Introduction: More than 150,000 women die worldwide every year of Triple-Negative Breast Cancer (TNBC). There are a range of treatment options, but no good way to match patients to their optimal treatment. For most newly diagnosed patients with early TNBC, the current standard of care is neoadjuvant chemo/immunotherapy before surgery, with patients who achieve a pathological complete response (pCR) having a better prognosis. We have developed a Functional Precision Medicine (FPM) test that uses a fresh biopsy, dissociates the cells, embeds them in a 3D hydrogel matrix, cultures them in a microfluidics device and tests them against a range of systemic therapies, while using a computer vision pipeline to measure responses to therapies ex vivo. Methods: We designed and conducted an observational multi-centre clinical trial to assess the feasibility of using our FPM assay in patients with newly diagnosed TNBC undergoing neoadjuvant therapy. Patients underwent an additional core needle biop