PD-L1 Immune Checkpoint Inhibitors Research Articles

Acral Necrosis After PD-L1 Immune Checkpoint Inhibitor Therapy

Acral Necrosis After PD-L1 Immune Checkpoint Inhibitor Therapy

Outcomes of responders to PD-1/PD-L1 inhibitors who discontinue therapy after sustained disease control.

PD-1/PD-L1 immune checkpoint inhibitors (ICIs) are widely used in the treatment of metastatic malignancies. Judiciously balancing disease control (DC) against development of immune-related adverse events (irAE) remains a crucial aspect of treatment. The effect of treatment discontinuation after sustained disease control (SDC) is unknown. The purpose of this analysis was to evaluate outcomes of responders to ICI who discontinue treatment after a minimum of 12 months (SDC). We retrospectively reviewed the database of the University of New Mexico Comprehensive Cancer Center (UNMCCC) between 2014 and 2021 and identified patients who had received ICI. Patients with metastatic solid tumors who had stopped ICI therapy after achieving SDC [stable disease, partial response, complete response (SD, PR, CR)] were selected and outcomes reviewed from their electronic health records. We identified 204 patients who were treated with ICI for various solid cancers. Forty-four patients (21.6%) met the criteria, of whom 35 with follow-up data were included in the final analysis; including 11 melanoma, 5 non-small cell lung, 4 head & neck, 8 renal, 4 urothelial, 1 anal, 1 Merkel cell carcinoma, and 1 liposarcoma. Patients were divided into two groups: those who stopped ICI due to an irAE [irAE group, n = 14, median treatment time (MTT), 16.6 mo] and those who stopped due to other reasons (eg completion of 2 years of therapy, n = 20, non-cancer related surgery, n = 1) (non-irAE group, n = 21, MTT, 23.7 mo). Among the irAE group, the most common irAE included pneumonitis, rash, transaminitis, and fatigue. As of data cutoff date, 9 of 14 (64%) patients continued to show SDC. Only 5 of 14 (36%) patients in this group experienced progression of disease (PD), with 1 of 2 patients achieving DC (median follow-up of 19.2 mo after last dose of treatment, range 3-50.2 mo). Among the non-irAE group, 13 of 21 (62%) continued to have SDC. Eight of 21 (38%) experienced PD after stopping treatment, 7 of whom received ICI rechallenge, with 2 of 7 achieving DC (median follow-up of 22.2 mo, range 3.6-54.8 mo). At a median follow-up of 21.3 mo from stopping ICI therapy (range, 3-54.8 mo), 10 patients (71%) from the irAE group and 13 (61.9%) from the non-irAE group are in DC and have not experienced PD. We demonstrate that 22 (66%) patients experienced SDC, regardless of cancer type or development of irAE. After including patients who were re-challenged with ICI due to PD, 25 (71%) remain in DC. Future prospective malignancy-specific trials are warranted to evaluate optimal treatment duration.

Abstract 5618: Multi-institutional validation of a radiomics-based artificial intelligence method for predicting response to PD-1/PD-L1 immune checkpoint inhibitor (ICI) therapy in stage IV NSCLC

