METRIC: A randomized international study of the antibody-drug conjugate glembatumumab vedotin (GV or CDX-011) in patients (pts) with metastatic gpNMB-overexpressing triple-negative breast cancer (TNBC).

TPS1110 Background: The internalizable transmembrane glycoprotein NMB (gpNMB) is overexpressed in 20% of BC, including 40% of TNBC (Yardley JCO, in press), where it is a poor prognostic marker (Rose CCR 2010). gpNMB enhances tumor invasion and metastasis and promotes angiogenesis in preclinical models. GV is a novel antibody drug conjugate targeting the potent cytotoxin monomethylauristatin E (MMAE) to gpNMB+ tumor cells. In a Phase I/II study (Bendell JCO, 2014) and the Phase II “EMERGE” study (Yardley JCO, in press), GV demonstrated promising activity, particularly in pts with TNBC and gpNMB overexpression, and was well-tolerated (treatment related toxicities: rash, neutropenia and neuropathy). In subset analyses, for GV vs. “investigator’s choice” (IC) single-agent chemotherapy, objective response rate (ORR) was 30% (7/23) vs. 9% (1/11) in pts with gpNMB overexpression (in ≥ 25% of tumor epithelium); 18% (5/28) vs. 0% (0/11) in TNBC; and 40% (4/10) vs. 0% (0/6) in gpNMB-overexpressing TNBC, with appare...