CDX-011 Shows Promise in Phase 2 Study in Advanced Breast Cancer

Celldex Therapeutics announced final results from the Company's randomized Phase 2b EMERGE study of CDX-011 in patients with glycoprotein NMB (GPNMB)-expressing, advanced, heavily pretreated breast cancer. CDX-011 is an antibody-drug conjugate that targets and binds to GPNMB, a specific protein that is expressed in breast cancer which promotes the migration, invasion and metastasis of the disease.

A total of 122 patients were treated on the study, with 81 patients randomized to the CDX-011 arm and 41 patients to the investigator's choice (IC) single-agent chemotherapy arm, of which 15 later crossed over to receive CDX-011. In total, 81 CDX-011 patients (including cross overs) and 36 IC patients had on-study radiographic assessments and were evaluable for response. Nearly all patients had Stage IV, or metastatic, disease. Patients on the CDX-011 arm received a median of six prior courses of therapy and patients on the IC arm received a median of five prior courses of therapy.

Treatment of patients with both triple negative breast cancer and high GPNMB expression showed high overall response rates (ORR) for the CDX-011 arm (CDX-011 ORR of 33% vs. 0% in the IC arm) and an overall survival and progression free survival (PFS) benefit for CDX-011 that reached statistical significance (CDX-011 median survival of 10 months vs IC of 5.5 months; P=0.003); (CDX-011 median PFS of 3 months vs. IC of 1.5 months; P=0.008). In patients with high GPNMB expression, a high response rate was observed in the CDX-011 arm (CDX-011 ORR of 32% vs. IC of 13%) and a trend of improvement in overall survival and PFS was demonstrated for the CDX-011 arm (CDX-011 median survival of 10 months vs. IC of 5.7 months; P=0.18); (CDX-011 median PFS of 2.7 months vs. IC of 1.5 months; P=0.14). Patients receiving IC alone who crossed over to receive CDX-011 upon disease progression appeared to represent the better outcomes in the control arm, with a median survival of 12.5 months, as compared to those who did not cross over, with a median of 5.4 months.

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