Intra-channel bi-epitopic crosslinking unleashes ultrapotent antibodies targeting Na_V1.7 for pain alleviation

Crucial for cell activities, ion channels are key drug discovery targets. Although small-molecule and peptide modulators dominate ion channel drug discovery, antibodies are emerging as an alternative modality. However, challenges persist in generating potent antibodies, especially for channels with limited extracellular epitopes. We herein present a bi-epitopic crosslinking strategy to overcome these challenges, focusing on Na_V1.7, a potential analgesic target. Aiming to crosslink two non-overlapping epitopes on voltage-sensing domains II and IV, we construct bispecific antibodies and ligand-antibody conjugates. Enhanced affinity and potency are observed in comparison to the monospecific controls. Among them, a ligand-antibody conjugate (1080-PEG₇-ACDTB) displays a two-orders-of-magnitude improvement in potency (IC₅₀ of 0.06 ± 0.01 nM) and over 1,000-fold selectivity for Na_V1.7. Additionally, this conjugate demonstrates robust analgesic effects in mouse pain models. Our study introduces an approach to developing effective antibodies against Na_V1.7, thereby initiating a promising direction for the advancement of pain therapeutics.