What Is Kisqali® (ribociclib)?

Reviewed by: HU Medical Review Board | Last reviewed: June 2023

Kisqali (ribociclib) is a kinase inhibitor used in combination with certain hormone therapies to treat people with certain forms of advanced or metastatic breast cancer that are hormone receptor-positive and human epidermal growth factor receptor 2 (HER2) negative.1,2

What are the ingredients in ribociclib?

The active ingredient in Kisqali is ribociclib.1

How does ribociclib work?

Ribociclib is a kinase inhibitor. Kinase inhibitors block certain proteins that control cellular functions like signaling, cell division, and survival.1,3

Ribociclib is a CDK4/6 inhibitor. CDK4 and CDK6 are proteins that are important during a cell’s growth and replication cycles. These 2 proteins may be overactive in breast cancer cells, especially those that are hormone receptor-positive. Breast cancer cells that are hormone receptor-positive are stimulated by the presence of hormones like estrogen. This can increase the activity of CDK4/6 and cause cancer cells to grow uncontrollably.1,3

By blocking CDK4/6, ribociclib can help slow the growth and division of breast cancer cells. However, it may also interfere with the normal growth and division of healthy cells.1,3

What are the possible side effects?

The most common side effects of ribociclib include:1

  • Diarrhea
  • Headache
  • Nausea, vomiting
  • Constipation
  • Infections
  • Rash
  • Fatigue
  • Hair loss
  • Cough
  • Back pain
  • Low blood sugar

Ribociclib may also cause serious side effects, including:1

  • Lung problems like trouble breathing or shortness of breath
  • Severe skin reactions like blistering, skin peeling, or reddened skin
  • Heart rhythm problems
  • Liver problems
  • Low white blood cell counts

These are not all the possible side effects of ribociclib. Talk to your doctor about what to expect when taking ribociclib. You also should call your doctor if you have any changes that concern you when taking ribociclib.

Other things to know

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

Before starting treatment with ribociclib, tell your doctor if you have:1,4

  • Heart problems, including heart failure, irregular heartbeat, QT prolongation, history of heart attack, or slow heartbeat
  • Problems with the amount of calcium, potassium, phosphorus, or magnesium in your blood
  • Liver problems
  • Signs of infection, such as fever or chills

Ribociclib can harm an unborn baby. If you can become pregnant, you should use birth control during treatment and for some time after the last dose of ribociclib. You should also not breastfeed during treatment with DrugName and for some time after the last dose. Talk to your doctor about your options for birth control and breastfeeding while taking ribociclib.1,4

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

Before beginning treatment for breast cancer, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

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

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