Part A - Inclusion and exclusion criteria to be fulfilled both prior to study enrolment and prior to commencement of study drug  Inclusion Criteria:  Age >= 21 years. Histological confirmed breast carcinoma of any subtype (any estrogen receptor, progesterone receptor and HER2 receptor status) ECOG 0-1. At least 1 tumour lesion (primary or metastatic) amenable to fresh biopsy At least 1 measurable tumour lesions based on RECIST 1.1 criteria Estimated life expectancy of at least 12 weeks. Has documented progressive disease from last line of therapy. Has received at least 1 line of palliative systemic therapy Expected adequate organ function (bone marrow, hepatic, renal) after recovering from treatment-induced acute toxicities at the time of study treatment. Signed informed consent from patient or legal representative. Able to comply with study-related procedures.  Exclusion Criteria:  Patients will be excluded from the study for any of the following reasons:  Pregnancy. Breast feeding. Serious concomitant disorders that would compromise the safety of the patient or compromise the patient's ability to complete the study, at the discretion of the investigator. Active bleeding disorder or bleeding site. Second primary malignancy that is clinically detectable at the time of consideration for study enrollment. History of significant neurological or mental disorder, including seizures or dementia.  Part B - Additional inclusion and exclusion criteria to be fulfilled prior to commencement of study drug  Inclusion criteria  Patients may be included in the study only if they meet all of the following criteria:  • Adequate organ function including the following:  Bone marrow:  Absolute neutrophil (segmented and bands) count (ANC) >= 1.5 x 109/L Platelets >= 100 x 109/L Hemoglobin >= 8 x 109/L  Hepatic:  Bilirubin <= 1.5 x upper limit of normal (ULN), ALT or AST <= 2.5x ULN, (or <=5 X with liver metastases)  Renal:  - Creatinine <= 1.5x ULN  Exclusion criteria  Patients will be excluded from the study for any of the following reasons:  Treatment within the last 30 days with any investigational drug. Concurrent administration of any other tumour therapy, including cytotoxic chemotherapy, hormonal therapy, and immunotherapy at time of commencement of study drug. Major surgery within 28 days of study drug administration. Active infection that in the opinion of the investigator would compromise the patient's ability to tolerate therapy. Non-healing wound. Poorly controlled diabetes mellitus. Symptomatic brain metastasis. Contraindication to receiving anti-cancer therapy within drug screening panel (e.g., poorly controlled diabetes mellitus for alpelisib, left ventricular ejection fraction of <50% for trastuzumab-emtansine) Received more than 2 lines of empirical therapy between tumor biopsy for organoids growth and commencement on QPOP-directed study treatment (including endocrine therapy, chemotherapy, targeted therapy or immunotherapy) Biopsy for organoids growth performed more than 12 months from time of study drug commencement Has not recovered from acute toxicities from prior anti-cancer therapy