Three-drug therapy helps women with aggressive breast cancer live longer – trial
The treatment could also delay the need for gruelling chemotherapy, according to the trial.
A new three-drug combination could help women with a common form of aggressive breast cancer live longer, research suggests.
The treatment could also delay the need for gruelling chemotherapy, according to a trial.
Researchers are hopeful the combination could become the “new go-to option” for women with PIK3CA-mutated hormone receptor positive (HR+) human epidermal growth factor receptor 2 negative (HER2-) breast cancer.
This mutation in the PIK3CA gene causes cells to divide and replicate uncontrollably.
The final results from the INAVO120 study, led by experts at The Institute of Cancer Research, London, and the Royal Marsden NHS Foundation Trust, have been published in the New England Journal of Medicine and presented at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago.
The trial included 325 patients from across 28 countries.
More than half had metastatic breast cancer that had spread to three or more organs and the majority had already had chemotherapy.
Researchers used a blood test known as a liquid biopsy, which detects tumour DNA in the blood, to test for the PIK3CA mutation.
Of the total, 161 were given a three-drug combination comprising two targeted drugs – palbociclib, a type of cancer growth blocker, and a new drug called inavolisib, which blocks the activity of the PI3K protein – as well as the hormone therapy fulvestrant.
The placebo group, which included 164 patients, was given a dummy pill plus palbociclib and fulvestrant.
The study found the median overall survival in the inavolisib group was 34 months, compared with 27 months in the placebo group.
The three-drug therapy also delayed disease progression by 17.2 months, compared with 7.3 months in the placebo group, with patients also able to delay chemotherapy treatment by almost two years longer.
The latest results come after previous analysis of the study, published in October, showed the three-drug therapy delayed disease progression by an average of 15 months compared with 7.3 months in the placebo group.
Lead author Nick Turner, a professor of molecular oncology at The Institute of Cancer Research, London, and consultant medical oncologist at The Royal Marsden NHS Foundation Trust, said: “The key findings from this study showed that the inavolisib-based therapy not only helped patients live longer but it more than doubled the time before their cancer progressed or worsened.
“It also gave them more time before needing subsequent chemotherapy which we know is something that patients really fear and want to delay for as long as possible.
“These results give us confidence that this treatment could become the new go-to option for patients who have HR+, HER2- breast cancer with a PIK3CA mutation, as it has shown significant improvements in both survival and quality of life.”
It is estimated that about 55,000 women are diagnosed with breast cancer in the UK every year, some 70% of whom will have HR+, HER2- breast cancer.
PIK3CA mutations are found in 35-40% of HR+ breast cancers.
The three-drug therapy of inavolisib, palbociclib and fulvestrant is not approved in the UK.
However, the combination of palbociclib and fulvestrant has been available as an option for patients with certain types of breast cancer on the NHS since 2022.
Prof Kristian Helin, chief executive of The Institute of Cancer Research, London, added: “If we are to continue improving cancer survival rates, we need to tackle treatment resistance head on.
“This research demonstrates how this triple combination approach effectively shuts down cancer’s escape routes, giving people with metastatic breast cancer the opportunity to live well for longer.
“One of the challenges with combination therapies is ensuring the right drug dosages and understanding their individual effects.
“It is extremely encouraging that this study not only demonstrates the effectiveness of this approach but also shows that the therapy was generally well tolerated by patients.”
Reacting to the findings, Dr Simon Vincent, director of research, support and influencing at Breast Cancer Now, said: “This is a significant breakthrough and we’re proud that it builds on a series of discoveries that our funded scientists have been making at the Breast Cancer Now Toby Robins Research Centre at The Institute of Cancer Research, London, since it opened 25 years ago.
“We now hope to see this new combination therapy can be licensed by the MHRA (Medicines and Healthcare Products Regulatory Agency) and assessed by Nice (the National Institute for Health and Care Excellence) and the Scottish Medicine Council as soon as possible so that it can reach the NHS patients who could benefit from it.”
