Celldex Therapeutics announced positive results from its Phase 1/2 study of CDX-011, an antibody drug conjugate, being evaluated for the treatment of metastatic melanoma. Thirty-four patients were enrolled in the Phase 2 expansion portion of the multicenter, open-label study of CDX-011 in patients with unresectable Stage III/IV melanoma. The primary endpoint of overall response rate (ORR) in the cohort was achieved with an ORR of 15%; median progression free survival was 3.9 months. In the Phase 2 expansion study, CDX-011 was administered at the pre-defined maximum tolerated dose once every three weeks. A more frequent dosing schedule at maximum tolerated dose was evaluated in two additional, parallel dose-escalation arms in which patients received CDX-011 weekly (n=15) or twice every three weeks (n=6). The response rate was observed to be 20% and 33%, respectively.

CDX-011 consists of the potent cellular toxin monomethyl-auristatin E (MMAE) conjugated to a fully-human monoclonal antibody (CR011) to transmembrane glycoprotein NMB (GPNMB). The destruction of GPNMB-expressing cells, a novel glycoprotein expressed in over 80% of melanomas, may be involved in growth delay and reduction of a tumor’s metastatic potential. CDX-011 is designed to be stable in the bloodstream but to release MMAE upon internalization in GPNMB-expressing tumor cells, resulting in a targeted cell-killing effect.

For more information call (781) 433-0771 or visit www.celldextherapeutics.com.