NCT06774027 · University of California, San Francisco
Prospective Registry of ADC as First- and Second-line Treatment for Breast Cancer
(ENCORE)
What this study is about
Antibody-drug conjugates (ADCs) have demonstrated substantial improvement in time without the disease getting worse (PFS) and how long patients live (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.
View original scientific description
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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 criteria
- 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.
Where
- San Francisco, California
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Dec 18, 2025 · Source of record for eligibility and locations