A toll-like receptor type 7 and 8 (TLR7/8) agonist with potential immunostimulating and antitumor activities. Upon intratumoral administration, telratolimod binds to and activates TLR7 and 8, thereby stimulating antigen-presenting cells (APCs), including dendritic cells (DCs). Activation of DCs results in the production of proinflammatory cytokines, and the activation of cytotoxic T-lymphocyte (CTL) and B-lymphocyte immune responses. This may cause tumor cell lysis. TLR7 and 8, members of the TLR family, play fundamental roles in the activation of the immune system.