Real-World Study of Post-Resistance Treatment Strategies in Advanced Breast Cancer Following CDK4/6i, PIK3CA Inhibitors, or T-DXd

This is a real-world observational study aiming to evaluate the effectiveness of post-progression treatment strategies in patients with advanced breast cancer who have developed resistance to prior targeted therapies, including CDK4/6 inhibitors, PIK3CA inhibitors, trastuzumab deruxtecan (T-DXd), or other targeted agents commonly used in clinical practice. As resistance to these therapies becomes increasingly common, optimal sequencing strategies for subsequent treatment remain unclear. This study will collect clinical information on post-resistance systemic treatments and their outcomes, including progression-free survival, overall survival, and response rate. Baseline patient and tumor characteristics will also be collected to explore potential prognostic and predictive factors and to develop outcome prediction models that may help guide future clinical decision-making. This is a non-interventional study based on retrospective and prospective data from routine medical care. The results are expected to provide real-world evidence to inform personalized treatment strategies for patients with advanced breast cancer following resistance to targeted therapies.

NCT Number	NCT07073755
Lead Sponsor	Hunan Cancer Hospital
Conditions	Metastatic Breast Cancer, Drug Resistance, Hormone Receptor-Positive Breast Cancer, HER2-positive Breast Cancer, Triple-Negative Breast Cancer (TNBC), Treatment Decisions
Enrollment	200 participants
Start Date	2023-01-01
Primary Completion	2025-12-30 (estimated)
Study Completion	2026-06-01 (estimated)
Updated on ClinicalTrials.gov	2025-07-18