Abstract There is an urgent clinical need to identify patients likely to benefit from immune checkpoint inhibitor ICI treatment. Approaches available in the clinic today, such as PD-L1 immunohistochemistry (IHC) and tumor mutation burden (TMB), are insufficient for this task, in part as differences in microenvironments expressed by individual tumors may lead to heterogeneous response patterns. Recent efforts exploring the utility of quantitative imaging (radiomic) biomarkers to predict response to ICIs have shown promise to provide a more accurate and scalable method. In contrast to previously published models, our work focuses on generalizable models for predicting individual lesion-level as well as patient-level response at 3-month follow-up per RECIST criteria, using a large multi-institutional “real-world” dataset. The models combine radiomics features with demographic, molecular, and laboratory values routinely available in patients’ electronic medical records. We analyzed radiomic characteristics of 6,295 primary and metastatic lesions from 1,206 metastatic NSCLC patients treated with anti-PD-1/anti-PD-L1 ICIs from 8 institutions across the US and Europe. Patients with unavailable PD-L1 IHC, imaging follow-up, or with oncogenic driver mutations were excluded from analysis, resulting in a total dataset of 766 subjects randomly assigned to training (N=514) and validation sets (N=252). Using gradient-boosted decision tree algorithms, we developed a multi-modal predictive model to identify patients responding to ICI therapy at 3-months and evaluated its performance against an imaging-only CT radiomics model and the clinical standard of care, biopsy-based PD-L1 IHC. The multi-modal model contains CT radiomic features capturing lesion heterogeneity and spicularity, patient demographics, PD-L1 TPS, and tumor burden volume in the lung, lymph nodes, and the liver. Under the two-tailed DeLong test, the multi-modal model demonstrated statistically significant benefit over the current standard of care (PD-L1 IHC) in predicting multi-lesion 3-month response: 0.81 (P=.005) area under the receiver operating characteristic curve (ROC-AUC) in first-line ICI monotherapy patients, 0.72 (P=.044) in all-lines ICI monotherapy, and 0.71 (P=.025) in all-lines ICI-chemotherapy combination. The imaging-only model demonstrated predictive performance comparable to PD-L1 IHC: 0.71 (P=.226), 0.61 (P=.905), 0.62 (P=.674) on the same cohorts respectively. A multi-modal CT radiomics-based approach demonstrated predictive accuracy benefit over the current clinical standard and may provide an opportunity for more personalized patient management, such as risk-based escalation/de-escalation of concurrent chemotherapy in NSCLC patients. We will evaluate this methodology in prospective studies. Citation Format: Ravi B. Parikh, Petr Jordan, Rita J. Ciaravino, Ryan A. Beasley, Arpan A. Patel, Dwight H. Owen, Arya Amini, Brendan D. Curti, Ray Page, Aurelie Swalduz, Jean-Paul Beregi, Jan Chrusciel, Eric Snyder, Pritam Mukherjee, Heather M. Selby, Soohee Lee, Roshanthi Weerasinghe, Shwetha Pindikuri, Jakob B. Weiss, Andrew L. Wentland, Anish Kirpalani, An Liu, Olivier Gevaert, George Simon, Hugo JWL Aerts. Multi-institutional validation of a radiomics-based artificial intelligence method for predicting response to PD-1/PD-L1 immune checkpoint inhibitor (ICI) therapy in stage IV NSCLC. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5618.

Abstract 6007: p16 epimutation modulates the tumor microenvironment and promotes malignancy of Apc-mutant colon cancer

Abstract Methylation of the p16 promoter resulting in mitotically stable gene silencing—known as p16 epimutation—is the most common epigenetic event in human colorectal cancer (CRC) and is also common in normal-appearing colonic mucosa of aging individuals. However, the functional role of p16 epimutation in CRC carcinogenesis is not completely understood. Here, using a mouse model of engineered p16 promoter hypermethylation, we show that p16 epimutation cooperates with mutant Apc to promote colon cancer development. Mice carrying combined Apc mutation and p16 epimutation display significantly shortened survival and increased tumor growth compared to those with Apc mutation only. Moreover, colon tumors from these animals express increased levels of programmed death-ligand 1 (Pdl1). Single-cell RNA sequencing (scRNA-seq) analysis further revealed the presence of dysfunctional cytotoxic CD8+ T cells together with Foxp3+ Tregs and γδT17 cells, which promote an immunosuppressive tumor microenvironment (TME). Lastly, we show that a combined therapy using an inhibitor of DNA methylation and a PD-L1 immune checkpoint inhibitor is more effective for improving survival in tumor-bearing mice than anti-PD-L1 treatment alone. These findings provide a mechanistic rationale for targeted epigenetic and immunotherapy in CRC patients, with the potential to improve colon cancer treatment. Citation Format: Li Yang, Xiaomin Chen, Christy Lee, Jiejun Shi, Emily B. Lawrence, Lanjing Zhang, Yumei Li, Nan Gao, Sung Yun Jung, Chad J. Creighton, Jingyi Jessica Li, Ya Cui, Sumimasa Arimura, Wei Li, Lanlan Shen. p16 epimutation modulates the tumor microenvironment and promotes malignancy of Apc-mutant colon cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6007.

