OBJECTIVES: Atezolizumab in combination with carboplatin-etoposide is indicated for the first-line treatment of extensive-stage small-cell lung cancer(ES-SCLC). The aim of our study is to analyze the effectiveness and safety of atezolizumab combined with chemotherapy in ES-SCLC in a tertiary hospital, and to compare with the pivotal IMpower133 trial.

METHODS: Retrospective observational study was conducted. We included patients treated with atezolizumab plus chemotherapy from January/2022-March/2023. Variables collected: sex, age, smoking-status, quality of life status according to the Eastern-Cooperative-Oncology-Group(ECOG) scale, location of metastases, comorbidities, duration of treatment, objective response rate(ORR) according to RECIST-v1.1 criteria(Response Evaluation Criteria in Solid Tumors), progression-free survival(PFS) and overall survival(OS) calculated by Kaplan-Meier method, and adverse events(AEs) according to Common Terminology Criteria for Adverse Events-v.5(CTCAE). Data obtained from the electronic medical record (Diraya®) and software Farmis_Oncofarm®, and processed with SPSS-Statistics-v.21.

RESULTS: Fourteen patients(100% male) were included; median age of 62 years [Interquartile range (IQR):57-64]; 100% smokers. 79% had an ECOG:1 at baseline(14% ECOG:2;7% ECOG:0). The most frequent locations of metastases were: hepatic(57%), bone(50%) and renal(50%). The most frequent comorbidities were: arterial hypertension(43%), dyslipidemia(21%) and diabetes mellitus II(14%). Median duration of treatment was 5.2 months(IQR:4-7). At the date of analysis(13/04/2023), 7 patients are still on treatment. ORR was partial in 64% of patients(36% not evaluated). Median PFS and OS were 4.9(95%CI 2.1-7.8) and 5.8(95%CI 5.3-6.4) months, respectively.

93% of patients had some AE during treatment. Most frequent AEs were: anemia 77%(G3:38.5%), neutropenia 77%(G3-4:38.5-15.4%), asthenia 53.8%(G3:7.7%), thrombocytopenia 53.8%(G3:15.4%), elevated transaminases 30.8%(G3:0%), nausea 23%(G3:0%), and diarrhea 15.4%(G3:0%). No patient discontinued treatment due to AEs.

CONCLUSIONS: Median OS and PFS were lower than that obtained in the pivotal IMpower133 trial. Although the majority of patients presented some AE, in no case were these AEs forced to discontinue treatment. Further studies with a larger sample size and longer follow-up period are needed to confirm these real-life results.