A phase II study of copper-depletion using tetrathiomolybdate (TM) in patients (pts) with breast cancer (BC) at high risk for recurrence: Updated results.

2557Background: The tumor microenvironment (TME) plays a critical role in the spread of tumors. Bone marrow derived VEGFR2+endothelial progenitor cells (EPCs) and copper-dependent lysyl oxidase (LOX) are key in tumor progression. We hypothesized TM-associated copper depletion inhibits tumor metastases by reducing the number of EPCs and other copper dependent (CD) processes in the pre-metastatic niche. These results are an update with longer follow-up. Methods: Phase II study of BC pts at high risk for recurrence, defined as node+ triple negative (TNBC), stage 3 and 4 with no evidence of disease (NED) were enrolled on a trial of CD with TM. Ceruloplasmin (Cp) levels were maintained between 8-16 mg/dl for two years with an extension phase or until relapse. The primary endpoint was change in EPCs measured by flow cytometry before and during treatment. Secondary endpoints included tolerability, safety, PFS and LOXL-2 levels. Results: 75 pts received 2650 cycles of TM on primary and extension study. The median...