Abstract 3473: High throughput screening of combination therapies to improve response to checkpoint inhibitors in solid tumors using a myelomonocytic and T cell co-culture assay

Abstract Background: Immune checkpoint inhibitors (ICI) targeting the PD-1/PD-L1 pathway are part of the new “standard of care” treatment for a number of advanced cancers. However, for many types of cancer, targeting either PD-1 or PD-L1 is associated with clinical benefit in a minority of patients. Combination strategies are needed to improve clinical benefit rates in ‘immune responsive’ cancers, and to expand treatment options for non-responsive cancers. Preclinical models have revealed that tumor-associated macrophages (TAMs) possess T cell-suppressive activities associated with resistance to PD-1/PD-L1 targeted therapies. To reveal therapeutic targets to relieve this suppression, we developed a robust cell-based high-throughput screening (HTS) assay to identify small molecules that can relieve myelomonocytic cell-dependent T cell-suppression, and that enhance T cell activities when combined with PD-1/PD-L1 ICI. Methods: Bone marrow-derived myelomonocytic cells and splenic T cells were used to develop the HTS assay. After exposure to libraries of small molecules, co-cultures were evaluated for enhanced T cell activity, followed by in vivo investigations of emerging small molecules in syngeneic murine models of breast cancer to reveal anti-tumor activity. Results: Over 1,400 FDA-approved drugs, used for both cancer or non-cancer indications, were screened in the HTS assay, 66 of which demonstrated activity in the HTS assay. Approximately 50% of these were known anti-inflammatory agents, with the highest density reflecting various COX-2 inhibitors (COX-2i). In vivo, combination therapy of the COX-2i with PD-1/PD-L1 ICI resulted in a significant reduction in tumor growth kinetics in both 4T1 and EMT6 breast cancer models, both of which are resistant to PD-1/PD-L1 inhibitors as monotherapy. In the 4T1 model, slowed tumor kinetics was associated with ICI increased T cell activation as compared to controls or monotherapy anti-PD-1/PD-L1 therapy. Conclusions: A myelomonocytic cell-dependent T cell-suppression assay can be used to develop a HTS platform for discovering combination therapies showing antitumor responses in preclinical models. COX-2 inhibitors can be repurposed to enhance therapeutic benefits of PD-1/PD-L1 targeting agents in breast cancer patients. Keywords: Myelomonocytic cells, T-cell, immunotherapy, PD-1, PD-L1, breast cancer Citation Format: Sushil Kumar, Dhanir Tailor, Arpit Dheeraj, Wenqi Li, Jee Min Lee, Kirsten Stefan, Dylan Nelson, Shivaani Kummar, Lisa M. Coussens, Sanjay V. Malhotra. High throughput screening of combination therapies to improve response to checkpoint inhibitors in solid tumors using a myelomonocytic and T cell co-culture assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3473.

Computational Approaches Drive Developments in Immune-Oncology Therapies for PD-1/PD-L1 Immune Checkpoint Inhibitors.

