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Background The predictive value of immune monitoring with circulating CD8+ T lymphocytes for treatment response to programmed cell death protein 1 (PD-1) inhibitors has not been explored in non-small-cell lung cancer (NSCLC), prompting us to investigate whether dynamic changes in PD-1+CD8+ T lymphocytes have predictive value for durable clinical benefit (DCB) and survival after PD-1 blockade. Methods Patients with recurrent and/or metastatic NSCLC treated with PD-1 inhibitors were enrolled (discovery cohort; n = 94). Peripheral blood was obtained immediately before and after one cycle of treatment with PD-1 blockade. Phenotyping of circulating CD8+ T lymphocytes was conducted using multi-colour flow cytometry. Predictive values of dynamic changes in circulating PD-1+CD8+ T lymphocytes during the first cycle were validated in an independent cohort (validation cohort; n = 54) of a prospective trial with a PD-1 inhibitor (NCT03486119). Results Circulating PD-1+CD8+ T lymphocytes were enriched with effector/memory populations with elevated expression of activation- and exhaustion-related markers. Reduction in the frequency of PD-1+ cells among CD8+ T lymphocytes after one cycle of treatment was associated with a higher probability of DCB and superior survival outcomes in the discovery cohort. Similar results were obtained in the analysis of tumour antigen NY-ESO-1-specific CD8+ T lymphocytes and the validation cohort. Mechanistically, PD-1 molecule expression on CD8+ T lymphocytes suppresses the effector functions of tumour antigen-specific CD8+ T lymphocytes. Conclusions Dynamic changes in circulating PD-1+CD8+ T lymphocytes predict clinical, and survival benefit from PD-1 blockade treatment in NSCLC, providing a useful tool to identify patient subgroups who will optimally benefit from PD-1 inhibitors.

Background Recurrent and/or metastatic squamous cell carcinoma of head and neck (R/M SCCHN) is a common cancer with high recurrence and mortality. Current treatments have low response rates (RRs). Methods Fifty-three patients with R/M SCCHN received continuous oral buparlisib. In parallel, patient-derived xenografts (PDXs) were established in mice to evaluate resistance mechanisms and efficacy of buparlisib/cetuximab combination. Baseline and on-treatment tumour genomes and transcriptomes were sequenced. Based on the integrated clinical and PDX data, 11 patients with progression under buparlisib monotherapy were treated with a combination of buparlisib and cetuximab. Results For buparlisib monotherapy, disease control rate (DCR) was 49%, RR was 3% and median progression-free survival (PFS) and overall survival (OS) were 63 and 143 days, respectively. For combination therapy, DCR was 91%, RR was 18% and median PFS and OS were 111 and 206 days, respectively. Four PDX models were originated from patients enrolled in the current clinical trial. While buparlisib alone did not inhibit tumour growth, combination therapy achieved tumour inhibition in three of seven PDXs. Genes associated with apoptosis and cell-cycle arrest were expressed at higher levels with combination treatment than with buparlisib or cetuximab alone. Conclusions The buparlisib/cetuximab combination has significant promise as a treatment strategy for R/M SCCHN. Clinical Trial Registration NCT01527877.

EGFR exon 20 insertion driver mutations (Exon20ins) in non–small cell lung cancer (NSCLC) are insensitive to EGFR tyrosine kinase inhibitors (TKI). Amivantamab (JNJ-61186372), a bispecific antibody targeting EGFR–MET, has shown preclinical activity in TKI-sensitive EGFR-mutated NSCLC models and in an ongoing first-in-human study in patients with advanced NSCLC. However, the activity of amivantamab in Exon20ins-driven tumors has not yet been described. Ba/F3 cells and patient-derived cells/organoids/xenograft models harboring diverse Exon20ins were used to characterize the antitumor mechanism of amivantamab. Amivantamab inhibited proliferation by effectively downmodulating EGFR–MET levels and inducing immune-directed antitumor activity with increased IFNγ secretion in various models. Importantly, in vivo efficacy of amivantamab was superior to cetuximab or poziotinib, an experimental Exon20ins-targeted TKI. Amivantamab produced robust tumor responses in two Exon20ins patients, highlighting the important translational nature of this preclinical work. These findings provide mechanistic insight into the activity of amivantamab and support its continued clinical development in Exon20ins patients, an area of high unmet medical need. Significance: Currently, there are no approved targeted therapies for EGFR Exon20ins–driven NSCLC. Preclinical data shown here, together with promising clinical activity in an ongoing phase I study, strongly support further clinical investigation of amivantamab in EGFR Exon20ins–driven NSCLC. This article is highlighted in the In This Issue feature, p. 1079

Simple Summary Patients with epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer can have central nervous system (CNS) metastases during their disease course. A high unmet medical need exists especially for patients with T790M-positive NSCLC whose disease progressed after first-line EGFR-TKI. Osimertinib is a third-generation EGFR-TKI with selective activity for both sensitizing and EGFR T790M mutations and has improved CNS activity over first- and second-generation EGFR TKIs and chemotherapies. This study confirmed the clinical activity and CNS efficacy of osimertinib in an unselected real-world population. Abstract Up to 40% of patients with epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) may develop central nervous system (CNS) metastases throughout their disease. Moreover, the first- and second-generation EGFR-tyrosine kinase inhibitors have limited efficacy because of their poor blood–brain barrier permeability. Therefore, we conducted preplanned analyses of ASTRIS, a clinical study of the third-generation EGFR-TKI osimertinib to demonstrate its potential role in intracranial response efficacies. We retrospectively examined 89 NSCLC patients with brain evaluation who were not amenable to curative surgery or radiotherapy and received osimertinib upon confirmation of the presence of the T790M mutation. We collected the information regarding patients’ baseline characteristics, baseline intracranial status, including leptomeningeal metastases (LM), and intracranial responses measured by Response Evaluation Criteria in Solid Tumors version 1.1, using independent central review. The median age was 60 years, and 69.7% of the patients were female. Sixty-five patients (73.0%) had brain metastases (BM) at baseline and nineteen patients (23.5%) had additional LM. Among patients with brain metastases, 24 (36.9%) had ≥1 measurable brain metastases and 16 were evaluated for the objective response. In the CNS evaluable for response set, the intracranial objective response rate (cORR) and disease control rate (cDCR) were 62.5% (95% confidence interval (CI), 38.3–82.6%) and 93.8% (95% CI, 74.3–99.3%), respectively. The median intracranial progression-free survival (cPFS) was 13.0 (95% CI, 7.21–18.8) months, including patients with measurable and non-measurable BM or LM. Our cORR, cDCR, and cPFS were comparable to those observed in previous clinical trials. The outcome of this study helps to demonstrate the potential role of intracranial efficacies of osimertinib 80 mg administration in T790M-positive advanced NSCLC with/without BM or LM.

Objectives The treatment for stage III non-small cell lung cancer (NSCLC) is quite variable because stage III NSCLC is a heterogenous disease. Programmed death ligand 1 (PD-L1) and CD8+ tumor infiltrating lymphocytes (TILs) are thought to be related to treatment outcome in many tumors. To improve treatment outcome in stage III NSCLC, it is necessary to obtain data on PD-L1 expression and CD8+ TIL counts following CCRT and their relationship to treatment outcome. Materials and methods We retrospectively enrolled 43 patients with stage III NSCLC treated with neoadjuvant CCRT followed by surgery at Yonsei Cancer Center Severance Hospital in Korea between June 2008 and October 2010. PD-L1 level and CD8+ TIL numbers in tumors following CCRT were analyzed by immunohistochemistry, and their association with patient survival was evaluated with Kaplan-Meier method. Results More than half patients (52%) showed up- or downregulation of PD-L1 expression, and most patients (81%) showed change in CD8+ TIL counts by CCRT. Patients with PD-L1 expression following CCRT tended to have shorter recurrence free survival (RFS) (P = 0.182) or overall survival (OS) (P = 0.215) compared to the ones without PD-L1 expression. In the survival analysis with pre-CCRT specimens, neither RFS nor OS showed statistically significant differences. Patients with increased CD8+ TIL counts following CCRT regardless of pathological response strongly showed longer OS (median: not reached vs. 14.2 months for others; P = 0.017). Conclusions CCRT dynamically alters PD-L1 expression and CD8+ TIL numbers in stage III NSCLC. Our data provide a rationale for combining CCRT and immunotherapy for the treatment of potentially resectable NSCLC.

Background Immune checkpoint blockade with Programmed cell death 1 (PD-1)/PD-L1 inhibitors has been effective in various malignancies and is considered as a standard treatment modality for patients with non-small-cell lung cancer (NSCLC). However, emerging evidence show that PD-1/PD-L1 blockade can lead to hyperprogressive disease (HPD), a flair-up of tumor growth linked to dismal prognosis. This study aimed to evaluate the incidence of HPD and identify the determinants associated with HPD in patients with NSCLC treated with PD-1/PD-L1 blockade. Patients and methods We enrolled patients with recurrent and/or metastatic NSCLC treated with PD-1/PD-L1 inhibitors between April 2014 and November 2018. Clinicopathologic variables, dynamics of tumor growth, and treatment outcomes were analyzed in patients with NSCLC who received PD-1/PD-L1 blockade. HPD was defined according to tumor growth kinetics (TGK), tumor growth rate (TGR), and time to treatment failure (TTF). Immunophenotyping of peripheral blood CD8+ T lymphocytes was conducted to explore the potential predictive biomarkers of HPD. Results A total of 263 patients were analyzed. HPD was observed in 55 (20.9%), 54 (20.5%), and 98 (37.3%) patients according to the TGK, TGR, and TTF. HPD meeting both TGK and TGR criteria was associated with worse progression-free survival [hazard ratio (HR) 4.619; 95% confidence interval (CI) 2.868–7.440] and overall survival (HR, 5.079; 95% CI, 3.136–8.226) than progressive disease without HPD. There were no clinicopathologic variables specific for HPD. In the exploratory biomarker analysis with peripheral blood CD8+ T lymphocytes, a lower frequency of effector/memory subsets (CCR7−CD45RA− T cells among the total CD8+ T cells) and a higher frequency of severely exhausted populations (TIGIT+ T cells among PD-1+CD8+ T cells) were associated with HPD and inferior survival rate. Conclusion HPD is common in NSCLC patients treated with PD-1/PD-L1 inhibitors. Biomarkers derived from rationally designed analysis may successfully predict HPD and worse outcomes, meriting further investigation of HPD.

Purpose: Given that osimertinib is the only approved third-generation EGFR-TKI against EGFR activating and resistant T790M mutated non–small cell lung cancer (NSCLC), additional mutant-selective inhibitors with a higher efficacy, especially for brain metastases, with favorable toxicity profile are still needed. In this study, we investigated the antitumor efficacy of YH25448, an oral, mutant-selective, irreversible third-generation EGFR-TKI in preclinical models. Experimental Design: Antitumor activity of YH25448 was investigated in vitro using mutant EGFR-expressing Ba/F3 cells and various lung cancer cell lines. In vivo antitumor efficacy, ability to penetrate the blood–brain barrier (BBB), and skin toxicity of YH25448 were examined and compared with those of osimertinib using cell lines and PDX model. Results: Compared with osimertinib, YH25448 showed a higher selectivity and potency in kinase assay and mutant EGFR-expressing Ba/F3 cells. In various cell line models harboring EGFR activating and T790M mutation, YH25448 effectively inhibited EGFR downstream signaling pathways, leading to cellular apoptosis. When compared in vivo at equimolar concentrations, YH25448 produced significantly better tumor regression than osimertinib. Importantly, YH25448 induced profound tumor regression in brain metastasis model with excellent brain/plasma and tumor/brain area under the concentration–time curve value. YH25448 rarely suppressed the levels of p-EGFR in hair follicles, leading to less keratosis than osimertinib in animal model. The potent systemic and intracranial activity of YH25448 has been shown in an ongoing phase I/II clinical trial for advanced EGFR T790M mutated NSCLC (NCT03046992). Conclusions: Our findings suggest that YH25448 is a promising third-generation EGFR inhibitor, which may be more effective and better tolerated than the currently approved osimertinib.

