Prospective Registry of ADC as First- and Second-line Treatment for Breast Cancer
ENCORE: Multicenter ProspectivE Registry of Sequential ANtibody Drug COnjugates (ADCs) in HER2 Negative Metastatic BREast Cancer (MBC)
University of California, San Francisco
100 participants
Oct 8, 2025
OBSERVATIONAL
Conditions
Summary
Antibody-drug conjugates (ADCs) have demonstrated substantial improvement in progression free survival (PFS) and overall survival (OS) in phase III clinical trials in patients with metastatic triple negative breast cancer (mTNBC) and hormone receptor positive/HER2 negative (HR+/HER2-) metastatic breast cancer (MBC), offering an effective new treatment strategy. Several outstanding questions drive the decision to use ADC drugs clinically. This is a prospective, multi-site observational study of patients with metastatic breast cancer (mBC) who are being treated with FDA-approved antibody drug conjugates (ADCs) as part of routine care and aims to collect real-world data to evaluate the impact of ADC treatment as part of routine care.
Eligibility
Inclusion Criteria9
- Male or female patients aged 18 years or greater with ability to provide written informed consent for this prospective registry study.
- Estimated life expectancy of at least at 3 months per investigator assessment.
- Willingness to provide an archival tissue sample and blood samples (20cc research blood collection at several timepoints) for research purposes.
- Cohort-specific enrollment criteria:
- Cohort 1: Histologically documented HR+/HER2- MBC with plan to start an FDA-approved ADC as their first ADC per standard of care (SOC).
- Cohort 2: Histologically documented metastatic TNBC with plan to start an FDA-approved ADC as their first ADC per standard of care
- Cohort 3: Histologically documented HR+/HER2- MBC with plan to start an FDA-approved ADC as their second ADC per standard of care (ADC1 should be an approved ADC administered per SOC or as monotherapy in a clinical trial; no prior experimental ADCs allowed). Clinical data from the first ADC must be available for retrospective review.
- Cohort 4: Histologically documented metastatic TNBC with plan to start an FDA-approved ADC as their second ADC per standard of care (ADC1 should be an approved ADC administered per standard of care or as monotherapy in a clinical trial; no prior experimental ADCs allowed). Clinical data from the first ADC must be available for retrospective review.
- Measurable disease is not required for any cohort.
Exclusion Criteria3
- Prior receipt of an experimental ADC in the metastatic setting. Of note, patients who received an FDA-approved ADC as their first ADC (as monotherapy, not in combination) can participate in cohorts 3 or 4 prior to starting their second FDA-approved ADC per standard of care. Of note, for all cohorts, experimental therapies are not allowed as intervening therapies after starting ADC1. If a patient enrolls on a clinical trial of an experimental therapy after ADC1, they will be taken off study.
- Current participation in a clinical trial with an ADC.
- Contraindication to research phlebotomy to collect \~20cc blood at each research blood draw timepoint.
Interventions
Blood specimens will be collected during regular clinical visits for correlative and exploratory analysis
ADC given under usual care for the treatment of cancer
Prospective and retrospective medical chart reviews will be conducted to obtain data for analysis.
Locations(1)
View Full Details on ClinicalTrials.gov
For the most up-to-date information, visit the official listing.
NCT06774027