Analysis of the Modulation of the Tumor Microenvironment by MK-3475 (Pembrolizumab) Using a Systems Biology Approach (PEMSYS)

This is a monocentric, prospective, interventional and translational phase II study. Metastatic melanoma (mMEL) patients who are naive to immune therapy in the metastatic setting, and for whom an anti-Programmed Cell Death-1 (PD-1) therapy is needed could be eligible. The aim of the study is to identify biological markers which allow to better understand and predict the tumor response to pembrolizumab treatment, and thus to establish more efficient treatments for selected patients. Eligible patients will be registered (n=30) and will be treated with pembrolizumab monotherapy at 200 mg every three weeks for 2 years maximum until progression, unacceptable toxicity, or withdrawal of consent, whichever happens first. Patients may be treated for up to one year of additional treatment with pembrolizumab via the Second Course Phase. Patients will be followed medically and radiographically during pembrolizumab treatment. Patients will be followed radiographically every 9 weeks (+/- 7 days) until progression and disease evaluation will be assessed by RECIST 1.1 criteria. After progression, patients will be followed every 6 months for 5 years to collect survival data.