Q-CROC-03: A prospective biopsy driven clinical trial to study the mechanisms of resistance to chemotherapy in triple-negative breast cancer patients

TPS1139 Background: Resistance to chemotherapy or targeted agents is the cause of death in most patients dying of breast cancer and one of the major challenges presently faced by oncologists. In triple negative breast cancers (TNBCs), drug resistance emerges quicker than in other breast cancer subtypes and contributes to the poor prognosis seen in these patients. The lack of targeted therapies to treat TNBC highlights the important need to better understand the molecular mechanisms contributing to chemotherapy resistance in order to develop new therapeutic strategies. However, the difficulty in obtaining tissue samples from drug resistant tumors has been one of the limiting factors in this field of study. Methods: We have designed a prospective phase II clinical trial where paired biopsies are collected from chemotherapy resistant TNBCs (NCT01276899). Four needle core biopsies are collected before the initiation of treatment and 2 weeks before surgery or at the time of progression in the neoadjuvant and metastatic settings respectively. Metastatic sites eligible for biopsy include liver, lung, skin and lymph nodes. This study is presently recruiting at 5 major health centers in Quebec and will soon open in the USA. We have currently enrolled 13 patients in the neoadjuvant setting and 2 metastatic patients. Major challenges in patient enrolment will be discussed. We have standardized the methods of collection and processing of tissue and blood specimens to ensure their molecular integrity and compatibility with different genomic and proteomic molecular platforms. Analysis of tumor cellularity has been incorporated into our quality control and we have optimized the extraction of nucleic acids to obtain high yields and optimal quality. Paired biopsies will undergo Next Gen Sequencing, flow sorted aCGH analysis, gene expression and miRNA profiling as well as phosphoproteomic profiling using reverse phase protein arrays. Collection of clinical data will allow molecular profiling data to be linked to clinical response data so as to determine DNA, RNA and protein factors correlated with tumor resistance to chemotherapy.