Nivolumab is FDA-approved for the treatment of patients with recurrent/metastatic Head and Neck Squamous Cell Carcinoma (HNSCC).

HNSCC whose disease has progressed within 6 months after platinum-based chemotherapy. The development of predictive biomarkers is needed to optimize patient benefit, minimize risk of toxicities and guide combination strategies.

Nivolumab is FDA-approved for the treatment of patients with recurrent/metastatic Head and Neck Squamous Carcinoma (HNSCC) whose disease has progressed within 6 months after platinum-based chemotherapy. The development of predictive biomarkers is needed to optimize patient benefit, minimize risk of toxicities and guide combination strategies. The greatest focus has been on tumor-cell programmed death Ligand 1 (PD-L1) expression. Although PD-L1 positivity enriches for populations with clinical benefit, PD-L1 testing alone is insufficient for patient selection in most malignancies. PD-L1 expression can be transient, and intrapatient and even intratumor heterogeneity in PD- L1 tumor expression can exist. Therefore, tumor sampling at one timepoint might not accurately reflect the state of PD1 axis in a patient. Another important aspect is that PD-L1 immunohistochemistry alone does not take into account factors that could impede the anti-PD1 therapy response such as whether or not active immune cell engagement of the PD1 axis occurs in the tumor microenvironment or other concurrent immune suppressive pathways are present.

Assessment of biomarkers at baseline may not predict benefit from immunotherapy. In a phase II study of ipilimumab in patients with metastatic melanoma baseline tumor infiltrating lymphocyte status was not associated with clinical activity. However, increase in tumor infiltrating lymphocyte density in tumor biopsy samples collected after the second dose of ipilimumab was associated with significantly greater clinical activity with ipilimumab compared to samples without increase in lymphocyte density. For a better understanding of the mechanisms of resistance to nivolumab in HNSCC, the investigators propose to study a cohort of longitudinal HNSCC samples from recurrent/metastatic HNSCC patients treated with nivolumab and identify biomarkers of response and resistance. The investigators will specifically focus on modulation of immune phenotype (ImmR) following two cycles of nivolumab as surrogate biomarker for response to nivolumab.

The primary endpoint will be the change in the percentage of immune cells that is caused by nivolumab treatment. Secondary endpoint will be safety of performing a biopsy after second nivolumab dose. Translational correlates will be tested in tumour tissue, plasma and germline DNA.

Investigator assessment of best overall response (BOR), determined between the date of first dose and the last tumor assessment (TA), will be image-based and scored using the RECIST 1.1. criteria. BOR will be defined as categorical variable with 3 levels { Benefit (complete response (CR), partial response (PR), stable disease (SD) lasting 6 months from the first nivolumab dose), no benefit (PD, progressive disease or SD lasting less than 6 months from the first nivolumab dose), and unknown} Longitudinal tissue biopsies will be collected from HNSCC patients treated with nivolumab . Biopsies will be taken at baseline, 24-72 hours after the second cycle of nivolumab and at progression.

Inclusion Criteria:

• Signed written informed consent before any trial-related procedure is undertaken
• Male or female subjects aged ≥18 years
• Availability of a formalin-fixed, paraffin-embedded tissue sample (FFPE) containing tumor

Exclusion Criteria:

• no inform consent provided

The investigators will include recurrent/metastatic HNSCC patients who progressed after cisplatin-based chemotherapy and are to be treated with nivolumab.