Objective Anti–programmed death (PD)-1 therapy confers sustainable clinical benefits for patients with non–small-cell lung cancer (NSCLC), but only some patients respond to the treatment. Various clinical characteristics, including the PD-ligand 1 (PD-L1) level, are related to the anti–PD-1 response; however, none of these can independently serve as predictive biomarkers. Herein, we established a machine learning (ML)–based clinical decision support algorithm to predict the anti–PD-1 response by comprehensively combining the clinical information. Materials and methods We collected clinical data, including patient characteristics, mutations and laboratory findings, from the electronic medical records of 142 patients with NSCLC treated with anti–PD-1 therapy; these were analysed for the clinical outcome as the discovery set. Nineteen clinically meaningful features were used in supervised ML algorithms, including LightGBM, XGBoost, multilayer neural network, ridge regression and linear discriminant analysis, to predict anti–PD-1 responses. Based on each ML algorithm's prediction performance, the optimal ML was selected and validated in an independent validation set of PD-1 inhibitor–treated patients. Results Several factors, including PD-L1 expression, tumour burden and neutrophil-to-lymphocyte ratio, could independently predict the anti–PD-1 response in the discovery set. ML platforms based on the LightGBM algorithm using 19 clinical features showed more significant prediction performance (area under the curve [AUC] 0.788) than on individual clinical features and traditional multivariate logistic regression (AUC 0.759). Conclusion Collectively, our LightGBM algorithm offers a clinical decision support model to predict the anti–PD-1 response in patients with NSCLC.

Background Although cancer immunotherapy showed promising results in hematological malignancies, it has come up with relatively low tumor response for many solid tumors partly due to immune-suppressive tumor microenvironment (TME). Because of the immune-suppressive nature of TME, TME has been an active area of research and therapeutic target for restoring immune system and subsequent tumor growth inhibition. Among the many components in TME, cancer-associated fibroblasts (CAFs) are one of the key cell components of TME where one of the promising solid-tumor TME marker, fibroblast-activating protein (FAP) is highly expressed. Here we have developed an antibody-cytokine fusion protein from our TMEkine™ platform containing anti-FAP and IL-12. Our TMEkine™ (anti-FAP-IL-12) molecule induced strong anti-cancer effects in preclinical solid tumor models by immune-modulation. Methods IL-12 cytokine was mutated in TMEkine™ (anti-FAP-IL-12) to reduce systemic toxicity and its binding affinity was tested to FAP and IL-12 receptor. The anti-tumor activity of anti-FAP-IL-12 was investigated on CT26 (murine colorectal cancer) syngeneic mouse models with/without NIH-3T3 (murine fibroblast). Additionally, mice showing complete response after anti-FAP-IL-12 administration were re-injected CT26 with/without 4T1 cells for re-challenge study to monitor long-term durable response generated from the initial immune activation. Results We showed that TMEkine™ (anti-FAP-IL-12) interacts with FAP and IL-12 receptor. IL-12 activity was attenuated by our IL-12 mutants. We also showed that TMEkine™ (anti-FAP-IL-12) induced IFN-γ from primary human T cells and NK cells. TMEkine™ (anti-FAP-IL-12) administration resulted in significant reduction of the tumor burden in both CT26+NIH-3T3/FAP+ and CT26/FAP+ models. In the re-challenge experiments, CT26 tumor growth was inhibited significantly compared to 4T1 tumor suggesting memory immune response was generated in TMEkine™ (anti-FAP-IL-12) treated mice. Conclusions These findings provide evidences that the treatment of anti-FAP/IL-12 TMEkine™ induced anti-cancer effects without serious adverse effects. Anti-FAP/IL-12 has a strong potential to provide a therapeutic option for cancer-specific immunomodulator and cancer cell eradication.

Background Targeting transforming growth factor-β (TGF-β) is reported to augment the efficacy of immune checkpoint inhibitors (ICIs) through either enhanced anti-tumor immunity or the correction of tumor microenvironment (TME). Therefore, the combination of vactosertib, a highly selective TGF-β RI kinase inhibitor, and durvalumab is anticipated to improve anti-tumor activity of the ICI. A phase 1b/2a study was conducted to evaluate the combination of vactosertib and durvalumab in patients with advanced NSCLC who progressed after platinum-based chemotherapy. Methods Patients were treated with vactosertib at a dose of 200 mg twice daily (five days on and two days off) and durvalumab at a dose of 1500 mg every four weeks. Eligible patients were ≥19 years old with good performance status (ECOG 0–1) and have no prior exposure to immune checkpoint inhibitors or other TGF- β R1 kinase inhibitors. The objectives of this analysis were to evaluate the safety, antitumor activity including objective response rate (ORR), duration of response (DOR), and time to response (TTR) as well as circulating pharmacodynamic biomarkers related to TGF-β signaling. Response was assessed per RECIST (v1.1). Results By August 4 2020, twenty-six PD-L1 positive (SP263 assay) patients were analyzed. Median age was 61.5 years (range 48–83), 69.2% were male, median number of previous lines of chemotherapy was 1 (range 1–4), and all patients were PD-L1 positive (15 patients with PD-L1≥25% and 11 patients with PD-L1 1–24%). The most frequently reported treatment-related adverse events (TRAE) were itching (38.5%) and skin rash (34.6%), but no Gr≥3 itching and rash were observed. Each case of the following was reported as Grade 3 TRAEs: adrenal insufficiency, anemia, and pneumonitis; Grade 4 TRAE, CPK increase, was observed in one patient. Objective response rate was 30.8% and 40.0% in patients with PD-L1≥1% and ≥25% respectively. Circulating PAI-1 and CTGF evaluated in 15 patients decreased significantly on Cycle 1 day 5. Ongoing biomarker results will be presented. Conclusions The combination of vactosertib and durvalumab has demonstrated a manageable safety profile and encouraging anti-tumor activity as a potential therapeutic strategy in patients with advanced NSCLC. The efficacy outcomes of this combination in a larger number of patients with advanced NSCLC will be followed. Trial Registration NCT03732274 Ethics Approval The study was approved by Ethics Board of Severance Hospital (4-2018-0892), National Cancer Center (NCC2019-0057), St. Vincent’s Hospital (VC19MDDF0205), and Chungbuk National University Hospital (2019-08-015).

BackgroundEML4-ALK is a distinct molecular entity that is highly sensitive to ALK tyrosine kinase inhibitors (TKIs). Immune checkpoint inhibitors (ICIs) have not proved efficacy in ALK-positive non-small cell lung cancer so far. In this study, we performed a mouse clinical trial using EML4-ALK transgenic mice model to comprehensively investigate immunomodulatory effects of ALK TKI and to investigate the mechanisms of resistance to ICIs.MethodsEML4-ALK transgenic mice were randomized to three treatment arms (arm A: antiprogrammed death cell protein-1 (PD-1), arm B: ceritinib, arm C: anti-PD-1 and ceritinib), and tumor response was evaluated using MRI. Progression-free survival and overall survival were measured to compare the efficacy. Flow cytometry, multispectral imaging, whole exome sequencing and RNA sequencing were performed from tumors obtained before and after drug resistance.ResultsMouse clinical trial revealed that anti-PD-1 therapy was ineffective, and the efficacy of ceritinib and anti-PD-1 combination was not more effective than ceritinib alone in the first line. Dynamic changes in immune cells and cytokines were observed following each treatment, while changes in T lymphocytes were not prominent. A closer look at the tumor immune microenvironment before and after ceritinib resistance revealed increased regulatory T cells and programmed death-ligand 1 (PD-L1)-expressing cells both in the tumor and the stroma. Despite the increase of PD-L1 expression, these findings were not accompanied by increased effector T cells which mediate antitumor immune responses.ConclusionsALK-positive tumors progressing on ceritinib is not immunogenic enough to respond to immune checkpoint inhibitors.

Background We investigated whether head and neck squamous cell carcinoma (HNSCC) patient-derived xenografts (PDXs) reaffirm patient responses to anti-cancer therapeutics. Methods Tumors from HNSCC patients were transplanted into immunodeficient mice and propagated via subsequent implantation. We evaluated established PDXs by histology, genomic profiling, and in vivo anti-cancer efficacy testing to confirm them as the authentic in vivo platform. Results From 62 HNSCCs, 15 (24%) PDXs were established. The primary cancer types were tongue (8), oropharynx (3), hypopharynx (1), ethmoid sinus cancer (1), supraglottic cancer (1), and parotid gland (1); six PDXs (40%) were established from biopsy specimens from advanced HNSCC. PDXs mostly retained donor characteristics and remained stable across passages. PIK3CA (H1047R), HRAS (G12D), and TP53 mutations (H193R, I195T, R248W, R273H, E298X) and EGFR, CCND1, MYC, and PIK3CA amplifications were identified. Using the acquisition method, biopsy showed a significantly higher engraftment rate when compared with that of surgical resection (100% [6/6] vs. 16.1% [9/56], P P P = 0.311), suggesting that HPV positivity tends to show a low engraftment rate. Drug responses in PDX recapitulated the clinical responses of the matching patients with pan-HER inhibitors and pan-PI3K inhibitor. Conclusions Genetically and clinically annotated HNSCC PDXs could be useful preclinical tools for evaluating biomarkers, therapeutic targets, and new drug discovery.

The development of cancer therapies using monoclonal antibodies has been successful during the last 30 years. Recently much progress was achieved with technologies involving bispecific and multi-specific antibodies. Bispecific antibodies (BsAbs) are antibodies that bind two distinct epitopes, and a large number of potential clinical applications of BsAbs have been described. Here we review mechanism of action, clinical development and future challenges of BsAbs which could be a serve as a valuable arsenal in cancer patients.

