Chemo Experts, the easiest way to learn about cancer treatment
Find a Treatment:
Cancer Types

Tap along the timeline to move to different parts of the audio file.

Treatment Name: Ribociclib (Kisqali®) + Letrozole (Femara®)

Ribociclib (Kisqali®) + Letrozole (Femara®) is a Treatment Regimen for Breast Cancer - metastatic

How does Ribociclib (Kisqali®) + Letrozole (Femara®) work?

Certain breast cancers overproduce proteins known as Cyclins. When there are extra cyclins, the cancer begins to grow and become less sensitive to certain anti-hormone breast cancer medications such as letrozole (Femara®).

  • Ribociclib is designed to inhibit (stop) cyclin proteins, which means the cancer cells quit actively growing and dividing
  • Letrozole is designed to block an enzyme (a type of protein) in your body called aromatase

Aromatase is responsible for helping produce a female hormone known as estradiol (an estrogen). When letrozole inhibits aromatase, there is less estrogen produced. When estrogen is not available to bind to the receptors in breast cancer cells, those cells cannot grow or divide. Patients with breast cancers that are not hormone-receptor positive (HR+) may not respond to treatment with letrozole or ribociclib.

Goals of therapy:

Ribociclib and letrozole are taken together to slow the growth of breast cancer and prevent it from spreading further. Ribociclib and letrozole are not commonly given with the goal of cure.


Tap along the timeline to move to different parts of the audio file.


Create your own Treatment Tracker

How is ribociclib + letrozole therapy for breast cancer given?

  • Usual ribociclib (Kisqali®) starting dose: 600 mg (three 200 mg tablets) by mouth Once Daily for 21 consecutive days, followed by a 7-day “ribociclib-free” rest period (no tablets taken on Days 22 through 28). This “21-Day on, 7-Day off” treatment period is known as one Cycle
  • Usual letrozole (Femara®) starting dose:  2.5 mg oral tablet by mouth Once Daily, continuously (no days off)
  • Letrozole and ribociclib are taken at the same time, preferably in the morning

Ribociclib and letrozole are usually taken at home. Ribociclib is preferably taken in the morning and at the same time as letrozole. Treatment is continued until it no longer works or until unacceptable side effects are experienced. Each cycle is repeated every 28 days.

Note: Letrozole is only indicated for use in post-menopausal women and should not be used by pre-menopausal women.


Tap along the timeline to move to different parts of the audio file.

Side Effects

What are the most common side effects from ribociclib + letrozole for breast cancer?

In a multi-drug regimen, each medication has unique side effects. When these medicines are given together, drug-related side effects reported in clinical studies give the best estimate of what to expect. In clinical studies, the most commonly reported ribociclib (Kisqali®) and letrozole (Femara®) side effects are shown here:

On average, 8% of patients discontinue both ribociclib (Kisqali®) and letrozole (Femara®) due to unacceptable side effects.

Watch videos on common ribociclib + letrozole side effects below

Side effect videos Side Effect Videos
Nausea and VomitingNausea and VomitingFatigue Fatigue DiarrheaDiarrheaHair LossHair LossPainPainConstipationConstipationAnemiaAnemiaNeutropenic FeverNeutropenic Fever


Tap along the timeline to move to different parts of the audio file.


How often is monitoring needed?

Labs (blood tests) may be checked before the start of treatment, every two weeks during the first two cycles, then prior to the start of each cycle thereafter. Labs often include: Complete Blood Count (CBC), Comprehensive Metabolic Panel (CMP), magnesium, phosphorous, plus any others your doctor may order.

How often is imaging needed?

Imaging may be checked before treatment, then as often as every two months for the first 18 months, then every three months thereafter. Imaging may include: magnetic resonance imaging (MRI) or computerized tomography (CT) scans.

Electrocardiograms (ECG, or EKG) are typically done prior to starting treatment, approximately two weeks after starting treatment, before Cycles 2 and 3, then at the discretion of your doctor thereafter. DEXA (dual energy x-ray absorptiometry) scans may be performed to monitor your bone mineral density (bone strength).

How might blood test results/imaging affect treatment?

Depending upon the results, your doctor may advise to continue ribociclib and letrozole as planned, reduce the dose of future ribociclib treatments (there are no dose reduction recommendations for letrozole), delay the next dose until the side effect goes away, discontinue ribociclib but continue letrozole, or switch to an alternative therapy.

