At the 32nd San Antonio Breast Cancer Symposium, Sunday, Celldex Therapeutics Inc. (CLDX) revealed positive results from a mid-stage study of its product candidate CDX-011 in advanced breast cancer.
CDX-011 is a fully-human monoclonal antibody-drug conjugate that targets GPNMB (glycoprotein NMB), also known as osteoactivin, a protein overexpressed on the surface of cancer cells, including melanoma, breast cancer and gliomas. CDX-011 utilizes fully human monoclonal antibodies to deliver the potent cellular toxin, MMAE, directly to tumor cells by targeting GPNMB.
In the phase II study, the safety of the maximum tolerated dose was confirmed in breast cancer patients and the primary activity endpoint, which called for at least 5 of 25 (20%) patients to be progression-free at twelve weeks, has also been met. The study enrolled a total of 34 locally advanced or metastatic breast cancer patients who were heavily pre-treated.
The median progression-free survival, or median PFS, in all patients was 9.1 weeks, but in patients whose tumors expressed GPNMB, median PFS was 18.3 weeks, compared to median PFS of 5.9 weeks for patients whose tumors did not express GPNMB.
According to the company, in patients with *triple negative disease, 5 of 7 (71%) analyzed samples expressed GPNMB, 7 of 9 (78%) evaluable patients had tumor shrinkage, and the median PFS for these patients was 17.9 weeks. (* triple negative disease means advanced, refractory and heavily pre-treated breast cancers). In triple-negative disease, treatment options are relatively limited due to lack of hormone receptor or HER2-neu expression.
Celldex is planning expanded phase II trial of CDX-011 focused on patients with tumors expressing GPNMB.
The company has three other programs currently under clinical evaluation for the therapy of cancer - CDX-110, CDX-1307 and CDX-1401.
CDX-110 is in phase II development for the treatment of glioblastoma multiforme and CDX-1401 is in phase 1 development for the treatment of cancers known to express NY-ESO-1, including cancers of the bladder, breast, ovary, non-small cell lung cancer, myeloma, sarcoma and melanoma.
CDX-110 is being developed under a license and development agreement with Pfizer Inc. (PFE). The FDA has granted orphan drug designation for CDX-110 for the treatment of EGFRvIII expressing glioblastoma multiforme as well as fast track designation.
Celldex is planning the initiation of a phase II study of CDX-1307 in patients with newly diagnosed bladder cancer in the first quarter of 2010.
CLDX has traded in the range of $4.16-$14.19 in the past twelve months. The stock closed Friday's trade at $4.49, down 0.44%.
For comments and feedback contact: editorial@rttnews.com
May 01, 2026 15:54 ET Central banks dominated the economics news flow this week with almost all major ones announcing their latest policy decisions and many boosted expectations for a rate hike in June. In other news, several countries released the preliminary data for first quarter economic growth. In the U.S., comments by Fed Chair Jerome Powell were also in focus as his term ends this month.