A DPC Database Study on the Safety of Atezolizumab/Carboplatin/Etoposide in Extensive-Disease Small Cell Lung Cancer in Japanese Patients.

Introduction: Atezolizumab, carboplatin, and etoposide (ACE) therapy is a standard of care for extensive-disease small cell lung cancer (SCLC); however, its safety data are scarce, limiting generalization to the Japanese population.

Methods: This study aimed to compare the safety of ACE versus carboplatin and etoposide (CE) therapies in Japanese patients using the Diagnosis Procedure Combination (DPC) database by comparing the incidence of adverse events (AEs). Retrospective data on clinical background and AEs were extracted from the DPC database. Incidence rates and restricted mean survival times (RMSTs) up to 6 months were analyzed for 19 clinically important AEs. Covariates were adjusted using the inverse probability weighting method.

Results: A total of 330,774 patients were identified using the International Statistical Classification of Diseases and Related Health Problems 10th Revision codes, of whom 277 were included in the ACE cohort and 478 in the CE cohort. Among the 19 AEs, the incidence of skin disorder and thyroid dysfunction was significantly higher in the ACE cohort compared with the CE cohort. The adjusted incidence rate ratios were 2.38 (95% confidence interval [CI] 1.04-5.43) for skin disorder and 6.92 (95% CI 2.00-23.89) for thyroid dysfunction. The adjusted RMST differences were - 8.2 days (95% CI - 16.0 to - 0.4 days) for skin disorder and - 8.8 days (95% CI - 15.7 to - 1.9 days) for thyroid dysfunction.

Conclusions: This study provides evidence regarding the safety of ACE combination therapy in Japanese clinical practice using the DPC database, with results comparable to those reported in pivotal clinical trials.

Trial registration: UMIN Clinical Trials Registry ID UMIN000041508.