Motolimod (VTX-378/VTX-2337) is a potent and selective small molecule agonist of Toll-like receptor 8 (TLR8), exhibiting an EC50 of 100 nM and over 50-fold selectivity against TLR7. It is utilized in immunological research to study innate immune activation and has been investigated in preclinical models for its potential in cancer immunotherapy and as a vaccine adjuvant.