Lipid 87 is a proprietary ionizable lipid developed by Generation Bio. Used as a key ingredient in stealth LNPs, it greatly prolongs blood circulation time, maintains high nucleic acid encapsulation efficiency and low cytotoxicity, and enables effective liver targeting. Its relevant applications are documented in PCT patent WO2026/080826A1. As a core component (47.5–57.5 mol%) of stealth lipid nanoparticles (LNPs), it works synergistically with steric-stabilizing polymers like DSG-PEG₂₀₀₀-OMe to extend the in vivo blood half-life of LNPs to over 24 hours (compared to merely 30 minutes of conventional LNPs). It achieves an encapsulation efficiency above 95% for mRNA and closed-ended DNA (ceDNA), exhibits low cytotoxicity with an IC₅ value greater than 100 μM, and delivers robust liver-targeting performance, obtaining over 80% hepatocyte transfection at a dosage of 0.5 mpk. In preclinical models of hemophilia B, LNPs formulated with Lipid 87 can restore around 40% of clotting factor IX (FIX) activity for more than seven days.
