Sylus Bio Therapeutics

Stylus Medicine is a private biotechnology company developing in vivo genetic medicines using engineered recombinases and targeted lipid nanoparticle delivery. The company is focused initially on creating in vivo CAR-T therapies by delivering therapeutic payloads directly to immune cells inside the body, with the goal of avoiding the complexity and cost of ex vivo cell therapy manufacturing. Its platform is designed for sequence-specific insertion of large, multigenic payloads with high specificity and fidelity and without exposed double-stranded DNA breaks. Stylus emerged from stealth in 2025 with $85 million in Series A financing and is led by cell and gene therapy veterans including CEO Emile Nuwaysir and CSO Jason Fontenot. The company appears to remain at the preclinical stage, with no disclosed clinical-stage assets as of April 9, 2026.