Electrolytes and liver function will be monitored using a CMP blood test. If the serum potassium or magnesium are low, your doctor may prescribe potassium or magnesium supplements to help prevent heart rhythm problems. If the liver function decreases, your doctor may delay therapy or reduce the dose of ribociclib.

If the echocardiogram (ECG, EKG) shows a prolonged QTc interval, your doctor may recommend to hold therapy until the ECG returns to normal. In addition, the dose of ribociclib may be decreased.

Neutropenia will be monitored using a CBC blood test. If the neutrophil count decreases, your doctor may delay therapy for one or more weeks, and resume ribociclib at a reduced dose. Stopping treatment for neutropenia is rare and occurs in about 1% of patients taking ribociclib.

Questions to Ask Your...

A better understanding of your treatments will allow you to ask more questions of your healthcare team. We then hope that with the answers, you will get better results and have greater satisfaction with your care. Because we know it's not always easy to know what questions to ask, we've tried to make it easy for you!

Choose any healthcare provider below to see common questions that you may want to ask of this person. Then, either print each list to bring to your clinic visits, or copy the questions and send them as a message to your healthcare team through your electronic medical record.


Tap along the timeline to move to different parts of the audio file.

ChemoExperts Tips

What are the 7 most important things to know about ribociclib + letrozole when receiving treatment?

  • Electrocardiograms (EKG or ECG) are checked during therapy to check your heart QTc interval because ribociclib can affect this. Many other medications can also affect the QTc interval so check with your doctor or pharmacist if you are taking any of those medications
  • To help prevent heart rhythm problems, your doctor will monitor blood tests for low potassium and magnesium levels and may prescribe potassium or magnesium supplements if your levels are low
  • If you take the pain medication fentanyl, you may need your dose decreased because ribociclib may cause increased blood levels of fentanyl when taken together. Methadone must NOT be taken with ribociclib as it could increase the risk of arrhythmia and death
  • Do not take estrogen replacement therapy or other medications that contain estrogen as they may decrease the effectiveness of letrozole
  • Neutropenia with ribociclib may be more common if you are of Asian descent, compared to other ethnicities
  • A pharmacist should ALWAYS review your medication list to ensure that drug interactions are prevented or managed appropriately. Make sure your pharmacist performs a drug interaction screen before you start any new medicine to make sure it will be compatible with ribociclib (Kisqali®) and letrozole (Femara®)
  • Clinical trials may exist for breast cancer. Ask your doctor if any studies are currently enrolling in your area. If not, go to to search for other centers offering study medications

Patient Assistance & Co-payment Coverage

Patients under the age of 65 years, or those with private insurance plans:
If you have insurance and are looking for patient assistance or copay assistance for Ribociclib (Kisqali®) + Letrozole (Femara®), we have provided links that may help.

Visit our Patient Assistance page and click the links to various patient assistance programs for help paying for Ribociclib (Kisqali®) + Letrozole (Femara®). Depending upon your income, they may be able to help cover the cost of:

  • Riboci­clib
  • Letrozole

For Branded medications (may be available for generic medications too), check with the manufacturer to determine if a co-pay card is offered and if it could reduce your monthly copay.

  • If you are uninsured, check with the manufacturer to determine if you are eligible to receive medication at no cost.

Medicare and Medicaid patients (Patients 65 years or older):
The clinic providing treatment will likely pre-authorize medications and immune therapies such as Ribociclib (Kisqali®) + Letrozole (Femara®) and are the best source to help you understand drug cost.

  • Ask to speak with a patient assistance technician or financial counselor at the clinic or hospital administering this therapy.

Emotional Wellness

What is Emotional Wellness?
Emotional wellness is having a positive outlook balanced with a realistic understanding of current life events. This requires both an awareness and acceptance of your emotions. It is with this knowledge that you can develop a plan to take the necessary actions to positively impact your life.

Emotional wellness uses an ongoing process to continually reflect on the stressors of life in a constructive manner to move forward and create happiness.

Because emotional wellness is deeply connected with physical, social, and spiritual wellness, pursuing it often becomes particularly difficult in times of major illness. Despite this difficulty, working toward emotional wellness has been connected to improved treatment outcomes and a higher likelihood of achieving goals of therapy.

