Cell Death Receptor Research Articles

Safety, antitumor activity, and pharmacokinetics of dostarlimab, an anti-PD-1, in patients with advanced solid tumors: a dose\u2013escalation phase 1 trial

PurposeNew immuno-oncology therapies targeting programmed cell death receptor 1 (PD-1) have improved patient outcomes in a broad range of cancers. The objective of this analysis was to evaluate the PK, pharmacodynamics (PDy), and safety of dostarlimab monotherapy in adult patients with previously-treated advanced solid tumors who participated in parts 1 and 2A of the phase 1 GARNET study.MethodsPart 1 featured a 3 + 3 weight-based dose–escalation study, in which 21 patients received dostarlimab 1, 3, or 10 mg/kg intravenously every 2 weeks. The 2 fixed-dose nonweight-based dosing regimens of dostarlimab 500 mg every 3 weeks (Q3W) and 1000 mg every 6 weeks (Q6W) were evaluated using a modified 6 + 6 design in part 2A (n = 13). In parts 1 and 2A, treatment with dostarlimab could continue for up to 2 years or until progression, unacceptable toxicity, patient withdrawal, investigator’s decision, or death.ResultsThe dostarlimab PK profile was dose proportional, and maximal achievable receptor occupancy (RO) was observed at all dose levels in the weight-based and fixed-dose cohorts. Trough dostarlimab concentration after administration of dostarlimab 500 mg Q3W was similar to that after dostarlimab 1000 mg Q6W, the values of which (≈40 µg/mL) projected well above the lowest dostarlimab concentration required for full peripheral RO. No dose-limiting toxicities were observed.ConclusionsDostarlimab demonstrated consistent and predictable PK and associated PDy. The observed safety profile was acceptable and characteristic of the anti-PD-1 drug class.Trial registration: ClinicalTrials.gov, NCT02715284. Registration date: March 9, 2016.

Priming Death Receptor Mediated Apoptosis with Arginine Starvation Sensitises Arginine Auxotrophic B-ALL to CAR-T

BackgroundChimeric antigen receptor (CAR)-T cell therapy has revolutionised the treatment of relapsed or refractory B-ALL in children and young adults with unprecedented response rates. However, primary resistance and relapse are unresolved challenges that limit long term benefit in a significant proportion of patients. Death receptor mediated extrinsic apoptosis is a key component of CAR-T cytotoxicity and impairment of this system, of which CAR-T derived TRAIL (tumour necrosis factor related apoptosis inducing ligand) is a key initiator, is a principal driver of primary resistance. Arginine deprivation with the therapeutic enzyme ADI-PEG20 (pegylated arginine deiminase) sensitises cancers deficient in the enzyme argininosuccinate synthase (ASS1) to the apoptosis initiating activity of TRAIL through tumour cell surface upregulation of death receptors DR4 and DR5. Whether this effect could potentiate the TRAIL-DR activity in CAR-T therapy has not been explored.AimWe tested the hypothesis that ADI-PEG20 treatment can sensitise susceptible B-ALL to anti-CD19 CAR-T through priming of death receptor mediated apoptosis signalling.MethodsThe effect of ADI-PEG20 on cell survival and death receptor expression in B-ALL cell lines and primary samples was analysed by flow cytometry. Second generation anti-CD19 CAR-T cells with a CD28 costimulatory domain were generated by retroviral transduction of activated peripheral blood mononuclear cells (PBMC) from healthy donors. For CAR-T co-culture experiments, B-ALL cell lines were pre-treated with ADI-PEG20 before washing and re-suspending in arginine replete media prior to CAR-T cell addition.ResultsTo establish potential susceptibility of B-ALL to ADI-PEG20 we measured expression of ASS1, which inversely correlates with sensitivity to the drug, using combined in situ immunohistochemistry (n=6) and RT-qPCR (n=7). ASS1 deficiency was consistently seen in this series of primary samples suggesting the potential utility of ADI-PEG20 in B-ALL, with comparable expression levels to those seen in a cohort of primary AML samples proven to be sensitive to the drug (figure 1a).Next, to examine variation in ASS1 expression between genetically defined subtypes of B-ALL we re-analysed transcriptome data from a cohort of 215 patients treated on the ECOG E2993 trial, filtered into a network of 58 genes generated according to known or predicted interaction with ASS1. We found an enrichment of Philadelphia chromosome positive (Ph+) and Philadelphia-like (Ph-L) samples in the cluster characterised by lowest ASS1 expression along with high HIF1A expression, matching a recurrent pattern reported in other ADI-PEG20 sensitive tumours. This therefore predicts that among B-ALL subtypes, Ph+ and Ph-L are likely to be most sensitive to therapeutic arginine deprivation.We then functionally confirmed, using in vitro cell line (n=3) and in vivo patient derived xenograft models of B-ALL (n=2), that ASS1 deficiency is required for ADI-PEG20 sensitivity. Using the ASS1-low, Ph-L cell line MUTZ-5, we established that ADI-PEG20 induced apoptosis accompanies cell surface upregulation of both DR4 and DR5 expression. Upregulation of DR4 was observed to follow an upwards trend after treated cells were washed and re-suspended in arginine replete media, suggesting that transient arginine starvation can commit ASS1-low B-ALL to a state of apoptotic priming (figure 1b).With confirmed engagement of arginine starvation and death receptor upregulation we tested the synergy potential of ADI-PEG20 pre-treatment of MUTZ-5 followed by CAR-T, utilising calculated combination drug indices (CDIs). Across independent PBMC donors (n=3) we observed greater potency killing of CD19 + leukaemia cells in the combination treated co-cultures when compared to the single agent treated conditions, with CDIs consistently less than 1 confirming a synergistic effect (figure 1c).ConclusionOur study proposes a synergistic interaction between the arginine depleting enzyme ADI-PEG20 and anti-CD19 CAR-T for the treatment of ASS1 deficient B-ALL, whereby priming of death receptor signalling may underlie enhanced CAR-T cytotoxicity against CD19 + tumour cells. These data support an emerging framework for CAR-T optimisation based on targeting of the death receptor mediated extrinsic apoptosis pathway and can inform future refinements in the development of cellular immunotherapy. [Display omitted] DisclosuresBomalaski: Polaris Pharmaceuticals Inc.: Current Employment. Maher: Leucid Bio: Other: Chief Scientific Officer. Gribben: Abbvie: Honoraria; AZ: Honoraria, Research Funding; BMS: Honoraria; Gilead/Kite: Honoraria; Janssen: Honoraria, Research Funding; Morphosys: Honoraria; Novartis: Honoraria; Takeda: Honoraria; TG Therapeutis: Honoraria.

