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

Launched by HUNAN CANCER HOSPITAL · Jul 9, 2025

Keywords

ClinConnect Summary

This study is looking at how well different treatments work for people with advanced breast cancer when their cancer no longer responds to certain targeted therapies. These therapies include medicines like CDK4/6 inhibitors, PIK3CA inhibitors, and trastuzumab deruxtecan (T-DXd), which are commonly used to slow down or stop cancer growth. Because cancer can become resistant to these treatments over time, doctors need to understand the best options for what to try next. This study collects information from patients’ regular medical care to see how different follow-up treatments affect things like how long the cancer stays under control and overall survival.

Adults with advanced or metastatic breast cancer who have already been treated with one of these targeted therapies and whose cancer has started to grow again may be eligible to take part. Participants must have started a new treatment after their cancer became resistant and have medical records available for review. The study does not involve giving new treatments but looks at the results of treatments patients are already receiving. By gathering this real-world information, researchers hope to find better ways to choose treatments that can help patients live longer and improve their quality of life after their cancer stops responding to initial targeted medicines.

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • 1. Adults (≥18 years old) with histologically or cytologically confirmed advanced or metastatic breast cancer
• • 2. Received prior treatment with at least one of the following: CDK4/6 inhibitors, PIK3CA inhibitors, trastuzumab deruxtecan (T-DXd), or other targeted therapies
• • 3. Documented disease progression following prior targeted therapy
• • 4. Initiated a subsequent line of systemic therapy (chemotherapy, endocrine therapy, targeted therapy, or combination) after resistance
• • 5. Available clinical data including baseline characteristics and treatment details
• • 6. At least one follow-up evaluation after initiation of post-resistance therapy
• Exclusion Criteria:
• • 1. Incomplete medical records or missing key clinical follow-up data
• • 2. Concurrent diagnosis of other active malignancies (except non-melanoma skin cancer or in situ cervical cancer)
• • 3. Known central nervous system disease requiring immediate local treatment (unless clinically stable)
• • 4. Poor general condition with an Eastern Cooperative Oncology Group (ECOG) performance status ≥2
• • 5. Life expectancy estimated to be less than 6 months based on clinical judgment