Elacestrant (Korserdu)

Elacestrant is a type of hormone therapy. You pronounce it as el-a-kes-trant. It is also known as Korserdu.

It is a treatment for some people with locally advanced or secondary breast cancer that is:

• oestrogen receptor positive
• HER2  negative
• has a change (mutation) in the gene known as ESR1

Your doctor will check for these before you start treatment.

Women need to have been through the menopause to have this treatment.

You may have elacestrant as part of a clinical trial.

How does elacestrant work?

Breast cancer cells can contain proteins called oestrogen receptors. The receptors receive messages from the oestrogen in our body which tell the cancer cells to grow and divide.

Elacestrant stops the oestrogen receptors in the cancer cells from working. This stops oestrogen from telling the cancer cells to grow. 

How do you have elacestrant?

You take elacestrant as a tablet. You swallow it whole. You should try and take elacestrant at the same time every day with a light meal.

Speak to your pharmacist if you have problems swallowing the tablets.

Whether you have a full or an empty stomach can affect how much of a drug gets into your bloodstream.

You should take the right dose, no more or less.

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

How often do you take elacestrant?

You usually take elacestrant once a day.

You take it for as long as it is working and the side effects aren’t too bad.

Tests

You might have blood tests before starting treatment and during your treatment. They check your general health and might check your levels of blood cells and other substances in the blood.

Side effects

Side effects can vary from person to person. They also depend on what other treatment you are having. 

When to contact your team

Your doctor, nurse, or pharmacist will go through the possible side effects. They will monitor you closely 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

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:

Breathlessness and looking pale

You might be breathless and look pale due to a drop in red blood cells. This is called anaemia.

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.

Taking elacestrant with food helps to stop you feeling or being sick.

Raised cholesterol level

You can have raised amounts of fats called cholesterol in your blood. A build up of fat and cholesterol can increase your risk of heart problems and stroke . You have regular blood tests to check your cholesterol.

Tiredness and weakness

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.

Indigestion or heartburn

Contact your doctor or pharmacist if you have indigestion or heartburn. They can prescribe medicines to help.

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.

Constipation

Constipation is easier to sort out if you treat it early. Drink plenty and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking. Tell your healthcare team if you think you are constipated. They can give you a laxative if needed.

Changes in the levels of minerals in your blood

You may have some changes in levels of minerals and salts in your blood, such as low sodium, potassium and calcium. Your doctor might ask for blood tests to check for these.

Joint, muscle and back pain

You might have pain in your back or joints.

Occasionally you might get pains in your arms, legs and bones.

You may also get pain in the bones and muscles in your chest. Chest pain can also be caused by health problems such as a heart attack or a blood clot in your lung (pulmonary embolism).

High levels of creatinine in your blood

Your blood tests might show that you have high levels of a substance called creatinine.

Creatinine is a waste product made by the muscles. The kidneys remove this from our blood and get rid of it in our urine. Your doctor tests your creatinine levels regularly. This tells them how well your kidneys are working.

Headaches 

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

Hot flushes

We have some tips for coping with hot flushes in women and hot flushes in men. This information also includes some of the possible treatments. Talk to your doctor if your hot flushes are hard to cope with. They might be able to prescribe some medicines to help.

Tummy (abdominal) pain

Tell your doctor or nurse if you have this. They can check for the cause of the pain and give you medicine to help. 

Liver changes

You might have liver changes that are usually mild and unlikely to cause symptoms. Your doctor might change your dose of your treatment to help with this. They usually go back to normal when treatment finishes.

Rarely this treatment can damage your liver and cause it to stop working properly. Symptoms include jaundice , feeling sleepy during the day, personality changes, confusion, and pain in the tummy.

You have regular blood tests to check how your liver is working.

Decreased appetite

You might not feel like eating as much. Eating several small meals and snacks throughout the day can be easier to manage. You can talk to a dietitian if you are concerned about your appetite or are losing weight.

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:

• urine infection
• low levels of white blood cells called lymphocytes
• difficulty falling asleep or staying asleep (insomnia)
• feeling dizzy
• fainting
• feeling short of breath
• cough
• sore mouth
• rash

Rare side effects

Blood clots are a rare side effect of elacestrant. They can happen in fewer than 1 in 100 people (less than 1%).

Blood clots can be life threatening. Signs include pain, redness and swelling where the clot is. Feeling breathless can be a sign of a blood clot in the lung.

Possible rare and long term side effects

This is a new drug in cancer treatment. So there is limited information available at the moment about possible rare and longer term effects that it may cause. Tell your doctor if you notice anything that is not normal for you.

Coping with side effects

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

What else do you need to know?

Other medicines, food and drink

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.

Loss of fertility

You may not be able to become pregnant after treatment with this drug. Women should only have this treatment if they have been through the menopause.

Men may not be able to get someone pregnant after treatment. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Pregnancy and contraception

This treatment might harm a baby developing in the womb. It is important not to become pregnant while you're having treatment and for at least 1 week afterwards. Or to get someone pregnant while you are having treatment.

Talk to your doctor or nurse about effective contraception before starting treatment. It is important you use it before, during and after your treatment. Your doctor or nurse will talk with you about how long to use it for. Let them know straight away if you or your partner become pregnant.

Women should only have this treatment if they have been through the menopause. 

Breastfeeding

It is not known whether this drug comes through into the breast milk.

Breastfeeding is not recommended while you are having this treatment and for a period of time afterwards. Talk with your doctor about when you can start breastfeeding after you have finished treatment.

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.

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 and Healthcare products Regulatory Agency (MHRA) as part of their Yellow Card Scheme.