Celldex Therapeutics has initiated a Phase IIb study of CDX-011, an antibody drug conjugate for the treatment of patients with advanced breast cancer.

The randomised, controlled and multi-centre trial will enroll 120 patients with heavily pre-treated, glycoprotein NMB-expressing advanced breast cancer, who are unlikely to benefit from other approved therapies.

Patients will be randomised in 2:1 ratio to receive either CDX-011 or single-agent investigator’s choice chemotherapy. The study endpoints will be progression-free survival, overall survival and response rate.

The study will be conducted in about 25 community and academy sites across the US, and the results are expected to be available in fourth quarter of 2011.

CDX-011 has received US Food and Drug Administration fast-track designation for this indication in May 2010.