Roche announced positive Phase III results from its evERA Breast Cancer study, showing that the investigational drug giredestrant, when combined with everolimus, significantly improved outcomes for patients with advanced oestrogen receptor (ER)-positive, HER2-negative breast cancer.
The study found that the combination reduced the risk of disease progression or death by 44% in the overall study population and by 62% among patients with ESR1 mutations, compared with standard-of-care endocrine therapy plus everolimus. The results were presented at the European Society for Medical Oncology (ESMO) Congress 2025.
This marks the first positive head-to-head Phase III trial of a selective oestrogen receptor degrader (SERD)-containing regimen versus a standard-of-care combination in this patient group.
In the intention-to-treat population, median progression-free survival (PFS) was 8.77 months with giredestrant plus everolimus compared to 5.49 months with standard therapy. Among those with ESR1 mutations, median PFS reached 9.99 months versus 5.45 months. A positive trend was also observed for overall survival, with follow-up ongoing.
Dr. Levi Garraway, Roche’s Chief Medical Officer, said the findings could redefine treatment standards. “A particularly high unmet need remains for people who become resistant to endocrine therapies and CDK inhibitors. These results support the potential for the giredestrant combination to become a new standard-of-care,” he said.
Dr. Erica L. Mayer of the Dana-Farber Cancer Institute described the results as “clinically meaningful,” adding that the all-oral combination offers a new way to tackle treatment resistance in the post-CDK inhibitor setting.
The safety profile of the giredestrant combination was manageable and consistent with that of the individual medicines, with no new safety signals observed.
ER-positive breast cancer represents about 70% of all breast cancer cases, and resistance to current endocrine treatments remains a major challenge. Roche’s giredestrant program is part of a broad clinical development effort aimed at delivering innovative, effective, and more convenient oral therapies for people living with this common breast cancer subtype.