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What are the possible side effects of Itovebi?

Itovebi may cause serious side effects, including:

• High blood sugar levels (hyperglycemia). High blood sugar is common with Itovebi and may be severe or fatal. Untreated severe hyperglycemia can lead to a condition called diabetic ketoacidosis that can happen in people treated with Itovebi. Diabetic ketoacidosis is a serious condition that requires treatment in a hospital and that can lead to death. Your healthcare provider will monitor your blood sugar levels before you start and during treatment with Itovebi. Your blood sugar levels may be monitored more often if you have a history of Type 2 diabetes. Your healthcare provider may also ask you to self-monitor and report your blood sugar levels at home. This will be required more frequently in the first 4 weeks of treatment. If you are not sure how to test your blood sugar levels, talk to your healthcare provider. You should stay well-hydrated during treatment with Itovebi. Tell your healthcare provider right away if you develop symptoms of high blood sugar, including:

  • difficulty breathing
  • nausea and vomiting (lasting more than 2 hours)
  • stomach pain
  • excessive thirst
  • dry mouth
  • more frequent urination than usual or a higher amount of urine than normal
  • blurred vision
  • unusually increased appetite
  • weight loss
  • fruity-smelling breath
  • flushed face and dry skin
  • feeling unusually sleepy or tired
  • confusion
• Mouth sores (stomatitis). Mouth sores are common with Itovebi and may be severe. Tell your healthcare provider if you develop any of the following in your mouth:
  • pain
  • redness
  • swelling
  • ulcers
• Diarrhea. Diarrhea is common with Itovebi and may be severe. Severe diarrhea can lead to the loss of too much body water (dehydration) and kidney injury. Tell your healthcare provider right away if you develop diarrhea, stomach-area (abdominal) pain, or see mucus or blood in your stool during treatment with Itovebi. Your healthcare provider may tell you to drink more fluids or take medicines to treat your diarrhea.

Your healthcare provider may tell you to decrease your dose, temporarily stop your treatment, or completely stop your treatment with Itovebi if you develop certain serious side effects.

The most common side effects and abnormal blood test results of Itovebi when used in combination with palbociclib and fulvestrant include:

• decreased white blood cell counts, red blood cell counts, and platelet counts
• decreased blood levels of calcium, potassium, sodium, and magnesium
• increased creatinine blood levels
• tiredness
• increased blood levels of the liver enzyme alanine transaminase (ALT)
• nausea
• rash
• loss of appetite
• COVID-19 infection
• headache

Itovebi may affect fertility in males and in females who are able to become pregnant. Talk to your healthcare provider if this is a concern for you.

These are not all of the possible side effects of Itovebi. Call your healthcare provider for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. You may also report side effects to Genentech at (877) 436-3683.

Before you take Itovebi, tell your healthcare provider about all of your medical conditions, including if you:

• have a history of diabetes or high blood sugar
• have kidney problems
• are pregnant or plan to become pregnant. Itovebi can harm your unborn baby.
  Females who are able to become pregnant:
  • Your healthcare provider will check to see if you are pregnant before you start treatment with Itovebi.
  • You should use effective non-hormonal birth control (contraception) during treatment with Itovebi and for 1 week after your last dose. Talk to your healthcare provider about what birth control method is right for you during this time.
  • Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment with Itovebi.
  Males with female partners who are able to become pregnant:
  • You should use effective birth control (contraception) during treatment with Itovebi and for 1 week after your last dose.
• are breastfeeding or plan to breastfeed. It is not known if Itovebi passes into your breastmilk. Do not breastfeed during treatment with Itovebi and for 1 week after your last dose. Talk to your healthcare provider about the best way to feed your baby during treatment with Itovebi.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Please see the full Prescribing Information, including Patient Information, for additional Important Safety Information.