Treatment options after targeted therapy stops working in advanced breast cancer

A Real-World Observational Study on Post-Resistance Treatment Outcomes in Advanced Breast Cancer Patients After CDK4/6 Inhibitors, PIK3CA Inhibitors, or Trastuzumab Deruxtecan Therapy

Observational Hunan Cancer Hospital · NCT07073755

This study will see how well different treatments work for people with advanced breast cancer who have stopped responding to CDK4/6 inhibitors, PIK3CA inhibitors, or T-DXd.

Quick facts

Study typeObservational
Enrollment200 (estimated)
Ages18 Years and up
SexAll
SponsorHunan Cancer Hospital Academic / other
Drugs / interventionstrastuzumab, chemotherapy
Locations1 site (Changsha, Hunan)
Trial IDNCT07073755 on ClinicalTrials.gov

What this trial studies

This real-world observational project collects retrospective and prospective routine-care data on patients with advanced or metastatic breast cancer who progressed after targeted therapies such as CDK4/6 inhibitors, PIK3CA inhibitors, or trastuzumab deruxtecan (T-DXd). Researchers will record subsequent systemic treatments (chemotherapy, endocrine therapy, targeted agents, or combinations) and capture outcomes including progression-free survival, overall survival, objective response rate, and duration of response. Baseline patient and tumor characteristics, prior treatment history, and follow-up information will be gathered to explore prognostic and predictive factors. The dataset will be used to describe treatment patterns and to develop outcome-prediction models to help guide future sequencing decisions in routine clinical practice.

Who should consider this trial

Good fit: Adults with histologically confirmed advanced or metastatic breast cancer who progressed after prior CDK4/6 inhibitors, PIK3CA inhibitors, T-DXd, or similar targeted therapies and who started a subsequent systemic therapy with available follow-up data.

Not a fit: Patients with incomplete medical records, concurrent active non-skin malignancies, or rapidly progressing central nervous system disease requiring immediate local treatment are unlikely to benefit from inclusion.

Why it matters

Potential benefit: If successful, the results could help doctors choose better next treatments after targeted therapy stops working, potentially prolonging survival or delaying progression.

How similar studies have performed: Similar real-world and registry studies have provided useful observational data on treatment patterns, but randomized evidence on optimal sequencing after these newer targeted agents remains limited.

Eligibility criteria

Show full inclusion / exclusion 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

Where this trial is running

Changsha, Hunan

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Metastatic Breast CancerDrug ResistanceHormone Receptor-Positive Breast CancerHER2-positive Breast CancerTriple-Negative Breast CancerTreatment DecisionsReal-World StudyTreatment Resistance
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.