FUnctional selection of advanced breast cancer patients for Talazoparib treatment Using the REpair Capacity (RECAP) test:The FUTURE trial

• Age ≥18 years
• WHO performance status 0-2
• Locally advanced breast cancer without options for treatment with curative intent or metastatic breast cancer
• Objective progressive disease (PD) according to RECIST within 4 months prior to study entry
• The breast cancer must be high grade (Bloom & Richardson grade 3) ER positive (>10%) and HER2 negative primary breast cancer or triple negative (ER<10%, PR<10% and HER2 negative). The Bloom & Richardson grading is always based on the primary tumor. The receptor status can be based on the primary tumor or a metastatic lesion whichever comes latest. Patients with breast cancer and a known BRCA1 and/or BRCA2 germline or somatic mutation are eligible independent of the Bloom & Richardson grading and receptor status.
• The site of the metastatic lesion (or primary tumor in case it is still in situ) should be easily amendable for biopsy. NB lung metastases (high risk of hemato/pneumo-thorax) and bone metastases (not suitable for RECAP test because calcifications interfere with experimental procedures) are excluded. The local guidelines will be used for stopping and restarting of anticoagulation. Bilirubin <1.5 ULN (except elevated bilirubin due to Gilbert’s disease or a similar syndrome involving slow conjugation of bilirubin) and both AST and ALT <5x ULN in case a liver biopsy is planned.
• The tumor must be HRD, defined as HRD identified by the RECAP test determined just before the start of potential Talazoparib treatment within this study (also in case a proven germline BRCA1/2 mutation is present).
• Maximum of four prior lines of chemotherapy for advanced disease; Patients who received platinum compounds are eligible if they have had at least a progression free interval of four months.
• Measureable or evaluable disease according to RECIST 1.1 criteria (appendix 2)
• Life expectancy ≥ 3 months
• Hemoglobin ≥ 10 g/dL (6,2 mmol/L) and ANC of ≥ 1.5 x 109 /L
• Platelets >100 x 10e9/L
• Hepatic function as defined by total serum bilirubin ≤ 1. 5 x ULN (except elevated bilirubin due to Gilbert’s disease or a similar syndrome involving slow conjugation of bilirubin), ASAT and ALAT < 3 x ULN or <5 x ULN in case of liver metastasis
• Adequate renal function as defined by either serum creatinine ≤ 1.5 x ULN or creatinine clearance ≥ 50 mL/min (by Cockcroft-Gault formula)
• Negative pregnancy test (urine/serum) for female patients with childbearing potential
• Written informed consent

• Any psychological condition potentially hampering compliance with the study protocol
• Any treatment with investigational antitumor drugs within 28 days prior to receiving the first dose of investigational treatment; or within 21 days for standard chemotherapy; or within 14 days for weekly scheduled chemotherapeutic regimens or endocrine therapy
• Radiotherapy within the last four weeks prior to receiving the first dose of investigational treatment; except 1 or 2 x 8 Gy for pain palliation, then seven days interval after the last radiation should be maintained
• Known persistent (>4 weeks) ≥ Grade 2 toxicity from prior cancer therapy (except for alopecia grade 2)
• Symptomatic brain or leptomeningeal metastases. Patients completely free of symptoms and without corticosteroids for at least four weeks after adequate treatment by resection and/or irradiation could be eligible (consult PI).
• Women who have a positive pregnancy test (urine/serum) and/or who are breastfeeding;
• Unreliable contraceptive methods. Women and men enrolled in this trial must agree to use a reliable contraceptive method throughout the study (adequate contraceptive methods are: intra-uterine devices or systems, condom or other barrier contraceptive measures, sterilization and true abstinence)
• Concomitant use of P-gp inhibitors or inducers or BCRP inhibitors (see Appendix A)
• Any known history of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML)
• Uncontrolled infectious disease (such as Human Immunodeficiency Virus HIV-1 or HIV-2 infection) or known active hepatitis B or C
• Recent myocardial infarction (< six months) or unstable angina