Immunotherapy in nonendemic nasopharyngeal carcinoma: Real-world data from two nonendemic regions

Background: nasopharyngeal carcinoma (NPC) is a complex disease entity that mainly predominates in endemic regions. Real-world data with immunotherapy from nonendemic regions are limited. Methods: we collected data from patients with recurrent/metastatic (R/M) NPC treated at a center in Greece and 8 centers in Italy. Between 2016 and 2021, 46 patients who were treated with at least one cycle of immune checkpoint inhibitors (ICI) were identified. Herein, we present our results and a review of the literature. Results: assessment of response was available in 42 patients. Overall, 11 patients responded to immunotherapy (Overall Response Rate-ORR 26.2%). Three patients had complete response (CR), and 8 patients had partial response (PR). Disease control rate (DCR) was 61.9%. Median Progression Free Survival (PFS) was 5.6 months and median Overall Survival (OS) was 19.1 months. Responders to ICI improved PFS and OS as compared to that of nonresponders. A lower probability of responding to ICI was shown in patients with more than three metastatic sites (p = 0.073), metastatic disease at initial diagnosis, (p = 0.039) or EBV DNA positive before ICI initiation, (p = 0.074). Decline in EBV DNA levels was found to be statistically significant associated with best response to ICI (p = 0.049). Safety was manageable. Conclusions: among 46 patients with R/M NPC treated with immunotherapy in two nonendemic regions, ORR was 26.2% and durable responses were observed. Low disease burden could serve as a biomarker for response to ICI.