First-line real-world outcomes of atezolizumab- and pembrolizumab-based regimens in non-squamous non–small-cell lung cancer.

e20591 Background: Direct prospective comparisons of first-line treatment options for advanced non-squamous non–small-cell lung cancer (NSCLC) are lacking. This study evaluated whether real-world clinical data could provide insight into potential differences in effectiveness between two widely applied first-line regimens in the Russian Federation: atezolizumab combined with bevacizumab, carboplatin, and paclitaxel (ABCP) and pembrolizumab combined with pemetrexed and carboplatin (PPC). Methods: A retrospective, single-center analysis was conducted in adult patients with histologically or cytologically confirmed locally advanced, metastatic, or recurrent non-squamous NSCLC. Patients received ABCP or PPC as part of routine clinical care. Progression-free survival (PFS) was analyzed using Kaplan–Meier methodology, with adjustment for baseline imbalances performed via inverse probability of treatment weighting (IPTW). Results: Overall, 189 patients were analyzed (PPC, n = 113; ABCP, n = 76), with a median follow-up of 14.1 months. Prior to IPTW adjustment, median PFS was 9.0 months in the PPC group and 8.1 months in the ABCP group (HR 1.12; 95% CI 0.81–1.55; p = 0.50). Following weighting, PFS outcomes remained comparable between groups (9.2 and 8.8 months), respectively (HR 1.15; 95% CI 0.83–1.61; p = 0.40). Rates of objective response and disease control did not differ significantly (81.3% vs 82.6%; p = 0.70). Subgroup analyses revealed no meaningful interaction between treatment effect and baseline characteristics. In contrast, economic evaluation demonstrated a higher mean annual treatment cost associated with ABCP, exceeding that of PPC by 25% (cost ratio 1.25; 95% CI 1.10–1.43; p = 0.0007). Conclusions: In a real-world retrospective cohort, ABCP and PPC showed similar effectiveness with respect to PFS and tumor response in advanced non-squamous NSCLC. These findings support individualized first-line regimen selection based on patient-specific clinical and molecular considerations rather than expected efficacy differences. Prospective randomized studies are warranted to validate these results.