Immune Checkpoint Inhibitor In High Risk Oral Premalignant Lesions

This trial is designed as a prospective, multi-centre, open-label, single-arm, phase II study. Oral Premalignant Lesions (OPL) may be considered the equilibrium phase of the immunoediting concept, i.e. a dynamic process between the tumour cells and the immune system including surveillance by the immune system or tumour progression. Thus, an imbalance in immunosuppressive microenvironment is a possible key in malignant transformation. In this regard, the activation of the PD-1/PD-L1 pathway has a central role, witnessed by the expression of PD-L1 by multiple cell types within the microenvironment of OPL (tumour-associated macrophages, fibroblasts, lymphocytes) and by the fact that PD-L1 expression in epithelial and subepithelial cells is associated with malignant transformation. The use of checkpoint inhibitors in this setting seems to be justified by this rationale. Employing intermediate end-point markers during preventive strategies against OPL may allow the conduction of smaller trials, able to give insights for designing larger studies and to better select the population receiving benefit from the treatment. In this regard, the evaluation of phenotypic changes (reduction in size or in grade of dysplasia) may not be enough to assess the potential benefit of an intervention. Modulation of molecular markers may be more precise indicator of oral cancer risk in patients with OPL. Thus, the change in LOH at critical loci may be considered intermediate end-point biomarkers of prevention as well as predictors of cancer risk at baseline. Previous experience with anti-EGFR agents showed the feasibility of such measures in a prevention trial.