O1-2-4Efficacy of nivolumab for head and neck cancer arising from subsites which were not included in CheckMate 141

Abstract Background In the CheckMate 141 trial, nivolumab, a human IgG4 anti-PD-1 monoclonal antibody, provided a significant improvement in overall survival (OS) of patients with recurrent or metastatic squamous cell carcinoma (SCC) of the oral cavity, pharynx, or larynx. In Japan, nivolumab has been approved for platinum pretreated head and neck cancers regardless of histologic type and subsite. In other words, nivolumab is also available for non-SCC and subsites of head and neck cancer which were not included in the CheckMate 141 trial. However, the efficacy of nivolumab for cancers arising from these other subsites has not been clarified. Methods: We retrospectively reviewed data for 122 consecutive patients with head and neck cancers treated with nivolumab in our institution between March 2017 and December 2018. Patients with head and neck SCC of oral, oropharyngeal, hypopharyngeal, and laryngeal cancer were excluded. Final analysis of the study population was restricted to those 37 patients with non-SCC histological type or SCC arising from other subsites of the head and neck. Results: Median age was 57 years (range 30 to 77). Primary sites were nasopharynx/sinonasal/salivary/other regions of the head and neck (n = 8/10/8/11). Nineteen patients had SCC and 18 had non-SCC. In patients who could be evaluated by RECIST (n = 32), objective response rate was 18.8% in the total study population, 37.5% in NPC, 10.0% in sinonasal cancer and 25.0% in salivary cancer. Median OS and time to treatment failure (TTF) in the total study population was 12.1 months and 2.3 months, respectively. Median TTF in NPC patients was better than that in patients with other primary sites (7.6 vs. 2.5 months, p = 0.016). There was a trend toward improved TTF in SCC group compared to non-SCC group (4.2 vs. 2.4 months, p = 0.31). Conclusion: Nivolumab showed favorable efficacy in head and neck cancers arising from subsites which were not included in the CheckMate141 trial, especially NPC patients.