Introduction: GI-101 was designed to address the significant unmet needs in immunotherapy for noninflamed tumor. The harmonized mechanisms of action consist of the extracellular domain of CD80 acting as a CTLA-4 inhibitor, together with a long-acting IL-2 variant that preferentially binds to the IL2Rβ. Therefore, GI-101 can play a role in the activation of cytotoxic immune cells and inhibition of CTLA-4-B7.1 axis-based immune suppression. Methods: The binding affinity of GI-101 to IL-2Rs, CTLA-4, and CD28 was performed by SPR and immune cell proliferation was analyzed by CFSE assay in vitro. GI-101 induced dose-dependent pharmacodynamics effects with consistent magnitude following repeat administration in monkeys. Direct anti-tumor effect of GI-101 was tested by single or combination treatment manner in multiple syngeneic and humanized models. Immune profiling in TME was analyzed by flow cytometry, IHC and IFN-γ ELISPOT assay. To mimic the standard care (SOC) in clinic, TC1 lung cancer model was involved in evaluating the efficacy of both 1st line and maintenance therapy of GI-101 with or without immuno-chemotherapy (Cisplatin, Pemetrexed, and anti-PD-1). Results: CD80 of GI-101 highly binds to CTLA-4 (Kd, 2.9nM), acting as a decoy ligand. IL-2 variant induces CD8+ T and NK cell proliferation. However, GI-101 had no evidence of toxicity related to IL-2 activity in the non-GLP monkey study, including vascular leakage syndrome and cytokine storm. GI-101 elicits improved restoration of immune functions in human PBMCs co-cultured setting with PD-L1/CTLA-4 co-expressed tumor cells. A dose-dependent (3 to 12 mg/kg) single inhibition of tumor growth was observed in CT26 syngeneic model. Immune profiling revealed a robust increase of M1 macrophages, CD8+ central memory T (Tcm) and NK cells but not Tregs in TME. Splenocyte tumor-specific immune cells were strongly proliferated when stimulated with CT26 neoantigens (gp70). IFN-γ+ T cells were significantly increased in draining lymph nodes from GI-101 treated mice. Furthermore, GI-101 was superior at inhibiting tumor growth when co-treated with anti-PD-1 in syngeneic (MC38, TC1, and B16F10) and MDA-MB-231 humanized mice models. Finally, the combination of GI-101 and immuno-chemotherapy showed not only suppressed tumor growth but also improved survival compared to immuno-chemotherapy alone. Conclusion: The complementary modes of action of GI-101 via checkpoint blockade and IL-2 activity to enhance the proliferation and activation of Tcm and NK cells are projected to translate into superior clinical efficacy and safety as indicated even in ‘cold tumor' models. GI-101 has promising potential to replace the first-generation ICBs as a monotherapy or in combination with other immunotherapies. Our findings provide a rationale for further clinical investigations. Citation Format: Kyoung-Ho Pyo, Young Jun Koh, Chun-Bong Synn, Jae Hwan Kim, Youngseon Byeon, Ha Ni Jo, Young Seob Kim, Wongeun Lee, Do Hee Kim, Seul Lee, Dong Kwon Kim, Eun ji Lee, Beung-Chul Ahn, Min Hee Hong, Myoung Ho Jang, Sun Min Lim, Hye Ryun Kim, Su Youn Nam, Byoung Chul Cho. Comprehensive preclinical study on GI-101, a novel CD80-IgG4-IL2 variant protein, as a therapeutic antibody candidate with bispecific immuno-oncology target [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1826.

Background: AXL has been identified to play multiple roles in the tumor microenvironment including the promotion of epithelial-mesenchymal transition and immune evasion. SKI-G-801, a small molecule inhibitor targeting phosphorylation of AXL, presented strong inhibition of cancer migration and invasion. Anti-PD-1(αPD-1) combined with paclitaxel(Pac)/carboplatin(Carbo) and pemetrexed(Pem)/cisplatin(Cis) are standard therapy in non-squamous and squamous lung cancer patients, respectively. Herein, we present that adding AXL inhibition with SKI-G-801 on αPD-1 plus chemotherapy suppressed tumor growth and improved overall survival and also enhanced anti-tumor T cell immunity in both non-squamous and squamous lung cancer models. Methods: C3PQ squamous and TC-1 non-squamous lung cancer bearing mouse models were established. In C3PQ squamous model, mice were treated with 2 cycles of induction Carbo + Pac + αPD-1 and 13 cycles of maintenance with αPD-1. In TC-1 non-squamous model, mice were treated with 3 cycles of induction with Cis + Pem + αPD-1 and 14 cycles of maintenance therapy. Both models included the groups of SKI-G-801 treatment from induction therapy and/or maintenance therapy. The tumor growth and survival were monitored for 60 days in both models. The tumor infiltrated lymphocytes were analyzed by flow cytometry. Results: In TC-1 non-squamous model, upfront addition of SKI-G-801 on αPD-1 plus Pem/Cis chemotherapy followed by αPD-1 and Pem maintenance showed the superior overall survival to the others (vs. αPD-1+ Pem/Cis and αPD-1 + Pem maintenance; p Conclusion: Incorporation of SKI-G-801, a novel AXL inhibitor, with αPD-1 combined with chemotherapy significantly improved overall survival and anti-tumor activity in both non-squamous and squamous lung cancer model through enhancing cytotoxicity of CD8+ T cells and memory CD4+ T cells. These findings provide mechanistic insight into the activity of SKI-G-801 combined with standard therapy and support its clinical development in metastatic NSCLC as first line therapy. Citation Format: Kyoung-Ho Pyo, Wongeun Lee, Hee Kyu Lee, Dong Kwon Kim, Ha Ni Jo, Chun-Bong Synn, Jae Hwan Kim, Yeongseon Byeon, Young Seob Kim, Beung-Chul Ahn, Min Hee Hong, Sun Min Lim, Byoung Chul Cho, Hye Ryun Kim. Incorporation of SKI-G-801, novel AXL inhibitor, with anti-PD-1 inhibitor plus chemotherapy improved anti-tumor activity and survival outcome via enhancing anti-tumor T cell immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1471.

Objectives: Patients with epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC) ultimately acquire resistance to EGFR tyrosine kinase inhibitors (TKIs) during treatment. In 5–22% of these patients, resistance is mediated by aberrant mesenchymal epithelial transition factor (MET) gene amplification. Here, we evaluated the emergence of MET amplification after EGFR-TKI treatment failure based on clinical parameters. Materials and Methods: We retrospectively analyzed 186 patients with advanced EGFR-mutant NSCLC for MET amplification status by in situ hybridization (ISH) assay after EGFR-TKI failure. We collected information including baseline patient characteristics, metastatic locations and generation, line, and progression-free survival (PFS) of EGFR-TKI used before MET evaluation. Multivariate logistic regression analysis was conducted to evaluate associations between MET amplification status and clinical variables. Results: Regarding baseline EGFR mutations, exon 19 deletion was predominant (57.5%), followed by L858R mutation (37.1%). The proportions of MET ISH assays performed after first/second-generation and third-generation TKI failure were 66.7% and 33.1%, respectively. The median PFS for the most recent EGFR-TKI treatment was shorter in MET amplification-positive patients than in MET amplification-negative patients (median PFS 7.0 vs. 10.4 months, p = 0.004). Multivariate logistic regression demonstrated that a history of smoking, short PFS on the most recent TKI, and less intracranial progression were associated with a high probability of MET amplification (all p &lt, 0.05). Conclusions: Our results demonstrated the distinct clinical characteristics of patients with MET amplification-positive NSCLC after EGFR-TKI therapy. Our clinical prediction can aid physicians in selecting patients eligible for MET amplification screening and therapeutic targeting.

Adequate preclinical model and model establishment procedure are required to accelerate translational research in lung cancer. We streamlined a protocol for establishing patient-derived cells (PDC) and identified effective targeted therapies and novel resistance mechanisms using PDCs. We generated 23 PDCs from 96 malignant effusions of 77 patients with advanced lung adenocarcinoma. Clinical and experimental factors were reviewed to identify determinants for PDC establishment. PDCs were characterized by driver mutations and in vitro sensitivity to targeted therapies. Seven PDCs were analyzed by whole-exome sequencing. PDCs were established at a success rate of 24.0%. Utilizing cytological diagnosis and tumor colony formation can improve the success rate upto 48.8%. In vitro response to a tyrosine kinase inhibitor (TKI) in PDC reflected patient treatment response and contributed to identifying effective therapies. Combination of dabrafenib and trametinib was potent against a rare BRAF K601E mutation. Afatinib was the most potent EGFR-TKI against uncommon EGFR mutations including L861Q, G719C/S768I, and D770_N771insG. Aurora kinase A (AURKA) was identified as a novel resistance mechanism to olmutinib, a mutant-selective, third-generation EGFR-TKI, and inhibition of AURKA overcame the resistance. We presented an efficient protocol for establishing PDCs. PDCs empowered precision medicine with promising translational values.

// Kyoung-Ho Pyo 1, 4 , You-Won Lee 1 , Sun Min Lim 2 , Eun-Hee Shin 1, 3 1 Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul, Republic of Korea 2 Division of Medical Oncology, Department of Internal Medicine, CHA Bundang Medical Center, CHA University, Republic of Korea 3 Seoul National University Bundang Hospital, Seongnam, Republic of Korea 4 Current address: JE-UK Laboratory of Molecular Cancer Therapeutics, Yonsei Cancer Institute, Yonsei University College of Medicine, Seoul, Republic of Korea Correspondence to: Eun-Hee Shin, email: ehshin@snu.ac.kr Keywords: Toxoplasma gondii, Toll-like receptor, profilin, antitumor, vaccine Received: July 15, 2016 Accepted: September 21, 2016 Published: September 28, 2016 ABSTRACT Profilin-like protein in Toxoplasma gondii (TgPLP) is a Toll-like receptor (TLR) agonist. In this study, we investigated whether TgPLP has an adjuvant effect on immune function in autologous whole-tumor-cell vaccine (AWV) treatment. Mice vaccinated with AWV together with recombinant TgPLP protein had smaller CT26 tumors and increased survival. TgPLP treatment strongly increased the production of IL-12 through MyD88 signaling and several chemokines, including CCL5, CCL12, and XCL1, in bone marrow-derived macrophages (BMMs). In addition, TgPLP increased the phagocytosis of tumor cells by BMMs and promoted immune cell mobility on a tumor-matrigel scaffold. TgPLP triggered immune responses as demonstrated by increased expression of antigen presenting cell markers (MHC class I and II, B7.1, and B7.2) in BMMs and increased IL-12 and IFN-γ expression in mice. Mice vaccinated with AWV and TgPLP had more immune cells (CD4 + and CD8 + T cells, natural killer cells, and macrophages) in the spleen and higher total IgG and IgG2a concentrations in the blood than mice vaccinated with AWV alone. These findings suggest that TgPLP is a TLR-based vaccine adjuvant that enhances antitumor immune responses during vaccination with AWV.

