A recently developed treatment strategy for lung cancer that combines immune checkpoint inhibitors with chemotherapy has been applied as a standard treatment for lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), and it has improved the outcomes of chemotherapy. Maintenance treatment with anti-PD-1 antibody (aPD-1) enhances the effect of immunochemical combination therapy and improves therapeutic efficacy, which contributes toward a significant improvement in patient survival rates. The AXL receptor tyrosine kinase (AXL), which is expressed in tumor cells, plays an essential role in the resistance of cancers to chemotherapy and immunotherapy, and stimulates signaling associated with epithelial-mesenchymal transition (EMT) in metastatic cancer. AXL is thus an attractive target for controlling resistance to anti-tumor therapies. In this study, we examined the effect of AXL inhibitors on immune activation and tumor growth in TC1 and C3PQ mouse tumor models, in the context of clinical immunotherapy/chemotherapy and maintenance treatment, using an aPD-1 with/without pemetrexed. To determine the optimal timing for administration of SKI-G-801, an AXL inhibitor, we investigated its anti-tumor effects based on inclusion at the immunochemotherapy and maintenance therapy stages. We also performed flow cytometry-based immune profiling of myeloid cells and lymphoid cells at different points in the treatment schedule, to investigate the immune activation and anti-tumor effects of the AXL inhibitor. The addition of SKI-G-801 to the immune checkpoint inhibitor and chemotherapy stage, as well as the maintenance therapy stage, produced the best anti-tumor results, and significant tumor growth inhibition was observed in both the TC1 and C3PQ models. Both models also exhibited increased proportion of effector memory helper T cells and increased expression of CD86+ macrophages. Especially, regulatory T cells were significantly reduced in the TC1 tumor model and there was an increase in central memory cytotoxic T cell infiltration and an increased proportion of macrophages with high CD80 expression in the C3PQ tumor model. These results suggest increased infiltration of T cells, consistent with previous studies using AXL inhibitors. It is expected that the results from this study will serve as a stepping stone for clinical research to improve the existing standard of care.

Purpose: Patient-derived cells (PDCs) and organoids (PDOs) are constructed from patient tissue to mimic the biological features of patients. In cancer research, PDC/PDOs have been crucial as they can recapitulate tumor mutations. As heterogeneity between traditional cell lines and the human body leads to clinical trial failure, PDC/PDOs are widely used for predicting the preclinical drug efficacy. The aim of this study is to show that the PDC/PDOs can be used as effective tools for screening novel therapies on non-small cell lung cancer (NSCLC). Experimental design: PDC/PDO models from malignant effusions were established as following. We succeeded the establishment with samples which are positive for malignancy in cytology tests and tumor colony formation. Genotypes are analyzed by Sanger sequencing, Whole exome sequencing, or RNA-sequencing. Cell viability assay was performed using currently approved drugs or drugs in clinical development or their combinations. Results: A total of 46 PDCs and 150 PDOs was established from NSCLC patients, including models harboring sensitizing EGFR mutations, ALK fusions, ROS1 fusions, EGFR exon20 insertion, BRAF V600E, and those harboring various resistance mechanisms to EGFR-TKIs (T790M, C797S/C797G, MET amplification), to ALK-TKIs (G1202R), and to ROS1 TKI (G2032R). Osimertinib-resistant YU-1097 harboring EGFR resistance mutation (E19del/T790M/C797S) revealed sensitivity to BLU-945 (IC50, 108nM), a novel fourth-generation EGFR-TKI. A similar inhibition of cell viability was observed with repotrectinib (IC50, 21nM), a next-generation ROS1-TKI and lorlatinib (IC50, 9nM) in YU-1078 harboring CD74-ROS1, whereas more robust tumor regression was seen with repotrectinib in YU1078-derived xenograft model. Amivantamab, a EGFR-MET bispecific antibody, showed a robust activity in YU-1163 and YUO-036 in vitro and in vivo. YU-1077 harboring ALK G1202R solvent-front mutation showed sensitivity to NVL-655, a next-generation ALK-TKI, with a potency > 10-fold than that of lorlatinib. YUO-010 with MET amplification following osimertinib was sensitive to RGEN 5093-M114, a METxMET bispecific antibody-drug conjugate. Conclusions: PDC/PDO models can be utilized for evaluating activity of novel agents and will accelerate novel drug development in NSCLC. Citation Format: Yunjoo Joo, Sewon Park, Ju-hyeon Lee, Mi Ran Yun, Mi Ra Yu, Chun-Bong Synn, Seung Yeon Oh, Eun Ji Lee, Dong Kwon Kim, Seul Lee, Kyumin Lim, Min Hee Hong, Sun Min Lim, Chang Gon Kim, Ji Yun Lee, Jii Bum Lee, Byoung Chul Cho. Patient-derived cells (PDCs) and organoids (PDOs) as platforms for screening novel therapeutics for NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2857.

