Rituximab and idelalisib (R-Idelalisib)

R-Idelalisib is the name of a cancer drug combination. You have:

• rituximab (pronounced rih-tuk-sih-mab)
• idelalisib (eye-del-uh-lih-sib)

It is a treatment for chronic lymphocytic leukaemia (CLL). You might have this treatment if:

• your CLL has come back after treatment (relapsed CLL)
• it’s your first treatment and your CLL has specific gene changes (mutations) known as 17p deletion or TP53 mutation

How does R-Idelalisib work?

Rituximab and idelalisib are targeted cancer drugs.

Idelalisib works by blocking a protein called PI3K inside cancer cells which tell the cancer to grow. Some leukaemia and lymphoma cells have too much PI3K. So by blocking this protein, idelalisib may shrink the cancer or stop it growing for some time. Idelalisib is also called a PI3K inhibitor. 

Rituximab is a monoclonal antibody. It targets a protein called CD20 on the surface of the leukaemia and lymphoma cells. Rituximab sticks to all the CD20 proteins it finds. Then the cells of the immune system pick out the marked cells and kill them.

How do you have R-Idelalisib?

You have rituximab as a drip into the bloodstream (intravenously).

You take idelalisib as a tablet twice a day. You can take it with or without food and swallow it whole with a glass of water. 

Taking your tablets or capsules

You should take the right dose, not more or less.

Talk to your healthcare team before you stop taking a cancer drug, or if you miss a dose.

Having rituximab into your bloodstream

You might have treatment through a long plastic tube that goes into a large vein in your chest. The tube stays in place throughout the course of treatment. This can be a:

• central line
• PICC line
• portacath

If you don't have a central line

You might have treatment through a thin short tube (a cannula) that goes into a vein in your arm. You have a new cannula each time you have treatment.

How often do you have R-Idelalisib?

You have R-Idelalisib as cycles of treatment. This means you have the drugs and then a rest to allow your body to recover.

Each cycle lasts for 28 days (4 weeks). You usually have a total of 8 doses of rituximab, which takes up to 6 cycles of treatment. But you continue idelalisib for as long as it is working and the side effects aren’t bad. 

How you have R-Idelalisib can vary between hospitals. This is an example of one way you can have it.

You usually have cycle 1 in the following way:

You usually have cycle 2 in the following way:

You usually have cycle 3 to cycle 6 in the following way:

You then continue to take idelalisib tablets twice a day for as long as its working and the side effects aren’t too bad.

Tests

You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

Before treatment starts you may have a blood test to check for viruses such as hepatitis B, hepatitis C, and HIV . This is called a viral screen.

It’s important for your doctor to know if you have had any of these viruses. This is because this treatment can weaken your immune system and can cause the virus to become active again (reactivation). 

What are the side effects of R-Idelalisib?

Side effects can vary from person to person. They also depend on what other treatments you're having. 

When to contact your team

Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

• you have severe side effects 

• your side effects aren’t getting any better

• your side effects are getting worse

Early treatment can help manage side effects better. 

We haven't listed all the side effects here. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.

Remember it is very unlikely that you will have all of these side effects. But you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Risk of infection 

Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, cough, headaches, feeling cold and shivery, pain or a burning feeling when peeing, or generally feeling unwell. You might have other symptoms depending on where the infection is.

Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection. 

Your doctor may give you antibiotics to prevent infections. You might carry on taking antibiotics for a few months after stopping idelalisib.

Bruising, bleeding gums or nosebleeds

This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. You may have nosebleeds or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs. This is known as petechiae.

Allergic reaction

An allergic reaction that can cause a rash, shortness of breath, redness or swelling of the face and throat  and dizziness - some allergic reactions can be life threatening, alert your nurse or doctor if notice any of these symptoms.

You might also have a high temperature (fever) and chills. This sometimes happens during the first infusion.

Loose or watery poo (diarrhoea)

Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. If you have a stoma , you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.

Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain fibre. But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables. 

Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.

You may get diarrhoea several months after you start idelalisib. This drug can also cause inflammation of the bowel (colitis). Tell your doctor straightaway if you notice any blood or mucus in your poo.

Skin changes

Skin problems include a skin rash, dry skin and itching. This usually goes back to normal when your treatment finishes. Your healthcare team can tell you what products you can use on your skin to help.

Less commonly you might get hives (urticaria).

Rarely you may develop a severe skin reaction. This may start as tender red patches on the skin which then leads to peeling or blistering of the skin. You might also feel feverish, and your eyes may be more sensitive to light. These symptoms can be caused by conditions such as toxic epidermal necrolysis (TEN) or Stevens Johnson syndrome (SJS).

These rare conditions can be life threatening. Contact your team straight away.

Liver changes

You might have liver changes that are usually mild and unlikely to cause symptoms. They usually go back to normal when treatment finishes. Less commonly you might have liver damage.

You have regular blood tests to check for any changes in the way your liver is working.

