A Phase I clinical trial evaluated the Fc-optimized CD40 agonistic antibody 2141.V11 administered intratumorally in metastatic cancer patients. The study reported tumor shrinkage in half of the 12 participants, including complete responses in melanoma and breast cancer cases, with responses also observed in non-injected lesions. Published in Cancer Cell, these findings highlight the antibody's safety and remarkable systemic antitumor effects, marking a significant advance in immunotherapy approaches for metastatic malignancies.