PURPOSE: Although EGFR exon20 insertion (ex20ins) mutations account for 4~12 % of EGFR mutant NSCLC patients, there is no effective and selectable anticancer drugs targeting ex20ins mutations so far due to various variant mutations in ex20ins mutations. Moreover, most EGFR ex20ins mutants show primary resistance to EGFR TKIs. JNJ-61186372 (JNJ-372), a bispecific antibody that targets the EGFR and cMet receptors, is currently being explored in a first-in-human study in patients with NSCLC. To better understand the mechanism of JNJ-372 activity in this patient population, we conducted preclinical studies exploring the activity of JNJ-372 in different EGFR ex20ins models. METHODS: To elucidate whether JNJ-372 has antitumor effect in EGFR ex20ins mutants via EGFR and c-MET inhibition, cell viability, western blot, cell cycle, colony formation assay, FACS analysis were performed in JNJ-372 treated BaF3 cells, PDCs, PDOs, and PDX expressing EGFR ex20ins mutation. For mouse tumor models, JNJ-372 was administered i.p. twice a week at 10 mg/kg or 30 mg/kg. Antibody dependent cellular cytotoxicity (ADCC) assay was assessed to figure out whether JNJ-372 had ADCC effects. Referenced patients with ex20ins disease were administered 1050 mg JNJ-372 i.v. weekly for the first 4-week cycle, then biweekly for each subsequent cycle RESULTS: JNJ-372 inhibited the growth of BaF3 cells, PDCs, and a PDO harboring a range of ex20ins, which were resistant to osimertinib and gefitinib. Mechanistic assays revealed the reduction of EGFR and cMet receptor levels and decreases in phospho-EGFR and c-Met, as well as inhibition of their downstream signaling pathways. Cleaved caspase-3 and BIMEL were upregulated at anti-proliferative doses, suggesting caspase-mediated cell death. JNJ-372 demonstrated corresponding antitumor activity in PDC and PDX models harboring different ex20ins; inhibition of signaling and engagement of the apoptotic pathway was confirmed in tumors of JNJ-372-treated mice. In PDCs with EGFR ex20ins mutation, we verified that JNJ-372 had a significant ADCC effect compared to EGFR antibody drug cetuximab. In the first-in-human trial, CT scans from two patients treated with JNJ-372 revealed reductions in tumor burden. A 58-year patient harboring H773delinsNPY showed -63% tumor reduction with progression-free survival of > 20 months and a 48-year patient harboring S768_D770dup showed -38.9% tumor reduction. CONCLUSION: JNJ-372 drives antitumor activity in preclinical models of EGFR ex20ins, which have no therapeutic options in clinic, by decreasing EGFR and cMet receptor levels, inhibiting downstream signaling cascades, activating apoptotic signaling as well as ADCC. These results provide a promising therapeutic option to patients with EGFR ex20ins mutations and an understanding of the activity of JNJ-372 being observed in the first-in-human study. Citation Format: Jiyeon Yun, Han Na Kang, Soo-Hwan Lee, Seo-Yoon Jeong, Chae Won Park, Jae-Hwan Kim, Kyoung-Ho Pyo, Ji Min Lee, Seok-Young Kim, Min Hee Hong, Hye Ryun Kim, Meena Thayu, Joshua Curtin, Roland Knoblauch, Matthew Lorenzi, Byoung Chul Cho. JNJ-61186372, an EGFR-cMet bispecific antibody, in EGFR Exon 20 insertion-driven advanced non-small cell lung cancer (NSCLC) [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 5199.

Introduction: Therapeutic monoclonal antibodies targeting immune checkpoints inhibitors (ICIs) are game changers in the treatment landscape of multiple solid tumors. However, response rate remains relatively low in most cases. Particularly, anti-PD-1 or PD-L1 therapies are not effective in EML4-ALK rearranged- and EGFR mutant-NSCLC patients due to their cold immune microenvironment. Recently, activation of stimulator of interferon genes (STING) has shown potential to enhance antitumor immunity through induction of various pro-inflammatory cytokines and chemokines. In this study, we attempted to induce inflamed tumor microenvironment by artificially generating skin metastasis using intratumoral STING activation in EML4-ALK transgenic mice. Methods: EML4-ALK transgenic mice were implanted with a new EML4-ALK tumor subcutaneously. The size of lung primary tumor and subcutaneous tumor were each measured by micro-MRI and calipers, respectively. The treatment groups were divided into the control group, tumor-implanted group, and intratumor STING activation group (skin). On day 14, subcutaneous tumor, primary tumor (lung), and systemic immune organs were collected for further analysis. Results: STING agonist promotes pIRF3 signaling and massive immune cell recruitment in skin region, the subcutaneous tumor was dramatically reduced with hyperinflammation. In addition, primary tumor (lung) was observed with increased T cell population in tumor with necrotic regions. IFN-gamma expression was increased in bronchoalveolar fluid in STING activation group compared to control and tumor only groups (P < 0.05). Tumor macrophages and NK cells were increased compared to control group (P < 0.05, P = ns, respectively). We considered that skin consists of cutaneous innate immune cells, especially, macrophage. Increased T cells and macrophages were observed in STING activated tumor within 6 hours. The in vitro assay proved that macrophages highly express chemokines (CCL5, CCL2, and CCL12) which is recruiting T cells and myeloid cells. This initial immune activation results in increased tumor-specific T cell, especially, memory helper T cell (CD3+CD4+CD44+) in spleen, LN and MLN. We tested anti-IFN-beta antibody for neutralization of STING activity in vivo. The IFN-gamma expression of lymphocytes in MLN was reduced but not significant. Conclusion: This study confirmed that STING activation in cold tumor alters inflamed-immunologic milieu of primary tumor via hyper cutaneous immune activity with pivotal roles of macrophage. Our findings provide a rationale for further clinical investigations. Keywords: STING, cutaneous metastasis, EML4-ALK Citation Format: Chun-Bong Synn, Ji Min Lee, SunMin Lim, Do Hee Kim, Bianca-Ioana Gheorghiu, Jae-Hwan Kim, Wongeun Lee, Sung-Eun Kim, Sungwon Park, Beung-Chul Ahn, Ha Ni Jo, Min Hee Hong, Hye Ryun Kim, Kyoung-Ho Pyo, Byung Chul Cho. Intratumoral STING activation on artificially generated cutaneous metastasis of EML4-ALK lung cancer alters immunologic milieu of primary tumor [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 3325.

To better understand the immune profile within the tumor microenvironment (TME) and the potential immune-evasion capacity that may arise from administration of immune checkpoint inhibitors, we investigated immunological phenotypes and their correlations with genomic alterations in order to provide predictive/prognostic implications in lung adenocarcinoma (LAC).Surgical sections with corresponding peripheral blood mononuclear cells were collected from 76 patients with pathologically confirmed Ia-IIIa. The histological contents expressing immune checkpoint molecules in the tumor nest and stromal area were imaged and quantified using a multi-spectral imaging system. Distribution of tumor mutation burden (TMB) and non-synonymous somatic mutations were analyzed in whole exome sequencing (WES) data.Total 76 patients consisted of EGFR-mutant (n=37) and EGFR-wild type (n=39) tumors. As is well known, the number of tumor-infiltrating cytotoxic T cells (174.7 ± 24.4 cells/mm2) and TMB (3.8 ± 0.4) in EGFR-mutant tumors was significantly lower than those of EGFR wild type tumors (394.2 ± 82.3 cells/mm2 and 6.7 ± 1.2) (p=0.0146 and p=0.0254, respectively), elucidating EGFR mutation-mediated immune evasion. The subjects carrying EGFR wild-type were classified into two subgroups by the density of tumor-infiltrating cytotoxic T cells, defined as the high TIL (n=20) and low TIL (n=19). There was great difference of mean density of cytotoxic T cells between low TIL group (129.6 ± 16.8 cells/mm2) and high TIL group (672.8±143.5 cells/mm2). Tumor-infiltrating T cells were granzyme B-positive, suggesting most cells were tumor-specific. Interestingly, no significant difference in TMB was found between the two subgroups (7.5 ± 1.9 in low TIL group vs. 5.8±1.3 in high TIL group; p=0.4642). Tumor proportion score (TPS) of PD-L1 was remarkably higher in high TIL group than low TIL group (29.7 ± 6.5% vs. 13.9 ± 2.8%, p=0.0008, respectively), but no significant differences of tumoral CD73 and IDO between the two groups (p=0.643 and p=0.923, respectively). Even there were no significant differences in counts of tumor-infiltrating macrophages in all types of macrophage, significantly higher counts of PD-L1+ M1-type macrophages (CD68+ CD163low) in the stromal area were discovered in the high TIL group compared to those of the low TIL group (396.2 ± 93.6 vs. 139.8 ± 30.1, p=0.0114, respectively), indicating that most of macrophages resided in the stromal area. Interestingly, the low TIL group exhibited higher counts of CD73+ M2-type macrophages (CD68+ CD163high) in the stromal area than the high TIL group (644.5 ± 110.9 vs. 387.9 ± 73.2, p=0.0639, respectively). Cell count ratio (M1/M2) of macrophages was significantly higher in the high TIL group (p=0.0042), suggesting that the TME with a smaller number of TILs tends to contain more M2-type macrophages. The tumor recurrence was more frequent in the low TIL group compared to the high TIL group with no statistical significance (p=0.127). In surgically resected lung adenocarcinoma patients, the subgroup with a low density of tumor-infiltrating cytotoxic T cells had a large number of CD73+ M2-type macrophages, which may contribute to poor prognosis. Acknowledgement: This study was sponsored by Ono Pharma Co., Ltd Citation Format: Jae-Hwan Kim, Tae-Min Kim, Sung-Gu Her, Kyoung-Ho Pyo, Jeong- Oh Kim, Beung-Chul Ahn, Byoung Chul Cho, Jin Hyoung Kang. Comprehensive analysis of immune phenotypes identifies CD73+ CD163high macrophages as a prognostic biomarker in lung adenocarcinoma [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 4981.

Introduction: Neoadjuvant therapy suggests the systemic treatment of cancer prior to surgical therapy. The main purpose of neoadjuvant therapy is to improve surgical outcomes in patients for whom a primary surgical approach is difficult to practice. Recently, Anti-PD-1 has been applied to neoadjuvant and adjuvant therapy, but the anti-cancer responses are not sufficient to prevent tumor recurrence. According to our previous study, a novel AXL inhibitor, SKI-G-801 strongly inhibits metastasis of syngeneic tumor with immune responses. The primary goal of this study is to overcome limitation of anti-PD-1 based neoadjuvant and adjuvant therapy with SKI-G-801. Methods: 4T1 cancer bearing mouse models were established for neoadjuvant or adjuvant treatment. Mice were treated with single anti-PD-1 (BIW), SKI-G-801 (QD) or a combination for 6 days, followed by the surgical dissection of tumor tissue in a subcutaneous xenograft model. In five mice per group, their survival rates were monitored for 50 days. We used flow cytometry and immunohistochemistry for comprehensive immune profiling and tumor-infiltrating lymphocytes (TILs) from three mice per group surgically removed tumor tissues. Three tumors per group were stained, and CD3-positive cells per unit area (mm2) were analyzed using Vectra Polaris. Results: According to results, the median survival of control group (only surgical operation without treatment) was 16 days (N=5), whereas, the longest survival group was neoadjuvant-combination (median survival = 37 days). Two out of five mice were survived until end of experiment (D-50). Most of the groups had similar outcomes excluding neoadjuvant-combination group. The median survival of adjuvant-anti-PD-1 group was 30 days, and adjuvant-SKI-G-801 and neoadjuvant-anti-PD-1 group were 25 days. The Neoadjuvant-SKI-G-801 was recorded 23.5 days. Statistically, survival rate of neoadjuvant-combination therapy was significantly higher than of neoadjuvant-anti-PD-1 and neoadjuvant-SKI-G-801 (log-rank test, p Conclusion: This study confirmed that a potential combination with aPD-1 and SKI-G-801 applies to neoadjuvant therapy, as evidenced by increased T cell infiltration and function. Our findings provide a rationale for further clinical investigations. Keywords: Axl inhibitor, Neoadjuvant therapy, Adjuvant therapy, Immunotherapy, Anti-PD-1 Citation Format: Ha Ni Jo, Wongeun Lee, Chun-Bong Synn, Hee Kyu Lee, Jae-Hwan Kim, Yeongseon Byeon, Sung Eun Kim, Ji Min Lee, Do Hee Kim, Jung-Ho Kim, Beung-Chul Ahn, Min Hee Hong, Hye Ryun Kim, Kyoung-Ho Pyo, Byoung Chul Cho. Neoadjuvant and adjuvant anti-PD-1 based combination immunotherapy with a novel AXL inhibitor, SKI-G-801 in syngeneic tumor model: A combined analysis of immune profiling [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 5189.

