Study Evaluating DNA Double-strand Breaks (DSBs) REpair Factors (POLQ, Shieldin Complex and 53BP1) Expression as Biomarker of PARP Inhibitor Resistance in Patients With Deleterious Germline Mutation in BRCA 1/2 and HER2-negative, Metastatic or Locally Advanced Breast Cancer.

Study Overview
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Brief Summary
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The purpose of this study is to assess whether expression of not only POLQ/Polθ, but also Shieldin complex and/or 53BP1 are correlated with primary and/or acquired resistance to PARPi (Poly(ADP-Ribose) Polymerases inhibitors) in a sub-population of locally advanced or metastatic breast cancer patients and vary regarding type and location of gBRCA1/2 mutations. This translational research program is composed of two multicentric, non-randomized prospective studies in patients with HER2-negative locally advanced or metastatic breast cancer: The main study concerns 80 patients eligible for PARPi (according to the investigators).PARPi treatments (talazoparib or olaparib) will be administered and dosed according to the standard of care administration. The sub-study concerns 40 patients in progression disease under PARPi alone. For each included patient in the main study or sub-study, tumor biopsy specimen and blood samples will be collected at different times during the study.

Official Title
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Prospective and Multicentric Study Evaluating DNA Double-strand Breaks (DSBs) REpair Factors (POLQ, Shieldin Complex and 53BP1) Expression as Biomarker of PARP Inhibitor Resistance in Patients With Deleterious Germline Mutation in BRCA 1/2 and HER2-negative, Metastatic or Locally Advanced Breast Cancer.

Conditions
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Breast Cancer

Intervention / Treatment
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* Other: Main study:
* Other: Sub-study:


Participation Criteria
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Eligibility Criteria
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MAIN STUDY INCLUSION CRITERIA: Women (or men) aged ≥ 18 years with histologically proven breast cancer Metastatic relapse or locally advanced breast cancer No-HER2 overexpression or amplification Triple-negative (defines as ER<1%, PR<1% and HER2-negative as per ASCO CAP guidelines) or hormone receptor positive (defines as ER and/or PR ≥ 1%) breast cancer Patients with metastases that can be biopsied except bone metastases. At baseline, if patients already have an archived biopsy from a secondary or a primary site (if stage IV) of their current disease, this material can be used for the study, provided that, it was collected within 3 months prior enrollment and a frozen and a FFPE sample are both available for research ECOG Performance Status ≤ 2 Patients must have measurable or evaluable disease according to RECIST v1.1 Patient with deleterious germline BRCA 1 and/or 2 mutation, eligible for PARP inhibitor therapy (olaparib or talazoparib), according each investigator Any number of prior lines therapy are allowed Current treatment with PARP inhibitor not yet started Women should be post-menopaused or willing to accept the use of an effective contraceptive regimen during the treatment period by PARP inhibitor Patient able to participate and willing to give informed consent prior performance of any study-related procedures and to comply with the study protocol Patient affiliated to a Social Health Insurance in France NON-INCLUSION CRITERIA: Abnormal coagulation contraindicating biopsy Bone metastases when this is the only site of biopsiable disease Patients with all target in a previously irradiated region, except if clear progression has been observed prior to study in at least one of them Patients with known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin or squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer Patients with known untreated CNS metastases and/or carcinomatous meningitis Patients with a known history of Human Immunodeficiency Virus (HIV) Patients with known active Hepatitis B or C Patients should not be on any other anti-cancer therapy (chemotherapy, endocrine therapy, immunotherapy, tailored therapy or alternative investigational therapy) Patient pregnant, or breast-feeding Any psychological, familial, geographic or social situation, according to the judgment of investigator, potentially preventing the provision of informed consent or compliance to study procedure Patient who has forfeited his/her freedom by administrative or legal award or who is under legal protection (curatorship and guardianship, protection of justice) SUB-STUDY INCLUSION CRITERIA: Women (or men) aged ≥ 18 years with histologically proven breast cancer Metastatic relapse or locally advanced breast cancer No-HER2 overexpression or amplification Triple-negative (defines as ER<1%, PR<1% and HER2-negative as per ASCO CAP guidelines) or hormone receptor positive (defines as ER and or PR ≥ 1%) breast cancer Patients with metastases that can be biopsied except bone metastases ECOG Performance Status ≤ 2 Patients, with deleterious germline BRCA 1 and/or 2, in progression under PARPi alone (talazoparib or olaparib) Patient able to participate and willing to give informed consent prior performance of any study-related procedures and to comply with the study protocol Patient affiliated to a Social Health Insurance in France NON-INCLUSION CRITERIA: Abnormal coagulation contraindicating biopsy Bone metastases when this is the only site of biopsiable disease Patient pregnant, or breast-feeding Patients with a known history of Human Immunodeficiency Virus (HIV) Patients with known active Hepatitis B or C Any psychological, familial, geographic or social situation, according to the judgment of investigator, potentially preventing the provision of informed consent or compliance to study procedure Patients already participating in the main REPARP study Patient who has forfeited his/her freedom by administrative or legal award or who is under legal protection (curatorship and guardianship, protection of justice)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Patients with breast cancer<br>Patients With Deleterious Germline Mutation in BRCA 1/2 and HER2-negative, Metastatic or Locally Advanced Breast Cancer. | Other: Main study:<br>* For each included patient, tumor biopsy specimen and blood samples will be collected at baseline visit (before the first dose of PARPi treatment). During the treatment period: blood samples will be scheduled every 8 weeks (i.e. 2 cycles). At the time of progression: tumor biopsy and blood samples will be collected.<br>Other: Sub-study:<br>* For each included patient, tumor biopsy specimen and blood samples will be collected as soon as possible after progression (before initiation of the post PARPi anti-tumoral treatment).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Main study: the primary endpoint is the Area under the Receiver Operating Characteristic Curve (ROC Curve) of POLQ expression to identify patients presenting progressive disease or death at 6 months under PARPi alone (primary resistance). | Progression will be determined using RECIST v1.1 criteria. | 6 months for each patient | 
| Sub-study: the primary end point is the rate of patients presenting loss of Shieldin complex and/or 53BP1. |  | 1 month for each patient | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Main study: Progression-Free Survival defined as the time from inclusion until progression according to RECIST v1.1 criteria or death from any cause, whichever occurs first. |  | 12 months for each patient | 
| Main study: Objective Response (i.e. complete or partial response) defined using RECIST v1.1 criteria. |  | 12 months for each patient | 
| Main study: Duration Of Response defined as the time from initial objective response until progression according to RECIST v1.1 criteria or death from any cause. |  | 12 months for each patient | 
| Sub-study: expression of the Shieldin complex and 53BP1. |  | 1 month for each patient | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Breast cancer, Germline BRCA mutation, PARP inhibitor, Biomarkers, POLQ, Polθ, Shieldin complex, 53BP1