Real‐world effectiveness of pembrolizumab in previously treated non‐small cell lung cancer: A population‐based cohort study

Purpose Immunotherapy is promising for lung cancer treatment, although at significant financial impact. The aim of this study was to evaluate the effectiveness and the efficacy‐effectiveness gap of pembrolizumab in previously treated non‐small cell lung cancer (NSCLC). Methods A population‐based ambispective cohort study was conducted. Cases of interest were identified through the National Cancer Registry database and additional data sources. Patients aged ≥18 years, diagnosed with NSCLC and exposed to pembrolizumab, between 23 June 2016 and 31 October 2018, as second or later lines of treatment for advanced disease were included. Patients were followed‐up until death or cut‐off date (30 April 2019). Primary outcome was overall survival (OS). Secondary outcomes were progression‐free survival (PFS), event‐free survival (EFS), and adverse events (AEs) leading to treatment discontinuation. The efficacy‐effectiveness gap was evaluated comparing results with clinical trial data. Results A total of 181 patients were included. Median age was 63 years (range 33‐94); 74.6% were male. Median treatment duration was 5.6 months (interquartile range: 1.4‐10.4) and, at cut‐off date, treatment had been discontinued in 141 patients, mainly due to disease progression. Median OS was 13.0 months (95% confidence interval [CI] 9.3‐15.9) and 1‐year OS was 53.1% (95% CI 45.2%‐60.3%). Median PFS was 5.6 months (95% CI 4.6‐7.2), median EFS was 4.7 months (95% CI 3.2‐6.0), and treatment was discontinued due to AE in 8.3% of cases (n = 15). The efficacy‐effectiveness gap seems to favor pembrolizumab use in clinical practice. Conclusion Real‐world data suggest the performance of pembrolizumab to reflect the clinical trial outcomes in previously treated NSCLC.