e21690 Background: The predictive value of dynamic changes in the expression of programmed cell death-1 (PD-1) among circulating CD8+ T lymphocytes for treatment response to PD-1 inhibitors has not been explored in non-small-cell lung cancer (NSCLC). This study aimed to investigate whether dynamic changes in PD-1+CD8+ T lymphocytes have predictive value with respect to durable clinical benefit (DCB) and survival after PD-1 blockade. Methods: Patients with recurrent and/or metastatic NSCLC treated with PD-1 inhibitors were enrolled between March 2016 and August 2018 (discovery cohort; n = 94). Peripheral blood was obtained immediately before and after one cycle of treatment with PD-1 blockade. Phenotyping of circulating CD8+ T lymphocytes was conducted using multi-color flow cytometry. Predictive values of dynamic changes in circulating PD-1+CD8+ T lymphocytes during the first cycle were validated in an independent cohort (validation cohort; n = 54) of a prospective trial with PD-1 inhibitor (NCT03486119). Results: Circulating PD-1+CD8+ T lymphocytes were enriched with effector/memory populations with elevated expression of activation- and exhaustion-related markers. Reduction in the frequency of PD-1+ cells among CD8+ T lymphocytes after one cycle of treatment was associated with a higher probability of DCB and superior survival outcomes in the discovery cohort. Similar results were obtained in analysis of tumor antigen NY-ESO-1-specific CD8+ T lymphocytes and in the validation cohort. Conclusions: Dynamic changes in circulating PD-1+CD8+ T lymphocytes predict clinical and survival benefit from PD-1 blockade treatment in NSCLC. Thus, tracking these changes may be useful for identifying NSCLC patients who will optimally benefit from the treatment.

Background With the advance of immunotherapy, treatment of non-small-cell lung cancer (NSCLC) has revolutionized by having anti-PD-1 therapy in front-line setting. In this era of cancer immunotherapy, humanized mouse models which recapitulate human immune system, are needed for predicting immunotherapy response in patients. We established a Hu-PBL-NSG mouse model which can be used as a preclinical testing platform for assessing efficacy of different immunotherapeutic agents. Materials and methods Hu-PBL-NSG mouse model was established by engrafting human peripheral blood mononuclear cells (PBMCs) into NOD/scid/IL-2Rγ−/− (NSG) mice. Cytokine array was performed to assess serological similarity between patient and the Hu-PBL-NSG mouse, and microscopic immune cell infiltration was observed in various organs mouse model. Human anti-PD-1 therapy was treated for assessing drug efficacy in patient-derived tumor. Results hCD3+hCD45+ T-cells and antigen presenting cells (dendritic cells, macrophages, and MDSC) increased in the serum of Hu-PBL-NSG mouse 24 h after the transfusion of human PBMCs, and CD3 + T cells were observed in lung, liver, kidney, spleen sections. Cytokine arrays of human and Hu-PBL-NSG mouse revealed high similarity of Th1, Th2, Th17-related cytokines. A tumor xenograft was engrafted from an EML4-ALK patient, and Hu-PBL-NSG mouse was sacrificed for histological analyses. hCD3+ T cells were infiltrated within the tumor, and CD11c + cells, which represent antigen-presenting capability, were seen in spleen, lung, liver and kidney. When anti-PD-1 Ab was treated intraperitoneally, xenograft tumor showed significant reduction in volume after day 6, and increased expression of immune response-related genes on microarray analysis in the tumor. Mostly IFN-gamma and its related gene sets were significantly changed (FDR Conclusion Hu-PBL-NSG mouse model which highly resembles human immune system was successfully established. This model could be a strong preclinical model for testing efficacy of immunotherapeutic agents, and also for pursuing novel immunotherapy treatment strategies in advanced NSCLC.

Background Preclinical models that can better predict therapeutic activity in clinical trials are needed in this era of personalized cancer treatment. Herein, we established genomically and clinically annotated patient-derived xenografts (PDXs) from non-small-cell lung cancer (NSCLC) patients and investigated whether these PDXs would faithfully recapitulate patient responses to targeted therapy. Methods Patient-derived tumors were implanted in immunodeficient mice and subsequently expanded via re-implantation. Established PDXs were examined by light microscopy, genomic profiling, and in vivo drug testing, and the successful engraft rate was analyzed with the mutation profile, histology, or acquisition method. Finally, the drug responses of PDXs were compared with the clinical responses of the respective patients. Results Using samples from 122 patients, we established 41 NSCLC PDXs [30 adenocarcinoma (AD), 11 squamous cell carcinoma (SQ)], among which the following driver mutation were observed: 13 EGFR-mutant, 4 ALK-rearrangement, 1 ROS1-rearrangement, 1 PIK3CA-mutant, 1 FGFR1-amplification, and 2 KRAS-mutant. We rigorously characterized the relationship of clinical features to engraftment rate and latency rates. The engraft rates were comparable across histologic type. The AD engraft rate tended to be higher for surgically resected tissues relative to biopsies, whereas similar engraft rates was observed for SQ, irrespective of the acquisition method. Notably, EGFR-mutants demonstrated significantly longer latency time than EGFR-WT (86 vs. 37days, P = 0.007). The clinical responses were recapitulated by PDXs harboring driver gene alteration (EGFR, ALK, ROS1, or FGFR1) which regressed to their target inhibitors, suggesting that established PDXs comprise a clinically relevant platform. Conclusion The establishment of genetically and clinically annotated NSCLC PDXs can yield a robust preclinical tool for biomarker, therapeutic target, and drug discovery.

// Hyo Song Kim 1,* , Sung-Moo Kim 2,* , Hyunki Kim 3 , Kyoung-Ho Pyo 2 , Jong-Mu Sun 4 , Myung-Ju Ahn 4 , Keunchil Park 4 , Bhumsuk Keam 5 , Nak-Jung Kwon 6 , Hwan Jung Yun 7 , Hoon-Gu Kim 8 , Ik-Joo Chung 9 , Jong Seok Lee 10 , Kyung Hee Lee 11 , Dae Joon Kim 12 , Chang-Geol Lee 13 , Jin Hur 14 , Hyunsoo Chung 15 , Jun Chul Park 15 , Sung Kwan Shin 15 , Sang Kil Lee 15 , Hye Ryun Kim 1 , Yong Wha Moon 1 , Yong Chan Lee 15 , Joo Hang Kim 1 , Soonmyung Paik 16,17 and Byoung Chul Cho 1 1 Division of Medical Oncology, Department of Internal Medicine, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea 2 Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Korea 3 Department of Pathology, Yonsei University College of Medicine, Seoul, Korea 4 Department of Hematology-Oncology, Samsung Medical Center, Seoul, Korea 5 Department of Hematology-Oncology, Seoul National University Hospital, Seoul, Korea 6 Macrogen Inc., Seoul, Korea 7 Division of Hemato-Oncology, Chungnam National University Hospital, Daejeon, Korea 8 Division of Hematology-Oncology, Department of Internal Medicine, Gyeongnam Regional Cancer Center, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea 9 Department of Hematology-Oncology, Chonnam National University Hwasun Hospital, Hwasun, South Korea 10 Department of Hematology-Oncology, Seoul National University Bundang Hospital, Seongnam, Korea 11 Department of Hematology-Oncology, Yeungnam University Medical Center, Daegu, South Korea 12 Department of Thoracic and Cardiovascular Surgery, Yonsei University College of Medicine, Seoul, Korea 13 Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea 14 Department of Radiology, Yonsei University College of Medicine, Seoul, Korea 15 Division of Gastroenterology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea 16 Division of Pathology NSABP, Pittsburgh, PA, USA 17 Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea * These authors have contributed equally to this work as co-first authors Correspondence to: Byoung Chul Cho, email: // Keywords : epidermal growth factor receptor, tyrosine kinase inhibitor, esophageal squamous cell carcinoma, biomarker Received : June 25, 2015 Accepted : September 23, 2015 Published : October 09, 2015 Abstract The purpose of this study was to investigate the clinical activity, safety and predictive biomarkers of dacomitinib, an irreversible pan-HER inhibitor, in patients with recurrent or metastatic esophageal squamous cell carcinoma (R/M-ESCC). Patients, whose diseases were not amenable to curative treatment and had progressed on platinum-based chemotherapy, were treated with dacomitinib 45mg/day. The primary endpoint was objective response rate by RECISTv 1.1. Predictive biomarker analyses included the characterization of somatic mutations and gene expression using the Ion Torrent AmpliSeq Cancer Hotspot Panel and Nanostring nCounter, and investigation of their relationship with clinical outcomes. Of the 48 evaluable patients, 6 (12.5%) achieved partial responses and 29 (60.4%) had stable disease. The median response duration was 7.1 months. The median progression free survival (PFS) and overall survival (OS) was 3.3 months (95% CI, 2.4-4.3 months) and 6.4 months (95% CI, 4.4-8.4 months). Adverse events were mostly grade 1-2. Gene set enrichment analysis revealed that ERBB signaling pathway is significantly enriched in patients with PFS ≥4 months ( n = 12) than PFS < 4 months ( n = 21) ( p < 0.001). Upregulation of ERBB signaling pathway was significantly associated with longer PFS (5.0 vs. 2.9 months, P = 0.016) and OS (10.0 vs. 4.8 months, P = 0.022). The most frequent mutations were TP53 (61%) followed by CDKN2A (8%), MLH1 (8%), FLT3 (8%) and EGFR (8%). Dacomitinib demonstrated clinical efficacy with manageable toxicity in platinum-failed R/M-ESCC. Screening of ERBB pathway-related gene expression profiles may help identify patients who are most likely benefit from dacomitinib.

Background We conducted co-clinical trials in patient-derived xenograft (PDX) models to identify predictive biomarkers for the multikinase inhibitor dovitinib in lung squamous cell carcinoma (LSCC). Methods The PDX01-02 were established from LSCC patients enrolled in the phase II trial of dovitinib (NCT01861197) and PDX03-05 were established from LSCC patients receiving surgery. These five PDX tumors were subjected toin vivo test of dovitinib efficacy, whole exome sequencing and gene expression profiling. Results The PDX tumors recapitulate histopathological properties and maintain genomic characteristics of originating tumors. Concordant with clinical outcomes of the trial enrolled-LSCC patients, dovitinib produced substantial tumor regression in PDX-01 and PDX-05, whereas it resulted in tumor progression in PDX-02. PDX-03 and -04 also displayed poor antitumor efficacy to dovitinib. Mutational and genome-wide copy number profiles revealed no correlation between genomic alterations ofFGFR1-3 and sensitivity to dovitinib. Of note, gene expression profiles revealed differentially expressed genes including FGF3 and FGF19 between PDX-01 and 05 and PDX-02-04. Pathway analysis identified two FGFR signaling-related gene sets, FGFR ligand binding/activation and SHC-mediated cascade pathway were substantially up-regulated in PDX-01 and 05, compared with PDX-02-04. The comparison of gene expression profiles between dovitinib-sensitive versus -resistant lung cancer cell lines in the Cancer Cell Line Encyclopedia database also found that transcriptional activation of 18 key signaling components in FGFR pathways can predict the sensitivity to dovitinib both in cell lines and PDX tumors. These results highlight FGFR pathway activation as a key molecular determinant for sensitivity to dovitinib. Conclusions FGFR gene expression signatures are predictors for the response to dovitinib in LSCC.