Learn more about pursuing emotional wellness while receiving treatment with Ribociclib (Kisqali®) + Letrozole (Femara®)

Individual Drug Label Information

Riboci­clib (Kisqali®)

  • Is an oral 200 mg tablet
  • Ribociclib may be taken with or without food. Swallow tablet whole and do not chew, crush, or break
  • If you miss a dose, do not take the dose later that day. Take the next dose the next day as scheduled
  • Store at room temperature (68°F to 77°F) in its original packaging. Do not remove tablets from blister packs until you are ready to take it
  • Dosage adjustments may be required if certain side effects are experienced
  • May interact with certain antifungal, antibiotic, and seizure medications. Ask your doctor or pharmacist to review your medications for any possible interactions 
  • May interact with pomegranate or pomegranate juice, grapefruit or grapefruit juice, star fruit, or Seville oranges (found in marmalade) causing increased blood levels of ribociclib. This could increase your risk of experiencing side effects. Avoid eating pomegranate, grapefruit, marmalade, and star fruit or drinking anything containing grapefruit and pomegranate juice during treatment. Lemon, lime, and other oranges and their juices are acceptable.
  • Avoid therapy with St. Johns Wort as it will decrease blood levels of ribociclib. This could decrease the effectiveness of treatment.
  • May interact with medications known to interfere with heart rhythm. Ask your pharmacist to double-check if you are taking any of these types of interacting medicines
  • May cause fetal harm if taken while pregnant. Women of childbearing age should use effective contraception while taking ribociclib and for at least 3 weeks after the last dose. Do not breastfeed during treatment or for at least 3 weeks after the last dose
General side effects from ribociclib (Kisqali®):
  • Low white blood cells [neutropenia] and low red blood cells [anemia]
  • Liver injury
  • Nausea and vomiting
  • Infections
  • Diarrhea or constipation
  • Hair loss
  • Joint pain or back pain
  • Headache
  • Cough
  • Fatigue
  • Decreased appetite
  • Skin rash
  • Click on the Ribociclib (Kisqali®) package insert below for reported side effects, possible drug interactions, and other ribociclib prescribing information

Side Effect Videos
Nausea and VomitingNausea and VomitingDiarrheaDiarrheaHair LossHair LossFatigue Fatigue ConstipationConstipationPainPainAnemiaAnemia

See DailyMed package insert.

Letrozole (Femara®)

  • Letrozole is an oral tablet 
  • Letrozole can be taken with or without food. Swallow tablets whole and do not crush tablets. If you miss a dose, take the dose as soon as you remember if it is still the same day. If it is the next day, take your regular dose as scheduled. Do not double your dose to make up for the missed dose 
  • Letrozole should be stored at room temperature in a cool, dry place 
  • Dosage adjustments may be required due to side effects or liver dysfunction 
  • May cause fetal harm; avoid pregnancy 
General Letrozole (Femara) Side Effects 
  • One of the most common side effects reported is hot flashes. Talk to your doctor about ways to minimize and treat hot flashes. Do not take any medicines, herbs, or natural supplements without speaking with your doctor or pharmacist first 
  • Joint pain 
  • Decreased bone strength 
  • Increase in blood cholesterol 
  • May cause dizziness and/or drowsiness 
  • High blood pressure 
  • Increase risk of blood clots 
  • Mood swings 
  • Fluid retention 
  • Skin rash 
  • Decreased sexual drive 
  • Nausea and vomiting 
  • Constipation
  • Click on the letrozole (Femara) package insert below for reported side effects and possible drug interactions

Side Effect Videos
Nausea and VomitingNausea and VomitingFatigue Fatigue ConstipationConstipationPainPainBlood ClotsBlood Clots

See DailyMed package insert.

Share this page:


Hortobagyi GN, Stemmer SM, Burris HA, et al. Ribociclib as First-Line Therapy for HR-Positive, Advanced Breast Cancer. N Engl J Med. 2016;375:1738-1748.

Created: March 17, 2017 Updated: October 17, 2018

What is Breast Cancer - metastatic?

What is Metastatic Breast Cancer?
A disease of the milk-producing glands known as lobules, milk ducts, or other cells found in the breast. Metastatic breast cancer is one that has moved from the breast to other areas of the body, which may include the brain, liver, or bone. Breast cancer is one of the most common types of cancers in women, but may rarely affect men as well. Known causes of breast cancer include genetic causes, such as the BRCA mutation, or obesity. The effectiveness of the treatment may depend upon the stage at diagnosis.

