Intratumoral sotigalimab with pembrolizumab induces rapid activation of antigen presenting cells and drives anti-tumor responses in non-injected tumors in metastatic melanoma: A phase I/II study.

Immune checkpoint blockers (ICBs) improve outcomes in metastatic melanoma (MM), but resistance limits benefit. This phase I/II (NCT02706353) study evaluated intratumoral sotigalimab (anti-CD40 agonist) with pembrolizumab in 32 ICB-naïve MM patients. Primary endpoints were safety, and objective response rate (ORR). Sotigalimab was well tolerated. At the recommended phase 2 dose (RP2D), the ORR was 50% and the disease control rate (DCR) was 92%, with ORR of 67% in injected and 50% in non-injected tumors. Multiomic analyses of tumor and blood showed sotigalimab effectively engaged the CD40 pathway, boosting infiltration and activation of myeloid cells, including CD11c+DC-LAMP+ dendritic cells (DCs) and macrophages. The combination therapy activated innate and adaptive immunity in injected tumors and cytotoxic responses in non-injected tumors. TCR sequencing showed increased T-cell clonality with expanded new clones shared across tumors. Clinical responses correlated with these immunologic changes, but not with baseline features associated with response to anti-PD1 monotherapy.