serious infection occurs a doctor will most likely stop Tremfya.

Although side effects are possible with this, and any, treatment, it is important to remember that people taking Tremfya have regular blood tests to check for health issues. If you are worried about the side effects of Tremfya, you should discuss these with your doctor.

How long will Tremfya take to work?


It can take a number of weeks before a person’s psoriasis improves on Tremfya. If considerable improvement is not seen in 16 weeks, treatment with Tremfya will be stopped. If this happens, a Dermatologist should discuss the next available options with you - there are a number of other biologic or systemic treatments that can be tried if Tremfya does not work.

Psoriatic Arthritis

It can take a number of weeks before a person’s psoriatic arthritis symptoms improve on Tremfya. An assessment will be made after 16 weeks of treatment, and then if the psoriatic arthritis has not responded adequately following 24 weeks of treatment, Tremfya will be stopped. However, if there has been a good response to your skin psoriasis, it may be appropriate to continue treatment with Tremfya for this purpose. Whilst it can be disappointing when a treatment does not work, there are a number of alternative biologic and systemic treatments that can be tried if Tremfya does not work.

How safe and effective is Tremfya?

Tremfya is a new medication that was licensed to treat psoriasis in the UK in 2017 and psoriatic arthritis in 2020. ‘Real-world’ (ie. Non-clinical trial) safety and effectiveness data is being collected by a long-running study, the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR). It is recommended that all people taking biologic treatments for their psoriasis should be asked for their information to be included in this register.

A Psoriatic Arthritis (PsA) Register is run by the British Society for Rheumatology and it is recommended that all people taking biologic treatments for their psoriatic arthritis should be asked for their information to be included in this register.


The information on this page is also available in our Tremfya (Guselkumab) information sheet.

May 2021 (Review Date: April 2024)

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