Search

Introduction: Immunotherapy with immune checkpoint inhibitors (ICI) is the standard of care for advanced non-small-cell lung cancer (NSCLC) without driver gene alterations. However, survival benefits with ICI are limited to a small subset of NSCLC patients, and particularly ICI combinations with cytotoxic agents produce serious physical and large financial toxicities. Tumor PD-L1 expression levels/proportion score (TPS) are universally used as predictive biomarkers in ICI monotherapy response and outcomes. However, PD-L1/TPS assays are imperfect because of low analytical validity and reproducibility due to the visual-scoring system by pathologists. Therefore, additional biomarkers are urgently needed to predict ICI therapy response and outcomes. Recently, we reported that serum antibodies (Abs) against NY-ESO-1 and XAGE1 cancer-testis antigens were probably useful biomarkers in the prediction of clinical benefits with anti-PD-1 monotherapy for NSCLC (J Thorac Oncol, 2019). Additionally, we developed a fully automated immunoassay system (HISCLTM) to measure the Abs easily and rapidly (Sakai Y, et al. Clin Chim Acta 2021). In this study, we retrospectively examined whether the Abs measured by HISCLTM predict the clinical benefits with ICI monotherapy for NSCLC.Patients and Methods: Sera were obtained from controls of non-malignant lung diseases (n=75) and healthy subjects (n=100), and advanced NSCLC patients (n=263) to to determine a cutoff value in HISCLTM. In NSCLC patients analyzed here (n=78), sera were obtained before anti-PD-1 monotherapy with nivolumab in second-line or later settings. The serum NY-ESO-1/XAGE1 Abs were measured by HISCLTM, and we examined the relationships between the Abs levels, objective response rate (ORR), progression free survival (PFS), and overall survival (OS) after nivolumab monotherapy.Results: NY-ESO-1/XAGE1 Abs levels in NSCLC patients (n=263) were significantly higher than those in the controls (n=175). A cutoff value was determined as the Abs level of 10 SU/mL, calculated from the Abs values in the controls. The Abs (≥ 10 SU/mL) were detected in 21/78 (27%) of the NSCLC patients treated with nivolumab, and one patient had both NY-ESO-1 and XAGE1 Ab. An ORR was 62%, 16%, and 29% in the Abs-positives, the Abs-negatives, and overall, respectively. The Abs levels in responders were significantly higher than those in non-responders. The NSCLC patients with high-Abs values (≥ 10 SU/mL) had significantly better survivals with nivolumab monotherapy than those with low-Abs (PFS, HR 0.51, 95%CI 0.31-0.83, p < 0.01; OS, HR 0.51, 95%CI 0.31-0.84, p < 0.01). Interestingly, a few NSCLC patients with both high-Abs and driver genes responded well to nivolumab.Conclusions: Serum NY-ESO-1/XAGE1 Abs measured by HISCLTM are potential biomarkers that predict clinical benefits with anti-PD-1 monotherapy for NSCLC, even including driver genes. These findings warrant further biomarker studies using NY-ESO-1/XAGE1 Abs in clinical trial and practice of NSCLC immunotherapy. Citation Format: Kanako Sakaeda, Koji Kurose, Minoru Fukuda, Nanae Sugasaki, Akitoshi Kinoshita, Takashi Kitazaki, Masaaki Fukuda, Takeshi Masuda, Noboru Hattori, Yusuke Atarashi, Yumiko Sakai, Yasuhiro Irino, Mami Yamaki, Toshiyuki Sato, Hiroshi Mukae, Toru Oga, Mikio Oka. Development of automated immunoassay to detect serum biomarkers predicting response to immune checkpoint inhibitors in NSCLC [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy; 2022 Oct 21-24; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(12 Suppl):Abstract nr A61.

