Palbociclib (Ibrance)

Palbociclib is a targeted therapy drug. 

Palbociclib belongs to a group of drugs called CDK4/6 (cyclin dependent kinase) inhibitors. These drugs block the action of kinase, which is a protein that helps cells to grow and divide. This stops the growth and spread of cancer.

Palbociclib is the drug’s non-branded name. You may hear it called by its brand name Ibrance.

Palbociclib is used to treat breast cancer that’s oestrogen receptor positive (ER-positive) and HER2-negative. Men and women can both take it.

You may be offered palbociclib if you have:

• Locally advanced breast cancer
• Metastatic (secondary) breast cancer

Palbociclib is not given for primary breast cancer.

The usual starting dose of palbociclib is 125mg, taken as a tablet once a day.

You’ll take palbociclib every day for 21 days, followed by a 7-day break. This is called a cycle. The cycle is then repeated.

You must take your tablet:

• About the same time each day
• Whole with water (do not crush, chew or dissolve it)

You can take it with or without food.

Palbociclib and hormone therapy

Palbociclib is always given alongside a hormone therapy drug.

You might have palbociclib with:

• An aromatase inhibitor (anastrozole, exemestane or letrozole) if you have not already had hormone therapy for locally advanced or metastatic breast cancer
• Fulvestrant if you have had hormone therapy for locally advanced or metastatic breast cancer

If you had hormone therapy for primary breast cancer and now have locally advanced or metastatic breast cancer, you may be offered palbociclib with an aromatase inhibitor or fulvestrant. This will depend on your circumstances. 

Taking palbociclib and an aromatase inhibitor

You take an aromatase inhibitor drug once a day throughout the cycle. 

Taking palbociclib and fulvestrant

Fulvestrant is given in 2 injections, 1 in each buttock. These are known as intramuscular injections. They are usually given every 2 weeks for the first 3 doses, then every 4 weeks for as long as you’re having palbociclib. 

If you have not been through the menopause 

You can take aromatase inhibitors and fulvestrant if you’ve been through the menopause (when your periods stop).

If you have not been through the menopause, you may also have treatment to stop your ovaries producing oestrogen, either temporarily or permanently. This is called ovarian suppression. Your treatment team will talk to you about this.

If you’re a man

Men who are prescribed palbociclib will usually have it with tamoxifen. Or they may be given an aromatase inhibitor with an injection to suppress their testosterone production.

What if I miss a dose?

If you miss a dose of palbociclib or you’re sick (vomit) soon after taking it, do not take an extra dose to make up for the one you missed. 

Take the next dose at the usual time and speak to someone in your treatment team.

How long will I take palbociclib for?

You’ll have palbociclib alongside hormone therapy for as long as your treatment team feels you’re benefiting from the treatment and any side effects are manageable.

Like any treatment, palbociclib can cause side effects. Everyone reacts differently to drugs and some people have more side effects than others. These side effects can usually be managed and those described here will not affect everyone. 

As palbociclib is given with hormone therapy, it’s sometimes difficult to know which side effects are being caused by which treatment. 

If you’re worried about any side effects, regardless of whether they’re listed here, talk to your treatment team. 

Common side effects of palbociclib include:

• Effects on the blood
• Liver changes
• Cancer-related fatigue (extreme tiredness)
• Sore mouth
• Nausea and vomiting
• Loss of appetite
• Diarrhoea and constipation
• Rash
• Dry skin
• Hair thinning and hair loss

Effects on the blood 

Palbociclib can temporarily affect the number of blood cells in the body. Blood is made up of red cells, white cells and platelets. 

You’ll have regular blood tests. If these show the number of blood cells is too low, your next cycle of treatment may be delayed or the dose of palbociclib reduced.

Your treatment team may change the dose of a drug to suit you and help manage its side effects. This may help you stay on the treatment for longer. 

Risk of infection 

Not having enough white blood cells can increase your risk of getting an infection. 

Before starting palbociclib, you should be given a 24-hour contact number or told who to contact if you feel unwell at any time during your treatment, including overnight or at the weekends.

You may need treatment if you get an infection.

Sometimes your treatment team may recommend injections of drugs called growth factors. This helps the body make more white blood cells to reduce your risk of infection.

Anaemia 

Having too few red blood cells is called anaemia. If you feel breathless, dizzy or particularly tired, let your treatment team know.

Bruising and bleeding 

Palbociclib can reduce the number of platelets. Platelets help the blood to clot.

If your platelets are low, you may: 

• Bruise more easily 
• Have nosebleeds 
• Notice that your gums bleed when you brush your teeth 
• Take longer to stop bleeding if you cut yourself 

Tell your treatment team if you have any of these symptoms. 

Liver changes

Palbociclib can affect how the liver works. This does not usually cause any symptoms.

You’ll have blood tests to check your liver enzyme levels during treatment. Treatment may need to be delayed or the dose reduced if the blood tests show any problems with your liver. Liver enzyme levels usually return to normal once treatment is paused or stopped.

Extreme tiredness (cancer-related fatigue)

Fatigue is extreme tiredness that does not go away with rest or sleep.

Fatigue is a common side effect of palbociclib and may last for weeks or months after your treatment has finished.

Fatigue may affect how you cope with your cancer and its treatment. It can also make everyday activities harder and affect your quality of life. 

If you think you have fatigue, tell your treatment team or GP. They can assess you and offer advice on how to manage your energy levels. 

Find out more about managing fatigue.

Sore mouth

Looking after your mouth, including your teeth and gums, is very important during treatment. 

You may be given mouthwash to try to reduce soreness and prevent mouth ulcers developing. It’s a good idea to use a small, soft toothbrush during this time.

See your dentist for a check-up before treatment begins. Avoid dental work during these treatments if possible.