Computational approaches in immune-oncology therapies focus on using data-driven methods to identify potential immune targets and develop novel drug candidates. In particular, the search for PD-1/PD-L1 immune checkpoint inhibitors (ICIs) has enlivened the field, leveraging the use of cheminformatics and bioinformatics tools to analyze large datasets of molecules, gene expression and protein-protein interactions. Up to now, there is still an unmet clinical need for improved ICIs and reliable predictive biomarkers. In this review, we highlight the computational methodologies applied to discovering and developing PD-1/PD-L1 ICIs for improved cancer immunotherapies with a greater focus in the last five years. The use of computer-aided drug design structure- and ligand-based virtual screening processes, molecular docking, homology modeling and molecular dynamics simulations methodologies essential for successful drug discovery campaigns focusing on antibodies, peptides or small-molecule ICIs are addressed. A list of recent databases and web tools used in the context of cancer and immunotherapy has been compilated and made available, namely regarding a general scope, cancer and immunology. In summary, computational approaches have become valuable tools for discovering and developing ICIs. Despite significant progress, there is still a need for improved ICIs and biomarkers, and recent databases and web tools have been compiled to aid in this pursuit.

Targeting YAP/TAZ in Combination with PD-L1 Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer (NSCLC)

The survival of non-small cell lung cancer (NSCLC) patients has improved in the last decade as a result of introducing new therapeutics, such as immune checkpoint inhibitors, in the clinic. Still, some NSCLC patients do not benefit from these therapies due to intrinsic resistance or the development of acquired resistance and their malignant disease progresses. Further research on the molecular underpinnings of NSCLC pathobiology is required in order to discover clinically relevant molecular targets that regulate tumor immunity and to develop reasonable therapeutic combinations that will promote the efficacy of immune checkpoint inhibitors. Yes-associated Protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), the final effectors of the Hippo signaling transduction pathway, are emerging as key players in NSCLC development and progression. Herein, we overview studies that have investigated the oncogenic role of YAP/TAZ in NSCLC, focusing on immune evasion, and highlight the therapeutic potential of combining YAP/TAZ inhibitory agents with immune checkpoint inhibitors for the management of NSCLC patients.

Establishment of Cell-Based Assay System for Evaluating Cytotoxic Activity Modulated by the Blockade of PD-1 and PD-L1 Interactions with a Therapeutic Antibody

ABSTRACT Background Therapeutic antibodies targeting the PD-1/PD-L1 immune checkpoint are widely used in cancer therapy and are under active further development. Historically, the antitumor activity of PD-1/PD-L1 immune checkpoint inhibitors has been evaluated using in vivo and ex vivo test methods; however, a simple in vitro assay method to evaluate antitumor activity accurately is needed for the efficient development of new therapeutic agents. In the present study, we attempted to establish a simple cell-based assay system to evaluate the modulating effect of PD-1/PD-L1 immune checkpoint inhibitors on cytotoxic activity. Methods We established a new natural killer (NK) cell line stably transfected with the PD-1 and IL-2 genes and a new NK-sensitive target cell line stably transfected with the PD-L1 gene. Then, the assay system was established by co-cultivation of the established cell lines and measurement of the cytotoxic activities using the europium release assay. To confirm the performance of the established assay system, model therapeutic antibodies to block the PD-1/PD-L1 signal, nivolumab and atezolizumab were added to the co-culture system and the modulating effect on the cytotoxic activities were evaluated. Results Nivolumab and atezolizumab clearly showed a modulating effect on cytotoxic activity in a dose-dependent manner in our assay system, whereas a human IgG isotype control antibody did not show any modulating effect on the assay system. Conclusion The newly established cell-based assay system can quantitatively evaluate the modulating effect of PD-1/PD-L1 immune checkpoint inhibitors by measuring cytotoxic activity, playing an important role in antitumor effects as innate immunity.

Immunotherapy as a Promising Option for the Treatment of Advanced Chordoma: A Systemic Review

