Glembatumumab vedotin: Final Phase IIb data

Final data from the open-label, U.S. Phase IIb EMERGE trial in 122 breast cancer patients with >=5% of their tumor cells expressing GPNMB showed that CDX-011 non-significantly improved median OS (7.5 vs. 7.4 months, p=0.24) and PFS (2.1 vs. 2 months, p=0.38) vs. single agent chemotherapy of the investigator's choosing. CDX-011 led to an ORR of 16% vs. 14% for chemotherapy and a DCR of 57% vs. 53% for chemotherapy. Celldex said the trial was not powered to detect statistical significance. In patients with high GPNMB expression, CDX-011 led to a median OS of 10 months vs. 5.7 months for chemotherapy (p=0.18) and a median PFS of 2.7 months vs. 1.5 months for chemotherapy (p=0.14). In the subgroup, CDX-011 led to an ORR of 32% vs. 13% for chemotherapy and a DCR of 64% vs. 38% for chemotherapy.

Additionally, in a subgroup of patients with both triple-negative breast cancer (TNBC) and high GPNMB expression (expression in >=25% of tumor cells), CDX-011 led to a median OS of 10 months vs. 5.5 months for chemotherapy (p=0.003) and a median PFS of 3 months vs. 1.5 months for chemotherapy (p=0.008). In the subgroup, CDX-011 led to an ORR of 33% vs. 0% for chemotherapy and a DCR of 75% vs. 25% for chemotherapy. In patients with TNBC, CDX-011 led to a median OS of 6.9 months vs. 6.5 months for chemotherapy (p=0.3) and a median PFS of 2.3 months vs. 1.6 months for chemotherapy (p=0.43). In the subgroup, CDX-011 led to an ORR of 19% vs. 0% for chemotherapy and a DCR of 67% vs. 33% for chemotherapy. Additionally, in the 15 patients who initially received chemotherapy and subsequently crossed over to receive CDX-011 upon disease progression, median OS was 12.5 months vs. 5.4 months for patients who did not cross over. Data were presented at the San Antonio Breast Cancer Symposium. ...