T-DXd Based Therapy Followed by Endocrine Therapy Plus Dual HER2 Blockade in First-line HER2+/ HR+ Metastatic Breast Cancer and Retreatment With T-DXd

Summary

This study will evaluate a structured sequential treatment strategy starting with T-DXd + pertuzumab upfront therapy, followed by an optimized maintenance therapy with dual HER2+blockade + CDK4/6i + ET and the opportunity to retreat with T-DXd once patients progress under maintenance aimed to maximizing disease control, optimizing tolerability, and preserving T-DXd as a future therapeutic option, while ensuring participant safety and regulatory compliance in participants with HER2+/HR+ advanced/metastatic breast cancer.

Shortened from the sponsor's brief summary. View official record on ClinicalTrials.gov

Conditions studied

• Advanced Breast Cancer
• Metastatic Breast Cancer
• HER2 Positive
• HR Positive

Eligibility basics and study details

Study type

Interventional

Phase

Phase 3

Ages

18 years and older

Sex

All

Healthy volunteers

Not accepted

Sponsor

Daiichi Sankyo

Last updated on ClinicalTrials.gov

October 16, 2026

These are the basic criteria only. The full inclusion and exclusion criteria are on the official record, and the study team decides who can take part.

US recruiting sites