Celldex Therapeutics, Inc. Announces Updated EGFRvIII Vaccine Data in Glioblastoma Multiforme Presented at American Society of Clinical Oncology Annual Meeting

PHILLIPSBURG, N.J., June 3 /PRNewswire/ -- Celldex Therapeutics announced today that Dr. John Sampson of Duke University Medical Center presented data at the 43rd Annual Meeting of the American Society of Clinical Oncology (ASCO), which included updated data from the Phase 2 ACTIVATE trial and ACT II continuation study of CDX-110, an immunotherapy that targets the tumor specific molecule EGFRvIII, in patients with newly diagnosed glioblastoma multiforme (GBM) that are EGFRvIII positive. The ACTIVATE study currently shows a median survival time of 126.1 weeks, or almost 2.5 years, as well as a median time-to-progression of 64.5 weeks (p=0.0001) versus the historical control’s median of 28.52 weeks. ACT II has not reached median time-to- progression or survival, but preliminary findings indicate that chemotherapy and CDX-110 can be administered concurrently without diminishing the induced immune responses.

In the ACTIVATE trial, 23 patients with newly diagnosed glioblastoma who tested positive for EGFRvIII received radiation and temozolomide (TMZ) (75 mg/m2) concurrently, followed by vaccination with CDX-110. The current median survival data of 126.1 weeks compares favorably with the published results of Gliadel (59.6 weeks, Westphal et al, 2003) and Temodar (58.4 weeks, Stupp et al, NEJM 2005).

In ACT II, the ACTIVATE continuation study, 14 patients received the same concurrent radiation and TMZ, but received their vaccination on day 21 of repetitive 28-day TMZ cycles (200 mg/m2). These interim results show that EGFRvIII-specific CD3+CD8+gamma-IFN producing T-cells induced by CDX-110 vaccination do not appear to be diminished during cycles of concurrently administered TMZ. Both chemotherapy and CDX-110 can be delivered concurrently without negating the effects of the immunotherapy. TMZ-induced lymphopenia may prove to be synergistic with a peptide vaccine like CDX-110.

“CDX-110 has the potential to be a breakthrough treatment for patients with glioblastoma,” said Thomas Davis, M.D., Chief Medical Officer of Celldex Therapeutics. “These updated clinical data provided at ASCO revealed two significant findings: a truly significant median survival figure from the open-label Phase 2a trial that more than doubles that observed through the use of two FDA-approved products, and data demonstrating that giving appropriately-timed chemotherapy can enhance immune responses from the CDX-110 vaccine. We recently initiated and are currently enrolling our Phase 2/3 ACT III clinical trial, which will evaluate CDX-110 in 90 patients at over 20 brain tumor centers across North America.”

About CDX-110

CDX-110 is an investigational immunotherapy that targets the tumor specific molecule EGFRvIII, a functional variant of the epidermal growth factor receptor (EGFR), which is a protein that has been well validated as a target for cancer therapy. This particular variant, EGFRvIII, was discovered in a collaborative effort between Dr. Bert Vogelstein and Dr Albert Wong at Johns Hopkins University and Dr. Darell Bigner at Duke University. Unlike EGFR, EGFRvIII is not present in normal tissues, suggesting this target will enable the development of a tumor-specific therapy for cancer patients. Furthermore, EGFRvIII is a transforming oncogene that can directly contribute to cancer cell growth. While originally discovered in Glioblastoma Multiforme (GBM), the most common and aggressive form of brain cancer, the expression of EGFRvIII has also been observed in various other cancers such as breast, ovarian, metastatic prostate, colorectal, and head & neck cancers. Celldex has exclusive rights to EGFRvIII vaccines and is pursuing the development of CDX-110 for GBM therapy, as well as in other cancers through additional clinical studies.

About Celldex Therapeutics, Inc.

Celldex Therapeutics, Inc. is a biotechnology company focused on developing therapeutic vaccines that target and stimulate the body’s immune system for the treatment of cancer, infectious and autoimmune diseases. Celldex has three product candidates already in or about to enter clinical development targeting multiple cancers and Hepatitis B. Four additional product candidates are in preclinical development for cancer and autoimmune disease. Celldex’s proprietary technology platform uses fully human monoclonal antibodies administered directly to patients to target and stimulate dendritic cells -- key cells within the immune system. Celldex was formed in 2004 as a spin-out from Medarex, Inc. The Company is headquartered in Phillipsburg, New Jersey. For more information, please visit the website: http://www.celldextherapeutics.com .

Celldex Therapeutics

CONTACT: Robert Burns, Chief Executive Officer, +1-90-454-7120, or ThomasDavis, Chief Medical Officer, +1-908-454-7120, both of CelldexTherapeutics, Inc.; or Dan Budwick of BMC Communications, +1-212-477-9007x14, for Celldex Therapeutics

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