A real-world multicentre evaluation of atezolizumab plus platinum-etoposide chemotherapy as first-line treatment in patients with extensive-stage small cell lung cancer in Italy.

INTRODUCTION: The aim of this study was to analyze real-life data from a cohort of adult patients receiving atezolizumab in combination with carboplatin and etoposide for first-line treatment of ES-SCLC, in order to assess relative dose intensity (RDI), time-to-treatment discontinuation (TTD), time-to-treatment failure (TTF), progression-free survival (PFS), overall survival (OS) of treatments as well as the correlation between these outcomes.

METHODS: An observational retrospective study was conducted. All patients treated with atezolizumab combined with carboplatin and etoposide for first-line treatment of ES-SCLC were included. Median TTD, TTF, PFS and OS were calculated in our cohort of patient by the Kaplan Meier method.

RESULTS: The curves obtained with the Kaplan Meier method of TTF and TTD are substantially similar, indicating a good concordance of the information extracted by the two different data sources. This tendency was confirmed also when the TTD versus PFS curves were compared. The median OS registered was 11.8 months. Patients with no liver metastases showed a longer median time of OS than patients with liver metastases. The mean value of RDI for the entire cohort was 87.4%.

CONCLUSIONS: Our study showed that TTD, calculated from the administration data is a useful proxy of TTF as registered in the clinical chart. TTD is a real-world outcome that can be used to demonstrate the efficacy of drugs used for administered therapies. It can be used as an end point for RWE studies, where the evaluation is less structured and standardized.