The study will enroll patients with Her2 negative (negative on immunohistochemistry or nonamplified by immunofluorescence in situ hybridization) metastatic breast cancer. Cohorts will enroll according to patient hormone receptor status as hormone receptor-positive or triple-negative. In Part 2, the trial will enroll six patients with triple-negative breast cancer and six patients with ER and/or PR receptor-positive breast cancer. Patients diagnosed with metastatic disease upfront or after a variable interval from completion of definitive therapy for local or locally advanced breast cancer will be eligible.~Patients with triple-negative metastatic breast cancer will be offered to participate in the trial at the time of diagnosis. Patients with hormone receptor-positive disease will be offered the option to participate in the study when they have exhausted endocrine monotherapy or endocrine therapeutic combinatorial options. Blood will be collected, and a biopsy will be performed prior to starting the first systemic therapy (triple-negative) or first chemotherapy (hormone receptor-positive). If enough tumor is collected, the patient will be deemed eligible for the trial. Malignant tissue collected from this biopsy will be used for genomic sequencing and for the development of organoid models for drug screening. Drugs selected for sensitivity testing will be guided by the results of the genome analysis and NCCN guidelines. Following tissue acquisition, the patient will begin therapy as selected by the treating physician. This first-line of on study therapy, either standard-of-care or investigational in the context of another existing active clinical trial, will be defined as the first uninformed line of therapy.~The results from the drug screening and mutation testing will be summarized and returned to the treating physicianbefore the assignment of on study, second-line therapy. Before and after returning results, the treating physician will be administered a survey to assess the potential effect that the precision medicine results have on the selection of the following line of therapy. If a patient begins a therapy that was recommended by the precision medicine results, the therapy will be defined as the informed line of therapy.~Patient response will be tracked for up to two uninformed lines of therapy. The first line of therapy started after the biopsy will count as the first uniformed line. If a patient does not begin an informed line of therapy after two lines of uninformed therapy they will be taken off study. Response and time of progression will be recorded on both informed and uninformed lines of therapy.~The trial will open to enrollment in two stages. Stage One will enroll three patients to assess preliminary program feasibility and to optimize the genomics pipeline and time frames. After enrollment of the first three patients, enrollment will be put on hold. Upon return of results to the treating physicians, the genomics pipeline and time frames will be evaluated. If necessary, the process will be amended to maximize pipeline efficiency and decrease the interval of time between tumor tissue acquisition and the return of results.~Stage Two will enroll 12 additional patients to further evaluate on a larger scale our functional precision oncology program in metastatic breast cancer.
This is a pilot study to assess the feasibility of comprehensive genomic characterization and drug screening in metastatic breast cancer. The trial will seek to provide personalized genomic and drug sensitivity information to eligible patients with metastatic breast cancer prior to disease progression on standard treatment. The trial will also explore how these results influence physician selection of next-line therapy.