1324P Pembrolizumab as a monotherapy (P) or in combination with platinum-based chemotherapy (PCT) in advanced non-small cell lung cancer (aNSCLC) with PD-L1 tumour proportion score (TPS) ≥50%: A real-world data (Israeli Lung Cancer Group)

Both P and PCT represent standard 1st-line treatment options for aNSCLC with PD-L1 TPS ≥50%. The two strategies have never been compared in a randomized trial. 256 consecutive patients (pts) with EGFR/ALK/ROS1-wild-type PD-L1 TPS ≥50% aNSCLC receiving P (group A, n-203) or PCT (group B, n-53) as a 1st-line treatment were identified in the electronic databases of 4 Israeli cancer centers. Time-to-treatment failure (TTF) and overall survival (OS) were assessed. Baseline characteristics were well balanced, except for age and ECOG PS differences in favor of group B (Table). With median follow-up of 9.9 mo [IQR 2.7-18.9] and 6.7 mo [IQR 4.6-10.8] in groups A and B, respectively (p-0.003), 78% and 53% of pts stopped the treatment, and 57% and 30% of pts died in groups A and B, respectively. No statistically significant differences in TTF or OS between the groups were observed (Table). In the univariate analysis, ECOG PS (p-0.0002), age (p-0.01) and smoking history (p-0.003) significantly correlated with TTF; ECOG PS (p<0.0001) and age (p-0.0006) significantly correlated with OS; treatment group, sex, histology, presence of liver or brain metastases did not demonstrate a significant correlation with TTF or OS (p>0.1). In the propensity score matching analysis (n-106; 53 patients in each group matched for age, sex and ECOG PS), no differences in OS or TTF between the groups were observed (Table).Table:Group A (P; n-203)Group B (PCT; n-53)p-valueAge, y (range)68 (36-97)63 (35-87)0.02Men, %68580.2Smokers, %91890.8Adenoca/sq cellcarcinoma/other, %78/16/672/19/90.5ECOG PS 0+1/2-4/NA, %68/31/185/15/00.02Weight loss >5%, %26320.7Liver metastases, %13111.0Brain metastases, %27261.0OS, median (95%CI), mo12.5 (9.8-16.4)20.4 (10.8-NR)0.08TTF, median (95%CI), mo4.9 (3.1-7.6)7.9 (4.7-15.6)0.09Propensity score matching analysis (n-106)OS, median (95%CI), mo13.3 (6.8-20.3)20.4 (10.8-NR)0.2TTF, median (95%CI), mo7.9 (2.8-12.7)7.9 (4.7-15.6)0.4 Open table in a new tab P and PCT in the real-world setting are associated with similar outcomes; with the limitations of the retrospective study design and short follow-up, P emerges as a preferable 1st-line treatment option for aNSCLC with PD-L1 TPS ≥50%. Results of subgroup analysis will be presented during the conference.