SOUTH SAN FRANCISCO, Calif. — September 30, 2026
Genentech, a member of the Roche Group, announced detailed results from the Phase III evERA Breast Cancer study, showing that investigational giredestrant plus everolimus significantly improved progression-free survival (PFS) compared with standard endocrine therapy plus everolimus in people with ER-positive, HER2-negative locally advanced or metastatic breast cancer following treatment with a CDK4/6 inhibitor and endocrine therapy. In the intent-to-treat population, the combination reduced the risk of disease progression or death by 44%, with median PFS of 8.8 months compared with 5.5 months for the comparator arm. In patients with ESR1-mutated disease, the risk reduction was 62%, with median PFS of 10.0 months versus 5.5 months. The results were published in The New England Journal of Medicine. The FDA has set PDUFA goal dates of November 30, 2026, for early-stage breast cancer and December 18, 2026, for advanced disease.
Giredestrant Demonstrates PFS Benefit in Advanced Breast Cancer
The evERA Phase III study evaluated giredestrant in combination with everolimus in patients with ER-positive, HER2-negative locally advanced or metastatic breast cancer whose disease had progressed or recurred following treatment with a CDK4/6 inhibitor and endocrine therapy. In the ESR1-mutated population, median PFS was 10.0 months with giredestrant plus everolimus compared with 5.5 months with standard endocrine therapy plus everolimus, corresponding to a hazard ratio of 0.38. In the overall intent-to-treat population, median PFS was 8.8 months versus 5.5 months, with a hazard ratio of 0.56. Overall survival data remained immature at the time of analysis, although the company reported positive trends in both the ITT and ESR1-mutated populations. The findings support continued evaluation of giredestrant as an oral endocrine therapy designed to address resistance that develops during treatment of ER-positive breast cancer.
evERA Findings Highlight ESR1-Mutated Disease
The trial provides clinical evidence for targeting endocrine resistance in patients whose tumors have progressed after CDK4/6 inhibitor treatment. ESR1 mutations can emerge during endocrine therapy and contribute to treatment resistance in ER-positive breast cancer. In the evERA study, the benefit of giredestrant plus everolimus was particularly pronounced in the ESR1-mutated population, where the reported hazard ratio for progression or death was 0.38. Additional analyses presented at the 2026 American Society of Clinical Oncology Annual Meeting showed that the combination also prolonged PFS2 and chemotherapy-free survival compared with standard endocrine therapy, according to Genentech. The company reported that adverse events were manageable and consistent with the known safety profiles of the individual medicines, with no unexpected safety findings observed.
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Giredestrant Advances Across Multiple Breast Cancer Settings
The evERA results expand the clinical development profile of giredestrant across both advanced and early-stage breast cancer. Giredestrant is an investigational oral selective estrogen receptor degrader designed to block estrogen binding to the estrogen receptor and promote receptor degradation. Genentech is evaluating the medicine across multiple Phase III studies, including lidERA in early-stage ER-positive, HER2-negative breast cancer, persevERA in endocrine-sensitive recurrent advanced disease, pionERA in endocrine-resistant advanced disease and heredERA in ER-positive, HER2-positive advanced breast cancer. The FDA has accepted an NDA for giredestrant plus everolimus in ER-positive, HER2-negative, ESR1-mutated locally advanced or metastatic breast cancer, with a PDUFA goal date of December 18, 2026. A separate NDA for adjuvant giredestrant in early-stage breast cancer has received Priority Review, with a PDUFA goal date of November 30, 2026. The evERA findings therefore add to Genentech’s broader clinical development program aimed at addressing endocrine resistance across different stages and treatment settings.
Source:Genentech,, press release
