Immunotherapy Clearance and Phenotype of Circulating Tumor Cells in Lung and Head and Neck Cancers

Immunotherapy is widely administrated as anticancer treatment in metastatic setting. Despite a proved efficacy in several cancer types and clinical situations, it exists a wide variability of responses in terms of efficacy and toxicity. The rate of responders depends mostly on the type of pathology, with 40% of responders among melanoma patients, 20-30% among lung and head and neck cancer patients and only 1% of responders among pancreatic cancer patients. Thus, the main challenge today is to be able to select patients for whom the treatment is likely to be effective. Several studies suggested that tumors with a high mutational burden and expressing PD-L1 are better responders to immunotherapy. However, a proportion of PD-L1 negative cancers responds to immunotherapy, suggesting that other parameters have to be considered together with PD-L1 expression. Of that, the immunotherapy clearance seems to have an impact on overall survival, but larger studies, including different molecules and cancer types, are needed to better understand the correlation between the clearance and the response to immunotherapy. Tumor cells released from the primary tumor in the blood circulation (CTCs, for circulating tumor cells) are considered as "liquid biopsies", as they contain the entire genetic and phenotypic information representative of the tumor, including PD-L1 expression. Thus, the variation of PD-L1 expression under treatment can be easily followed-up on blood samples collected during the time. The objective of MADMAS is to study the correlation between the immunotherapy clearance, measured at the different times during treatment, and the variation of the number of CTCs expressing PD-L1 after two cures of treatment. MADMAS will enroll patients with lung or head and neck cancers, treated with an immunotherapy-based therapy. Blood samples will be collected at the baseline and before the first two cures of treatment. The immunotherapy clearance will be measured with an innovat