Durvalumab (MEDI4736) and Tremelimumab in Hormone Receptor-positive, Hypermutated Metastatic Breast Cancer Identified by Whole Exome Sequencing

Trial treatment should be administered on Day 1 of each cycle after all procedures/assessments have been completed as detailed on the Trial Flow Chart. Trial treatment may be administered up to 3 days before or after the scheduled Day 1 of each cycle due to administrative reasons. All trial treatments will be administered on an outpatient basis. Durvalumab 1500mg + tremelimumab 750 mg will be administered as a 60 minute each one IV infusion every 4 weeks. Sites should make every effort to target infusion timing to be as close to 60 minutes as possible. However, given the variability of infusion pumps from site to site.