Anti PD-L1 DUrvalumab combined with Cetuximab and RadiOtherapy in locally advanced squamous cell carcinoma of the head and neck: A phase I/II study (DUCRO)

Introduction and background: Head and neck squamous cell carcinoma (HNSCC) has been increasingly recognized as an immune suppressive malignancy. The efficacy of immune checkpoint inhibitors (ICI's) in the context of recurrent/metastatic (R/M) setting anticipates the possible integration of immunotherapy into the therapeutic armamentarium of locally advanced disease. Durvalumab (DUR) is a humanized monoclonal IgG1, anti-PD-L1 antibody with promising data in R/M HNSCC. The aim of our study is to test the antitumor activity of a combined regimen incorporating an immune checkpoint inhibitor into a conventional bio-radiation strategy for the cure of unfavorable locally advanced HNSCC.

Methods/design: In this open label, multi-center, single-arm, phase I/II study, enrolled patients will receive Radiotherapy (RT) (69.9 Gy/2.12 Gy in 33 fractions) with concurrent Cetuximab (CTX) (400 mg/m² 1 week before RT start followed by 250 mg/m² weekly) and DUR (fixed dose of 1500 mg every 4 weeks starting from RT-CTX week 1) followed by adjuvant DUR (to a maximum of 6 months after completion of RT-CTX). Primary endpoint of the study is 2-year progression-free survival (PFS). A safety run-in is planned after the enrollment of first 12, 24 and 36 patients. Patients affected by high-risk (≥N2a or ≥T3, any N) larynx, hypopharynx and HPV negative oropharynx or HPV-positive oropharynx (≥T2, ≥N2b, ≥10 pack/years) will be eligible.

Discussion: Conventional intensification strategies failed to provide any benefit for the cure of locally advanced HNSCC. For the still prevalent HPV-negative population and the high risk-HPV positive disease, there is an unmet need for alternative treatment paradigms. Potentially, the inhibition of the PD-1/PD-L1 checkpoint may synergize with both CTX and RT through immunologic interplay, ultimately aiming to reverse the HNSCC-induced immune suppression. The DUCRO study will seek to demonstrate if such a strategy may be safe and active.

Trial registration: NCT number: NCT03051906Eudract number: 2016-004668-20.