Immune Checkpoint Inhibitors (ICI) Enhance Cancer Associated Thrombosis (CAT) in Murine Model of Colon Carcinoma

AbstractBackground:Venous thromboembolism (VTE) is an important immune-related adverse event (irAE) associated with immune checkpoint inhibitors (ICI) cancer therapy. To better understand the pathogenesis of ICI-induced VTE during ICI treatment, we utilized a murine model of cancer associated thrombosis (CAT) to examine the impact of ICI treatment on the development of flow restriction-induced thrombosis.MethodsA syngeneic colon carcinoma murine model (CT26) on BALB/c background was utilized to evaluate venous thrombosis following inferior vena cava (IVC) ligation. Non-tumor-bearing and tumor-bearing animals were treated with therapeutic doses of ICI: anti-programmed cell death receptor 1 antibody (anti-PD1) and cytotoxic T‐lymphocyte-associated protein 4 (anti‐CTLA4) or isotype control antibodies. Mice underwent surgical treatment for IVC ligation followed by surgical retrieval of thrombus. Western blot analysis was performed on plasma cleaved high molecular weight kininogen (cHK), and citrullinated histone H3 (CitH3).ResultsTumor-bearing mice undergoing IVC ligation after anti-PD1 and anti-CTLA4 infusion developed larger thrombi compared to mice treated with isotype control IgG. Thrombus weights in CT26 tumor-bearing mice treated with ICI (19.56±4.41 mg) were significantly increased compared to those in mice treated with isotype control IgG (14.67±2.76 mg) (P=0.043). The weight of thrombi in non-tumor-bearing mice was not affected by ICI treatment (9.25±2.22 mg with control IgG vs 9.33±1.15 mg with ICI). In addition, there was a significant increase in thrombus length in mice treated with ICI (9±1.02 mm vs 7.61±0.99 mm with IgG, P=0.039). Cleaved high molecular weight kininogen (cHK), an indicator of contact activation was increased in plasma pre-IVC occlusion from ICI-treated mice compared to IgG-treated mice (68% vs 38% in HK cleavage). Citrullinated histone H3 (CitH3), a NETosis marker, was elevated in plasma (and in thrombus) post-IVC occlusion from ICI-treated mice compared to that of IgG-treated mice.ConclusionsICI treatment of tumor-bearing mice undergoing flow restriction-induced thrombosis resulted in enhanced clot formation. Larger thrombi in ICI treated mice was accompanied with enhanced contact activation and NETosis marker CitH3. [Display omitted] DisclosuresKhorana: Halozyme: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Bayer: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Anthos: Consultancy, Honoraria. McCrae: Dova, Novartis, Rigel, and Sanofi Genzyme: Consultancy; Sanofi, Novartis, Alexion, and Johnson & Johnson: Consultancy, Honoraria.

