SillaJen Presents Data Demonstrating Pexa-Vec Synergy With Angiogenesis Inhibitors: A Collaboration With University of California, San Francisco (UCSF)

SAN FRANCISCO, April 20, 2015 /PRNewswire/ -- SillaJen, Inc., a private clinical-stage biotherapeutics company focused on the development of oncolytic immunotherapy products for cancer, today announced an oral and poster presentation of research at the Annual Meeting of the American Association for Cancer Research (AACR) demonstrating the synergy of a murine adapted version of its lead product candidate, Pexa-Vec (JX-594) with angiogenesis inhibitors.

Pexa-Vec is an oncolytic immunotherapy designed to 1) rapidly de-bulk tumors via tumor cell lysis, 2) activate an antivascular effect with rapid tumor vascular knockout, and 3) induce a durable immune response against tumors. Pexa-Vec was derived from vaccinia, which has been used for decades as a vaccine in healthy individuals, and was engineered to selectively target cancer cells. Pexa-Vec was also engineered to express GM-CSF, a white blood cell growth factor leading to the activation of a systemic immune response to kill tumor cells throughout the body. Pexa-Vec has been safely administered to over 300 patients and is currently in clinical development for the treatment of advanced liver cancer (hepatocellular carcinoma).

Research from an ongoing collaboration with the laboratory of Donald M. McDonald, M.D., Ph.D., professor, Department of Anatomy, the University of California San Francisco was presented in the form of both an oral and poster abstract presentation. Dr. McDonald presented a talk entitled "Synergy of oncolytic viruses and angiogenesis inhibitors" during the Angiogenesis Revisited Major Symposium session.

The poster presentation (Abstract #296), titled "Synergistic actions of oncolytic vaccinia virus and sunitinib on pancreatic neuroendocrine tumors in RIP-Tag2 mice" provides additional evidence supporting murine adapted Pexa-Vec (mpJX-594)-induced anti-vascular effects and demonstrates that these effects are enhanced upon combination with sunitinib, a small-molecule tyrosine kinase inhibitor.  In this study, mouse-adapted mpJX-594 was infused intravenously into RIP-Tag2 transgenic mice bearing pancreatic neuroendocrine tumors with and without oral administration of sunitinib. Treatment with mpJX-594 alone reduced tumor vascularity and induced widespread apoptosis in the tumors. When mp-JX-594 was given together with sunitinib, the amount of viral infection in tumors was increased compared to that of mpJX-594 alone. The reduction of tumor vascularity and amount of apoptosis were greater after both agents than after either of them given alone.

"These data continue to validate and support this important mechanism-of-action of Pexa-Vec," said Caroline Breitbach, Ph.D., vice president of clinical and translational research at SillaJen. "These findings indicate that Pexa-Vec derived oncolytic immunotherapy amplifies the anti-vascular and anti-tumor effects of sunitinib, providing rationale to combine these therapies in future clinical trials."

Pexa-Vec Clinical Development Program

Pexa-Vec is the most advanced product candidate from SillaJen's proprietary SOLVE (Selective Oncolytic Vaccinia Engineering) platform.  The vaccinia poxvirus strain backbone of Pexa-Vec has been used safely in millions of people as part of a worldwide vaccination program. This strain naturally targets cancer cells due to common genetic defects in cancer cells; Pexa-Vec was engineered to enhance this by deleting its thymidine kinase (TK) gene, thus making it dependent on the cellular TK expressed at persistently high levels in cancer cells. Pexa-Vec is also engineered to express the immunogenic GM-CSF protein. GM-CSF complements the cancer cell lysis of the product candidate, leading to a cascade of events resulting in tumor necrosis, tumor vasculature shutdown and sustained anti-tumoral immune attack.

About SillaJen

SillaJen, Inc. is a South Korean based biotechnology company headquartered in Seoul South Korea, with satellite offices in Busan, South Korea and San Francisco, CA.  The company is focused on the development and commercialization of Pexa-Vec an oncolytic immunotherapy product in the SOLVE platform for the treatment of advanced primary liver cancer. For more information about SillaJen, please visit

Media Contact:
Jennifer Williams
Cook Williams Communications, Inc.


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SOURCE SillaJen, Inc.

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