# Real-World Data of First-Line Cemiplimab Monotherapy for Metastatic Non-Small Cell Lung Cancer (NSCLC) with PD-L1 Expression ≥ 50%: A National Spanish Multicentric Cohort (CEMI-SPA Study)

## TL;DR

This study evaluates cemiplimab's effectiveness in treating advanced lung cancer in real-world settings and finds it performs similarly to another drug, pembrolizumab.

## Contribution

The study provides real-world evidence on cemiplimab's efficacy and safety in metastatic NSCLC patients with high PD-L1 expression.

## Key findings

- Cemiplimab showed median progression-free survival of 8.1 months and overall survival of 12.6 months in real-world settings.
- Cemiplimab's outcomes were comparable to pembrolizumab after adjusting for baseline differences.
- A patient's physical condition strongly influenced treatment outcomes.

## Abstract

Immunotherapy has changed how we treat patients with advanced non-small cell lung cancer, especially those whose tumors show high levels of PD-L1, a marker that helps predict response to treatment. Cemiplimab is an immunotherapy drug approved for these patients based on results from clinical trials. However, information about how cemiplimab works in everyday clinical practice is lacking. In this study, we analyzed data from 150 patients treated at 21 hospitals across Spain to gain a better understanding of how cemiplimab performs outside the controlled environment of clinical trials. We also compared these results with a separate group of patients previously treated with another commonly used drug, pembrolizumab. Our findings show that cemiplimab is effective and safe in routine care and works similarly to pembrolizumab. Importantly, we confirmed that a patient’s overall health and physical condition strongly influence treatment outcomes, helping guide future treatment decisions.

Background/Objectives: Anti–PD-1/PD-L1 blockers have revolutionized the treatment landscape of non–small cell lung cancer (NSCLC) lacking oncogene-addicted alterations, particularly in tumors with high PD-L1 expression (tumor proportion score [TPS] ≥ 50%). Cemiplimab is approved as first-line monotherapy in this setting. However, real-world data remain scarce. This study aimed to evaluate the efficacy and safety of single-agent cemiplimab in a multicenter Spanish cohort and compare outcomes with a historical pembrolizumab cohort. Methods: Cemi-SPA is a retrospective multicenter study including 150 patients with advanced NSCLC and PD-L1 ≥ 50% treated with cemiplimab as first-line monotherapy across 21 Spanish centers. Clinical outcomes were analyzed and compared with a historical cohort of 144 patients treated with pembrolizumab. Propensity score matching (PSM) was performed to adjust for baseline differences. Results: Median progression-free survival (PFS) and overall survival (OS) were 8.1 and 12.6 months, respectively. ECOG performance status ≥ 2 was independently associated with worse outcomes, whereas the development of immune-related adverse events correlated with improved PFS and OS. After PSM, no significant differences were observed between cemiplimab and pembrolizumab in terms of efficacy. Conclusions: Cemiplimab demonstrated comparable real-world efficacy and safety to pembrolizumab in patients with advanced NSCLC and PD-L1 ≥ 50%. ECOG performance status emerged as the strongest prognostic factor, highlighting the importance of patient selection in routine clinical practice.