SIL204 May Enable Immune Targeting of KRAS Tumors in New Preclinical Data - Exclusive

The advance follows SIL204's progression into Phase 2/3 evaluation that started at Tel Aviv Sourasky Medical Center at the close of July.

Illustration of a pancreatic tumor surrounded by immune cells

(photo credit: Silexion spokesperson)

ByDANYA SAPERSTEIN

AUGUST 5, 2026 14:38

Updated: AUGUST 5, 2026 14:47

SIL204, under development by Israeli firm Silexion Therapeutics Corp., could allow the immune system to detect and strike KRAS-driven cancers, based on preclinical results published on Wednesday.

Alongside earlier company data, these results back SIL204's ability to counter three key tactics tumors use to dodge immune detection: increasing cancer cell visibility, restoring sensitivity to immune-triggered cell death, and lowering a checkpoint molecule that helps cells avoid immune monitoring.

The therapy employs small RNA molecules called siRNA to reduce expression of mutated KRAS genes, a primary driver of tumor growth in select cancer patients. KRAS mutations appear in about 90 percent of pancreatic cancers and 30-35 percent of lung adenocarcinomas.

Tests using human cancer cell lines for three distinct KRAS mutations in pancreatic and non-small cell lung cancer showed SIL204 produced notable rises in FAS expression, an immune death receptor that prompts programmed cell death. It also caused a clear drop in HLA-G, an immune checkpoint protein.

"These latest results build on and strengthen the immuno-oncology profile of SIL204 first shared in May. We see this profile as justification for testing SIL204 alongside anti-PD-(L)1 checkpoint inhibitors, especially in areas such as pancreatic cancer where such agents have shown modest single-agent results," said Silexion Chairman and CEO Ilan Hadar.

SIL204 Moves Forward with Trial Launch

The step occurs as researchers examine pairings of KRAS-focused therapies with checkpoint inhibitors.

Silexion moved SIL204 into Phase 2/3 clinical testing at the end of July after starting its initial trial at Tel Aviv Sourasky Medical Center. The study targets pancreatic cancer patients and, though it begins at this single site, is planned to grow to other centers across Israel, Germany, and additional nations.