Types of metastatic breast cancer:
1. Hormone-receptor positive or negative (60 - 65% of patients)

  • Estrogen Receptor positive (ER)+ or negative (ER)-
  • Progestin Receptor positive (PR)+ or negative (PR)-

2. Hormone Epidermal growth factor Receptor-2 (HER-2) positive or negative (20 - 25% of patients)

  • HER-2 +
  • HER-2 -

3. Triple Negative (15 - 18% of patients)

  • ER- and PR- and (HER-2)-
NOTE: Treatment Options listed below are not all-inclusive. Other treatments may be available. ChemoExperts provides drug information and does not recommend any one treatment over another. Only your Doctor can choose which therapy is appropriate for you.

What are Cyclins?

Two specific proteins inside cancer cells, known as Cyclin D4 and Cyclin D6, work together with another protein regulator called Cyclin D1. Together, these proteins regulate breast cancer cell growth in certain sub-types of breast cancer.

What does "Cure" mean?

The word “cure” means there are no cancer cells left in the body and cancer will never come back. Depending on the cancer type and stage, this may be the true goal of therapy. However, it is very difficult to prove all cancer cells are gone. Even though images, like X-rays and MRI’s, and blood tests may not show any signs of cancer, there can be a small amount of cancer cells still left in the body. Because of this, doctors use the word “remission” is used more often. This means there are no signs or symptoms of cancer. Patients in remission are followed closely for any signs of cancer returning. Sometimes, more chemotherapy may be given while in remission to prevent the cancer from coming back.

Doctors usually do not consider a patient “cured” until the chance of cancer returning is extremely low. If cancer does return, it usually happens within 5 years of having a remission. Because of this, doctors do not consider a patient cured unless the cancer has not come back within 5 years of remission. The five-year cutoff does not apply to all cancers.

What is a CBC?

A Complete Blood Count (CBC) is a frequently ordered blood test that tells clinicians the status of your: 1) White blood cell count, 2) Hemoglobin, and 3) Platelet count at the time the test was taken.

Common uses:
1) White blood cell count (WBC): is used to determine infection risk, or response to chemotherapy. Certain chemotherapy agents may harm our good infection-fighting cells. Sometimes chemotherapy may need to be delayed to allow these cells to recover.

2) Hemoglobin: is used to determine if someone is anemic. Anytime the hemoglobin is below 12 g/dL, the person is said to be anemic. Red blood cell transfusions, and sometimes iron can be given to restore the hemoglobin level, but anemia treatment should always aim at treating the underlying cause or condition.

3) Platelet count: is used to determine if the risk of bleeding is increased or if a platelet transfusion is required to prevent bleeding. Certain medications that increase bleeding risk, such as: aspirin, certain chemotherapy agents, and blood thinners, may need to be stopped temporarily until the platelet count is within a safe range.

What is a CMP?

A Comprehensive Metabolic Panel (CMP) is a frequently ordered blood test that tells clinicians the status of your: 1) Electrolytes & Acid/Base status2) Kidney function, 3) Liver function, 4) Blood sugar, and 5) Calcium at the time the test was taken. It is commonly used to monitor liver and kidney function when beginning new medications such as chemotherapy. A total of 14 tests are run simultaneously and are shown below.

Electrolytes & Acid/Base status:
1) Sodium, 2) Potassium, 3) Carbon dioxide, 4) Chloride

Kidney Function:
5) BUN (blood urea nitrogen), 6) Serum creatinine (Scr)

Liver Function:
7) AST, 8) ALT, 9) Total bilirubin, 10) Alk Phos, 11) Albumin, 12) Total protein

Blood sugar:
13) Serum glucose

14) Serum calcium

What is QTc interval?

The time it takes your heart to make one beat can be measured using an electrocardiogram (ECG, or EKG) and is reported as the QTc interval. Ribociclib is generally safe to take when the QTc interval is less than 480 milliseconds per beat.

The QTc interval is "prolonged" if the heart takes too long to make the next beat, which could lead to a dangerous heartbeat known as an arrhythmia. Certain medications, in addition to ribociclib, may prolong the QTc interval. Examples of these include, but are not limited to: ondansetron (Zofran®), Levofloxacin or ciprofloxacin antibiotics. Make sure your pharmacist checks all new medications to make sure they do not prolong the QTc interval.

What is neutropenia?

This occurs when there is an abnormally low amount of a certain type of white blood cells, called neutrophils, in the blood. These neutrophils help the body body fight infections caused by bacteria and viruses. Many chemotherapy drugs temporarily damage bone marrow where white blood cells are created, resulting in neutropenia. Please watch our video on neutropenic fever to learn more.