Background Despite mounting interest in combination immunotherapy including immune checkpoint inhibitors (ICIs) to improve anti-tumor responses, clinical translation has been disappointing. To address the significant unmet needs remaining, we designed GI101 comprising the extracellular domain of CD80 acting as a dual checkpoint (CTLA4/PD-L1) inhibitor, together with a long acting IL2v that preferentially binds to the IL2Rβ. Methods Affinity of GI101 for IL2Rs, CTLA4, and PD-L1 was determined by SPR. Immune cell proliferation was analyzed by CFSE assay and in vivo immune profiling. In vivo efficacy of GI101 were performed in a tumor-bearing mouse model. Results GI101 exhibits high affinity to both CTLA4 (Kd, 2.9 nM), PD-L1 (Kd, 8.5 nM), and preferential binding to IL2Rβ (Kd, 28.4 nM). GI101 induces the robust stimulation of in vitro and in vivo CD8+ T and NK cell proliferation without a significant increase in Treg cells. GI101 has high binding affinity to CTLA4 acting as a decoy ligand, thereby enhancing the interaction between endogenous CD80 and CD28, leading to the activation of T cells. GI101 elicits improved restoration of immune functions compared to a CD80-Fc in in vitro settings using human PBMCs co-cultured with PD-L1hi tumor cells. In the CT26 tumor-bearing mice, GI101 was superior at inhibiting tumor growth when compared to a combination of aPD-1/aCLTA4 in association with a profound increase in CD8+ T and NK cells without causing an increase in Tregs in the TME. In addition, a dose-dependent anti-tumor effect was observed in CT26 syngeneic models. Furthermore, isolated mortality was observed in the aPD-1/aCTLA4 combo-treated group whereas GI101-treated group has no evidence for toxicity associated with IL2 activity including vascular leakage syndrome and cytokine storm. Conclusions The complementary modes of action of GI101 via dual checkpoint blockade with IL2 activity to enhance the proliferation and activation of Teff and NK cells is projected to translate into superior clinical efficacy and safety as indicated even in ‘cold tumor’ models. GI101 has promising potential to replace first-generation ICIs as a monotherapy or in combination with chemo/radiotherapies and other immunotherapies. Legal entity responsible for the study GI innovation. Funding GI innovation. Disclosure J.C. Park: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. K.H. Pyo: Research grant / Funding (institution): Yonsei Medical Center. Y.J. Song: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. W.J. Lee: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. J. Kim: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. H.N. Ji: Full / Part-time employment: GI innovation. S.S. Park: Full / Part-time employment: GI innovation. Y.J. Koh: Full / Part-time employment: GI innovation. K. Lee: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. B. Cho: Research grant / Funding (institution): Yonsei Medical Center. B. Chun: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. Y.M. Oh: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. B. Yang: Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. S.Y. Nam: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation. M.H. Jang: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: GI innovation.

Introduction: Aberrant AXL expression plays a critical role in cancer cell migration, metastasis and drug resistance. Researchers have revealed that AXL signaling is also over expressed on cells associated with tumor microenvironment. These findings highlight AXL as an attractive drug candidate for targeting tumor evasion and metastasis. Here we present SKI-G-801, a small molecule inhibitor that targets phosphorylation of AXL (IC50 = 20 nM) and its downstream signals. Methods: Inhibitory effects of SKI-G-801 on cancer viability (MTT and colony formation assay), invasion and migration (trans-well invasion assay) were examined in AXL high-expressing lung cancer cells in vitro. LLC2 lung and 4T1 breast cancer bearing mouse models were established. in addition, C57BL/6 mice were injected intravenously with B16F10 melanoma cells to establish lung metastasis model. Mice were administrated with 30 mg/kg of SKI-G-801 orally before (metastasis model) or after (syngeneic model) tumor injection. To elucidate the involvement of AXL inhibitor on tumor microenvironment, the population of T cells and myeloid cells was analyzed by flow cytometry from the LLC2 tumor. Results: Treatment of SKI-G-801 showed strong inhibition of cancer migration and invasion, when its direct killing effect on cancer cells was modest. These results were reproduced in vivo test that pretreatment of SKI-G-801 significantly reduced metastatic burden in B16F10 model (p < 0.05). LLC2 and 4T1 tumors were decreased in SKI-G-801 treatment group (p < 0.05), but not in anthemic nude mice. CD3+CD8+ T cell population and memory Tc cells were increased in SKI- G-801 treatment group (p < 0.05). Especially, granzyme B+ Tc and gp70+ tumor specific Tc were increased (p < 0.05). SKI-G-801 increase the helper T cell population; CD3+CD4+ (p < 0.05), and CD44+ memory Th cells (p < 0.01). Conclusion: SKI-G-801 demonstrates great potential in anti-cancer activity though immune responses. The anti-cancer effects lead to a reversal of the metastatic phenotype in animal model. Our results suggest that SKI-G-801 is a promising drug for prevention against metastatic cancer. Citation Format: Chun-Feng Xin, Sung Eun Kim, Kyoung-Ho Pyo, Ha Ni Jo, Jae Seok Cho, Jae Hwan Kim, Wongeun Lee, Hee Kyu Lee, Jung-Ho Kim, Ho-Juhn Song, Jong Sung Koh, Byoung Chul Cho. SKI-G-801, an AXL kinase inhibitor, blocks metastasis and induces anti-tumor immune responses in various syngeneic cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2010.

Cancer immunotherapy with anti-PD-1 therapy (αPD-1) has greatly improved the survival outcome of patients with non-small cell lung cancer (NSCLC). However, the response rates of αPD-1 are around 20-30% based on clinical trials. The presence of PD-L1, tumor infiltrating lymphocyte or tumor mutation burden may be used as indicators of response, but are still limited to predict αPD-1 response. In this study, we established the machine learning based clinical decision support system (CDSS) to predict the αPD-1 response by comprehensively combining clinical information and blood-based data which are easily assessable in routine practice.We enrolled 126 patients with NSCLC treated with the αPD-1 at Yonsei cancer center. Clinical data including patient characteristics, mutation, treatment outcomes, and adverse events were collected and analyzed. Forty patients additionally had blood-based immune data by flow cytometry. There were two data sets; clinical data set (n=126) with 15 variables, and immune data set (n=40) with 37 variables. We found that 27 variables out of 52 variables are selected by recursive feature elimination. The responders are defined as PR or SD ≥6 months and the non-responders are defined as the others. Supervised learning algorithms such as the LASSO, Ridge, Elastic Net, SVM, ANN, and RF were applied to each data set for predicting the αPD-1 response. The performances of each model were evaluated according to the ROC curve or cross-validation errors. Variable importance was measured by using the random forest and gradient boosting.Patient characteristics included male (69.8%), age ≥ 60 years (66.2%), ECOG 0/1 (77.7%), adenocarcinoma (69.8%), EGFR mutations (15.1%), and PD-L1 positive (61.2%). We classified the patients into responders (38%) and non-responders (62%) in total 126 patients. A result from the clinical data set of 126 patients demonstrated that the Ridge regression model (AUC: 0.78) can more accurately predict the αPD-1 response than others. Of 15 clinical variables, some are considered to be important in the following order; tumor burden,age, PD-L1, ECOG PS, and irAE based on the random forest. When we performed the machine learning process with clinical and immune data, The Ridge regression model (AUC:0.82) showed the good performance to predict αPD-1 response, compared to the single clinical model. The machine learning based CDSS for aPD-1 to NSCLC patients has benefit for predicting aPD-1 responses. Our prediction model could be easily accessible and fast processed in routine practice. The supervised machine learning based non-invasive predictive score (NIPS) demonstrates the rate of aPD-1 response on NSCLC patients. We will validate NIPS in independent patient cohort and currently are establishing the NIPS as web-based software. Citation Format: Kyoung-Ho Pyo, Beung-Chul Ahn, Chun-Feng Xin, Dongmin Jung, Chang Gon Kim, Min Hee Hong, Byoung Chul Cho, Hye Ryun Kim. A machine learning based clinical decision support system (CDSS) for anti-PD-1 therapy using non-invasive blood marker and clinical information for lung cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 683.

Introduction: MERTK is thought to play a role in cancer immune evasion mechanism based on M2 type macrophage-driven immunosuppression in tumor microenvironment (TME). Thus, MERTK is a highly promising target for anti-cancer therapy under high tumor associated macrophages (TAMs) condition. We evaluated the anti-tumor effects and immune reaction of combination or single MERTK inhibitor in two lung squamous patients derived xenograft (PDX) tumor engrafted Hu-CD34-NSG models. Methods: The aPD-1 sensitive (YHIM2004) and aPD-1 non-sensitive (YHIM2009) squamous cell carcinoma PDX models were selected from pre-test with pembrolizumab. The selected two models were composed four groups; control, pembrolizumab, MERTK inhibitor, and combination. We applied pembrolizumab as aPD-1 blockade (10 mpk, q2w, i.p. inj.). The dose of MERTK inhibitor was 50 mpk, q1d by orally. The treatment was started when tumor size reached 100 mm3. Whole exome sequencing (WES), microarray (mRNA), flow cytometry, and multispectral image analysis were performed on the tumors. To elucidate the involvement of MERTK inhibitor in tumor, the tumor mutation burden, tumor microenvironment and immune cell phenotype were deconvoluted. Results: The TMB of YHIM2004 and YHIM2009 was 3.23 and 2.64 (mutations/Mb) respectively. The PD-L1 and TIL level of YHIM2004 were relatively higher than YHIM2009. Both two models were observed high macrophage in tumor. The two PDX-models, YHIM2004 (aPD-1 sensitive), YHIM2009 (aPD-1 non-sensitive) were observed anti-tumor effects in MERTK inhibitor single treatment groups (TGI = 44.23%, 67.40% respectively, p < 0.05, t-test). Especially, YHIM2004 tumor was reduced after combination therapy more than single treatment. Of note, the NOG-PDX model demonstrated no anti-tumor effect in MERTK inhibitor monotherapy, suggesting that this drug involves anti-cancer immune responses. Flow cytometry data showed increased PD-1+ and granzyme B+ T cells (p Conclusion: We concluded that MERTK signaling involves regulation of anti-cancer immune responses. Our results suggest an anti-cancer therapeutics of MERTK selective inhibitor on aPD-1 sensitive or non-sensitive tumors under high TAM tumor microenvironment. Citation Format: Kyoung-Ho Pyo, Ha-Ni Cho, Chun-Feng Xin, Jae Seok Cho, Han Na Kang, Jiyeon Yun, Hye Ryun Kim, Byoung Chul Cho. Efficacy of MERTK inhibitor in combination with pembrolizumab in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4081.

