Scribe Therapeutics ASGCT 2026 Data: ELXR Epigenetic Silencer and XE Editor Achieve Saturating Liver Editing With Zero Off-Target Effects in Non-Human Primates

Scribe Therapeutics released detailed preclinical data on May 18, 2026, following oral session presentations at the 2026 American Society of Gene & Cell Therapy (ASGCT) Annual Meeting in Boston (May 11-15). Two proprietary CRISPR engineering platforms were highlighted: (1) ELXR (Epigenetic Long-Term X-Repressor): achieves durable epigenetic silencing of target genes via CRISPR-guided chromatin remodeling, without permanent DNA double-strand breaks. ELXR is designed for persistent gene downregulation, particularly relevant for cardiovascular targets. (2) XE (X-Editor): a precision CRISPR gene editing platform using Scribe's engineered XCas9 variants. Also featured: DeepXE, an AI-powered CRISPR guide and protein design platform optimizing editing efficiency and specificity. In vivo studies in non-human primates (NHP) demonstrated potent, saturating liver editing across multiple target gene loci. Zero significant off-target editing was detected for multiple therapeutic guide RNAs tested at 10× the EC90 (supramaximal) dose in primary human hepatocytes — a critical safety benchmark. Lead cardiometabolic pipeline programs advancing toward IND: STX-1150 (LDL-C reduction via PCSK9-like target), STX-1200 (Lp(a) lowering), and STX-1400 (triglyceride reduction). All programs use LNP delivery targeting hepatocytes. The data underscore Scribe's differentiated position in the competitive in vivo CRISPR cardiovascular space, alongside CRISPR Therapeutics' CTX310 and Editas' EDIT-401.