Fc-optimized CD40 agonistic antibody elicits tertiary lymphoid structure formation and systemic antitumor immunity in...

CD40 agonism enhances antitumor immunity but is limited by systemic toxicity and poor efficacy. Here, we present a phase 1 study (NCT04059588) of intratumoral (i.t.) 2141-V11, an Fc-engineered anti-CD40 agonistic antibody with enhanced binding to the inhibitory receptor FcγRIIB. Among 12 metastatic cancer patients, 2141-V11 was well tolerated without dose-limiting toxicities. Six patients experienced tumor reduction, including two complete responses in melanoma and breast cancer. 2141-V11 induced regression in injected and non-injected lesions, correlating with systemic CD8⁺ T cell activation and mature tertiary lymphoid structures (TLSs) in complete responders. In CD40/FcγRs humanized mice bearing orthotopic tumors, i.t. 2141-V11 promoted de novo TLS formation, facilitating i.t. CD8⁺ T cell effector responses independent of lymph node priming. The resulting local immune responses by 2141-V11 mediated abscopal antitumor effects and sustained immune memory. These findings demonstrate that i.t. 2141-V11 is safe and promotes immune-privileged tumor microenvironments that promote systemic and durable antitumor immunity.