Background: Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) as an immune check point molecule is expressed in lung cancer cells. The homophilic interaction of CEACAM1 inhibits killing effect of T cells by co-inhibitory signal transduction. Thus, up-regulated CEACAM1 in the tumor microenvironment is considered as a promising therapeutic target for cancer. In this study, anti-cancer effect of anti-CEACAM1 monoclonal antibody (MG1124, from GC Pharma, Yongin, South Korea) was investigated with lung cancer-xenograft humanized mice. Materials & Methods: Multispectral image analysis using Vectra polaris system was performed in 49 of human lung cancers (36 adenocarcinoma; 13 squamous cell carcinoma) to evaluate the expressions of CEACAM1, PD-L1 and CD8. Four tumors (YHIM-01, YHIM-02, YHIM-03 and YHIM-04) with high CEACAM1 expression were subcutaneously implanted into humanized mice (hu-CD34 NSG) matched with HLA-A. Efficacy of MG1124 was performed by the single mouse trial format. Humanized mice were treated with MG1124 (q2w, 20 mpk, i.p. injection) with or without pembrolizumab (q2w, 10 mpk, i.p. injection). Findings: Among 49 lung cancers evaluated, proportion of tumor cells expressing CEACAM1 and PD-L1 with any intensity ranged 0.1- 89.2% (median, 15.4%) and 0.2% - 95.6% (median, 6.8%) respectively, and TIL counts ranged 0 - 1,200 cells/mm2 (median, 129 cells/mm2). Four tumors with high CEACAM1(14.5% in YHIM-01, 81.2% in YHIM-02, 23.8% in YHIM-03 and 36.7% in YHIM-04) were selected to establish humanized mouse models. MG1124 as a monotherapy demonstrated antitumor activity and also was superior to pembrolizumab in 1 (YHIM-02, TGI=63.4±1.7% for combination vs. TGI=58.7±9.1% for pembrolizumab alone) out of 4 humanized mouse models. Combination of MG1124 with pembrolizumab also demonstrated synergic anti-tumor effect in 3 models (YHIM-01, TGI= 39.6±19.7% vs. 0.6±11.4% for pembrolizumab alone, vs. 16.5±33.3% for MG1124 alone; YHIM-02, TGI=58.7±9.1% vs. 38.2±14.9% for pembrolizumab, vs. 63.4±1.7% for MG1124 alone; YHIM-03, TGI= 35.6±13.2% vs. TGI=0.0±13.2% for pembrolizumab alone, vs. TGI=3.1±13.3% for MG1124 alone). PD-L1 expression was not associated with MG1124 alone or in combination with pembrolizumab (PD-L1, 2.5% in YHIM-01, 0.5% in YHIM-02 and 14.0% in YHIM-03 respectively). Interestingly, however, combinational effects of MG1124 and pembrolizumab were shown only in 3 models showing high CD8+ T cell infiltration in the tumors (209, 432, 362 vs. 46 in a model without combination synergy). Conclusion: CEACAM1-targeting monoclonal antibody, MG1124, exhibits promising anti-cancer effects in CEACAM1-expressing lung cancers. Tumoral CEACAM1 expression and high intratumoral CD8+ T cell infiltration could serve as a predictive biomarker to MG1124 monotherapy or in combination with pembrolizumab and need to be further investigated. Citation Format: Jae-Hwan Kim, Kyoung-Ho Pyo, Min-Jee Jung, Minkyu Hur, Jonghwa Won, Byoung Chul Cho. Efficacy of CEACAM1-targeting immunoglobulin in combination with pembrolizumab in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2266.

e14138 Background: Immune checkpoint inhibitors have become breakthrough therapy for various types of cancers. However, regarding their total response rate around 20% based on clinical trials, predicting accurate aPD-1 response for individual patient is unestablished. The presence of PD-L1 expression or tumor infiltrating lymphocyte may be used as indicators of response but are limited. We developed models using machine learning methods to predict the aPD-1 response. Methods: A total of 126 advanced NSCLC patients treated with the aPD-1 were enrolled. Their clinical characteristics, treatment outcomes, and adverse events were collected. Total clinical data (n = 126) consist of 15 variables were divided into two subsets, discovery set (n = 63) and test set (n = 63). Thirteen supervised learning algorithms including support vector machine and regularized regression (lasso, ridge, elastic net) were applied on discovery set for model development and on test set for validation. Each model were evaluated according to the ROC curve and cross-validation method. Same methods were used to the subset which had additional flow cytometry data (n = 40). Results: The median age was 64 and 69.8% were male. Adenocarcinoma was predominant (69.8%) and twenty patients (15.1%) were driver mutation positive. Clinical data set (n = 126) demonstrated that the Ridge regression (AUC: 0.79) was the best model for prediction. Of 15 clinical variables, tumor burden, age, ECOG PS and PD-L1, were most important based on the random forest algorithm. When we merged the clinical and flow cytometry data, the Ridge regression model (AUC:0.82) showed better performance compared to using clinical data only. Among 52 variables of merged set, the top most important immune markers were as follows: CD3+CD8+CD25+/Teff-CD28, CD3+CD8+CD25-/Teff-Ki-67, and CD3+CD8+CD25+/Teff-NY-ESO/Teff-PD-1, which indicate activated tumor specific T cell subset. Conclusions: Our machine learning based model has benefit for predicting aPD-1 responses. After further validation in independent patient cohort, the supervised learning based non-invasive predictive score can be established to predict aPD-1 response.

To investigate the expression of programmed death-ligand 1 (PD-L1) and immune checkpoints and their prognostic value for resected head and neck squamous cell cancer (HNSCC). PD-L1 expression on tumor cells (TC) and tumor-infiltrating immune cells (IC), abundance of tumor-infiltrating lymphocytes (TILs), and expression of the immune checkpoints were investigated in 402 HNSCC patients. PD-L1 expression on TC and IC was categorized into four groups according to the percentage of PD-L1-positive cells. PD-L1 positivity was defined as ≥5% of cells based on immunohistochemistry. High PD-L1 expression on IC, but not TC, was an independent favorable prognostic factor for RFS and OS adjusted for age, gender, smoking, stage, and HPV. High frequencies of CD3+ or CD8+ TILs, Foxp3+ Tregs, and PD-1+ TILs were strongly associated with favorable prognosis. PD-L1 was exclusively expressed on either TC or IC. Transcriptome analysis demonstrated that IC3 expressed higher levels of the effector T cell markers than TC3, suggesting that PD-L1 expression is regulated via an adaptive IFNγ-mediated mechanism. High PD-L1 expression on IC, but not TC, and high abundance of PD-1+ T cells and Foxp3+ Tregs are favorable prognostic factors for resected HNSCC. This study highlights the importance of comprehensive assessment of both TC and IC.

Introduction: With the advance of immunotherapy, treatment of non-small-cell lung cancer (NSCLC) has revolutionized by having anti-PD-1 therapy in front-line setting. In this era of cancer immunotherapy, humanized mouse models which recapitulate human immune system, are needed for predicting immunotherapy response in patients. We established a Hu-PBL-NSG mouse model which can be used as a preclinical testing platform for assessing efficacy of different immunotherapeutic agents. Methods: Hu-PBL-NSG mouse model was established by engrafting human peripheral blood lymphocytes (PBLs) into NOD-scid (NSG) mice. The 6-7 week-old NSG mouse was transfused with 1 x 107 cells of PBL via tail vein, and human immune cells were characterized after 24 hours, and weekly thereafter. Cytokine array was performed to assess serological similarity between patient and the Hu-PBL-NSG mouse, and microscopic immune cell infiltration was observed in various organs mouse model. Human anti-PD-1 therapy was treated for assessing drug efficacy in patient-derived tumor. Results: hCD3+hCD45+ T-cells and antigen presenting cells (dendritic cells, macrophages, and MDSC) increased in the serum of Hu-PBL-NSG mouse 24 hour after the transfusion of human PBLs, and CD3+ T cells were observed in lung, liver, kidney, spleen sections. Cytokine arrays of human and Hu-PBL-NSG mouse revealed high similarity of Th1, Th2, Th17-related cytokines. A tumor xenograft was engrafted from an EML4-ALK patient, and Hu-PBL-NSG mouse was sacrificed for histological analyses. hCD3+ T cells were infiltrated within the tumor, and CD11c+ cells, which represent antigen-presenting capability, were seen in spleen, lung, liver and kidney. When anti-PD-1 Ab was treated intraperitoneally, xenograft tumor showed significant reduction in volume after day 6, and increased expression of immune response-related genes on microarray analysis in the tumor. Mostly IFN-gamma and its related gene sets were significantly changed (FDR < 0.25, GSEA). Conclusion: Hu-PBL-NSG mouse model which highly resembles human immune system was successfully established. This model could be a strong preclinical model for testing efficacy of immunotherapeutic agents, and also for pursuing novel immunotherapy treatment strategies in advanced NSCLC. Citation Format: Sun Min Lim, Kyoung-Ho Pyo, Jae Hwan Kim, Ji Min Lee, Seong Keun Kim, Sung Eun Kim, Ha Ni Jo, Jae Soek Cho, Hye Ryun Kim, Byoung Chul Cho. Promising preclinical platform for evaluation of immuno-oncology drugs using Hu-PBL-NSG lung cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1148.

EGFR mutated lung cancer shows approximately 10-15% of non-small cell lung cancer (NSCLC). Although the best therapeutic EGFR tyrosine kinase inhibitors (TKIs) targeting mutant EGFR, such as gefitinib and erlotinib, are used in the first line treatment of patients with advanced EGFR mutated NSCLC, the acquired resistance to the drugs usually appears in 10-12 months of therapy by the occurrence of a second EGFR mutation T790M. YH25448, a highly mutant-selective and irreversible 3rd generation EGFR TKI potently penetrating blood-brain barrier (BBB) penetration, targets both activating EGFR mutations Del19, L858R and T790M mutation while sparing wild type. In NSCLC cell lines and primary cancer cells from patients harboring EGFR mutations, YH25448 showed more potent inhibition of cancer cell growth and significantly increased tumor cell apoptosis compared to osimertinibs, which is one of 3rd generation EGFR TKIs. In vivo mouse model implanted with H1975 cells, YH25448 treatment at the once-daily showed a dramatic dose-dependent tumor regression in both subcutaneous and intracranial lesions with no abnormal signs such as skin keratosis shown in osimertinib-treated mice. Plasma half life of YH25448 was 5.9-6.8 hr and tumor to plasma AUC0-last ratio was 3.0-5.1 in tumor bearing mice. YH25448 also showed excellent penetration of the BBB, achieving CSF concentrations exceeding the IC50 value for pEGFR inhibition in the tumor-bearing mice. Taken together, these findings suggest important role for the further development of YH25448 as a novel therapeutic for the treatment of EGFR mutant-positive NSCLC patients with brain metastases. Citation Format: Jiyeon Yun, Min Hee Hong, Seok-Young Kim, Chae Won Park, So-Young Kim, Mi Ran Yun, Han Na Kang, Kyoung-Ho Pyo, Jong Sung Koh, Ho-Juhn Song, Young- Sung Lee, Se-Woong Oh, Soongyu Choi, Byoung-Chul Cho. YH25448, an irreversible 3rd generation EGFR TKI, exhibits superior anticancer effects with potent brain BBB penetration in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4790.