The quantitative range and reproducibility of current serological tests for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are not optimized. Herein, we developed a diagnostic test that detects SARS-CoV-2 IgG and IgM with high quantitativeness and reproducibility and low interference. The system was based on the high-sensitivity chemiluminescence enzyme immunoassay (HISCL) platform and detects IgG and IgM specific to SARS-CoV-2 spike and nucleocapsid proteins. Quantification accuracy and reproducibility were evaluated using serially diluted samples from 60 SARS-CoV-2-infected patients. Assay performance was evaluated using serum samples from the SARS-CoV-2-infected patients and 500 SARS-CoV-2-negative serum samples collected before the emergence of SARS-CoV-2. The system showed high quantification accuracy (range, 102), high reproducibility (within 5%), and no cross-reaction between SARS1- and MERS-S proteins. Detection accuracy was 98.3% and 93.3% for IgG and IgM against spike proteins and 100% and 71.7% for IgG and IgM against nucleocapsid proteins, respectively. Mean antibody levels were > 10 times that in negative samples upon admission and > 100 times that at convalescent periods. Clinical severity upon admission was not correlated with IgG or IgM levels. This highly quantitative, reproducible assay system with high clinical performance may help analyze temporal serological/immunological profiles of SARS-CoV-2 infection and SARS-CoV-2 vaccine effectiveness.

Background: Programmed cell death-1 (PD-1) and PD-ligand1 (PD-L1) inhibitors have become standard therapies for advanced non-small-cell lung cancer (NSCLC) due to prolonged patient survival. However, extended survival with anti-PD-1/PD-L1 therapy is limited to a small subset of NSCLC patients. Therefore, predictive biomarkers are needed to determine which patients will benefit. Recently, we reported that serum antibodies (Abs) against NY-ESO-1 and/or XAGE1 cancer-testis antigens are useful biomarkers that predict the clinical efficacy of anti-PD-1 monotherapy for NSCLC. The serum Abs were measured with enzyme-linked immunosorbent assay (ELISA); however, the ELISA method has several technical limitations for clinical applications. To overcome limitations in Ab measurement, we have developed a fully automated immunoassay system (HISCLTM) using chemiluminescent magnetic immunoassay technology. HISCLTM is widely used in many clinical fields because it is superior to ELISA due to its rapid reaction (17 minutes), wide dynamic ranges, and high reproducibility. Patients and Methods: Sera of NSCLC patients were obtained before anti-PD-1 monotherapy (nivolumab or pembrolizumab) as a part of standard care. NY-ESO-1/XAGE1 serum Abs were measured by ELISA and HISCLTM and their clinical performance was evaluated. In HISCLTM system, serum Abs were captured by magnetic beads coated with antigens, and the antigen-Ab complex was incubated with anti-human IgG conjugated with alkaline phosphatase. The chemiluminescent intensity acquired was then used for analyses. Results: Twenty-eight NSCLC patients were selected as the initial cohort for this study. Half of the patients responded to anti-PD-1 monotherapy and the remaining half did not. There were strong correlations between HISCLTM chemiluminescence signal intensity and titers of NY-ESO-1 and XAGE1 serum Abs in ELISA (r>0.93 for both). Twelve of thirteen Ab-positive patients in HISCLTM responded to anti-PD-1 therapy, while only two of fifteen Ab-negatives did (92% vs. 13%, p Conclusions: We have developed a rapid and highly reproducible immunoassay system for detecting the serum NY-ESO-1 and XAGE1 Abs as predictive biomarkers of clinical benefits with anti-PD-1 monotherapy in NSCLC. In the future, our system would be examined in large-scale clinical trials for various other cancers. Citation Format: Yumiko Sakai, Hirotaka Abo, Kanako Sakaeda, Yusuke Atarashi, Nobuyuki Ide, Takaaki Yamaoka, Koji Kurose, Kenta Noda, Toshiyuki Sato, Toru Oga, Mikio Oka. Development of a fully automated immunoassay system for detection of serum NY-ESO-1 and XAGE1 antibodies as biomarkers predicting the clinical efficacy of anti-PD-1 therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3180.