Guselkumab

What is guselkumab?

Guselkumab is a biological medicine known as an interleukin 23 (IL-23) inhibitor. Your healthcare team may give it to you if you have psoriatic arthritis. Guselkumab works by limiting the action of a chemical messenger (known as a cytokine) called IL-23. This is involved in inflammation that causes the symptoms of psoriatic arthritis.

Guselkumab isn’t a painkiller, and it’s not a cure for psoriatic arthritis, but it can reduce the symptoms and limit the joint damage that could be caused by your condition. Similar to other biological medicines, guselkumab can take up to 6 months to notice the full effect, however you may start to notice benefits sooner than this. Guselkumab should be taken regularly and should be considered a long-term treatment.

Who can take guselkumab?

There are national guidelines about when guselkumab can be used. It won’t be started if:

• your condition isn’t active
• you haven’t tried other treatments for your condition first
• you have an infection.

Before you are started on guselkumab, your healthcare team may use a scoring system to assess how active your condition is, and how it makes you feel. Before starting you may also need blood tests and a chest x-ray before treatment to make sure guselkumab is safe for you to take.

These tests may include tests for tuberculosis, hepatitis and HIV. If any of these tests are positive, your doctor may refer you to another specialist to decide on an appropriate treatment plan. If you have had other immunosuppressant medicines for your condition in the recent past, you may well have had all of these tests previously and may not necessarily need to have them repeated.

Your doctor may also decide not to prescribe guselkumab if you have any of the following:

• repeated or serious infections in the past
• pregnant or planning to become pregnant
• cancer.

If guselkumab isn’t suitable, your doctor will discuss other treatment options with you.

When and how do I take guselkumab?

Guselkumab is taken as an injection under your skin (subcutaneous injection) using either a pre-filled pen device or a syringe. You will be taught how to use the injection if needed beforehand. The injection should be made under the skin of the thighs or stomach. The syringes or pen should then then be disposed of into a special sharps bin which you will also be provided with.

You should give yourself one injection of guselkumab for the first dose, and then a second dose 4 weeks later. After that, you should inject yourself once every 8 weeks. Some patients may be told to inject once every 4 weeks; your team will advise you if they wish for you to do this.

Because guselkumab is a long-term treatment, it’s important to keep taking guselkumab:

• even if it doesn’t seem to be working at first
• even when your symptoms start to improve.

But if you have severe side effects or symptoms of an infection, tell your healthcare team. They may recommend that you delay or stop your treatment

How to store guselkumab

Guselkumab must be stored in a refrigerator, between 2 to 8 degrees C. It must not be frozen. Once guselkumab has been removed for the refrigerator and has reached room temperature, it must either be used or thrown away. There is currently no information on how long guselkumab can safely remain at room temperature, and it should not be returned to the refrigerator after being left out.

If you are travelling, guselkumab should be kept in a cool bag or cool box with icepacks to maintain the recommended temperature.

Side effects and risks of guselkumab

Most people don’t have any side effects with guselkumab, and for those who do, they are rarely serious.

You will normally need to have regular tests while you’re on guselkumab to make sure it isn’t having any unwanted effects on your blood, liver or general health.

If you do have very bad side effects, or are worried about your symptoms, you should ask a health professional for advice.

The most common side effects of guselkumab include:

• aching joints (arthralgia)
• diarrhoea
• headache
• increased risk of infection
• skin reactions.

You may also be more likely to pick up other infections while you’re on guselkumab, especially if you’re over 65, but the tips below should help reduce the risk of infections.

Tips to reduce your risk of infection:

• Try to avoid close contact with people you know have an infection.
• Wash your hands regularly and carry around a small bottle of antibacterial hand gel.
• Keep your mouth clean by brushing your teeth regularly.
• Stop smoking if you’re a smoker.
• Make sure your food is stored and prepared properly.
• Try to keep your house clean and hygienic, especially the kitchen, bathrooms and toilets.

If you get an infection or any symptom or sign of an infection that doesn’t go away, your team may suggest stopping guselkumab temporarily.

Contact your healthcare team if you come into contact with someone who has chickenpox or shingles. They may suggest a blood test to check your antibody levels. These illnesses can be more severe than usual if you’re on guselkumab, and you may need anti-viral treatment if you develop either chickenpox or shingles.

Carrying an alert card

It is recommended that you carry a biological therapy alert card so anyone treating you will know that you’re on guselkumab. Ask your healthcare team for a card.

Taking other medicines

Other medications are safe to take with guselkumab, however, it is important that your GP and other doctors are aware of the other medications you take.

Check with your doctor before starting any new medicines and remember to mention you’re on guselkumab if you’re treated by anyone other than your usual healthcare team.

You can carry on taking non-steroidal anti-inflammatory drugs (NSAIDs) or painkillers, if needed, unless your doctor advises otherwise.

Vaccinations

It is best to discuss vaccinations with your healthcare team before starting guselkumab.

You shouldn’t be given a live vaccination (this includes measles, mumps and rubella (MMR), chickenpox, yellow fever, oral typhoid, rotavirus, BCG or the live shingles vaccine (Zostavax)).

If you need a live vaccine, it’s usually recommended that you stop guselkumab for 12 weeks prior to the vaccine and can restart 2 weeks after the vaccine.

Non-live vaccines are safe and recommended while taking guselkumab. These include the annual flu vaccine, COVID-19 vaccines, RSV (respiratory syncytial virus) vaccine, Prevenar (pneumococcal) vaccine and the shingles vaccine (Shingrix).

Having an operation or dental treatment

If you’re going to have an operation or dental treatment, you should talk this over with your doctor or surgeon.

Depending on the type of surgery, your doctor may recommend that you stop guselkumab for a short period before and after the operation. This is because guselkumab affects your immune system, and so, you may have an increased risk of getting an infection after the surgery

Alcohol

There is no need to avoid alcohol while taking guselkumab.

Guidelines state that adults shouldn’t have more than 14 units a week, and that they should spread them out over the course of the week. In some circumstances your doctor may advise lower limits

Fertility, pregnancy and breastfeeding if you're taking guselkumab

Guselkumab is not usually recommended during pregnancy. Because guselkumab is a relatively new drug, we do not yet know fully how it might affect pregnancy or an unborn baby.

If you are considering a pregnancy, you should discuss this with your healthcare team in advance.

Current UK guidance recommends that women who could become pregnant should use effective contraception while taking guselkumab and for at least 12 weeks after stopping treatment before trying for a baby.

Tell your healthcare team immediately if you become pregnant while taking guselkumab

We do not yet know whether guselkumab passes into human breastmilk. For this reason, the current advice is that you should not breastfeed while taking guselkumab.

There is no evidence that guselkumab affects fertility.