Exceptional response to cetuximab monotherapy after failure of immunotherapy with a checkpoint inhibitor in a patient with metastatic head and neck squamous cell cancer: case report and review of the literature

The efficacy of cetuximab plus PD-1 inhibitors as salvage therapy in PD-1 refractory patients with recurrent or metastatic head and neck squamous cell carcinoma

Purpose: The prognosis of patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) that are refractory to programmed cell death protein 1 (PD-1) immunotherapy is relatively poor. The salvage therapy was rarely investigated and urgently needed. Methods: We conducted a single center retrospective real-world study to explore the efficacy of cetuximab plus PD-1 inhibitors as salvage therapy in patients progressed from first-line immunotherapy. Results: In the present study, 28 eligible patients were included between October 2020 and May 2023. By the cut-off date (Sep 24th, 2023), the objective response rate (ORR) was 46.4% (95% CI, 29.5%-64.2%). Kaplan-Meier survival analysis revealed the median progression free survival (mPFS) in the study was 6.87 months (95% CI, 4.77-8.97 months), and median overall survival (mOS) was 9.67 months (95% CI, 4.79-14.55 months). Multivariate Cox regression analysis indicated that ECOG performance status and best response to salvage therapy was found to be the prognosis factor of salvage therapy. For the safety, the most common treatment related adverse events (TRAEs) were rash (72.1%), anemia (64.3%) and fatigue (46.5%) during the salvage therapy. The most common potential irAEs were hypothyroidism (25%), and pneumonitis (14.3%). Only 3 patients (10.7%) experienced grade 3 TRAEs, and no treatment-related deaths occurred. Conclusions: Our study showed the combination of cetuximab with PD-1 inhibitors might be a potential efficacy and safety choice in PD-1 refractory patients with R/M HNSCC which need further investigation.