If you do need to have dental work during treatment, talk with your treatment team about the best time to have this.

If you’re having difficulty registering with a dentist, let your treatment team know.

Nausea and vomiting 

You may feel sick (nausea) or be sick (vomit). Your treatment team can prescribe anti-sickness drugs to help with this if needed. Contact your treatment team if you’re sick 3 or more times in 24 hours or are finding it difficult to eat and drink.

Loss of appetite 

You may not feel like eating, especially if you feel sick. It might help to eat small meals regularly and drink plenty of liquids.

Diarrhoea and constipation

Tell your treatment team or GP if you have diarrhoea or constipation as they can prescribe drugs to help. 

Contact your treatment team if you have diarrhoea 3 or more times in 24 hours, compared to what’s usual for you.

Drink plenty of fluids to avoid getting dehydrated.

Skin changes

You might get a rash anywhere on your body.

You may also have dry skin. You may notice your skin is scaly, rough, tight or itchy.

Your treatment team may suggest drugs such as antihistamines to reduce any itching.

It may also help to:

• Use a moisturiser regularly and avoid perfumed products
• Use a high factor sunscreen when out in the sun
• Protect your hands when doing household or outdoor chores
• Rinse and dry your hands carefully, particularly after contact with cleaning products
• Pat your skin dry with a soft towel, rather than rubbing vigorously
• Take care when shaving
• Wear clothing made of natural fibres (such as cotton) where possible and wash clothes in mild detergent

Hair thinning and hair loss

Taking palbociclib and hormone therapy can cause hair thinning or hair loss. 

Find out more about hair loss.

Less common side effects of palbociclib include:

• Damage to the lungs (interstitial lung disease)
• Eye problems
• Change in taste
• Hand-foot syndrome (palmar-plantar syndrome)

Damage to the lungs (interstitial lung disease)

Palbociclib can cause interstitial lung disease (ILD). ILD can cause inflammation in your lungs, which can lead to scarring.

If palbociclib has caused inflammation to your lungs, you may need to stop treatment temporarily to prevent further damage. You may have steroids to treat the inflammation.

Contact your treatment team straight away if you have: 

• Shortness of breath 
• A cough, with or without a high temperature 
• Any new or worsening breathing problems, such as chest tightness or wheezing 

These symptoms could have a number of causes including side effects of treatment or a lung infection. It’s important to let your treatment team know so that they can find out the cause. You may need a chest x-ray or CT scan to check what’s causing your symptoms. 

Eye problems

Palbociclib may cause changes to your eyes, like blurred vision, dry eyes and increased tear production.

Contact your treatment team if you have any of these symptoms so that they can prescribe you appropriate eye drops.

Change in taste

Your sense of taste can change and some food may taste different, for example more salty, bitter or metallic. 

It can help to try different types of food to see what tastes best to you.

Hand-foot syndrome (palmar-plantar syndrome)

You may develop soreness or redness on the palms of your hands and soles of your feet. This is called palmar-plantar or hand-foot syndrome.

Your doctor may prescribe creams to try to help with this.

Blood clots

People with breast cancer have a higher risk of blood clots. Having palbociclib also increases the risk of blood clots such as a DVT (deep vein thrombosis). If you have a DVT, there’s a risk part of the blood clot could break away and travel to the lung. This is known as a pulmonary embolism (PE).

Blood clots can be life-threatening and should be treated quickly. 

Medicines and food to avoid when taking palbociclib

When taking palbociclib:

• Do not take supplements containing St John’s Wort
• Do not eat grapefruit or drink grapefruit juice

Some drugs should not be taken with palbociclib. These include some commonly prescribed antibiotics, antifungal and anti-epileptic drugs. 

Tell your treatment team about any prescribed or over-the-counter medicines you’re taking. 

If a healthcare professional, such as your GP or dentist, prescribes you a new drug, tell them you’re taking palbociclib.

Always ask for advice from your treatment team before taking any herbal medicines or supplements.

Sex, contraception and pregnancy

You can still have sex during treatment. It’s thought some drugs used to treat breast cancer cannot pass into vaginal fluids or semen, but this cannot be completely ruled out. 

Most treatment teams will advise using barrier methods of contraception, such as condoms or female condoms, during treatment and for at least 3 weeks after your last dose.

You’re advised not to become pregnant while having treatment because palbociclib can harm a developing baby. If you have not been through the menopause, talk to your team about the most suitable method of contraception for you. It’s still possible to become pregnant even if your periods are irregular or have stopped naturally or because of treatment for breast cancer.

Fertility

If you’re a woman 

It’s not known if palbociclib affects fertility in women.

Conversations about fertility can be hard. It’s important to discuss any fertility concerns with your treatment team before you begin your treatment. They will be able to talk to you about fertility preservation options.

If you’re a man

Palbociclib may affect fertility in men. You may want to talk to your treatment team about sperm preservation before starting treatment.

Palbociclib and breastfeeding

You’ll be advised not to breastfeed during treatment and for at least 3 weeks after your last dose. This is because there’s a chance your baby may absorb the drug through your breast milk, which may be harmful for them.

Vaccinations

If you’re planning a holiday or need to travel overseas, check with your treatment team first. 

You should not have any live vaccines while you’re having treatment.

For more information about vaccines, including COVID-19 and flu vaccines, see our information on vaccines and breast cancer.

Being diagnosed with breast cancer can make you feel lonely and isolated. But there’s support available. And you might find it helpful to talk to someone who knows what it’s like.

You can call our helpline to speak to one of our specialist nurses if you’ve got any questions or worries. See the bottom of this page for ways to get in touch.

And you can join our online forum to speak to others who are having similar treatment to you.

Our Living with Secondary Breast Cancer groups let you share experiences with other people who are also dealing with the uncertainty and challenges of metastatic breast cancer.