Sintilimab Plus Hypofractionated Radiotherapy Followed by Chemoradiotherapy for Locally Advanced Head and Neck Squamous Cell Carcinoma

Most patients with head and neck squamous cell carcinoma (HNSCC) are diagnosed with locally advanced disease. While cisplatin-based chemoradiotherapy remains the standard-of-care treatment for this patient population, it is still associated with a high rate of disease recurrence. Given the relatively high mutational burden of HNSCC, immunotherapy has emerged as a promising therapeutic strategy. The addition of PD-1 inhibitors to induction chemotherapy has been shown to improve antitumor responses without increasing treatment-related toxicity. In addition, radiotherapy can further potentiate systemic antitumor immune responses. Sintilimab, a PD-1 monoclonal antibody, has demonstrated robust antitumor activity across multiple solid malignancies. Early clinical evidence indicates a synergistic antitumor effect when combined with hypofractionated radiotherapy. Nevertheless, clinical data regarding the combination of sintilimab with chemoradiotherapy in locally advanced HNSCC remain limited. Accordingly, we designed a multicenter, single-arm phase II trial to evaluate the efficacy and safety of sintilimab in combination with definitive chemoradiotherapy for patients with locally advanced HNSCC.