To summarize the function and efficacy of immunotherapy as an adjunctive therapy in the treatment of advanced chordoma. Literature search was conducted by two reviewers independently. Case reports, case series and clinical trials of immunotherapy for chordoma were retrieved systematically from Pubmed, Web of Science, Scoupus and Cochrane Library. Clinical outcome data extracted from the literature included median progression-free survival (PFS), median overall survival (OS), clinical responses and adverse events (AEs). All studies were published between 2015 and 2022. Twenty-two eligible studies were selected for systemic review. PD-1/PD-L1 immune checkpoint inhibitors (ICIs) were the most common used immunotherapy agents in chordoma, among which Pembrolizumab was the most frequently prescribed. CTLA-4 antibody was only used as combination therapy in chordoma. Dose Limiting Toxicity (DLT) was not observed in any vaccine targeting brachyury, and injection site response was the most frequent AV. The response evaluation criteria in solid tumors (RECIST) were the most generally used evaluation standard in chordoma immunotherapy, and none of the included studies employed the Choi criteria. No clinical data have demonstrated that CTLA-4 ICIs combined with PD-1/PD-L1 ICIs is more effective than ICIs monotherapy in treating chordoma, and ICIs in combination with other therapies exhibit more toxicity than monotherapy. PD-1/PD-L1 ICIs monotherapy is recommended as an immunotherapy in patients with advanced chordoma, which may even benefit PD-L1-negative patients. The brachyury vaccine has shown good safety in chordoma patients, and future clinical trials should focus on how to improve its therapeutic efficacy. The use of immunomodulatory agents is a promising therapeutic option, though additional clinical trials are required to evaluate their safety and effectiveness. RECIST does not seem to be an appropriate standard for assessing medications of intratumoral immunotherapy.

Innate immune function during antineoplastic treatment is associated with 12-months survival in non-small cell lung cancer.

The immune system has proven to be a key player in the progression as well as containment of cancer with new treatment strategies based on immunotherapy targeting this interaction. Assessing immune function could reveal critical information about the immune response to therapeutic interventions, revealing predictive biomarkers for tailored care and precision medicine. We investigated immune function in 37 patients with inoperable non-small cell lung cancer (NSCLC) undergoing treatment with PD-L1 immune checkpoint inhibitor (ICI), chemotherapy (CT) or chemo-radiotherapy (CT/RT). Blood samples before (day 0) and during therapy (day 7, 21 and 80) were investigated by a standardized immunoassay, TruCulture®. Outcomes revealed a developing innate immune response induced by both immunotherapy and chemotherapy. NSCLC-patients displayed evidence of chronic innate immune activation and exhaustion prior to treatment. This pattern was particularly pronounced during treatment in patients dying within 12-months follow-up. Compared to treatment with CT, ICI demonstrated a higher ex vivo-stimulated release of proinflammatory cytokines. These preliminary findings may pave the way for tailored treatment and immune-monitoring.

Targeting 4-1BB and PD-L1 induces potent and durable antitumor immunity in B-cell lymphoma

Although PD-1/L1 mAb has demonstrated clinical benefits in certain cancer types, low response rate and resistance remain the main challenges for the application of these immune checkpoint inhibitors (ICIs). 4-1BB is a co-stimulator molecule expressed in T cells, which could enhance T cell proliferation and activation. Herein, the synergetic antitumor effect and underlying mechanism of 4-1BB agonist combined with PD-1/PD-L1 blockade were determined in B-cell lymphoma (BCL). Subcutaneous transplantation BCL tumor models and metastasis models were established to evaluate the therapeutic effect of PD-L1 antibody and/or 4-1BB agonist in vivo. For the mechanistic study, RNA-seq was applied to analyze the tumor microenvironment and immune-related signal pathway after combination treatment. The level of IFN-γ, perforin, and granzyme B were determined by ELISA and Real-time PCR assays, while tumor-infiltrating T cells were measured by flow cytometry and immunohistochemical analysis. CD4/CD8 specific antibodies were employed to deplete the related T cells to investigate the role CD4+ and CD8+ T cells played in combination treatment. Our results showed that combining anti-PD-L1 ICI and 4-1BB agonists elicited regression of BCL and significantly extended the survival of mice compared to either monotherapy. Co-targeting PD-L1 and 4-1BB preferentially promoted intratumoral cytotoxic lymphocyte infiltration and remodeled their function. RNA-sequence analysis uncovered a series of up-regulated genes related to the activation and proliferation of cytotoxic T lymphocytes, further characterized by increased cytokines including IFN-γ, granzyme B, and perforin. Furthermore, depleting CD8+ T cells not CD4+ T cells totally abrogated the antitumor efficacy, indicating the crucial function of the CD8+ T cell subset in the combination therapy. In summary, our findings demonstrated that 4-1BB agonistic antibody intensified the antitumor immunity of anti-PD-1/PD-L1 ICI via promoting CD8+ T cell infiltration and activation, providing a novel therapeutic strategy to BCL.

