From 1 April 2020, patients with HER2-positive early breast cancer have another subsidised treatment option. Kadcyla (trastuzumab emtansine) is now available under Australia’s Pharmaceutical Benefits Scheme (PBS) for women and men following breast cancer surgery.
To access the drug, patients must have undertaken “preoperative treatment” with HER2- targeted therapy prior to surgical intervention and still have residual invasive disease. This is increasingly the standard of care treatment approach for women with HER2-positive breast cancer. Such an approach allows one to functionally assess the tumours response to current standard systemic therapy before surgery. Patients with a complete treatment effect do well in general, while patients who do not achieve a complete treatment effect should be considered for additional therapy. This is where Kadcyla fits in.
It is great news for women with the often-aggressive HER2+ tumours, which account for up to 20% of breast cancer cases. Kadcyla is a drug designed to bond to the HER2 protein on cancer cells, and then directly deliver a toxic chemical to the cell to kill it quickly and effectively. In a large clinical trial of almost 1500 women, known as the KATHERINE study, it was demonstrated that Kadcyla after breast cancer surgery can reduce the risk of recurrence of invasive breast cancer or death by 50% in patients who have not obtained a complete treatment response from their preoperative chemotherapy. This was compared to the standard treatment of Herceptin (trastuzumab).
A key point of this week’s announcement was that Kadcyla is only accessible if women have already trialed neoadjuvant therapy. This is line with international guidelines, which state that these early chemotherapy options are a key strategy in optimal treatment planning.
According to medical oncologist, Dr Richard de Boer, from St Vincent’s Private Hospital Melbourne, “The changing algorithm of treatment in early breast cancer means we can offer patients with HER2+ breast cancer better treatment options that can reduce the risk of disease recurrence – which is a significant cause of anxiety for breast cancer patients.”
The Federal government’s decision to provide expedited access to Kadcyla under the PBS means that eligible men and women will be able to access Kadcyla at a much reduced cost.