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

NCT07073755 | Recruiting

• 1 other identifier: HNCA-PoReBC
• Study Type: observational
• Target: 200
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Metastatic Breast Cancer; Drug Resistance; Hormone Receptor-Positive Breast Cancer; HER2-positive Breast Cancer; Triple-Negative Breast Cancer (TNBC); Treatment Decisions

Keywords

Real-World Study; Treatment Resistance; Post-Progression Therapy; Metastatic Breast Cancer; Predictive Factors

Outcome Measures

Primary Outcomes (1)

• Progression-Free Survival (PFS)

  Progression-Free Survival (PFS) is defined as the time from the initiation of post-progression systemic treatment (after resistance to CDK4/6 inhibitors, PIK3CA inhibitors, T-DXd, or other targeted therapies) to the date of documented disease progression or death from any cause, whichever occurs first. Disease progression will be determined based on radiological or clinical assessment, as per real-world documentation standards. Patients without progression or death at the time of analysis will be censored at the date of last follow-up.

  From the start of post-resistance systemic treatment until documented disease progression or death, up to 36 months.

Secondary Outcomes (4)

• Overall Response Rate (ORR)

  From start of post-resistance systemic treatment to best documented response, assessed up to 24 months.

• Disease Control Rate (DCR)

  From treatment initiation to disease progression or last follow-up, assessed up to 24 months.

• Overall Survival (OS)

  From start of post-progression treatment to death or last follow-up, up to 48 months.

• Treatment-Related Adverse Events

  From the start of post-resistance treatment until 30 days after treatment discontinuation, assessed up to 24 months.

Study Arms (1)

Post-Resistance Advanced Breast Cancer Patients

This cohort includes patients with advanced or metastatic breast cancer who experienced disease progression after treatment with CDK4/6 inhibitors, PIK3CA inhibitors, trastuzumab deruxtecan (T-DXd), or other targeted therapies. All patients subsequently received further systemic therapy, including chemotherapy, endocrine therapy, targeted agents, or their combinations, based on physician discretion and routine clinical practice. This observational cohort will be analyzed to assess treatment patterns, clinical outcomes (e.g., progression-free survival and overall survival), and potential prognostic or predictive factors.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients with advanced breast cancer who developed resistance to targeted therapies and subsequently received systemic treatment in routine clinical practice. The study population includes diverse subtypes (HR+/HER2-, HER2+, TNBC) and reflects real-world treatment patterns in post-progression settings.

You may qualify if:

• Adults (≥18 years old) with histologically or cytologically confirmed advanced or metastatic breast cancer
• Received prior treatment with at least one of the following: CDK4/6 inhibitors, PIK3CA inhibitors, trastuzumab deruxtecan (T-DXd), or other targeted therapies
• Documented disease progression following prior targeted therapy
• Initiated a subsequent line of systemic therapy (chemotherapy, endocrine therapy, targeted therapy, or combination) after resistance
• Available clinical data including baseline characteristics and treatment details
• At least one follow-up evaluation after initiation of post-resistance therapy

You may not qualify if:

• Incomplete medical records or missing key clinical follow-up data
• Concurrent diagnosis of other active malignancies (except non-melanoma skin cancer or in situ cervical cancer)
• Known central nervous system disease requiring immediate local treatment (unless clinically stable)
• Poor general condition with an Eastern Cooperative Oncology Group (ECOG) performance status ≥2
• Life expectancy estimated to be less than 6 months based on clinical judgment

Sponsors & Collaborators

• Hunan Cancer Hospital: lead

Study Sites (1)

Hunan Cancer Hospital

Changsha, Hunan, 410013, China

RECRUITING

MeSH Terms

Conditions

Breast Neoplasms; Triple Negative Breast Neoplasms

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Central Study Contacts

Binliang Liu, M.D

CONTACT

+8617370789834; liubinliang_onco@163.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 9, 2025
• First Posted: July 18, 2025
• Study Start: January 1, 2023
• Primary Completion: December 30, 2025
• Study Completion (Estimated): June 1, 2026
• Last Updated: July 18, 2025

Record last verified: 2025-07

Locations

CN (1)