TY - JOUR T1 - Clinical significance of plasma-free amino acids and tryptophan metabolites in patients with non-small cell lung cancer receiving PD-1 inhibitor: a pilot cohort study for developing a prognostic multivariate model JF - Journal for ImmunoTherapy of Cancer JO - J Immunother Cancer DO - 10.1136/jitc-2021-004420 VL - 10 IS - 5 SP - e004420 AU - Koichi Azuma AU - Huihui Xiang AU - Tomoyuki Tagami AU - Rika Kasajima AU - Yumiko Kato AU - Sachise Karakawa AU - Shinya Kikuchi AU - Akira Imaizumi AU - Norikazu Matsuo AU - Hidenobu Ishii AU - Takaaki Tokito AU - Akihiko Kawahara AU - Kenta Murotani AU - Tetsuro Sasada AU - Yohei Miyagi AU - Tomoaki Hoshino Y1 - 2022/05/01 UR - http://jitc.bmj.com/content/10/5/e004420.abstract N2 - Background Amino acid metabolism is essential for tumor cell proliferation and regulation of immune cell function. However, the clinical significance of free amino acids (plasma-free amino acids (PFAAs)) and tryptophan-related metabolites in plasma has not been fully understood in patients with non-small cell lung cancer (NSCLC) who receive immune checkpoint inhibitors.Methods We conducted a single cohort observational study. Peripheral blood samples were collected from 53 patients with NSCLC before treatment with PD-1 (Programmed cell death-1) inhibitors. The plasma concentrations of 21 PFAAs, 14 metabolites, and neopterin were measured by liquid chromatography–mass spectrometry. Using Cox hazard analysis with these variables, a multivariate model was established to stratify patient overall survival (OS). Gene expression in peripheral blood mononuclear cells (PBMCs) was compared between the high-risk and low-risk patients by this multivariate model.Results On Cox proportional hazard analysis, higher concentrations of seven PFAAs (glycine, histidine, threonine, alanine, citrulline, arginine, and tryptophan) as well as lower concentrations of three metabolites (3h-kynurenine, anthranilic acid, and quinolinic acid) and neopterin in plasma were significantly correlated with better OS (p<0.05). In particular, the multivariate model, composed of a combination of serine, glycine, arginine, and quinolinic acid, could most efficiently stratify patient OS (concordance index=0.775, HR=3.23, 95% CI 2.04 to 5.26). From the transcriptome analysis in PBMCs, this multivariate model was significantly correlated with the gene signatures related to immune responses, such as CD8 T-cell activation/proliferation and proinflammatory immune responses, and 12 amino acid-related genes were differentially expressed between the high-risk and low-risk groups.Conclusions The multivariate model with PFAAs and metabolites in plasma might be useful for stratifying patients who will benefit from PD-1 inhibitors.Data are available upon reasonable request. Data are available from the corresponding authors upon reasonable demand, with the exception of absolute values of PFAA and metabolite analysis. ER -