Circulating predictive markers of immune checkpoint inhibitors in non-small cell lung cancer

Immune checkpoint inhibitors (ICIs) alone or in combination with chemotherapy have become one of the key approaches in the treatment of patients with advanced non-small cell lung cancer (NSCLC). Evaluation of level of PD-L1 (ligand of the programmed cell death receptor 1) expression on tumor cells using immunohistochemistry is the only approved option for determining the indications of ICIs in this group of patients. However, despite high level of PD-L1 expression, up to 80 % of patients do not respond to therapy due to the presence of primary or acquired resistance, which determines the limited effectiveness of ICI. In addition, 8–17 % of PD-L1-negative patients with NSCLC are also able to respond to ICIs. The limitation of this marker is that it does not allow assessing both intratumoral and systemic immune status. It is necessary to search for additional predictive markers to improve the accuracy of the selection of candidates for immunotherapy, which will avoid costs, wasted time, and a high risk of immune-related adverse events in potentially unresponsive patients. The attention of researchers is devoted to circulating markers in peripheral blood, as a non-invasive alternative to biopsy for predicting and monitoring the response. This review focuses on the most promising immunological markers in peripheral blood as potential predictors of response to ICIs in patients with advanced NSCLC.

First-line Cemiplimab versus Standard Chemotherapy in Advanced Non-small Cell Lung Cancer Patients with at Least 50% Programmed Cell Death Receptor Ligand-1 Positivity: Analysis of Cost-effectiveness

AimsThe EMPOWER-Lung 1 trial showed that cemiplimab significantly prolongs the duration of progression-free survival and overall survival in advanced non-small cell lung cancer (NSCLC) patients with at least 50% programmed cell death receptor ligand-1 (PD-L1) positivity, yet the financial burden may limit its use. The aim of the present study was to evaluate the cost-effectiveness of cemiplimab versus chemotherapy in a US setting. Materials and methodsA Markov model, with three mutually exclusive health states, was used to compare the expected health outcomes and cost of cemiplimab with chemotherapy. Survival data and transition probabilities were collected from the EMPOWER-Lung 1 trial. Utility values and costs are publicly available from open sources. One-way and probabilistic sensitivity analyses were conducted in both the whole population and subgroups to test the robustness of the parameters and structure. ResultsTreatment of NSCLC with cemiplimab yielded an extra 1.07 quality-adjusted life years (QALYs) at an additional cost of $98 211 compared with chemotherapy, associated with an incremental cost-effectiveness ratio of $91 891/QALY and an incremental net health benefit of 0.087 QALYs at a willingness to pay threshold of $100 000/QALY. The probabilistic sensitivity analysis indicated that cemiplimab provided an 83.2% probability of being cost-effective. One-way sensitivity analysis suggested that the price of cemiplimab was the chief driver in this model. A subgroup analysis showed that cemiplimab was the preferred incremental net health benefit in more than half of the subgroups, including patients with squamous type disease and metastases. ConclusionsCemiplimab is a cost-effective option in the first-line treatment of NSCLC in patients who are at least 50% PD-L1 positive from an American perspective.

Tumor PD-L1 and VEGF Expression, and CD8 T Cell Infiltration Predict Clinical Response to Immune Checkpoint Inhibitors in Non-small Cell Lung Cancer.

We evaluated the efficacy of "the tumor immune microenvironment (TIME) classification" for predicting clinical response to immune checkpoint inhibitors (ICIs) in patients with non-small cell lung cancer (NSCLC). In addition, we aimed to evaluate the "modified TIME classification", which adds the vascular endothelial growth factor (VEGF) status to TIME. Programmed cell death receptor ligand-1 (PD-L1), CD8 T cell tumor-infiltrating lymphocytes (CD8+TILs) count and VEGF expression analyses were performed using immuno - histochemistry in 44 patients who had undergone ICI monotherapy. Regarding TIME classification, type-I (PD-L1 high and CD8+TILs high) had a significantly higher response than the other types. Using the modified TIME classification, type-IA (PD-L1 high, CD8+TILs high, and VEGF low) had a significantly higher response than the other types. The modified TIME classification, which adds tumor VEGF expression to "the TIME classification", could be useful in predicting clinical response to ICI monotherapy.

