Inavolisib

Inavolisib is a prescription medication indicated in combination with palbociclib and fulvestrant for endocrine-resistant, PIK3CA-mutated, hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)--negative, locally advanced or metastatic breast cancer following recurrence on or after completing adjuvant endocrine therapy.

•  Inavolisib is available under the following different brand names: Itovebi.

Common side effects of Inavolisib include:

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

Serious side effects of Inavolisib include:

• high blood sugar levels (hyperglycemia) symptoms include 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) symptoms include pain, redness, swelling, ulcers
• diarrhea

Rare side effects of Inavolisib include:

• none 

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, coordination loss, unsteady, very stiff muscles, high fever, profuse sweating, or tremors.
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult dosage

Tablet

• 3 mg
• 9 mg

Breast cancer

Adult dosage

• 9 mg orally daily, plus
• Palbociclib 125 mg orally daily for 21 consecutive days followed by 7 days off repeated in 28-day cycles, and
• Fulvestrant 500 mg IM on Days 1 and 15 of cycle 1, then 500 mg IM on Day 1 of every 28-day cycle thereafter
• Continue until disease progression or unacceptable toxicity

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Inavolisib has no noted severe interactions with any other drugs
• Inavolisib has no noted serious interactions with any other drugs
• Inavolisib has no noted moderate interactions with any other drugs
• Inavolisib has no noted minor interactions with any other drugs

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, health questions, or concerns.

Contraindications

• None

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Inavolisib?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Inavolisib?”

Cautions

• Hyperglycemia
  • Severe hyperglycemia can occur
  • Safety is not known in patients with type 1 or type 2 diabetes mellitus requiring ongoing antihyperglycemic treatment
  • Median time to first onset: 7 days (range, 2-955)
  • Evaluate fasting plasma glucose (FPG) or blood glucose (FBG) and HbA1C levels prior to starting therapy
  • Optimize glycemic control with antihyperglycemic medications before starting therapy; manage hyperglycemia during therapy as clinically indicated
  • Consider endocrine consultation and home glucose monitoring in patients at high risk for hyperglycemia or who develop hyperglycemia during therapy
  • Monitor fasting glucose levels once every 3 days for the first week (Days 1-7), once weekly for the next 3 weeks (Days 8- 28), once every 2 weeks for the next 8 weeks, once every 4 weeks thereafter, and as clinically indicated
  • Obtain HbA1C every 3 months and as clinically indicated
  • Intensified antihyperglycemic treatment and close FBG monitoring may be needed in patients with a history of well-controlled type 2 diabetes mellitus
  • Advise patients of signs and symptoms of hyperglycemia, counsel on lifestyle changes
  • Hold, reduce dose, or permanently discontinue based on severity
• Stomatitis
• Severe stomatitis reported
  • Median time to first onset: 13 days (range, 1-610)
  • Monitor for signs and symptoms of stomatitis
  • Corticosteroid-containing mouthwash has been used for management or prophylaxis
  • Hold, reduce dose, or permanently discontinue based on severity
• Diarrhea
  • Severe diarrhea resulting in dehydration and acute kidney injury can occur
  • Median time to first onset: 15 days (range, 2-602)
  • Monitor for signs and symptoms of diarrhea
  • Advise patients to increase oral fluids and start antidiarrheal treatment at the first sign of diarrhea
  • Hold, reduce dose, or permanently discontinue based on severity
• Embryo-fetal toxicity
  • Can cause fetal harm if administered during pregnancy
  • Advise pregnant patients and females of reproductive potential of the potential fetal risk
  • Effective contraception is recommended during and after therapy in females of reproductive potential and males with female partners of reproductive potential

Pregnancy and Lactation

• May cause fetal harm when administered during pregnancy, based on its mechanism of action and data from animal reproduction studies
• No available data to inform a drug-associated risk in pregnant patients
• Verify pregnancy status before initiating in females of reproductive potential
• Advise pregnant patients and females of reproductive potential of the potential fetal risk
• Contraception requirements
• Females of reproductive potential
• Use effective non-hormonal contraception during therapy and for 1 week after the last dose
• Males with female partners of reproductive potential
• Use effective contraception during therapy and for 1 week after the last dose
• Infertility
  • May impair fertility in females and males of reproductive potential, based on animal studies
• Lactation
  • No data available on the presence of inavolisib in  human milk, its effects on milk production or breastfed children
  • Advise lactating women to not breastfeed during therapy and for 1 week after the last dose due to the potential for serious adverse reactions in breastfed children