Moxifloxacin is a fourth generation widely used fluoroquinolone antibiotic. There are three cases of moxifloxacin-induced neutropenia reported in the literature and we report the fourth case. A 26-year-old man with pneumonia was treated with moxifloxacin because of penicillin allergy. On the second day of therapy, leukopenia [White blood cell (WBC) count 2.7×10³/μL] and neutropenia (neutrophils 1.21×10³/μL) occurred. Rothia mucilaginosa was isolated in sputum culture. On the fourth day of hospitalization moxifloxacin treatment was stopped and clarithromycin 500 mg PO twice daily was started. Leukopenia and neutropenia resolved one day after discontinuation of moxifloxacin that WBC and neutrophil count rose 4.5×10³/μL and 1.97×10³/μL, respectively. On the sixth day of hospitalization, WBC and neutrophil count was 4.3×10³/μL and 2.29×10³/μL, respectively. The immunomodulatory effects of moxifloxacin may result in the changes of WBC count like leukopenia with neutropenia. Moxifloxacin induced neutropenia may be more common and is an important adverse effect. More observational studies about safety profiles of moxifloxacin are needed.

Aim: Despite the survival benefit achieved with immune checkpoint inhibitors in advanced non–small-cell lung cancer (NSCLC), outcomes remain heterogeneous. While PD-L1 expression is an established biomarker, less is known about the prognostic relevance of on-treatment systemic inflammatory dynamics and the utility of endothelial stress–based indices such as the Endothelial Activation and Stress Index (EASIX) in patients receiving immunotherapy.Material and Methods: We retrospectively evaluated patients with advanced NSCLC treated with nivolumab. PD-L1 expression, metastatic burden, baseline inflammatory parameters, and baseline EASIX were recorded. On-treatment inflammatory markers, including derived neutrophil-to-lymphocyte ratio (dNLR) at 3 months and longitudinal changes in NLR (ΔNLR), were analyzed. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan–Meier and Cox regression models. To account for time-dependent bias, 3-month landmark analyses were performed.Results: Eighty-one patients were included. High PD-L1 expression (≥50%) was associated with significantly improved OS but did not retain independent prognostic significance for PFS. A high metastatic burden, particularly involvement of four or more metastatic organs, was associated with inferior OS. In landmark-adjusted analyses, dNLR at 3 months was independently associated with both OS and PFS, while ΔNLR was associated with OS, indicating that favorable on-treatment immune–inflammatory changes correlated with improved survival. Baseline EASIX was not associated with either OS or PFS.Conclusion: In nivolumab-treated advanced NSCLC, survival outcomes are primarily driven by tumor biology, disease burden, and immune–inflammatory dynamics evolving during therapy. On-treatment inflammatory markers, particularly dNLR and ΔNLR, provide more clinically relevant prognostic information than baseline indices, whereas baseline EASIX appears to have limited utility in this setting. These findings support a treatment-specific, time-dependent approach to biomarker-based risk stratification in immunotherapy.