Efficacy of Nivolumab for Head and Neck Cancer Patients with Primary Sites and Histological Subtypes Excluded from the CheckMate-141 Trial

BACKGROUND: In the CheckMate-141 trial, nivolumab conferred a survival benefit in patients with recurrent or metastatic refractory squamous cell carcinoma (SCC) head and neck cancer (HNC). Here, we examined the efficacy of nivolumab in patients with histological subtypes or primary sites of HNC not included in the CheckMate-141 trial. METHODS: This was a retrospective analysis of data collected prospectively from 97 patients who were treated with nivolumab for recurrent or metastatic HNC at our institution. The patients were assigned to three groups based on HNC primary site: 1) oral cavity, pharynx, and larynx, which were included in CheckMate-141 (n = 68), 2) nasopharynx (excluded in CheckMate-141, n = 7) and 3) other primary sites excluded in CheckMate-141 (n = 22) and assigned to two groups according to histological subtype: 1) SCC (included in CheckMate-141, n = 83) and 2) non-SCC (all sites excluded in CheckMate-141, n = 14). Survival outcomes and nivolumab treatment response were compared between the primary site and histological subgroups. RESULTS: The median number of nivolumab treatments was 7 cycles (range, 1–53 cycles) and the median follow-up time was 9.1 months (range, 0.66–33.0 months). There were no significant differences in response rates between the three primary site subgroups (CheckMate-141 sites 22%, nasopharynx 43%, others 18%; p=0) or the two histological subtype subgroups (SCC 25%, non-SCC 7%, p=0). Similarly, overall survival and progression-free survival were comparable for patients stratified by primary site or histological subtype. CONCLUSION: No significant difference in response rates or survival outcomes was detected between nivolumab-treated HNC patients with primary sites and histological subtypes that were included versus excluded in the CheckMate-141 trial. These data provide a potential rationale for nivolumab therapy for all HNC patients in clinical practice.