Abstract 1295P
Background
Pembrolizumab for pts with untreated advanced NSCLC PD-L1 ≥50% is a chemotherapy-free option. Data suggest that those with high tumour burden derive moderate benefits from pembrolizumab. We conducted a retrospective study to assess the impact of BTS on overall survival (OS) in untreated NSCLC pts treated with pembrolizumab or chemotherapy.
Methods
This French retrospective, multicentre study included all pts with untreated advanced NSCLC, receiving pembrolizumab (PD-L1≥50%) or a platinum-based chemotherapy (any PD-L1). The combination of chemotherapy plus pembrolizumab was not available at the time of this study. The primary endpoint was to assess the impact of BTS on OS in each group. BTS was defined as the sum of the dimensions of baseline target lesions according to RECIST 1.1.
Results
From 09-2016 to 06-2020, 188 pts were included in 3 centres, 96 in pembrolizumab and 92 in chemotherapy groups. Median follow-up was 26.9 (95%CI 24.1–30.0) and 44.4 months (95%CI 25.4–45.4) in pembrolizumab and chemotherapy groups. Median BTS was similar in both groups, 85.5 mm (Interquartile range (IQR) 57.2–113.2) and 86.0 mm (IQR 53.0–108.5) in pembrolizumab and chemotherapy groups (p = 0.42). In pembrolizumab group, BTS>86 mm was associated with a shorter OS in univariate analyses versus BTS≤86 mm (HR = 2.46, 95% CI 1.25–4.81, p = 0.009). Median OS was 18.2 months [95% CI 12.2–non reached (NR)] for BTS >86 mm versus NR (95%CI 27.2–NR) for BTS≤86 mm (p = 0.0026). After adjustment on confounding factors in multivariate analysis, BTS>86 mm remained associated with a shorter OS in the pembrolizumab group (HR 2.25, 95%CI 1.07–4.76, p = 0.033). In the chemotherapy group, the median OS was not statistically different between pts with low (≤86 mm) and high (>86 mm) BTS in univariate and multivariate analyses (HR = 1.27, 95%CI 0.75–2.16).
Conclusions
After adjustment on major baseline clinical prognostic factors, BTS was an independent prognostic factor for OS in pembrolizumab-treated pts in first-line for advanced NSCLC, PD-L1 ≥50%. Further studies are needed to assess the impact of BTS on the combination chemotherapy plus immunotherapy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Pr Bennouna.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.