Capivasertib on the PBS

Capivasertib has been added to the Pharmaceutical Benefits Scheme (PBS) for the treatment of locally advanced or metastatic breast cancer. Eligibility requires the condition to be human epidermal growth factor receptor-2 (HER2) negative and estrogen receptor positive, and treatment must be in combination with fulvestrant.

Capivasertib is an inhibitor of AKT, a serine/threonine kinase that is important in various cellular processes, including cell survival and proliferation. Inhibition of AKT has been shown to reduce growth in breast cancer cell lines.

The efficacy and safety of capivasertib was investigated in the CAPItello-291 study. Patients with hormone receptor-positive, HER2-negative advanced breast cancer were randomised to receive fulvestrant plus either capivasertib or placebo. The median progression-free survival was 7.2 months in the capivasertib group and 3.6 months in the placebo group. Patients receiving capivasertib maintained their global health status and quality of life for longer. The median time to deterioration was 24.9 months, compared to 12.0 months for the placebo group.

Diarrhoea, rash, and nausea were the most commonly reported adverse events. Hyperglycaemia has also been reported, including severe cases associated with diabetic ketoacidosis and ketoacidosis. Patients should be counselled to seek medical advice if they experience symptoms of hyperglycaemia (e.g. excessive thirst, increased urination).

Capivasertib is usually administered twice daily for four consecutive days, followed by three days off treatment. Cycles should continue until disease progression or unacceptable toxicity. Co-administration with strong CYP3A4 inhibitors should be avoided and dose adjustment considered with moderate CYP3A4 inhibitors.