Relationship between immune-related adverse events and the long-term outcomes in recurrent/metastatic head and neck squamous cell carcinoma treated with nivolumab

•Nivolumab, which is one of an immune checkpoint inhibitor (ICIs), has been shown to be effective for the treatment of recurrent/metastatic head and neck squamous cell carcinoma(R/MHNSCC).•In some cancers, ICIs have induced immune-related adverse events (irAEs), and irAEs have been shown to be associated with a better outcome.•In addition, in R/MHNSCC, the development of irAEs may aid in the earlier prediction of the anticancer effect in patients with R/MHNSCC during nivolumab monotherapy. Immune-related adverse events (irAEs) have been shown to be associated with higher antitumor responses and a clinical benefit in non-small cell lung carcinoma, renal cell carcinoma, and melanoma patients. However, little is known regarding the association between irAEs and the clinical effect of nivolumab for recurrent/metastatic head and neck squamous cell carcinoma (R/MHNSCC). We evaluated 108 patients treated with nivolumab for R/MHNSCC at 2 participating institutions. IrAEs were identified and profiled. We analyzed the association of each immune-related adverse effect with the clinical outcome of the patients. Among 108 patients, the objective response rate (ORR) was 29.6% (32/108 patients), and the disease control rate (DCR) was 50.0% (54/108 patients). IrAEs were observed in 41 patients (38.0%). Patients with irAEs had a significantly higher ORR and DCR than those without irAEs (46.3% vs. 19.4%, P = 0.004 and 75.6% vs. 34.3%, P