Agents blocking the Programmed Cell Death 1(PD1)/Programmed Cell Death 1-Ligand 1 (PD-L1) pathway have demonstrated objective, durable tumor regressions in patients with advanced solid malignancies and efficacy has been linked to PD-L1 expression. PD-L1 expression by tumour cells is the strongest single predictor of response to anti-PD1 therapy (J Taube, R Anders et al, Clin Cancer Res 2014). Pembrolizumab (MK-3475) is a high-affinity humanized monoclonal anti-PD1 antibody. It leads to dual PD1-ligand blockade of PD-L1 and PD-L2 that may reactivate the immune surveillance and elicit anti-tumour response. It has antitumor activity in melanoma and NSCLC (phase III trials). Pembrolizumab might be of interest in unresectable squamous cell carcinomas of the skin (SCCS).~Approximately 20% to 30% of non-melanoma skin cancers are SCCS. Most patients with primary SCCS have an excellent prognosis, but SCCS can progress to advanced stages that are impossible to treat by surgical excision or radiotherapy. Few therapeutic options are available for these tumors. Conventional chemotherapy, such as cisplatin-based combinations, has some efficacy, but the toxic effects of these combinations often prohibit their use in elderly patients. Epidermal Growth Factor (EGFR) signaling antagonists have activity only in a subset of patients. New therapeutic options are needed for patients with advanced SCCS.~No trial evaluating pembrolizumab in human SCCS is ongoing. Investigators hypothesize that:~i) PD-L1 is expressed in SCCS as in HNSCC ii) pembrolizumab may be effective as a single agent in patients with unresectable SCCS iii) Efficacy of pembrolizumab is correlated to PD-L1 expression in SCCS.~Investigators therefore intend to determine the efficacy and safety of single agent pembrolizumab in all patients and in patients with PD-L1-positive unresectable SCCS naïve of chemotherapy and of EGFR inhibitors.
The purpose of this study is to assess the efficacy and safety of pembrolizumab in patient with locally advanced or metastatic squamous cell carcinoma of the skin