Combined immunotherapy for metastatic triple-negative breast cancer based on PD-1/PD-L1 immune checkpoint blocking.

Metastatic triple negative breast cancer is not only the worst prognosis and the strongest invasive subtype of breast cancer, but also the most immunogenic subtype, so it can be reasonably predicted that immunotherapy can play a positive role in the treatment of metastatic triple negative breast cancer. However, the effect of using PD-1/PD-L1 immune checkpoint inhibitors alone is not very ideal. In recent years, the regimen of combined therapy has been emerging. This article reviews the application of combined immunotherapy based on PD-1/PD-L1 inhibitors in metastatic triple negative breast cancer, including chemotherapy, targeted therapy, radiotherapy and oncolytic virus therapy. The problems existing in combined therapy and the possibility of future research are discussed, which can provide a reference for the selection of treatment options for patients with metastatic triple negative breast cancer in different situations.

Novel Therapeutic Strategies for BCG-unresponsive Non-muscle Invasive Bladder Cancer

Development of therapeutic strategies for non-muscle-invasive bladder cancer (NMIBC) that failed intravesical Bacillus Calmette - Guerin (BCG) therapy remains an urgent priority for clinicians. Currently, radical cystectomy is the recommended standard of care treatment options for these patients. Intravesical chemotherapy using gemcitabine and docetaxel are regarded as the most effective treatment options for unresponsive NMIBC, however, these options are ineffective in the control of bladder cancer. In this review, we present the definition of BCG unresponsive NMIBC and discuss about the recent management options that include immunotherapy, intravesical chemotherapy, gene therapy, and targeted individualized therapy. Notably, immunotherapy is the most recent strategy utilizing the PD-1/PD-L1 and other immune checkpoint inhibitors (ICIs). Pembrolizumab (KEYNOTE-057), Atezolizumab (SWOG S1605) and Nivolumab were developed and are efficacious in BCG –unresponsive NMIBC. In summary, ICIs are considered as the most promising agent for BCG unresponsive NMIBC in the future.

Anti PD-1/Anti PDL-1 Inhibitors in Advanced Gastroesophageal Cancers: A Systematic Review and Meta-Analysis of Phase 2/3 Randomized Controlled Trials.

