Prognostic biomarkers for extensive-stage small cell lung cancer receiving amrubicin following failure of chemoimmunotherapy: a retrospective cohort study.

Backgrounds: Little is known about whether prior chemoimmunotherapy (CTI) affects the efficacy of sequential treatment in patients with extensive-stage (ES) small-cell lung cancer (SCLC). Our preliminary study explored what kinds of biomarkers are associated with the outcomes of CTI followed by amrubicin (AMR) as a second-line treatment. Methods: We retrospectively evaluated 45 patients with relapsed SCLC who underwent CTI followed by AMR monotherapy from December 2019 to December 2023. Clinical data and inflammatory and nutritional factors, such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, systemic immune-inflammation index, prognostic nutritional index (PNI), advanced lung cancer inflammation index (ALI), and Glasgow prognostic score before initial treatment of AMR, were analyzed to determine prognostic predictors. Survival analyses of variables were performed using the COX proportional hazards model. Results: The objective responses for prior CTI and AMR were 40.5% and 60.0%, respectively. Progression-free survival (PFS) and overall survival (OS) after AMR were closely related to the NLR and ALI (or PNI). However, there were no significant factors associated with AMR response. Univariate analysis identified NLR and ALI as significant predictors of PFS, and the presence of prior immune checkpoint inhibitor (ICI) maintenance, NLR, ALI, and duration from ICI to progressive disease as significant predictors of OS. Multivariate analysis demonstrated that the NLR was an independent prognostic factor for predicting worse PFS and OS after AMR administration. Conclusions: NLR was identified as a significant biomarker for predicting AMR outcomes after prior CTI in patients with ES-SCLC.