Tetrathiomolybdate

There are two parts to this study. It is a phase 1b followed by a randomized phase 2 study to assess whether adding 3 years of adjuvant tetrathiomolybdate (TM) to standard 6 months treatment of adjuvant capecitabine and pembrolizumab in high risk for relapse triple negative breast cancer. In the phase 1b part of the study, TM is added to adjuvant capecitabine and pembrolizumab in high risk for relapse triple negative breast cancer (RCB 2, 3, risk for relapse \>60% at 5 years) after completion of neoadjuvant chemo-immunotherapy and surgery to establish the safety of the combination. This will be followed by a randomized phase 2 clinical trial of adjuvant TM and capecitabine vs capecitabine alone. If pembrolizumab was administered in the neoadjuvant setting, it may be continued in the adjuvant setting per investigator discretion.