Importance: Immune checkpoint inhibitors (ICI) have revolutionized the treatment for gastroesophageal cancers (GEC). It is important to investigate the factors that influence the response to anti-PD-1/PD-L1 ICIs. Objective: To assess the benefits of PD-1/PD-L1 ICIs in advanced GEC and perform subgroup analysis to identify patient populations who would benefit from ICI. Data sources: PubMed, Embase, Scopus, and the Cochrane Library databases were systematically searched from database inception to September 2021 for all relevant articles. We also reviewed abstracts and presentations from all major conference proceedings including relevant meetings of the American Society of Clinical Oncology (ASCO), and the European Society for Medical Oncology (ESMO) during the last four years (2018 to 2021) and reviewed citation lists. Study selection, data extraction, and synthesis: Full articles and presentations were further assessed if the information suggested that the study was a phase 2/3 randomized controlled trial (RCT) comparing PD-1/PD-L1 inhibitor either alone, or in combination with standard therapy vs. standard therapy in advanced GEC. The full text of the resulting studies/presentations and extracted data were reviewed independently according to PRISMA guidelines. Main outcomes and measures: The main outcomes were OS, PFS, and treatment-related adverse events (TRAEs). Results: A total of 168 studies were assessed for eligibility, and 17 RCTs with 12,312 patients met the inclusion criteria. There was an OS benefit in the overall population with ICIs (HR 0.78; 95% CI 0.73–0.83 p < 0.001). Immunotherapy showed better OS benefit in males (HR 0.77 95% CI 0.72–0.83; p < 0.001) than females (HR 0.89; 95% CI 0.80–0.99 p < 0.03), esophageal primary tumors (HR 0.70 95% CI 0.64–0.76 p < 0.001) vs. gastric cancer (HR 0.84 95% CI 0.74–0.94 p 0.002) or GEJ cancer (HR 0.84 95% CI 0.72–0.98 p 0.024) and in squamous cell carcinoma (HR 0.71 95% CI 0.66–0.77 p < 0.001) vs. adenocarcinoma (HR 0.85 95% CI 0.78–0.93 p < 0.001). PD-L1 positive patients seemed to benefit more (HR 0.74 95% CI 0.67–0.82 p < 0.001) compared to PD-L1 negative patients (HR 0.86 95% CI 0.74–1.00 p < 0.043), and Asians showed OS benefit (HR 0.76 95% CI 0.67–0.87 p < 0.001) compared to their White counterparts (HR 0.92 95% CI 0.74–1.14; p 0.424). Conclusions and relevance: ICIs improve survival in advanced GEC without significantly increasing the side effects. However, certain subgroups of patients such as males, Asians, and those with esophageal primary, PD-L1 positive tumors and squamous cell carcinoma benefit more from such treatments. Further translational research is needed to understand the mechanistic links and develop new biomarkers.

The role of PD-1/PD-L1 and application of immune-checkpoint inhibitors in human cancers.

Programmed cell death protein-1 (PD-1) is a checkpoint receptor expressed on the surface of various immune cells. PD-L1, the natural receptor for PD-1, is mainly expressed in tumor cells. Studies have indicated that PD-1 and PD-L1 are closely associated with the progression of human cancers and are promising biomarkers for cancer therapy. Moreover, the interaction of PD-1 and PD-L1 is one of the important mechanism by which human tumors generate immune escape. This article provides a review on the role of PD-L1/PD-1, mechanisms of immune response and resistance, as well as immune-related adverse events in the treatment of anti-PD-1/PD-L1 immunotherapy in human cancers. Moreover, we summarized a large number of clinical trials to successfully reveal that PD-1/PD-L1 Immune-checkpoint inhibitors have manifested promising therapeutic effects, which have been evaluated from different perspectives, including overall survival, objective effective rate and medium progression-free survival. Finally, we pointed out the current problems faced by PD-1/PD-L1 Immune-checkpoint inhibitors and its future prospects. Although PD-1/PD-L1 immune checkpoint inhibitors have been widely used in the treatment of human cancers, tough challenges still remain. Combination therapy and predictive models based on integrated biomarker determination theory may be the future directions for the application of PD-1/PD-L1 Immune-checkpoint inhibitors in treating human cancers.

787O Adjuvant immunotherapy with nivolumab (NIVO) versus observation in completely resected Merkel cell carcinoma (MCC): Disease-free survival (DFS) results from ADMEC-O, a randomized, open-label phase II trial

MCC is a rare, immunogenic but aggressive skin cancer. Even after complete resection and radiation relapse rates are high. PD-1/PD-L1 immune checkpoint inhibitors (ICI) showed clinical benefit in locally advanced MCC. ADMEC-O is the first trial to investigate the efficacy/safety of adjuvant PD-1 blockade by ICI in completely resected MCC, i.e. in a situation with no systemic Standard of Care.

Arginine Deprivation in SCLC: Mechanisms and Perspectives for Therapy.

