Capivasertib is a kinase inhibitor. It is used in combination with fulvestrant for the treatment of HR-positive, HER2-negative advanced or metastatic breast cancer harboring PIK3CA/AKT1/PTEN gene mutations. As a novel targeted drug, its clinical application must strictly follow medication guidelines to help balance efficacy and safety.

What Are the Precautions for Capivasertib Administration?

Confirmation of Indication via Genetic Testing

Before use, the presence of PIK3CA/AKT1/PTEN gene mutations in tumor tissue must be confirmed using an FDA-approved detection method.

Additionally, patients must have experienced disease progression after receiving at least one endocrine therapy regimen in the metastatic setting, or relapsed within 12 months after completing adjuvant therapy.

Assessment of Baseline Metabolic Status

Fasting blood glucose and glycated hemoglobin (HbA1c) should be tested, and treatment can only be initiated after optimizing blood glucose levels.

In particular, it should be noted that the safety of this drug in patients with type 1 diabetes or diabetes requiring insulin therapy has not been established, and such populations should use it with caution.

Standard Dosing Schedule

The recommended dose is 400 mg taken orally twice daily (approximately 12 hours apart), with or without food. Administer continuously for 4 days followed by 3 days off, forming a cyclic schedule.

Treatment should continue until disease progression or the occurrence of unacceptable toxicity.

Effects of Enzyme Inhibitors and Inducers

Concomitant use with strong CYP3A inhibitors (e.g., itraconazole) should be avoided. If unavoidable, the dose should be reduced to 320 mg twice daily.

Dose adjustments are also required when used with moderate CYP3A inhibitors (e.g., erythromycin). Meanwhile, concomitant use with strong or moderate CYP3A inducers should be avoided.

Synergy with Other Antineoplastic Agents

Combination administration must strictly follow the prescribing information for fulvestrant.

For perimenopausal women, combination with a luteinizing hormone-releasing hormone (LHRH) agonist is required in accordance with standard clinical practice.

Male patients may also be considered for combination with similar agents to enhance efficacy.

Capivasertib Administration Monitoring

Self-Monitoring Guidance

Patients should be instructed to recognize the characteristics of hyperglycemia symptoms (e.g., polydipsia, polyuria, weight loss), diarrhea, and skin reactions, and report abnormalities promptly.

Lifestyle Adjustments

Patients are advised to avoid consuming grapefruit and its products to prevent interference with drug metabolism.

At the same time, blood glucose should be monitored regularly, and the hypoglycemic regimen should be adjusted as directed by a physician.