Capivasertib: Uses, Side Effects & Warnings

• Capivasertib is an AKT inhibitor used to treat hormone receptor-positive, HER2-negative advanced breast cancer with specific genetic alterations.
• It is typically administered in combination with fulvestrant after progression on endocrine-based therapy.
• Common side effects include diarrhea, skin rash, and hyperglycemia, requiring careful monitoring and management.
• Important warnings include the risk of severe hyperglycemia, gastrointestinal issues, and skin reactions, as well as potential harm to a fetus during pregnancy.
• Patients should adhere to their prescribed regimen, report any adverse effects promptly, and undergo regular medical monitoring as directed by their healthcare provider.

What is Capivasertib for?

Capivasertib is an oral kinase inhibitor specifically designed to target and block the activity of the AKT protein, which is a key component of the PI3K/AKT/PTEN signaling pathway. This pathway is frequently overactive in many cancers, promoting cell growth, proliferation, and survival. By inhibiting AKT, Capivasertib aims to disrupt these processes, thereby slowing or stopping the growth of cancer cells.

The primary use of Capivasertib is in the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative locally advanced or metastatic breast cancer. This treatment is indicated for patients whose tumors have one or more PIK3CA, AKT1, or PTEN alterations, and who have progressed on at least one endocrine-based regimen in the metastatic setting. It is administered in combination with fulvestrant, another anti-estrogen therapy. This targeted approach is significant because approximately 30-40% of HR-positive, HER2-negative breast cancers harbor these specific genetic alterations, making Capivasertib a vital option for a substantial patient population. (Source: National Cancer Institute).

Understanding Capivasertib uses involves recognizing its role in precision medicine. It is not a chemotherapy in the traditional sense but rather a targeted therapy that interferes with specific molecular pathways involved in cancer development. This distinction is crucial for patients, as targeted therapies often have different side effect profiles compared to conventional chemotherapy. The goal of Capivasertib, when used in combination with fulvestrant, is to improve progression-free survival and overall response rates in this specific subset of breast cancer patients.

Capivasertib Side Effects

Like all medications, Capivasertib can cause side effects, ranging from mild to severe. Patients receiving this medication should be aware of potential adverse reactions and report any new or worsening symptoms to their healthcare provider promptly. The most common Capivasertib side effects often involve the gastrointestinal system, skin, and metabolic processes.

Common side effects, experienced by a significant number of patients, include:

• Diarrhea: Often mild to moderate, but can be severe and lead to dehydration.
• Rash: Skin rash, often acneiform, can occur on the face, chest, and back.
• Hyperglycemia: Elevated blood sugar levels, which may require monitoring and management, especially in patients with pre-existing diabetes.
• Fatigue: General tiredness and lack of energy.
• Nausea and Vomiting: Digestive upset.
• Decreased Appetite: Loss of desire to eat.
• Stomatitis: Inflammation or sores in the mouth.
• Dry Skin: Xerosis or dryness of the skin.

More serious, though less common, side effects can also occur. These may include severe diarrhea requiring hospitalization, severe skin reactions such as erythema multiforme, and pneumonitis (inflammation of the lungs). Patients should receive a comprehensive Capivasertib medication guide from their pharmacist or healthcare provider, detailing these potential effects and how to manage them. Regular monitoring by a healthcare professional is essential to detect and manage these side effects early, ensuring patient safety and treatment adherence.

Important Safety Information and Warnings

Before starting treatment with Capivasertib, patients must be fully informed about critical safety information and potential warnings. Adherence to these guidelines is paramount for minimizing risks and ensuring the safe use of the medication. This section provides essential Capivasertib patient information regarding its safe administration.

Hyperglycemia Risk

Capivasertib can cause hyperglycemia, or high blood sugar, which can be severe and lead to serious complications, including diabetic ketoacidosis. This risk is particularly elevated in patients with pre-existing diabetes. Blood glucose levels should be monitored before starting treatment, regularly during treatment, and as clinically indicated. Patients may require initiation or adjustment of anti-hyperglycemic medications. It is crucial for patients to report symptoms such as increased thirst, frequent urination, or blurred vision to their doctor immediately.

Gastrointestinal Effects

Diarrhea is a very common side effect and can sometimes be severe, leading to dehydration, electrolyte imbalances, and acute kidney injury. Patients should be advised to have anti-diarrheal medication readily available and to start treatment at the first sign of loose stools. Maintaining adequate hydration is also critical. If severe diarrhea occurs, dose interruption or reduction may be necessary. Healthcare providers should assess and manage diarrhea promptly to prevent serious complications.

Skin Reactions

Skin rash, including maculopapular rash and acneiform dermatitis, is another frequent adverse event. In some cases, severe skin reactions, such as erythema multiforme, have been reported. Patients should be instructed on proper skin care and to report any worsening or severe skin changes. Management may involve topical corticosteroids, oral antihistamines, or dose modifications of Capivasertib.

Embryo-Fetal Toxicity

Based on its mechanism of action and animal studies, Capivasertib can cause fetal harm when administered to a pregnant woman. Women of reproductive potential should be advised of the potential risk to a fetus and to use effective contraception during treatment and for 1 month after the last dose. Men with female partners of reproductive potential should also use effective contraception during treatment and for 1 month after the last dose. Pregnancy testing should be performed before initiating treatment in women of reproductive potential.

Drug Interactions

Capivasertib is metabolized by cytochrome P450 3A (CYP3A) enzymes. Co-administration with strong CYP3A inhibitors (e.g., ketoconazole, clarithromycin) can increase Capivasertib exposure, potentially leading to increased adverse reactions. Conversely, co-administration with strong CYP3A inducers (e.g., rifampin, phenytoin) can decrease Capivasertib exposure, potentially reducing its efficacy. Patients should inform their healthcare provider about all medications, supplements, and herbal products they are taking to avoid potentially harmful drug interactions.

Frequently Asked Questions

What is the mechanism of action of Capivasertib?

Capivasertib is an oral selective inhibitor of all three AKT isoforms (AKT1, AKT2, and AKT3). It works by blocking the activity of the AKT protein, which is a crucial component of the PI3K/AKT/PTEN signaling pathway. This pathway is often hyperactive in certain cancers, promoting cell growth and survival. By inhibiting AKT, Capivasertib helps to disrupt these processes, thereby slowing or stopping the proliferation of cancer cells, particularly in specific breast cancer types.

How is Capivasertib administered?

Capivasertib is an oral medication taken by mouth. It is typically administered twice daily, approximately 12 hours apart, with or without food. It is crucial to take the medication exactly as prescribed by the healthcare provider. If a dose is missed or vomited, patients should not take an extra dose but continue with their next scheduled dose. Capivasertib is often prescribed in combination with fulvestrant, which is given via intramuscular injection.

What should I do if I experience severe side effects?

If you experience severe side effects such as severe diarrhea, persistent high blood sugar, or a widespread skin rash, you should contact your healthcare provider immediately. Do not attempt to manage severe symptoms on your own. Your doctor may advise you to interrupt treatment, reduce the dose, or provide supportive care to manage the side effect. Prompt reporting and management are essential to prevent complications and ensure your safety during treatment.