A new three-drug treatment has shown promising results in delaying the progression of advanced breast cancer. The trial, involving 325 patients across 28 countries, demonstrated that the novel combination could delay disease progression by twice the time compared to existing therapies for a specific subtype of breast cancer. This advance offers a potentially transformative option for women with PIK3CA-mutated HR+/HER2- breast cancer, a common and aggressive form of the disease.
The study, published in The New England Journal of Medicine, investigated the efficacy of adding inavolisib, a PIK3 protein inhibitor, to the standard treatment regimen of palbociclib (a cancer growth blocker) and fulvestrant (a hormone therapy). Patients with advanced breast cancer harboring the PIK3CA mutation were enrolled and randomized to receive either the standard two-drug combination or the novel three-drug therapy.
The results indicated a significant improvement in progression-free survival (PFS) with the addition of inavolisib. The median PFS in the three-drug group was 15 months, compared to 7.3 months in the control group. Furthermore, at 18 months, 46.2% of patients receiving the triple therapy showed no signs of disease progression, compared to only 21.1% in the standard treatment group.
Impact of PIK3CA Mutation
The PIK3CA mutation is a common driver of HR+/HER2- breast cancer, influencing cell growth and proliferation. By specifically targeting the PIK3 protein, inavolisib aims to disrupt this signaling pathway, potentially halting or slowing cancer progression. This targeted approach, combined with existing therapies, has demonstrated a substantial clinical benefit in this patient population.
Expert Commentary
Lead author Nick Turner, a professor of molecular oncology at the Institute of Cancer Research, London, hailed the findings as a "huge breakthrough" that could represent a transformative advance for people with this type of breast cancer. The results suggest a potential new standard of care for patients with PIK3CA-mutated HR+/HER2- advanced breast cancer.
Trial Details
The trial included patients with advanced breast cancer from 28 countries. Half of the patients received palbociclib and fulvestrant, while the other half received the same treatment plus inavolisib. The primary endpoint was progression-free survival. The study's findings highlight the potential of targeted therapies in improving outcomes for patients with specific genetic mutations driving their cancer.
