Investigation of poor prognostic factors in extensive-stage small cell lung cancer under etoposide- platinum-atezolizumab treatment

Abstract

The phase III trial IMpower133 showed that platinum and etoposide plus atezolizumab was associated with improved overall survival (OS) and progression free-survival (PFS) when compared to the placebo group in treatment-naïve extensive-stage (ES)-small cell lung cancer (SCLC). Due to superiority in clinical outcomes, combination immunotherapy plus chemotherapy became mainstay treatment modalities as first line treatment in ES-SCLC. Nevertheless, real-world data are still lacking and search for potential biomarkers is necessary. This study aims to evaluate potential predictive biomarkers applicable in ES-SCLC under the combination therapy. Patients with ES-SCLC who are under etoposide-platinum-atezolizumab enrolled from 7 university hospitals affiliated to the Catholic University of Korea were evaluated. Pretreatment clinical parameters were evaluated for association with OS and PFS. Adverse events (AEs) during induction and maintenance phases were also evaluated. P-value below 0.05 was counted as statistically significant. Total of 41 patients were evaluated. Six-month survival was 68.6%. As best response to treatment, 26 (63.4%) showed partial response, 9 (22.0%) showed stable disease, and 4 (9.8%) showed progressive disease. During induction phase, grade I-II AEs occurred in 22 (53.7%) patients, and grade III-IV AEs occurred in 26 (63.4%) patients. During maintenance phase, 9 out of 25 (36.0%) patients experienced any grade AEs. In multivariate analysis for OS, lactate dehydrogenase (LDH), c-reactive protein (CRP), and forced vital capacity (%) were significant factors. In multivariate analysis for PFS, sex, and LDH were significant. In ES-SCLC under etoposide-platinum-atezolizumab, pretreatment CRP, LDH and FVC (%) were independent prognostic factors.