Targeted drug offers 'landmark moment' in advanced breast cancer treatment
A phase 3 clinical trial of capivasertib alongside hormone therapy suggests the combination could become the new treatment for patients with advanced forms of the most common type of breast cancer.
A "landmark moment" in the treatment of advanced breast cancer could benefit thousands of women each year, scientists have said.
A new targeted drug has shown "fantastic" results — shrinking tumours and doubling the amount of time people have before their disease progresses.
A phase 3 clinical trial of capivasertib alongside hormone therapy suggests the combination could become the new treatment for patients with advanced forms of the most common type of breast cancer.
The findings, presented at the San Antonio Breast Cancer Symposium on Thursday, relate to oestrogen receptor (ER) positive, human epidermal growth factor receptor 2 (HER-2) negative breast cancer, which accounts for about 70% of all new breast cancer cases.
Capivasertib is being manufactured by pharmaceutical giant AstraZeneca following a programme of drug discovery research at the Institute of Cancer Research (ICR) in London.
The drug's novel action blocks activity of the cancer-driving protein molecule AKT.
All the men and women on the trial, led by researchers at the ICR and the Royal Marsden NHS Foundation Trust, had seen their cancer recur or progress on standard hormone treatments, and the majority had also previously been treated with CDK4/6 inhibitors — drugs that block cancer cells from multiplying.
At present, patients whose cancer progresses continue to receive fulvestrant hormone therapy, but this is often not effective, and many are left only with the option of chemotherapy.
For the research, scientists randomly assigned 355 patients to receive capivasertib plus fulvestrant and 353 patients to receive a placebo plus fulvestrant.
The results showed treatment with capivasertib plus fulvestrant typically gave patients 7.2 months without their disease progressing or getting worse, compared to 3.6 months for patients treated with placebo plus fulvestrant.
The treatment shrank tumours in 23% of patients, compared with 12% of patients who received fulvestrant plus a placebo.
The new drug regime was also more effective for the four in 10 patients whose cancers had mutations to the AKT signalling pathway, with 29% seeing their tumours shrink compared to 10% on the placebo combination.
Genetic alterations to the AKT pathway can drive both cancer's development and resistance to treatment.
Trial leader Nick Turner, professor of molecular oncology at the ICR and consultant oncologist at the Royal Marsden, said: "Even with the best current treatments, people with this type of advanced breast cancer will eventually see their cancer stop responding to treatment, and it will progress.
"We're delighted that this potential first-in-class drug combined with hormone therapy can lower the progression of these advanced cancers, and in almost a third of cases can shrink tumours.
Researchers in the ICR have worked for several years on the science behind getting such a drug to work, including how it would target AKT.
The drug was then developed by AstraZeneca with a view to potentially using it on several cancers.
