Publication-only abstracts (abstract number preceded by an "e"), published in conjunction with the 2019 ASCO Annual Meeting but not presented at the Meeting, can be found online only.
Impact of baseline number of metastases on the efficacy of PD-1 inhibitor monotherapy for non-small cell lung cancer with high PD-L1 expression.
Metastatic Non-Small Cell Lung Cancer
Lung Cancer—Non-Small Cell Metastatic
2019 ASCO Annual Meeting
J Clin Oncol 37, 2019 (suppl; abstr e20551)
Author(s): Taichi Miyawaki, Hirotsugu Kenmotsu, Eriko Miyawaki, Nobuaki Mamesaya, Takahisa Kawamura, Haruki Kobayashi, Kazuhisa Nakashima, Shota Omori, Kazushige Wakuda, Akifumi Notsu, Akira Ono, Tateaki Naito, Haruyasu Murakami, Keita Mori, Hideyuki Harada, Masahiro Endo, Toshiaki Takahashi; Shizuoka Cancer Center, Sunto-Gun, Shizuoka Prefecture, Japan; Division of Thoracic Oncology, Shizuoka Cancer Center, Shizuoka, Japan; Division of Thoracic Oncology, Shizuoka Cancer Center, Sunto-Gun, Shizuoka Prefecture, Japan; Shizuoka Cancer Center, Sunto-Gun, Japan; Clinical Research Center, Shizuoka Cancer Center, Shizuoka, Japan; Shizuoka Cancer Center, Nagaizumi, Japan; Division of Diagnostic Radiology, Shizuoka Cancer Center, Shizuoka, Japan
Background: Pembrolizumab monotherapy and pembrolizumab combined with platinum-based chemotherapy are the standard therapies for advanced non-small cell lung cancer (NSCLC) patients with a programmed death ligand 1 (PD-L1) tumour proportion score (TPS) ≥ 50%. Apart from PD-L1 status, predictive factors for the efficacy of pembrolizumab treatment remain unclear. High tumour burden has been shown to be a negative predictor for the efficacy of PD-1 inhibitors in melanoma. Hence, the purpose of this study was to evaluate the association between tumour burden and efficacy of pembrolizumab in NSCLC patients with PD-L1 TPS ≥ 50%. Methods: This single-center retrospective observational study evaluated patients with advanced NSCLC with PD-L1 TPS ≥ 50% who received pembrolizumab monotherapy as first line therapy between March 2016 and November 2018. The primary endpoint was progression-free survival (PFS). Tumour burden was estimated by the baseline number of metastases (BNM) and the baseline sum of the target lesions’ longest diameters (BSLD; measured according to RECIST criteria). Results: Of 52 patients with target lesions, the median age was 69 years; ECOG-PS 0-1 94%; non-squamous histology 79%; and PD-L1 TPS ≥ 75% was 65%. The optimal cut-off values for predicting PFS were 4 for BNM and 115 mm for BSLD, based on the minimum P-value method for PFS. The low BNM group included 20 (38%) patients, and the low BSLD group 33 (63%). Low BNM was significantly associated with longer PFS (median PFS not reached vs 4.0 months, HR = 0.35, P = 0.021) and with higher response rate (60% vs 31%, P = 0.041) compared to high BNM. There was no significant difference in PFS between low BSLD and high BSLD groups (12.4 vs 4.0 months, HR = 0.52, P = 0.098). Multivariate analysis showed that both low BNM (≤ 4 vs. > 4, HR = 0.32, P = 0.02) and PD-L1 TPS (75-100% vs. 50-74%, HR = 0.41, P = 0.032) were significantly associated with longer PFS. There was no association between PD-L1 TPS and BNM (Spearman’s rho = -0.0985, P = 0.487) Conclusions: BNM may be an independent predictive factor of efficacy of pembrolizumab monotherapy. Patients with low BNM can be candidates for pembrolizumab monotherapy.