Introduction: EML4-ALK is a distinct molecular entity that is highly sensitive to ALK tyrosine kinase inhibitors (TKIs). While many trials have showed the superiority of ALK TKIs over cytotoxic chemotherapy, the optimal sequencing of ALK TKIs is still obscure. Acquired resistance to ALK TKIs remains a key challenge, and unknown mechanisms of resistance need to be resolved. In this study, we aimed to identify optimal treatment sequence and acquired resistance mechanisms of ALK TKIs using EML4-ALK transgenic mice model that recapitulates human EML4-ALK lung adenocarcinoma. Methods: The tumorigenesis of EML4-ALK transgenic mice was based on Cre-ERT2/Lox system, and intraperitoneal injection with tamoxifen induced lung tumors. When tumor nodules were observed, EML4-ALK transgenic mice were treated with either crizotinib (150mg/kg) followed by ceritinib (75mg/kg) upon progression (N=13) or with ceritinib followed by crizotinib (N=12) upon progression. Tumor response was evaluated weekly using magnetic resonance imaging. Progression-free survival (PFS) was measured to compare the efficacy between two ALK TKIs. For the analysis of acquired resistance mechanism, whole-exome sequencing, RNA sequencing, and targeted sequencing of ALK gene were performed. Results: Head-to-head comparison of crizotinib and ceritinib was performed in the first-line setting. A total of 13 mice were treated with upfront crizotinib, and mice that showed progressive disease (PD) were crossed over to ceritinib (n=9). A total of 12 mice were treated with upfront ceritinib, and mice that showed PD (n=8) were crossed over to crizotinib. Four mice in each group were sacrificed for analysis of resistance mechanism at the time of PD. The PFS of ceritinib was significantly longer than that of crizotinib [24 weeks (95% CI, 21.4-26.5) vs. 8 weeks (95% CI, 6.5-9.0), P < 0.001]. Subsequent treatment with ceritinib following crizotinib resulted in significantly longer PFS than crizotinib following ceritinib [7 weeks (95% CI, 4.1-9.9) vs 3 weeks (95% CI, 2.5-3.5), P < 0.001]. Altogether, treatment with ceritinib followed by crizotinib showed a prolongation of PFS, compared to crizotinib followed by ceritinib (27 weeks vs. 15 weeks, P < 0.001). We noted that ALK-TKI resistant tumors harbored several copy number variations (CNVs), and nonsynonymous oncogenic mutations, but found no previously reported resistant mechanisms including secondary mutations, or CNVs. Wnt signaling related gene set was increased in both crizotinib- and ceritinib-resistant tumors, and Hippo signaling related gene set was increased in ceritinib-resistant tumors on KEGG pathway-based analysis. Conclusion: Our findings suggest that ceritinib is superior to crizotinib when used in the first-line setting. Novel mechanisms of acquired resistance such as increased Wnt and Hippo signaling need further validation. Citation Format: Kyoung-Ho Pyo, Lim Sun Min, Jae Hwan Kim, Ji Min Lee, Ha Ni Jo, Jae Soek Cho, Mi-Ran Yun, Sung Eun Kim, Hye Ryun Kim, Chun-Feng Xin, Tae-Min Kim, Byoung Chul Cho. Identification of optimal treatment sequence and acquired resistance mechanisms of ALK inhibitors using EML4-ALK transgenic mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2855.

Objectives The epidermal growth factor receptor (EGFR) abnormalities including amplification, mutation, and overexpression are frequent in non-small cell lung cancer (NSCLC). We investigated in vitro and in vivo antitumor activity of ER2, a novel human anti-EGFR monoclonal antibody, in NSCLC. Methods A panel of NSCLC cell lines (A549, H460, H322, H358, H1299, HCC827, PC9, H1975, and PC9-GR) was used to evaluate in vitro antitumor activity of ER2 and cetuximab. The inhibitory effects of ER2 and cetuximab on downstream signaling were assessed by western blot. Secreted VEGF was measured by Human VEGF Quantikine ELISA kit. Antitumor effects of ER2 and cetuximab as single agents and in combination with cisplatin were evaluated in H322, HCC827 and A549 xenograft models. Results ER2 efficiently inhibits EGFR and its downstream signaling molecules including Akt and Erk1/2 in NSCLC cell lines with wild-type or mutant EGFR. ER2 inhibited cell viability of H322, HCC827 and A549 cells in a dose-dependent manner by inducing cell cycle arrest and apoptosis. Also, ER2 suppressed EGF-stimulated VEGF production as efficiently as cetuximab in H322, HCC827 and A549 cells. Moreover, ER2 alone and in combination with cisplatin showed a significant anti-tumor efficacy in xenograft mouse models. Conclusion Taken together, ER2 has significant anti-tumor activity in in vitro and in vivo NSCLC models, suggesting a rationale for clinical development of ER2 in NSCLC.

Crizotinib is highly effective in patients with non-small cell lung cancer (NSCLC) harboring the echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) fusion. However, its efficacy has been limited by the development of acquired resistance, and the mechanisms of such resistance remain largely unknown. Herein, we investigated a possible candidate for circumventing the acquired resistance to crizotinib. We established a model of acquired resistance to crizotinib (H3122-CR) by exposing EML4-ALK-positive H3122 lung cancer cells to increasing doses of crizotinib, and performed MTT screening using a library of FDA (Food and Drug Administration)-approved drugs composed of a collection of 640 clinically used compounds. Our MTT screening identified that cerivastatin, a drug targeting 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, significantly inhibited the cell growth in H3122-CR cells, which was completely restored by addition of geranylgeranyl pyrophosphate (GGPP), a key metabolite of mevalonate pathway. We also found that yes-associated protein (YAP), a major effector of the Hippo tumor suppressor pathway, was robustly accumulated in nucleus with a concomitant decrement of YAP phosphorylation in H3122-CR cells compared to parental cells. Importantly, inhibition of geranylgeranylation (GGylation) by GGTI-298 or cerivastatin markedly increased YAP phosphorylation, led to cytoplasmic translocation of YAP, and subsequently induced YAP inactivation. Moreover, the enrichment of EGFR signaling pathway and cell cycle signature including transcriptional targets of YAP was enhanced in H3122-CR cells, whose induction contributed YAP-mediated resistance to crizotinib. Inhibition of YAP function with siRNA or verteporfin as a YAP inhibitor greatly abrogated cell growth of H3122-CR cells by modulating cell cycle regulators and EGFR activation. Finally, we confirmed up-regulation of nuclear YAP expression in crizotinib-acquired resistant patient derived tumor xenograft (PDTX) models established from EML4-ALK positive NSCLC patients. Collectively, our findings define the GGylation-mediated YAP transcriptional activation as a new mechanism of resistance to crizotinib, providing a rationale for further exploring statins as a possible anticancer agent to overcome the acquired resistance to crizotinib in EML4-ALK positive NSCLC cells. Citation Format: Miran Yun, Hun Mi Choi, Kyoung Ho Pyo, Byoung Chul Cho. Cerivastatin overcomes the acquired resistance to crizotinib in EML4-ALK positive non-small cell lung cancer by controlling YAP activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2054. doi:10.1158/1538-7445.AM2017-2054

Background: To investigate clinical activity, safety and biomarkers of a pan-PI3K inhibitor BKM120 in R/M-SCCHN and identify optimal combinational strategies by conducting mouse co-clinical trials mirroring the ongoing clinical study. Methods: Patients with R/M-SCCHN were eligible if they had progressed on platinum-based chemotherapy, and were treated with BKM120 100mg/day. The primary endpoint was disease control rate (DCR) at 8 weeks. Secondary endpoints included response rate (RR), progression-free survival rate (PFS), overall survival (OS) and safety. Patient-derived xenografts (PDXs) with genomic annotations were established directly from patients for evaluation of novel drug combinations and biomarkers. Based on the integrated clinical and preclinical data, study protocol had been revised to combine BKM120 and erbitux to explore whether erbitux increases the efficacy of BKM120 in R/M-SCCHN. Results: A total of 52 patients were enrolled. Patient characteristics included median age (55 years; range, 31-82); male (84.6%); ECOG performance status 0/1/2 (13.5%/73%/13.5%); locoregional/metastatic/both (30.8%/30.8%/38.4%); oral cavity/oropharynx/larynx primary (36.5%/30.8%/13.5%); prior chemotherapy regimens 1/≥2 (40%/60%). Seven patients were not evaluable due to rapid progression or withdrawal. DCR at 8 weeks was 60% (27/45) and RR was 2.2% (1/45) in BKM120 monotherapy. Median PFS and OS were 8.0 (95% CI, 5.3-9.5) and 30.7 weeks (95% CI, 11.8-26.6). After protocol revision, 11 patients were treated with BKM120 and erbitux after progression to BKM120. In combination phase, PR was observed in 18.1% (2/11) and SD was 45.5% (5/11) in patients who failed to BKM120. Toxicities were not increased in combination phase. In seven established PDXs, we tested BKM120 alone or in combination with erbitux. All PDXs showed strong resistance to single-agent BKM120, whereas three PDXs (3/7, 42.8%) demonstrated strong synergistic inhibition of tumor growth to combined BKM120 and erbitux, compared with single agent (vs. BKM120, P Conclusions: Combining BKM120 and Erbitux would be effective treatment strategies with manageable toxicity in R/M-SCCHN based on strong rationale of co-clinical trial with PDXs (NCT01527877). Citation Format: Han Na Kang, Mi Ran Yun, Kyoung Ho Pyo, Myung-Ju Ahn, Jong-Mu Sun, Sun Min Lim, Soonmyung Paik, Byoung Chul Cho, Hye Ryun Kim. Mouse-human co-clinical trials demonstrate superior efficacy with combinational approach of BKM120 and erbitux over BKM120 monotherapy in patients with recurrent and/or metastatic squamous cell carcinoma of head and neck (R/M-SCCHN) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5012. doi:10.1158/1538-7445.AM2017-5012

The present study investigated the effect of peanut sprout extract (PSE) as a natural resveratrol supplement on chronic bacterial prostatitis (CBP) and estradiol-induced benign prostatic hyperplasia (BPH). PSE contained a high level of resveratrol (148.51 ± 3.05 μg/g), and was tested on the mouse models of CBP (induced by Escherichia coli 292 infection) and BPH (induced by treatment with β-estradiol and dihydrotestosterone). PSE toxicity was assessed on the basis of changes in body weight, alanine aminotransferase activity (an indicator of hepatotoxicity), and expression of the kidney injury marker KIM-1. The effects of PSE on the histopathology of prostate tissue, the proportion of neutrophils, and immune cell profiles in the blood and spleen were examined. PSE administration did not result in any toxicity but reduced the bacterial burden and histopathological changes in the prostate. In addition, lymphocytes (CD4+, CD8+, and CD19+) in the spleen were significantly increased after PSE administration in CBP mice, suggesting immune enhancement. PSE treatment of bone marrow–derived macrophages increased the expression of CD40, which is related to the pro-inflammatory function and host defense against pathogens. It is concluded that PSE would be a good supplement for the mitigation of prostate hyperplasia and prostatitis.

6055Background: To investigate the frequency and distributing patterns of programmed death-ligand 1 (PD-L1), other immune checkpoints (ICP) and their prognostic impacts in resected HNSCC. Methods: ...