Kisqali® (ribociclib) for Advanced Breast Cancer Treatment

Kisqali is an oral kinase inhibitor used in combination with certain hormone therapies to treat women with advanced or metastatic breast cancer that are hormone receptor positive and human epidermal growth factor receptor 2 (HER2) negative. Depending on where a patient is in their treatment, ribociclib may be used in women who are premenopausal, perimenopausal, or postmenopausal. Ribociclib is a prescription medication manufactured by Novartis Pharmaceuticals.1,2

What is the ingredient in ribociclib?

The active ingredient in Kisqali is ribociclib, a kinase inhibitor that targets cyclin dependent kinase (CDK) 4 and 6.1

How does ribociclib work?

Ribociclib is a kinase inhibitor. Kinase inhibitors block certain proteins which control cellular functions like signaling, cell division, and survival. Ribociclib is a CDK4/6 inhibitor. CDK4 and CDK6 are proteins that are important during a cell’s growth and replication cycles. These two proteins may be overactive in breast cancer cells, particularly those which are hormone receptor-positive. Breast cancer cells that are hormone receptor-positive are stimulated by the presence of hormones like estrogen, which can increase the activity of CDK4/6. Overactivity of CDK4 and CDK6 can cause the cancer cells to grow uncontrollably. By blocking CDK4/6, ribociclib can help slow the growth and division of breast cancer cells, but it may also interfere with the normal growth and division of healthy cells.1,3

What are some of the possible side effects of ribociclib?

Ribociclib can cause serious side effects, including:

  • A heart rhythm condition called QT prolongation, which may potentially be life threatening
  • Liver toxicity, which can cause yellowing of the skin or whites of the eyes (jaundice), darkened or brown urine, fatigue, loss of appetite, abdominal pain on the right side, and/or more bleeding or bruising than normal – any of these symptoms should be reported immediately to a doctor
  • Lowered white blood cell counts (neutropenia), which may lead to serious infections1,4
  • Serious skin reactions, which may cause skin rash, redness, pain, blistering (blistering also may occur in the eyes, mouth, and lips, in addition to the skin), peeling, as well as flu-like symptoms and potentially a fever – any of these symptoms should be reported immediately to a doctor

The most common side effects experienced by patients taking ribociclib in clinical trials included lowered white blood cell counts, nausea, fatigue, diarrhea, hair loss, vomiting, constipation, headache, and back pain. These are not all the possible side effects of ribociclib. Patients should talk to their doctor about what to expect with treatment with ribociclib.1

Things to know about ribociclib

Before starting treatment with ribociclib, patients should talk to their doctor about all their medications (prescription and over-the-counter), herbal supplements, and vitamins they are taking. Some medications or supplements may interfere with each other and may cause side effects.1,4

Before starting treatment with ribociclib, patients should discuss with their doctor all their medical conditions, especially:

  • Any heart problems, such as heart failure, previous heart attack, irregular heartbeats, bradycardia (slow heartbeat), and/or QT prolongation
  • Any problems with the amount of calcium, potassium, phosphorus, or magnesium in the blood
  • Liver problems
  • Symptoms of infection, such as fever or chills
  • If patients are pregnant or planning to become pregnant
  • If patients are breastfeeding or planning to breastfeed1,4

Ribociclib can cause harm to an unborn fetus and should not be used in pregnant women. Women who can become pregnant are advised to use effective contraception while taking ribociclib and for at least three weeks after stopping treatment with ribociclib (patients should discuss appropriate birth control methods with their doctor).1,4

It is not known if ribociclib passes through breastmilk. Women should not breastfeed while taking ribociclib and for at least three weeks following the final dose.1,4

Ribociclib may cause fertility problems in men, which could affect the ability to conceive a child.1,4

People taking ribociclib should not eat grapefruit or drink grapefruit juice, as grapefruit products may increase the levels of ribociclib in the body, which can increase the potential for side effects.1,4

In addition, it should be noted that although it is rare, treatment with ribociclib can cause severe inflammation of the lungs. Patients should notify their health care professional right away if they have any new or worsening symptoms involving their lungs, as they may indicate a rare but life-threatening condition that can lead to death.5

Recieving ribociclib

Ribociclib is an oral medication. Your healthcare provider will determine the appropriate ribociclib dosing regimen and administration schedule for you. It is important to follow this schedule exactly as instructed, and not to stop taking ribociclib or any accompanying medications on your own, unless you are instructed to do so by your healthcare provider.1,2

Patients should take their medication as prescribed by their doctor. Patients should talk to their doctor if they have any questions, or if they have questions regarding their ribociclib regimen.

For more information, read the full prescribing information of ribociclib.

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Written by: Editorial Team | Last reviewed: October 2020.