Genentech’s Phase III evERA Data Showed Giredestrant Significantly Improved Progression-Free Survival in People With ER-Positive Advanced Breast Cancer

Genentech, a member of the Roche Group (SIX: RO, ROG; OTCQX: RHHBY), announced today positive results from the Phase III evERA Breast Cancer study. Data showed giredestrant in combination with everolimus significantly reduced the risk of disease progression or death (progression-free survival; PFS) by 44% and 62% in the intention-to-treat (ITT) and ESR1-mutated populations, respectively, compared with standard-of-care endocrine therapy plus everolimus. The evERA study is evaluating the investigational giredestrant combination in people with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, locally advanced or metastatic breast cancer previously treated with cyclin-dependent kinase (CDK) 4/6 inhibitor and endocrine therapy. This is the first positive head-to-head Phase III trial investigating a selective estrogen receptor degrader-containing regimen versus a standard-of-care combination. The results are being presented in an oral session at the European Society for Medical Oncology Congress 2025. Data will be shared with health authorities, with the aim of bringing this potential treatment option to people as soon as possible.

“A particularly high unmet need remains for people who become resistant to endocrine therapies and CDK inhibitors. These study results support the potential for the giredestrant combination to become a new standard-of-care for all patients in this setting,” said Levi Garraway, M.D., Ph.D., Genentech’s chief medical officer and head of Global Product Development.

“Resistance to standard-of-care therapies is common in the post-CDK inhibitor setting, and the results from evERA validate using a combination to address this challenge,” said Erica L. Mayer, M.D., Medical Oncologist at Dana-Farber Cancer Institute. “The clinically meaningful benefit observed with the giredestrant and everolimus all-oral combination is impressive and speaks to its potential to improve outcomes for patients in need of new treatment options.”

The giredestrant combination demonstrated a statistically significant and clinically meaningful improvement in PFS compared with standard-of-care endocrine therapy plus everolimus. In the ITT population, the median PFS was 8.77 months compared with 5.49 months in the giredestrant and comparator arm, respectively (stratified hazard ratio [HR]=0.56; 95% CI: 0.44-0.71, p-value= <0.0001). In the ESR1-mutated population, the median PFS was 9.99 months compared with 5.45 months in the giredestrant and comparator arm, respectively (HR=0.38; 95% CI: 0.27-0.54, p-value= <0.0001). The PFS benefit was consistent across pre-specified subgroups in both populations. Overall survival (OS) data were immature at the time of analysis, but a clear positive trend has been observed in the ITT (HR=0.69, 95% CI: 0.47-1.00, p-value=0.0473) and ESR1-mutated populations (HR=0.62, 95% CI: 0.38-1.02, p-value=0.0566). Follow-up for OS will continue to next analysis. Giredestrant in combination with everolimus also demonstrated improvements in key secondary endpoints (objective response rate and duration of response) compared with the comparator arm across both patient populations.