Celldex Therapeutics reports mature data from CDX-011 Phase 1/2 study in advanced breast cancer

Celldex Therapeutics, Inc. (NASDAQ: CLDX) today announced that mature results from a Phase 1/2 study evaluating CDX-011 in advanced stage breast cancer patients were presented at the 46th Annual Meeting of the American Society of Clinical Oncology (ASCO). CDX-011 is an experimental antibody-drug conjugate (ADC) directed against glycoprotein NMB (GPNMB) and linked to a potent cancer cell-killing drug, monomethyl-auristatin E (MMAE).

“A subset analysis using a newly optimized diagnostic assay for GPNMB showed that patients with strong stromal or tumor cell expression of GPNMB may be most likely to respond to CDX-011.”

Mature data from this study of CDX-011 show a progression free survival (PFS) rate at 12 weeks of 35% of patients, which is a positive outcome for a heavily treated advanced breast cancer population with very limited treatment options. "The results in triple negative disease are especially encouraging," said Anthony Marucci, President and Chief Executive Officer of Celldex Therapeutics. "A subset analysis using a newly optimized diagnostic assay for GPNMB showed that patients with strong stromal or tumor cell expression of GPNMB may be most likely to respond to CDX-011."

"A reliable and marketable assay to detect a target antigen is critical in the development of any targeted therapy," said Tom Davis, M.D., Chief Medical Officer of Celldex Therapeutics. "We are confident that we can use our GPNMB assay to identify target expression patterns and levels in breast cancer to allow appropriate patient selection in our next study. A Phase 2b trial in advanced, refractory breast cancer is planned, which will select patients on the basis of significant GPNMB expression."

The trial, planned for initiation in Q3-2010, is a Phase 2, randomized, multi-center, controlled trial that will enroll 120 patients with heavily pre-treated, advanced breast cancer who are refractory/resistant to all approved therapies and whose tumors are confirmed to express significant levels of GPNMB via a validated, centralized diagnostic assay. It is anticipated that a significant portion of the enrolled patients will be triple-negative, since GPNMB is frequently expressed in this population. Patients will be randomized (2:1) to receive either CDX-011 or single-agent "Investigator's Choice" chemotherapy. Activity endpoints will include response rate and PFS. The study will be conducted in approximately 25 academic and community sites across the U.S.