Giredestrant–everolimus combination improves progression-free survival in advanced breast cancer

Overview

Updated Yesterday

Patients with estrogen receptor (ER)-positive advanced breast cancer who progress on a CDK4/6 inhibitor are running out of options; no existing regimen has shown a large progression-free survival benefit in this hard-to-treat group. The Phase III evERA trial now reports that an all-oral combination of giredestrant, a pill that degrades the estrogen receptor, plus everolimus cut the risk of disease progression or death by 44% overall. Among patients whose tumors carry ESR1 mutations, the most common mechanism of endocrine resistance, the reduction reached 62%.

The results, published in the New England Journal of Medicine, are the first positive Phase III readout for giredestrant, an investigational oral selective estrogen receptor degrader (SERD) developed by Genentech, a member of the Roche Group. The U.S. Food and Drug Administration (FDA) accepted the new drug application for giredestrant plus everolimus in ESR1-mutated advanced disease, with a decision deadline of December 18, 2026.

Why it matters

In the hard-to-treat post-CDK4/6 setting, giredestrant plus everolimus cut progression or death risk by 44% overall (62% in ESR1-mutated tumors); FDA decision due December 2026.

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Key Indicators

44%

Reduction in risk of progression or death, intent-to-treat population

Hazard ratio 0.56 for giredestrant plus everolimus versus standard endocrine therapy plus everolimus.

62%

Reduction in risk of progression or death, ESR1-mutated population

Hazard ratio 0.38 among patients with ESR1 mutations, the most common endocrine resistance mechanism.

10.0 vs 5.5 months

Median progression-free survival, ESR1-mutated population

Giredestrant plus everolimus versus comparator arm in the primary evERA analysis.

Dec 18, 2026

FDA decision deadline for giredestrant plus everolimus

Prescription Drug User Fee Act goal date for the ESR1-mutated advanced breast cancer application.

Voices

Curated perspectives — historical figures and your fellow readers.

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People Involved

Dr. Mayer

Study investigator, evERA trial

Presented evERA trial results

Organizations Involved

Genentech

Biotechnology company; member of the Roche Group

Lead sponsor of evERA trial; submitted giredestrant NDAs to FDA

Developed giredestrant, an investigational oral selective estrogen receptor degrader (SERD).

Roche / Genentech

Multinational pharmaceutical company

Parent company of Genentech; co-announced evERA results

Parent company of Genentech, which developed giredestrant.

U.S. Food and Drug Administration

Federal Agency

Reviewing two giredestrant applications under priority review

Regulator reviewing giredestrant applications for advanced and early-stage breast cancer.

Timeline

August 2022 December 2026

6 events Latest: 2 days ago

Tap a bar to jump to that date

December 2026
FDA decision deadline for giredestrant plus everolimus
Upcoming Regulatory

PDUFA goal date for the combination in ESR1-mutated advanced breast cancer.
December 18th, 2026
November 2026
FDA decision deadline for adjuvant giredestrant
Upcoming Regulatory

PDUFA goal date for giredestrant as adjuvant therapy in early-stage breast cancer, based on lidERA results.
November 30th, 2026
September 2026
NEJM publishes evERA results; FDA accepts NDA
Latest Publication / Regulatory

Detailed results published in the New England Journal of Medicine; FDA accepts giredestrant application for ESR1-mutated advanced disease.
2 days ago
October 2025
Genentech announces evERA met primary endpoint
Results

Phase III data show giredestrant plus everolimus significantly improved progression-free survival.
October 17th, 2025
July 2025
evERA reaches primary completion
Milestone

Primary endpoint data collected; progression-free survival analysis follows.
July 16th, 2025
August 2022
Enrollment opens in Phase III evERA trial
Trial launch

Genentech begins enrolling ER-positive, HER2-negative advanced breast cancer patients after CDK4/6 inhibitor treatment.
August 3rd, 2022

Scenarios

FDA approves giredestrant plus everolimus for ESR1-mutated advanced breast cancer

Likely Resolves by Dec 18, 2026

Discussed by: Genentech and Roche, which cited evERA results in their FDA submission

Genentech filed the application after evERA results, and the FDA accepted it with priority review and a December 18, 2026 goal date. Approval would give patients with ESR1-mutated, endocrine-resistant disease a new all-oral option. It would make giredestrant the second oral SERD cleared in the post-CDK4/6 setting, after elacestrant.

FDA approves giredestrant as adjuvant therapy for early-stage breast cancer

Likely Resolves by Nov 30, 2026

Discussed by: Genentech and Roche, citing the lidERA Breast Cancer study

The FDA accepted a priority-review application for giredestrant as adjuvant treatment of ER-positive, HER2-negative stage I-III breast cancer, with a goal date of November 30, 2026. Approval would make it one of the first oral SERDs available for early-stage disease, expanding the drug's reach beyond the metastatic setting.

Overall survival benefit confirmed in evERA follow-up

Possible Resolves by End of 2027

Discussed by: Genentech and Roche, which reported positive OS trends in the evERA analysis

Overall survival data were immature at the evERA analysis, but trends favored giredestrant in both the intent-to-treat population (hazard ratio 0.69) and the ESR1-mutated population (hazard ratio 0.62). If survival reaches statistical significance at the next analysis, it would strengthen the combination's position as a post-CDK4/6 standard of care. If the trend fades, the progression-free survival benefit alone would still support approval but carry less weight.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

2012

BOLERO-2: everolimus plus exemestane (2012)

The first large trial of an mTOR inhibitor in ER-positive advanced breast cancer. Everolimus plus exemestane extended median progression-free survival from 2.8 months to 6.9 months for patients who had progressed on an aromatase inhibitor.

Then

The FDA approved the combination in 2012 for aromatase-inhibitor-resistant disease.

Now

No overall survival benefit emerged, and stomatitis, fatigue, and other side effects limited real-world use, so the regimen never became a dominant standard of care.

Why this matters now

BOLERO-2 is the direct predecessor of evERA. Both test everolimus in endocrine-resistant breast cancer, but giredestrant targets the estrogen receptor directly and reported a larger PFS effect, especially in ESR1-mutated disease.

2015-2017

CDK4/6 inhibitor era in ER-positive breast cancer (2015-2017)

Palbociclib (2015), ribociclib (2017), and abemaciclib (2017) transformed first-line treatment of ER-positive metastatic breast cancer, roughly doubling median progression-free survival when added to endocrine therapy.

Then

CDK4/6 inhibitor combinations became the global first-line standard of care.

Now

They created a new problem: a large population of patients who progress after CDK4/6 therapy, with no clear standard of care for what comes next.

Why this matters now

evERA enrolls exactly this post-CDK4/6 population, the group giredestrant is designed to help.

2023

Elacestrant: first oral SERD approved for ESR1-mutated breast cancer (2023)

The EMERALD trial led to FDA approval of elacestrant, the first oral SERD, for ER-positive, HER2-negative advanced breast cancer with ESR1 mutations after a CDK4/6 inhibitor. It established oral SERDs as a viable option in this setting.

Then

Elacestrant became the first oral endocrine therapy cleared specifically for ESR1-mutated, post-CDK4/6 disease.

Now

The approval validated the oral SERD class and ESR1 mutation as a target, setting the stage for competitors like giredestrant.

Why this matters now

Giredestrant is the second oral SERD to reach Phase III in this space and reported a larger risk reduction (HR 0.38) in ESR1-mutated disease than elacestrant's earlier results.