SillaJen Surges 14% on Publication of Platform Research in International Journal

SillaJen (215600.KQ), a South Korean oncolytic virus developer, surged 14% after its next-generation platform technology "SJ-650" research results were published in an international academic journal.

As of June 25, SillaJen's share price stood at 3,965 won on the Korea Exchange, up 485 won (+13.94%) from the previous closing price. The rally is attributed to the publication of research results on SillaJen's drug platform SJ-650 in *Molecular Therapy*, a journal specializing in cell and gene therapy.

SillaJen said the study demonstrated SJ-650's innovative mechanism capable of targeting cancer cells that have spread systemically through repeated intravenous administration. Conventional oncolytic virus therapies had been limited by the need for direct intratumoral injection, and SJ-650 offers a potential breakthrough to overcome this constraint.

Oncolytic virus therapies administered intravenously have traditionally been vulnerable to elimination by the complement system and other immune defenses before reaching tumor tissue. To address this problem, SJ-650 was engineered to express CD55, a complement regulatory protein, on the virus surface to evade immune clearance, SillaJen explained.

According to the study, conducted jointly with a research team led by Professor Lee Dong-sup of Seoul National University's College of Medicine, SJ-650 maintained higher survival rates than conventional oncolytic virus therapies even in the presence of neutralizing antibodies. SJ-650 that entered tumor tissue via the bloodstream demonstrated high efficacy, killing most tumor cells within 24 hours of administration.

SillaJen also reported that in metastatic cancer animal model studies, SJ-650 reduced overall tumor volume by more than 90% and showed effects in suppressing metastasis and extending survival. Meanwhile, no significant cell death was observed in normal tissue, and no signs of systemic toxicity appeared even after more than 20 repeated administrations, confirming a strong safety profile.

"SJ-650 demonstrated reproducible evasion of neutralizing antibodies even in serum experiments from actual patients carrying vaccinia virus antibodies," a SillaJen official said. "This represents a preemptive acquisition of human-relevance data, which the U.S. Food and Drug Administration has recently emphasized as a key indicator when approving investigational new drug applications. This is expected to serve as critical evidence in the global clinical approval process going forward."