Brief Report: Treatment Patterns and Outcomes in a Large Real-World Cohort of Patients With ES-SCLC Treated With First-Line Chemoimmunotherapy in the United States

Introduction Chemoimmunotherapy with atezolizumab or durvalumab has been the standard-of-care first-line (1L) treatment for extensive-stage small cell lung cancer (ES-SCLC) in the United States (US) since 2019. However, real-world evidence on treatment patterns, progression-free survival (rwPFS), and overall survival (rwOS) in this era is lacking. Methods This retrospective study identified patients with ES-SCLC treated with 1L chemoimmunotherapy from a claims database in the US (Komodo Research Data; 03/2018-09/2023); treatment patterns were described from diagnosis by line of therapy. rwPFS and rwOS were assessed from 1L chemoimmunotherapy initiation using the Kaplan-Meier estimator. Mortality risk factors were assessed using a multivariable Cox proportional hazards model. Results A total of 2,788 patients with ES-SCLC receiving 1L chemoimmunotherapy were identified (median age 65 years, 49.5% female); 89.5% received atezolizumab-based and 10.5% received durvalumab-based 1L chemoimmunotherapy. One-third (33.2%) of patients received a second-line regimen, and 10.3% received a third-line regimen. Among patients with sufficient follow-up, median rwPFS and rwOS from 1L chemoimmunotherapy was 4.2 (95% CI: 4.0-4.4) months and 10.8 (95% CI: 10.3-11.3) months, respectively. Risk factors significantly associated with increased mortality included older age (≥75 years), male sex, comorbidities (cardiovascular, renal, and chronic obstructive pulmonary diseases), and distant metastases (liver, brain, bone, adrenal gland). Conclusions In real-world clinical practice, patients with ES-SCLC treated with 1L chemoimmunotherapy experience rapid disease progression and death and infrequently receive subsequent treatment. Prognosis is particularly poor among older patients and those with comorbidities or distant metastases. These findings underscore a need for effective treatment options in 1L and beyond.