High-density brush-shaped polymer lipids reduce anti-PEG antibody binding for repeated administration of mRNA therapeutics.

Messenger RNA lipid-nanoparticle-based therapies represent an emerging class of medicines for a variety of applications. However, anti-poly(ethylene glycol) (anti-PEG) antibodies generated by widely used PEGylated medicines and lipid nanoparticles hinder therapeutic efficacy upon repeated dosing. Here we report the chemical design, synthesis and optimization of high-density brush-shaped polymer lipids that reduce anti-PEG antibody binding to improve protein production consistency in repeated dosing. Brush-shaped polymer lipid parameters, including side chain length, degree of polymerization, anchor alkyl length and surface regimes on lipid nanoparticles modulate anti-PEG antibody binding affinity and control their blood circulation pharmacokinetics. Compared to widely used 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000, lipid nanoparticles containing brush-shaped polymer lipids generate superior therapeutic outcomes in protein replacement therapy and genome editing models, reformulating structure-activity guidelines for the design of PEG lipid substitutes. Overall, these findings contribute to the general effort in the development of lipid nanoparticles with low immunogenicity to overcome current roadblocks to nucleic acid medicines.