Arginine deprivation has gained increasing traction as a novel and safe antimetabolite strategy for the treatment of several hard-to-treat cancers characterised by a critical dependency on arginine. Small cell lung cancer (SCLC) displays marked arginine auxotrophy due to inactivation of the rate-limiting enzyme argininosuccinate synthetase 1 (ASS1), and as a consequence may be targeted with pegylated arginine deiminase or ADI-PEG20 (pegargiminase) and human recombinant pegylated arginases (rhArgPEG, BCT-100 and pegzilarginase). Although preclinical studies reveal that ASS1-deficient SCLC cell lines are highly sensitive to arginine-degrading enzymes, there is a clear disconnect with the clinic with minimal activity seen to date that may be due in part to patient selection. Recent studies have explored resistance mechanisms to arginine depletion focusing on tumor adaptation, such as ASS1 re-expression and autophagy, stromal cell inputs including macrophage infiltration, and tumor heterogeneity. Here, we explore how arginine deprivation may be combined strategically with novel agents to improve SCLC management by modulating resistance and increasing the efficacy of existing agents. Moreover, recent work has identified an intriguing role for targeting arginine in combination with PD-1/PD-L1 immune checkpoint inhibitors and clinical trials are in progress. Thus, future studies of arginine-depleting agents with chemoimmunotherapy, the current standard of care for SCLC, may lead to enhanced disease control and much needed improvements in long-term survival for patients.

654MO High dimensional immuno-phenotyping of immunotherapy response in head and neck cancer

Immunotherapies, in particular immune check point inhibitors (ICI), have proven to be game changing treatments of mucosal head and neck squamous cell cancer (HNSCC). Emerging successes with anti-PD-1/PD-L1 ICI therapy have lead to durable responses and prolonged survival in human papillomavirus positive (HPV+) and negative (HPV-) patients, and there is now an urgent need for predictive biomarkers to guide patient selection for highly targeted ICI therapies. There are currently no means by which to determine whether a patient would respond to anti PD-1/PD-L1 immunotherapy.

Development of In Vitro Assays for Advancing Radioimmunotherapy against Brain Tumors.

Glioblastoma (GBM) is the most common primary brain tumor. Due to high resistance to treatment, local invasion, and a high risk of recurrence, GBM patient prognoses are often dismal, with median survival around 15 months. The current standard of care is threefold: surgery, radiation therapy, and chemotherapy with temozolomide (TMZ). However, patient survival has only marginally improved. Radioimmunotherapy (RIT) is a fourth modality under clinical trials and aims at combining immunotherapeutic agents with radiotherapy. Here, we develop in vitro assays for the rapid evaluation of RIT strategies. Using a standard cell irradiator and an Electric Cell Impedance Sensor, we quantify cell migration following the combination of radiotherapy and chemotherapy with TMZ and RIT with durvalumab, a PD-L1 immune checkpoint inhibitor. We measure cell survival using a cloud-based clonogenic assay. Irradiated T98G and U87 GBM cells migrate significantly (p < 0.05) more than untreated cells in the first 20–40 h post-treatment. Addition of TMZ increases migration rates for T98G at 20 Gy (p < 0.01). Neither TMZ nor durvalumab significantly change cell survival in 21 days post-treatment. Interestingly, durvalumab abolishes the enhanced migration effect, indicating possible potency against local invasion. These results provide parameters for the rapid supplementary evaluation of RIT against brain tumors.

Analysis of mutations in DNA damage repair pathway gene in Chinese patients with hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) has increased in these years. DNA damage repair (DDR) pathway is required in response to DNA damage Gene mutations in DDR pathway play an important role in different stages of tumorigenesis and development. Based on the importance of DDR pathway in precision therapy of multiple cancers, we analyzed DDR gene mutations in Chinese patients with HCC. The results showed that (tumor mutation burden) TMB was significantly higher in HCC patients who carried somatic mutations in DDR than in non-carriers, and TMB in patients with DS, MMR mutations and DDR genes mutations such as RAD50, MLH1, MSH2, CHEK2 was significantly higher than that in wild-type patients. Based on the results of next-generation sequencing (NGS) testing, we are trying to provide clues for targeted therapy and provide feasible basis for PD-1/PD-L1 immune checkpoint inhibitor therapy.