Capivasertib Plus Faslodex Meets Both Primary Endpoints in Phase 3 Trial for Breast Cancer

Fulvestrant (Faslodex; AstraZeneca) in combination with capivasertib (AstraZeneca) demonstrated a statistically significant and meaningful improvement in progression-free survival (PFS) compared with the placebo and fulvestrant in individuals with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-low of negative locally advanced or metastatic breast cancer, following progression or recurrence on or after endocrine therapy, according to results from the CAPItello-291 (NCT04305496) phase 3 trial.

“The CAPItello-291 phase 3 trial results show capivasertib offers a clinically meaningful improvement in progression free survival for patients with HR-positive breast cancer. This potential new medicine could give people more time with their cancer under control, which is a priority for patients and their families,” Nicholas Turner, MD, PhD, professor of molecular oncology at the Institute of Cancer Research in London and the Royal Marsden NHS Foundation Trust in London, United Kingdom, said in a statement.

The trial met both primary endpoints, which included improving PFS in the overall patient population and in a prespecified biomarker subgroup of individuals whose tumors had alterations in the PIK3CA AKT1 or PTEN genes. In the trial, approximately 40% of tumors had these alterations.

The overall survival data was immature at the analysis, but investigators said they will continue to assess it as a key secondary endpoint, as the early data are positive.

Additionally, the safety profile of the drug combination was similar to that observed in previous trials with the same combination.

The CAPIello-291 trial is a randomized trial that is part of a larger clinical program investigating capivasertib. Investigators enrolled 708 individuals with histologically confirmed HR+, Her2-low or negative breast cancer whose disease had progressed or recurred during or after aromatase inhibitor therapy with or without a CDK4/6 inhibitor and up to 1 line of chemotherapy for those with advanced disease.

“These exciting data in an all-comers population indicate that capivasertib could become a new first-in-class treatment option for patients with HR-positive breast cancer. These patients often experience tumor progression on, or resistance to, available endocrine therapies for advanced disease and urgently need new therapies that extend the effectiveness of endocrine-based treatment approaches,” Susan Galbraith, PhD, executive vice president of oncology research and development at AstraZeneca, said in the statement.

The data will be presented at an upcoming medical meeting, as well as shared with global health authorities.

Fulvestrant is indicted as a monotherapy for HR+, HER2- advanced breast cancer in postmenopausal women who were not previously treated with endocrine therapy and HR-positive advanced breast cancer in postmenopausal women with disease progression following endocrine therapy.

Furthermore, it is indicated as a combination therapy for HR+, HER2- advanced or metastatic breast cancer in postmenopausal womenwith ribociclib as initial endocrine-based therapy or following disease progression on endocrine therapy and HR+, HER2- advanced or metastatic breast cancer in combination with palbociclib or abemaciclib in women with disease progression after endocrine therapy.

Reference

Capivasertib plus Faslodex (fulvestrant) significantly improved progression-free survival vs. Faslodex in CAPItello-291 phase III trial in advanced HR-positive breast cancer. News release. Businesswire. October 26, 2022. Accessed October 27, 2022. https://www.businesswire.com/news/home/20221026005411/en