Efficacy and safety of immune checkpoint inhibitors in lung large-cell neuroendocrine carcinoma.

Background: Lung large-cell neuroendocrine carcinoma (L-LCNEC) is a rare and highly aggressive neuroendocrine tumor. There is currently no standard therapeutic regimen, and systemic chemotherapy results in poor prognosis. Due to the rarity of L-LCNEC, the efficacy and safety of immune checkpoint inhibitors (ICIs) remain unclear. Methods: This study included 34 L-LCNEC patients administered ICIs at Zhejiang Cancer Hospital, from February 6, 2018 to February 6, 2023. The treatment responses were evaluated. Fisher's exact test was used to compare categorical variables, and the Kaplan-Meier method was used for survival analyses. Cox regression was used for multivariate analysis. Results: The objective response rate (ORR) of 34 patients was 29.4%, the disease control rate (DCR) was 82.4%, the median progression-free survival (PFS) was 6.30 months, and the median overall survival (OS) was 14.77 months. The ORRs of combined LCNEC (n=7) and pure LCNEC (n=27) were 14.3% and 33.3%; the DCRs were 100% and 77.8%; the median PFSs were 12.48 and 5.6 months (P=0.032); and the median OSs were 21.27 and 14.73 months, respectively (P=0.233). The observed incidence of immune-related adverse events (irAEs) was 61.8%, primarily occurring in grades 1/2 (58.8%) and grade 3 (5.9%). Elevated aminotransferases (14.7%), pneumonia (8.8%), and fatigue (8.8%) were the most common irAEs. Conclusions: ICIs treatment showed efficacy and safety in advanced L-LCNEC, with the potential for greater benefits in the combined LCNEC subtype.