Background: The IDO is an enzyme responsible for catabolizing tryptophan (Trp) to kynurenine (Kyn). The kynurenine exert important immunosuppressive functions by activating Treg cells and myeloid-derived suppressor cells. YH29407 is a novel IDO1 inhibitor, improved the pharmacodynamics compared to previous IDO inhibitors. Methods: To evaluate antitumor effects and immune profiles of YH29407, YH29407 was dosed at 50 or 100 mg/kg twice daily (B.I.D.) alone or in combination with anti-PD-1 (10 mg/kg, B.I.W., i.p.) and BMS-986205 was dosed at 125 mg/kg once daily (Q.D.) alone or in combination with anti-PD-1 in a MC38 syngeneic tumor model. The antitumor effects during 11 days of administration of YH29407 alone or combinations and BMS-986205 alone or combination in the MC38 model were measured. Measurements were carried out up to day 50 for survival testing. After 3 days of treatment for each condition, immune cell profiles were evaluated by flow cytometry. Results: The YH29407 at dose of 100 mg/kg B.I.D combination treatment group showed the best effects on tumor size reduction. The group constituting >TGI:70% contained 100% (15/15) of the combination treatment group, whereas 15% (2/13) of competitor BMS-986205 combination group were contained. In addition, in the combination treatment group, most tumors showed an aspect of decrease including complete responses of 5 mice. Moreover, there was a complete response in YH29407 alone group but, not observed in BMS-986205 group. According to flow cytometry analysis, the combination treatment group showed higher CD3+ total T cells compared to the vehicle group (*p<0.05). Also, the effector T cells were respectively increased in the combination treatment group than BMS-986205 alone group. Significantly, helper T cells were increased in the combination treatment group against vehicle group (***p<0.001) and BMS-986205 combination group (*p<0.05). In addition, total macrophages were increased in the combination treatment group than BMS-986205 alone group (*p<0.05). On the other hand, M-MDSC were significantly decreased in the combination treatment group than BMS-986205 combination group (*p<0.05). We evaluated the tumor-infiltrating immune cells by immunohistochemistry, infiltrated CD3+ T cells were increased in the tumor of the combination treatment group than the vehicle group and BMS-986205 combination group (both *p<0.05). Likewise, tumor infiltrated CD8+ T cells were increased in the combination treatment group than vehicle group (**p<0.01) and BMS-986205 combination group (*p<0.05). However, dose-response effect or synergistic effect on immune cell profiles between YH29407 50 mg/kg alone or combination and YH29407 100 mg/kg alone or combination were not observed. Conclusion: Taken together, we suggest that YH29407 is the best combination partner with immune checkpoint inhibitors for solid tumor. Citation Format: Kyoung-Ho Pyo, Dong Kwon Kim, Se-Woong Oh, Gyu-Jin Lee, Ho-Woong Kang, Jae Hwan Kim, Youngseon Byeon, Young Seob Kim, Chun-Bong Synn, Wongeun Lee, Su Hwan Lee, Seul Lee, Seung Min Yang, Soyeon Lee, Yunjoo Joo, Eun Ji Lee, Sun Min Lim, Byoung Chul Cho. Combination therapy with anti-PD-1 and YH29407, a novel IDO1 inhibitor, enhances T cell-mediated antitumor immunity in MC38 tumor-bearing mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5481.