Clinical data demonstrates safe administration of Pexa-Vec in patients with metastatic colorectal cancer

SillaJen, Inc., a private clinical-stage biotherapeutics company focused on the development of oncolytic immunotherapy products for cancer, today announced a publication of data demonstrating that in a Phase Ib trial of Pexa-Vec, patients received multiple bi-weekly doses of its lead product Pexa-Vec, representing the first report of multiple intravenous administrations of an oncolytic vaccinia. Importantly, no dose-limiting toxicities were reported, and the maximum tolerated dose (MTD) was not reached. The trial was conducted in patients with refractory, metastatic colorectal cancer, and the data were published in the journal Molecular Therapy. Dr. Young Suk Park of Samsung Medical Center, Seoul, Korea was the principal investigator on the study and co-author of the report.

"While we have reported dose-dependent antitumor activity in the past with Pexa-Vec, we believe that demonstrating feasibility of administering Pexa-Vec by multiple intravenous infusions broadens the tumor types that can be targeted with this novel oncolytic immunotherapy," stated Eun Sang Moon, chief executive officer of SillaJen. "The data published today show excellent tolerability despite multiple administrations indicating the drug's ability to be administered systemically at regular intervals which may allow the targeting of systemic disease more effectively."

In the Phase Ib trial of Pexa-Vec, 15 patients with treatment-refractory colorectal cancer were enrolled and were given intravenous administrations of Pexa-Vec every 14 days. Nine patients were given infusions at three escalating dose levels, and the cohort receiving the highest dose was then expanded to include an additional six patients given that an MTD was not reached. No treatment related serious adverse events were reported. Ten patients (67 percent) on the study had radiographically stable disease.

"Pexa-Vec has been shown to target and kill tumor cells through multiple mechanisms of action," stated Caroline Breitbach, Ph.D., vice president of clinical and translational research at SillaJen. "The data published today further strengthen the growing body of Pexa-Vec safety and mechanism of action data, particularly relating to systemic Pexa-Vec administration."