OncoMatch/Clinical Trials/NCT06525766
Adaptive Therapy With Capecitabine for Treatment of Metastatic ER Positive, HER2 Negative Breast Cancer
Is NCT06525766 recruiting? Yes, currently enrolling (Sep 2026). This Phase 2 trial studies Capecitabine for anatomic stage iv breast cancer ajcc v8.
Treatment: Capecitabine — This phase II trial evaluates the effect of capecitabine on tumor response using imaging and tumor markers to adjust dose (adaptive therapy) in patients with estrogen receptor (ER) positive, HER2 negative breast cancer that has spread from where it first started to other areas in the body (metastatic). Capecitabine is in a class of medications called antimetabolites. It is taken up by tumor cells and breaks down into fluorouracil, a substance that kills tumor cells. Adaptive therapy with capecitabine based on tumor burden response may slow or stop the growth of tumor cells in patients with metastatic ER positive, HER2 negative breast cancer.
Check if I qualifyExtracted eligibility criteria
Treatments studied
Chemotherapy
Cancer type
Breast Carcinoma
Biomarker criteria
Required: ESR1 expression (positive)
estrogen-receptor positive (ER+)
Required: HER2 (ERBB2) wild-type
HER2-negative overexpression or amplification negative
Disease stage
Required: Stage IV (other)
Metastatic disease required
metastatic breast cancer; Measurable disease. Bone only disease allowed if associated with soft tissue component that is measurable by Response Evaluation Criteria is Solid Tumors (RECIST) 1.1 criteria
Performance status
ECOG 0–2(Ambulatory, capable of self-care)
Prior therapy
Cannot have received: chemotherapy for metastatic breast cancer
Exception: Cohort 2 only: up to two cycles of capecitabine before joining the study
Prior chemotherapy or use of antibody drug conjugate in the metastatic setting
Cannot have received: antibody-drug conjugate for metastatic breast cancer
Exception: Cohort 2 only: up to two cycles of capecitabine before joining the study
Prior chemotherapy or use of antibody drug conjugate in the metastatic setting
Cannot have received: investigational agent for primary neoplasm
Receiving any other investigational agent which would be considered as a treatment for the primary neoplasm
Lab requirements
Blood counts
Hemoglobin ≥ 9.0 g/dL (no transfusions ≤ 14 days prior); ANC ≥ 1500/mm^3; Platelet count ≥ 100,000/mm^3
Kidney function
Calculated creatinine clearance ≥ 30 ml/min using the Cockcroft-Gault formula
Liver function
Total bilirubin ≤ 1.5 x ULN; ALT and AST ≤ 3 x ULN (≤ 5 x ULN for patients with liver involvement)
Hemoglobin ≥ 9.0 g/dL (obtained ≤ 14 days prior to registration), no transfusions allowed ≤ 14 days prior to registration; Absolute neutrophil count (ANC) ≥ 1500/mm^3 (obtained ≤ 14 days prior to registration); Platelet count ≥ 100,000/mm^3 (obtained ≤ 14 days prior to registration); Total bilirubin ≤ 1.5 x upper limit of normal (ULN) (obtained ≤ 14 days prior to registration); Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 3 x ULN (≤ 5 x ULN for patients with liver involvement) (obtained ≤ 14 days prior to registration); Calculated creatinine clearance ≥ 30 ml/min using the Cockcroft-Gault formula (obtained ≤ 14 days prior to registration)
Structured fields extracted by AI. May contain errors — verify against the official protocol.
US trial sites
- Mayo Clinic in Arizona · Scottsdale, Arizona
Showing up to 5 US sites.
See all sites on ClinicalTrials.gov →Frequently asked questions
Is NCT06525766 currently recruiting?
Yes, this trial is currently recruiting patients.
Are there prior therapy exclusions?
Yes. Prior chemotherapy for metastatic breast cancer, antibody-drug conjugate for metastatic breast cancer, investigational agent for primary neoplasm disqualifies patients from enrollment.
Does this trial require ESR1?
Yes, ESR1 expression is a required biomarker for enrollment.
Does this trial require ERBB2?
Yes, ERBB2 wild-type is a required biomarker for enrollment.
What disease stage is eligible?
Stage IV is required (metastatic disease required).
Could you qualify for this trial?
Enter your biomarker results to see how this trial's eligibility criteria match your specific cancer profile.
Check if I qualifyRelated pages