What Is Afinitor® (everolimus)?

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

Afinitor® (everolimus) is a kinase inhibitor used in combination with a drug called Aromasin® (exemestane). Together, they are used to treat advanced breast cancer that is hormone receptor-positive (HR+) and human epidermal growth factor receptor 2 negative (HER2-) in postmenopausal women who have previously had treatment with Femara® (letrozole) or Arimidex® (anastrozole) and cancer progressed.1

What are the ingredients in Afinitor?

The active ingredient in Afinitor is everolimus.1

How does everolimus work?

Everolimus blocks the mammalian target of rapamycin (mTOR) pathway. Up to 70 percent of breast cancers have mutations on the mTOR pathway, which can fuel cancer growth.1

Everolimus is given in combination with Aromasin to delay or slow the growth of breast cancer cells in 2 ways:1

  • Aromasin helps block estrogen
  • Everolimus helps block the mTOR pathway

What are the possible side effects?

The most common side effects of everolimus in breast cancer treatment include:1

  • Mouth ulcers and sores
  • Infections
  • Diarrhea
  • Swelling in the arms, hands, feet, ankles, or face
  • Fatigue
  • Rash
  • Cough
  • Nausea
  • Fever
  • Decreased appetite
  • Abdominal pain
  • Headache
  • Weakness

Everolimus has a boxed warning, the strictest warning from the US Food and Drug Administration (FDA). It has this warning because it can cause serious side effects, including:1

  • Increased risk of getting certain cancers, including lymphoma and skin cancer
  • Increased risk of serious infections
  • Blood clots in the blood vessels of a transplanted kidney
  • Serious problems with transplanted kidneys
  • Increased risk of death related to infections in people who have had a heart transplant

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

Other things to know

People receiving everolimus should not receive live vaccinations or be around others who have recently received a live vaccine. Talk to your doctor if you are scheduled to get any vaccines or if you are unsure about them.1

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

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

  • Current or previous kidney or liver problems
  • Diabetes
  • A family history of skin cancer
  • High blood cholesterol
  • Any infections
  • Previous infections of hepatitis B
  • Recent or planned surgery
  • Any unhealed wounds

Everolimus may interact with certain drugs, vitamins, and supplements. Before taking everolimus, tell your doctor if you are taking:1

  • St. John’s wort
  • Any medicines that weaken the immune system
  • Any medicines for fungal or bacterial infections
  • Tuberculosis drugs
  • Seizure drugs
  • HIV/AIDS medicines
  • Heart or blood pressure drugs

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 everolimus.

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