Efficacy and safety of different PD-1 inhibitors combined with chemotherapy in locally advanced head and neck squamous cell carcinoma.

e18114 Background: Surgery or definitive chemoradiotherapy are mainstay treatment of locally advanced head and neck squamous cell carcinoma (HNSCC). The high rates of recurrence or metastasis still lead to poor survival outcomes. Neoadjuvant chemoimmunotherapy has emerged as a promising strategy. But the role of chemoimmunotherapy, and the efficacy and safety of different PD-1 inhibitors have not been fully elucidated. Methods: We retrospectively analyzed 92 patients with locally advanced HNSCC treated in our institution from January 2022 to October 2024. All patients received neoadjuvant chemotherapy combined with one kind of PD-1 inhibitors (pembrolizumab, camrelizumab, tislelizumab, toripalimab, sintilimab), followed by surgery and adjuvant radiotherapy or definitive chemoradiotherapy. Kaplan-Meier analysis was employed to calculate progression-free survival (PFS) and overall survival (OS). Results: The overall objective response rate (ORR) was 71.7%, and the complete response (CR) rate was 21.7%. Neoadjuvant chemotherapy with pembrolizumab or toripalimab significantly improved PFS compared with tislelizumab (hazard ratio: 0.10, 95% CI: 0.02-0.50, P<0.01). No significant differences were found in OS between different PD-1 inhibitors. The most common therapy-related adverse events (TRAEs) were alopecia, nausea, vomiting and fatigue. 17% of patients experienced grade 3 or 4 TRAEs, with grade 5 TRAEs at 0%. Conclusions: Neoadjuvant chemoimmunotherapy have demonstrated promising efficacy and safety in HNSCC. Pembrolizumab or toripalimab with chemotherapy showed improved PFS compared with tislelizumab. Further studies are required to evaluate the survival benefits of the treatment.