S-588210

The primary objective is to evaluate the safety and tolerability of S-588210 (S-488210+S-488211) in patients with unresectable recurrent and/or metastatic solid tumors.

A phase Ib study investigating the safety, the immunogenicity and the optimal administration frequency of the S-588210 5-peptide vaccine in MPM patients without progression after pemetrexed-based chemotherapy will be conducted. Additionally, to identify more accurate predictive biomarkers of response to S-588210, T-cell-receptor-sequencing (TCR) pre- and post-vaccination will be performed in blood samples of patients treated with the vaccine. Immunohistochemical analysis of the vaccine oncoantigens will also be correlated with induction of antigen-specific T-cell responses. Finally, to explore the infiltration of tumors with T-cells and the potential presence of an immunosuppressive tumor microenvironment, immunohistochemistry for immune checkpoints (including PDL1/PD1, CTLA4) and immune suppressive cell subsets (T-regs, macrophages) will be performed.