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OncoMatch/Clinical Trials/NCT04965766

Patritumab Deruxtecan (U3-1402) in Unresectable Locally Advanced or Metastatic Breast Cancer

Is NCT04965766 recruiting? Yes, currently enrolling (May 2026). This Phase 2 trial studies U3-1402 for metastatic breast cancer.

Phase 2RecruitingGustave Roussy, Cancer Campus, Grand ParisNCT04965766Data as of May 2026

Treatment: U3-1402This study aims to evaluate the efficacy and safety of U3-1402 in participants with advanced breast cancer (ABC). Participants have to be hormone-receptor positive (HR+) and have to be resistant to endocrine therapy and cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors. Participants may have received multiple lines of endocrine therapy with or without targeted therapies and must have received only one line of chemotherapy for ABC. Moreover, the immune effects, the predictors of resistance and response to treatment, the effect of the chemotherapy on deoxyribonucleic acid (DNA) replication will be assessed and will help identify the subgroups that will mostly benefit from the treatment. The pharmacokinetics of the product and the anti-drug antibody (ADA) will be also evaluated. A total of 99 participants are planned to be treated in the study. Participants will receive, every three weeks, a dose of U3-1402 equivalent to 5.6 mg/kg of body weight until progression or until unacceptable toxicity. Tumor evaluation will be performed every six weeks by the mean of a computed tomography for the thorax, abdomen and pelvis (TAP CT-scan) or a magnetic resonance imaging (MRI). Brain and/or bone CT scans will be also performed throughout the study for participants with brain and/or bone metastasis. A PET scan combined with contrast enhanced CT scan can replace all the above-mentioned imaging if performed at baseline considering that the same imaging technique should be used throughout the study. The safety of the product will be assessed at each cycle, through complete clinical exams, biological tests, electrocardiograms (ECGs), cardiac echographies (ECHOs) and through the collection of ongoing toxicities or adverse events.

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Extracted eligibility criteria

Cancer type

Breast Carcinoma

Biomarker criteria

Required: HER2 (ERBB2) wild-type

HER2 negative

Required: ESR1 positive

hormone receptor positive (HR+)

Required: PR (PGR) positive

hormone receptor positive (HR+)

Disease stage

Metastatic disease required

Performance status

ECOG 0–1(Restricted strenuous activity)

Prior therapy

Max 1 prior line
Min 1 prior line

Must have received: chemotherapy — advanced/metastatic

must have received one line of chemotherapy for Advanced breast cancer (ABC), but not more than one line

Must have received: CDK4/6 inhibitor — combined with endocrine therapy

documented evidence of tumor progression on or after cyclin dependent kinase 4/6 (CDK 4/ 6) inhibitor combined with endocrine therapy

Cannot have received: anti-HER3 antibody

Prior treatment with an anti-HER3 antibody

Cannot have received: ADC containing an exatecan derivative that is a topoisomerase I inhibitor

ADC containing an exatecan derivative that is a topoisomerase I inhibitor

Lab requirements

Blood counts

adequate bone marrow reserve and organ function, based on local laboratory data within 14 days prior to Cycle 1, Day 1

Kidney function

adequate bone marrow reserve and organ function, based on local laboratory data within 14 days prior to Cycle 1, Day 1

Liver function

Have normal transaminase values, or, if liver metastases are present, abnormal transaminases with a result of AST/ALT <3 × ULN, which are not attributable to HBV or HCV infection

Cardiac function

Corrected QT interval higher than 470 ms for females and 450 ms for males according to Fridericia's formula (QTcF) and assessed based on triplicate ECGs, approximately 1 minute apart; Left ventricular ejection fraction (LVEF) less than 50% by either ECHO or cardiac MRI or multigated acquisition scan (MUGA); Resting systolic blood pressure higher than 140 mmHg or diastolic blood pressure higher than 90 mmHg; Myocardial infarction within six months; Symptomatic congestive heart failure (NYHA Classes 2 to 4 within 28 days before treatment); Uncontrolled angina pectoris within six months; Cardiac arrhythmia requiring antiarrhythmic treatment

adequate bone marrow reserve and organ function, based on local laboratory data within 14 days prior to Cycle 1, Day 1; cardiac criteria as listed in exclusion criteria

Structured fields extracted by AI. May contain errors — verify against the official protocol.

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