T cells are a type of white blood cell called lymphocytes. They are good at fighting infection and diseases, such as cancer.

However, T cells can struggle to tell the difference between a cancer cell and a normal cell. This gives cancer cells the chance to hide and multiply.

CAR (chimeric antigen receptor) T cell therapy first involves white blood cells being removed from your body using a procedure called leukapheresis.

The T cells are separated from the white blood cells and sent to a laboratory. There, they are slightly changed and turned into CAR T cells.

The CAR T cells are designed to recognise and target a specific protein on the cancer cells to destroy them.

The changed T cells grow and multiply in the laboratory until there are hundreds of millions of them.

Your CAR T cells are safely transported back to The London Clinic and put back into your bloodstream, using a drip. Your care team may refer to this as an infusion.

In your body, the CAR T cells start to recognise and attack the cancer cells. They also release natural chemicals called cytokines that encourage other cells to join the attack.

Overall, your whole immune system starts to learn, seek out and destroy cancer cells.

The main benefit of CAR T cell therapy is that it successfully treats many people with blood cancers who have run out of treatment options.

This is clearly shown by the results of a clinical trial that used the CAR T cell therapy we use at The London Clinic (Yescarta, which is also known as axicabtagene ciloleucel).

The trial involved more than 100 people with large B-cell lymphoma whose cancer was still spreading after at least two previous treatments.

Out of this number, approximately half saw their cancer disappear completely, and nearly a third saw their cancer partly reduce.

Shorter treatment times

Your CAR T cell therapy will usually involve a one-off treatment followed by your care team monitoring you every day for less than two weeks.

Stem cell transplants also usually require just a single treatment. However, the whole process for a stem cell transplant can take months.

This is because of what needs to happen before the transplant and the long time it takes to recover from it.

Similarly, chemotherapy can take months to complete. This is because it typically involves multiple cycles of treatment and recovery.

Effective for years

The changes made to T cells in the laboratory mean they commonly last in a person’s body for several years.

As a result, CAR T cells may continue to find and destroy cancer cells long after the original cancer it was targeting has disappeared.

In contrast, traditional chemotherapy is only effective at killing cancer cells during and shortly after it’s been given to a person.

This means if cancer returns, a person needs to restart chemotherapy (or another treatment) to destroy the cancer cells.

A safer option

CAR T cell therapy doesn’t require aggressive chemotherapy, which can lead to severe side effects.

Patients receiving CAR T cells also don’t usually require immunosuppression, a treatment that reduces the body’s ability to fight infections and other diseases.

In contrast, immunosuppression is required before a stem cell transplant.

Your consultant will carefully talk you through the benefits and side effects of treatment, so you can make an informed choice.

Because CAR T cell therapy is a new treatment, we may not know about all its possible side effects yet, but the known ones are:

• Allergic reaction
• Symptoms of an allergic reaction include:
• High fever
• Chills
• Feeling or being sick
• Difficulty breathing

Your nurse will give you medicines before your treatment to help prevent this type of reaction.

Cytokine release syndrome (CRS)

Cytokines are proteins that play an important part in boosting your body’s immune system. CAR T cell therapy encourages the immune system to make large amounts of cytokines.

In the first couple of weeks after treatment, this may result in you experiencing cytokine release syndrome (CRS).

Its symptoms include:

• Fever (high temperature)
• Chills
• Dizziness
• Difficulty breathing
• Heart racing

We can give you treatment to reverse cytokine release syndrome.

Changes in the brain (neurological side effects)

CAR T cells cause problems in the brain for around two-thirds of people. Doctors call this neurotoxicity.

Symptoms can include:

• Headaches
• Altered consciousness
• Becoming confused or disorientated
• Speech changes
• Seizures

The treatment we provide for these side effects will depend on your symptoms.

Potential risk of infection

CAR T cell therapy for large B-cell lymphoma may destroy some of your healthy B cells as well as cancerous B cells. This may make it difficult for you to fight infections.

You might need immunoglobulin therapy to treat this side effect. It contains proteins used by the body (antibodies) to fight infection.

High uric acid levels in the blood

When CAR T cell therapy breaks down cancer cells, they release a chemical called uric acid into the blood.

If your blood has high levels of uric acid in it, your kidneys can struggle to function properly.

To avoid your kidneys being affected, you’ll have regular blood tests. And if you develop this side effect, we’ll give you fluids and medicine to help lower your levels of uric acid.

CAR T cell therapy at The London Clinic is overseen by world-class oncology and haematology consultants who are experts in this type of immunotherapy.

Before your treatment, your expert care team will guide you through all its stages, discuss your recovery plan and answer all your questions.

Whether you visit us as a day patient or stay overnight, we’ll do everything we can to make you as comfortable and relaxed as possible.

This includes us offering you extra touches, such as meals that are tailored to meet your body’s needs and support your recovery.

After treatment, we may schedule a weekly phone call with you. You’ll also be given:

• A number to call in case you have any side effects
• A card to show health professionals that explains you’ve had CAR T cell therapy
• Instructions on what to do if you feel unwell
• A personalised aftercare programme to help boost your recovery
• Your consultant will also keep in contact over the following weeks and months to check everything is going smoothly.