Feeling or being sick

Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also help.

It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treat it once it has started.

Hair loss

You could lose all your hair. This includes your eyelashes, eyebrows, underarms, legs and sometimes pubic hair. Your hair will usually grow back once treatment has finished but it is likely to be softer. It may grow back a different colour or be curlier than before. 

Headaches

Tell your healthcare team if you keep getting headaches. They can give you painkillers to help.

Tiredness and weakness (fatigue)

You might feel very tired and as though you lack energy.

Various things can help you to reduce tiredness and cope with it, for example exercise. Some research has shown that taking gentle exercise can give you more energy. It is important to balance exercise with resting.

Low levels of an antibody called immunoglobulin G in your body 

Immunoglobulin G is an antibody made by the immune system to fight bacteria and viruses. You have regular blood tests during and after treatment to check for this. 

Increased levels of fat in the blood

You may have higher than normal levels of triglycerides in the blood. Triglycerides are a type of fat. You have regular blood tests to check for this. 

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

• sepsis - a serious reaction to an infection. Signs can include feeling very unwell, not passing urine, a very high or very low temperature, shivering, slurred speech or confusion, breathlessness, mottled or discoloured skin, extreme shivering or muscle pain. Call 999 or go to accident and emergency (A&E) immediately if you have any of these symptoms
• lung problems such as inflammation of the lungs (pneumonitis), cough and shortness of breath. Rarely you might have swelling and narrowing of the airways (asthma)
• breathlessness and looking pale – caused by low levels of red blood cells (anaemia)
• high blood sugar levels – you might need to check your sugar levels more often if you are diabetic
• weight loss
• fluid build up in parts of the body such as the face, arms or legs
• changes to levels of substances in the blood such as a low calcium or a high level of the enzyme LDH - you have regular blood tests to check this
• numbness or pins and needles, often in the fingers or toes – tell your healthcare team if you're finding it difficult to walk or doing fiddly tasks such as doing up buttons
• feeling restless or anxious
• difficulty sleeping (insomnia)
• feeling dizzy or lightheaded
• watery eyes or inflammation of the outer covering of the eyeball (conjunctivitis)
• ringing in the ears (tinnitus) or possibly hearing loss
• heart problems such as changes to heart rhythm, changes to how the heart muscle is working, or a heart attack. Tell your healthcare team or call 999 if you have chest pain
• changes to your blood pressure
• runny nose
• tummy (abdominal) pain
• difficulty swallowing
• sore mouth and throat
• difficulty opening your bowels (constipation)
• indigestion - symptoms include heartburn, bloating and burping
• loss of appetite
• sweating more than usual, including at night
• pain in different parts of the body such as back, ear, neck, muscles or joints. You might have pain where your cancer is – this is usually during the infusion. Rarely you might get pain at the site of the infusion
• feeling generally unwell (malaise)
• being sick (vomiting)
• getting stiff and difficulty moving due to the brain telling the muscles in your body to tighten (hypertonia)
• episodes of feeling warm and reddening of the skin (flushing)

Rare side effects

These side effects happen in fewer than 1 in 100 people (less than 1%). You might have one or more of them. They include:

• taste changes
• feeling low (depression) or nervous
• enlarged tummy (abdomen)
• changes to the way your blood clots
• your bone marrow not making enough essential blood cells (aplastic anaemia)
• a blood disorder where your red blood cells get destroyed faster than they can be made (haemolytic anaemia)
• swelling of the lymph nodes or glands

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do I need to know?

Other medicines, foods and drinks

Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.

Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.

Contraception and pregnancy

This treatment might harm a baby developing in the womb. It is important not to become pregnant or father a child while you're having treatment and for 12 months afterwards.

It is unknown if idelalisib interferes with hormonal contraceptives such as the pill. So it is advised that women add a barrier method such as condoms as a second form of contraception during and after this treatment.

Talk to your doctor or nurse about effective contraception before starting treatment.

Loss of fertility

It is not known whether this treatment affects fertility in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Breastfeeding

It is not known whether these drugs come through into the breast milk. Doctors usually advise that you don’t breastfeed during this treatment and for 6 months afterwards.

Treatment for other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.

Immunisations

Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having.

Ask your doctor or pharmacist how long you should avoid live vaccinations.

In the UK, live vaccines include rubella, mumps, measles, BCG, and yellow fever.

You can usually have:

• other vaccines, but they might not give you as much protection as usual
• the flu vaccine (as an injection)
• the coronavirus (COVID-19) vaccine

Talk to your doctor or pharmacist about the best time to have a vaccine in relation to your cancer treatment.

Contact with others who have had immunisations 

You can be in contact with other people who have had live vaccines as injections. If someone has had a live vaccine by mouth or nasal spray there may be a small risk the vaccine virus can be passed onto you if your immune system is weakened.

Your healthcare team will let you know if you need to take any precautions if you are in close contact with someone who has had a live vaccine.

More information about this treatment

For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.