Scribe Therapeutics Receives Regulatory Clearance for STX-1150 — First CRISPR Epigenetic Silencer for Cardiovascular Disease to Reach Clinical Stage

Scribe Therapeutics announced on May 21, 2026 that it received regulatory clearance to initiate the first-in-human clinical study of STX-1150, an investigational CRISPR-based epigenetic silencing therapy targeting PCSK9 for durable LDL cholesterol reduction. Unlike conventional gene-editing approaches, STX-1150 uses Scribe's proprietary ELXR (Epigenetic Long-Term X-Repressor) platform — a CRISPR-based system delivered via lipid nanoparticles (LNPs) that achieves long-lasting transcriptional silencing of the PCSK9 gene in the liver without making permanent DNA cuts. This makes it distinct from traditional CRISPR-Cas9 gene editing: the epigenetic silencing is durable but potentially reversible, which may offer a more favorable safety profile for cardiovascular indications. PCSK9 silencing prevents the liver from degrading LDL receptors, allowing more LDL-C to be cleared from the bloodstream. STX-1150 is intended as a potential single-dose cardiovascular treatment for patients with elevated LDL-C who are unable to achieve target levels with existing therapies (statins, PCSK9 antibodies, inclisiran). Scribe simultaneously announced a late-breaking oral presentation of STX-1150 preclinical data at the 94th European Atherosclerosis Society (EAS) Congress in Athens, Greece (May 24–27, 2026), where NHP data showed potent, durable PCSK9 silencing with high specificity. This clearance marks Scribe's first clinical-stage program and positions the company as a leader in therapeutic epigenetic silencing using engineered CRISPR systems. The ELXR platform is in the same cardiometabolic pipeline as STX-1200 (Lp(a) silencing) and STX-1400 (triglyceride silencing), both approaching IND filings.