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Phase III: Giredestrant in BC (pionERA Breast Cancer (BC))

Clinical Trial Overview

A Phase III Randomized, Open-Label Study Evaluating Efficacy and Safety of Giredestrant Compared With Fulvestrant, Both Combined With a CDK4/6 Inhibitor, in Patients With Estrogen Receptor-Positive, HER2-Negative Advanced Breast Cancer With Resistance to Prior Adjuvant Endocrine Therapy

Objective

This is a Phase III, randomized, open-label multicenter study that will evaluate the efficacy and safety of giredestrant compared with fulvestrant, both in combination with the investigator's choice of a CDK4/6 inhibitor (palbociclib, ribociclib or abemaciclib), in participants with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer who have developed resistance to adjuvant endocrine therapy.

pionERA Breast Cancer Clinical Trial Recruitment: Dr. Kevin Kalinsky

Dr. Kevin Kalinsky speaks about the pionERA Breast Cancer clinical trial, eligibility criteria and the importance of early enrollment.

Trial Design

*Investigator's choice of CDK4/6 inhibitor (CDK4/6i): palbociclib, ribociclib, or abemaciclib.

Primary Endpoints

Progression-Free Survival (PFS)* in the ESR1 mutation (ESR1m) Subgroup
PFS* in the Full Analysis Set (FAS) Population

Secondary Endpoints

Efficacy**

PFS* in ESR1nmd subgroup
Overall survival (OS)
Overall response rate, confirmed (cORR*)
Duration of response (DOR*)
Clinical benefit rate (CBR*)
Time to chemotherapy (TTCtx)
PROs: time to confirmed deterioration (TTCD) in pain, physical & role functioning; global health status/quality of life (GHS/QoL)

Safety & Tolerability

AEs, change from baseline in labs

*tumor-assessment endpoints based on investigator according to RECIST v1.1; sensitivity analyses based on blinded independent central review (BICR) performed in the full study population
**secondary endpoints will be analyzed in the ESR1m and ESR1nmd subgroups and in the FAS/ITT

Giredestrant

Other names: GDC-9545; RG6171
Modality: Selective estrogen receptor degrader/downregulator (SERD)

QUICK LINKS

Clinical Trial Overview

Inclusion and Exclusion Criteria

Enrollment and Resources

View on ClinicalTrials.gov

Inclusion and Exclusion Criteria

Key Inclusion Criteria

Key Exclusion Criteria

Locally advanced or metastatic adenocarcinoma of the breast, not amenable to treatment with curative intent
Documented estrogen receptor-positive (ER+), HER2-negative (HER2-) tumor assessed locally on the most recent tumor biopsy (or an archived tumor sample if a recent tumor sample is not available for testing)
Confirmed ESR1 mutation status (ESR1m versus ESR1nmd) in baseline circulating tumor DNA (ctDNA) through central laboratory testing
Resistance to prior adjuvant endocrine therapy (ET), which is defined as having relapsed with prior standard adjuvant ET, on-treatment after >/=12 months or off-treatment within 12 months of completion. Prior use of adjuvant CDK4/6i is allowed (if relapse occurred >/=12 months since completion).
No prior systemic anti-cancer therapy for advanced disease
Measurable disease as defined per RECIST v.1.1 or non-measurable (including bone-only) disease
Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0-1
For pre/perimenopausal women and for men: willing to undergo and maintain treatment with approved LHRH agonist therapy (as per local guidelines) for the duration of study treatment

Prior systemic therapy (e.g., prior chemotherapy, immunotherapy, or biologic therapy) for locally advanced unresectable or metastatic breast cancer
Prior treatment with another SERD (e.g., fulvestrant, oral SERDs) or novel ER-targeting agents
Advanced, symptomatic, visceral spread that is at risk of life-threatening complications in the short term
Active cardiac disease or history of cardiac dysfunction
Clinically significant history of liver disease

Enrollment & Resources

Enrollment

For more information on eligibility criteria, view the study or reach out to our team.

Web

ClinicalTrials.gov
Identifier: NCT06065748

Phone

1-888-662-6728
(US and Canada)

Email

[email protected]

Clinical Trial Site Locations

Clinical Trial Site Locations

For more information on recruitment status, or where the study is being conducted

Visit ClinicalTrials.gov

Information is consistent with ClinicalTrials.gov as of April 17, 2025. Products under investigation have not been approved for use outside of the clinical trial setting. This information is presented only for the purposes of providing an overview of clinical trials and should not be construed as a recommendation for use of any product for unapproved purposes.

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Call the Trial Information Support Team: 1-888-662-6728 Hours: Monday-Friday, 5am-5pm PT