Navigating Inavolisib Treatment Safely: Adverse Events Explained

Inavolisib (Itovebi) 3 mg and 9 mg tablets for PIK3CA-mutated breast cancer treatment.

Every patient is different in responding to the same treatment. For some, it may show good therapeutic effects to some; for others, it may lead to harmful events. While the positive outcomes are widely recognised, this article focuses on the most overlooked adverse events. 

Understanding Inavolisib’s (Itovebi) Action

PIK3CA is a gene that provides instructions for making a part of an enzyme called PI3K. When a mutation occurs in the PIK3CA gene, the PI3K pathway can become overactive, which may encourage breast cancer cells to grow and survive. Inavolisib, the active ingredient in Itovebi, works by targeting the effects of the abnormal PIK3CA mutation and helping slow down the growth and spread of cancer cells.

Inavolisib is used in combination with palbociclib and fulvestrant to treat adults with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer that has a PIK3CA mutation. It is used for locally advanced or metastatic breast cancer that has become resistant to endocrine therapy and has returned during or after completing adjuvant endocrine treatment. This combination may help control the disease by targeting cancer growth through different treatment approaches.

Adverse events of Inavolisib:

1) Most common type

The most common adverse effects reported with Inavolisib treatment include increased fasting blood glucose levels, stomatitis, diarrhea, nausea, fatigue, rash, COVID-19 infection and headache. Some patients may experience one or more of these effects during treatment, and the severity can vary from person to person. Patients should inform their healthcare team if any new or worsening symptoms appear so they can be assessed and managed appropriately.

Inavolisib treatment may also cause changes in laboratory test results. These may include decreased levels of neutrophils, hemoglobin, platelets, lymphocytes, calcium, potassium, sodium and magnesium. Some patients may also have increased creatinine or alanine aminotransferase (ALT) levels. A decrease in appetite may also occur during treatment.

These laboratory changes may not always cause noticeable symptoms, which is why regular blood tests and other recommended monitoring are important during treatment. The healthcare provider may review these results along with the patient's symptoms to determine whether any additional treatment, dose adjustment or temporary interruption of Inavolisib is needed.

 2) Serious type

 a) Hyperglycemia

Itovebi can cause hyperglycemia in some patients.

Before starting the therapy: Test fasting glucose levels (FPG or FBG), HbA1C levels and optimize fasting glucose.

After initiating therapy, or in patients who experience hyperglycemia after initiating treatment: Monitor or self-monitor fasting glucose levels once every 3 days for the first week (Day 1 to 7), then once every week for the next 3 weeks (Day 8 to 28), then once every 2 weeks for the next 8 weeks, then once every 4 weeks thereafter and as clinically indicated. Monitor HbA1C every 3 months and as clinically indicated.

Manage hyperglycemia with anti-hyperglycemic medications as clinically indicated. During treatment with antihyperglycemic medication, continue monitoring fasting glucose levels. Patients with a history of well-controlled Type 2 diabetes mellitus may require intensified anti-hyperglycemic treatment and close monitoring of fasting glucose levels.

Consider consultation with a healthcare professional experienced in the treatment of hyperglycemia, and initiation of fasting glucose monitoring at home for patients who have risk factors for hyperglycemia or who experience hyperglycemia.

Advise patients of the signs and symptoms of hyperglycemia and counsel patients on lifestyle changes.

Itovebi may require dose interruption, reduction or discontinuation based on the severity of hyperglycemia.

 b) Stomatitis

Patients may experience stomatitis, which refers to inflammation or sores in the mouth, during Itovebi treatment.

Among patients who received Itovebi in combination with palbociclib and fulvestrant, 38% used a corticosteroid-containing mouthwash to help manage or prevent stomatitis.

Patients should be monitored for signs and symptoms of stomatitis during treatment. Depending on how severe the condition is, the healthcare provider may temporarily withhold Inavolisib, reduce its dose, or permanently discontinue treatment. Any mouth sores, pain, redness, swelling or difficulty eating or drinking should be reported to the treating healthcare team.

c) Diarrhoea

Severe diarrhea, including dehydration and acute kidney injury, can occur in Inavolisib-treated patients.

Monitor patients for signs and symptoms of diarrhea.

Advise patients to increase oral fluids and start antidiarrheal treatment at the first sign of diarrhea while taking Inavolisib. Withhold, reduce dose or permanently discontinue the therapy based on severity.

Be vigilant about the treatment and the adverse effects that may occur during Inavolisib therapy. Taking appropriate measures at the right time and staying in regular communication with your healthcare team can help you navigate the treatment more safely. For updated information and support regarding Inavolisib in India, feel free to contact us. Our team can also assist you with guidance on how to access Inavolisib through the appropriate import pathway.