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Introduction: Multiple programmed death-ligand 1 (PD-L1) immunohistochemistry assays performed using different antibodies including DAKO 22C3, DAKO 28-8, and Ventana SP142 PD-L1—predictive markers for response to various immune checkpoint inhibitors in NSCLC—have been approved in several countries. The differences in multiple PD-L1 immunohistochemistry assay results in predicting the therapeutic response to combined chemoimmunotherapy in patients with NSCLC remain unclear. Methods: In this multicenter prospective observational study, we monitored 70 patients with advanced NSCLC treated with combined chemoimmunotherapy at 10 institutions in Japan. The expression of PD-L1 in pretreatment tumors was evaluated using the 22C3, 28-8, and SP142 assays in all patients. Results: The PD-L1 level in tumor cells determined using the 22C3 assay was the highest among the three assays performed with different antibodies. According to the 22C3 assay results, the PD-L1 tumor proportion score greater than or equal to 50% group had a significantly longer progression-free survival period than the PD-L1 tumor proportion score less than 50% group. Nevertheless, the other assays did not reveal remarkable differences in the objective response rate or progression-free survival. Conclusions: In our study, PD-L1 expression determined using the 22C3 assay was more correlated with the therapeutic response of patients with NSCLC treated with combined chemoimmunotherapy than that determined using the 28-8 and SP142 assays. Therefore, the 22C3 assay may be useful for clinical decision-making for patients with NSCLC treated with combined chemoimmunotherapy. Trial registration number: UMIN 000043958.

Introduction: The use of immune checkpoint inhibitors (ICIs) with chemotherapy has increased the survival of patients with advanced NSCLC. Nevertheless, the efficacy of ICI treatment for NSCLC with EGFR mutations is limited. Previous studies have not evaluated the efficacy of ICI treatment after osimertinib treatment in real-world settings. Methods: This study performed a retrospective analysis of the association between clinical characteristics and ICI efficacy in patients with EGFR-mutant NSCLC treated with ICIs after osimertinib treatment at 12 institutions in Japan from March 2016 to March 2021. Results: Among 80 patients with EGFR-mutant lung cancer, 42 received ICI monotherapy and 38 received chemoimmunotherapy. In the chemoimmunotherapy group, the progression-free survival (PFS) was significantly longer in the group that exhibited PFS more than 10 months with osimertinib than in the group that exhibited PFS less than or equal to 10 months with osimertinib (8.4 mo versus 3.8 mo, p = 0.026). Nevertheless, there was no significant difference in PFS in the ICI monotherapy group (1.7 mo versus 1.5 mo, p = 0.45). Regardless of the EGFR mutation subtype, PFS of osimertinib treatment was a predictor of the PFS of chemoimmunotherapy (exon 19 deletion mutation: p = 0.03 and exon 21 L858R mutation: p = 0.001). Conclusions: The PFS of osimertinib might be a predictor of PFS of chemoimmunotherapy in patients with EGFR-mutant NSCLC. Further clinical investigations on the predictors of efficacy of administering ICIs after osimertinib treatment are required.

Introduction: To date, the efficacy and safety of programmed death-ligand 1 (PD-L1) inhibitor plus platinum-etoposide chemotherapy for patients with extensive-stage SCLC (ES-SCLC), with real-world evidence, stratified on the basis of age and performance status (PS), have not been fully investigated. The aim of this study was to evaluate the efficacy and safety of PD-L1 inhibitor plus platinum-etoposide chemotherapy in patients with ES-SCLC. Methods: This multicenter prospective study evaluated patients with ES-SCLC who received PD-L1 inhibitor plus platinum-etoposide chemotherapy between September 2019 and October 2021. Results: A total of 45 patients with ES-SCLC received the aforementioned treatment, including 18 elderly (≥75 y old) patients and six patients with a PS of 2. Multivariate analysis indicated that a PS of 2 was a significant independent prognostic factor for progression-free survival and overall survival (p = 0.008 and p = 0.001, respectively). Of patients with PS of 2 at the initial phase, those that achieved PS improvement during treatment had significantly longer progression-free survival and overall survival than those who did not (p = 0.02 and p = 0.02, respectively). The incidence of adverse events accompanied with treatment discontinuation was significantly higher in the elderly patients than in the non-elderly patients (p = 0.03). Conclusions: This real-world prospective study found that PD-L1 inhibitor plus platinum-etoposide chemotherapy had limited efficacy in patients with ES-SCLC with a PS of 2, except for cases with improvement of PS during treatment. Owing to the emergence of adverse events and treatment discontinuation, this treatment should be administered with caution in elderly patients with ES-SCLC.