Applying CRISPR/Cas13 to Construct Exosomal PD-L1 Ultrasensitive Biosensors for Dynamic Monitoring of Tumor Progression in Immunotherapy

Programmed cell death receptor 1 (PD-L1) protein on exosomes (exosomal PD-L1) is one of the most promising biomarkers for cancer immunotherapy monitoring. However, current approaches for exosomal PD-L1 detection are poorly sensitive, laborious, and time-consuming. Here, a new method, named Aptamer-RPA-TMA-Cas13a Assay (ARTCA) is established, which enables exosomal PD-L1 to be detected directly in serum with a lower limit of 10 particles mL−1. Mechanistically, using DNA aptamer specifically binding to exosomal PD-L1, the aptamer is amplified twice by recombinase polymerase amplification (RPA) coupled with transcription-mediated amplification (TMA) and simultaneously the TMA products are detected in real-time with CRISPR/Cas13a system. Utilizing ARTCA, PD-L1 levels in circulating exosomes seem to be a reliable marker of PD-L1 expression in tumor tissue. The level of circulating exosomal PD-L1 increases significantly in patients with tumor progression. Ultra-trace detection of serum exosomal PD-L1 by ARTCA provides a potentially convenient way for dynamic monitoring of tumor progression for patients undergoing immunotherapy. These results demonstrate the use of CRISPR-Cas13a for protein detection, and circulating exosomal PD-L1 levels seem to be a reliable marker as well as PD-L1 expression in tumor tissue, opening up new avenues for monitoring tumor progression.

Uncovering the Immunoregulatory Function and Therapeutic Potential of the PD-1/PD-L1 Axis in Cancer

Immune checkpoint blockade involves the targeted antagonism of immunosuppressive interactions between antigen-presenting cells and/or tumor cells and effector T cells. Blockade of B7-H1, also known as programmed death-ligand 1 (PD-L1), prevents the ligation of inhibitory PD-L1 molecules to programmed cell death receptor 1 (PD-1) on T cells, engendering a potentiated response of tumor-specific T cells against tumor cells. In a Cancer Research article, Hirano and colleagues showed that T-cell-mediated tumor immunity becomes impaired when tumor cells interact with T cells via PD-L1 in the mouse tumor microenvironment. They showed that targeting PD-L1 or PD-1 with mAbs increased tumor cell lysis by T cells and suggested that tumor PD-L1 forms a "shield" preventing tumor cell lysis. Alongside other original mouse and human studies, this work generated scientific rationales for a new generation of cancer treatment focused on targeting the inhibitory PD-1/PD-L1 signaling pathway in the tumor microenvironment.See related article by Hirano and colleagues, Cancer Res 2005;65: 1089-96.

Downregulation of inhibitor of apoptosis protein induces apoptosis and suppresses stemness maintenance in testicular teratoma.

Inhibitors of apoptosis (IAPs) are a family of cell death inhibitors found in viruses and metazoans that physically interact with a variety of pro-apoptotic proteins and inhibit apoptosis induced by diverse stimuli. Melanoma IAP (ML-IAP) is a potent anti-apoptotic protein that is strongly upregulated in melanoma and confers protection against a variety of pro-apoptotic stimuli. In the present study, it was revealed that ML-IAP was expressed at high levels in testicular teratoma. Deletion and mutational analysis demonstrated that ML-IAP silencing significantly decreased P19 cell proliferation while inducing cell cycle arrest and apoptosis. ML-IAP knockdown significantly induced caspase-3/8/9-mediated apoptosis in P19 cells. In addition, metabolism and stemness maintenance in P19 cells were suppressed by ML-IAP knockdown. These results indicated that ML-IAP silencing is a powerful inducer of apoptosis mediated by cell death receptors and may function as a direct activator of downstream effector caspases.

P14.07 PERLA: Randomized Phase II Trial of Dostarlimab + Chemotherapy (CT) vs Pembrolizumab + CT in Metastatic Non-Squamous NSCLC

NSCLC remains a leading cause of cancer mortality worldwide, with poor survival prospects for metastatic disease. Front-line treatment of NSCLC has been improved by programmed cell death receptor 1 (PD-1) and programmed death ligand 1 (PD-L1) inhibitors. KEYNOTE-189 showed that the addition of pembrolizumab to pemetrexed and platinum-based CT significantly improved overall survival (OS) and progression-free survival (PFS) in patients with untreated non-squamous metastatic NSCLC regardless of PD-L1 expression (Gandhi New Engl J Med 2018).

BEWO trophoblast cells and Toxoplasma gondii infection modulate cell death mechanisms in THP-1 monocyte cells by interference in the expression of death receptor and intracellular proteins

Crosstalk between trophoblast and monocytes is essential for gestational success, and it can be compromised in congenital toxoplasmosis. Cell death is one of the mechanisms involved in the maintenance of pregnancy, and this study aimed to evaluate the role of trophoblast in the modulation of monocyte cell death in the presence or absence of Toxoplasma gondii infection. THP-1 cells were stimulated with supernatants of BeWo cells and then infected or not with T. gondii. The supernatants were collected and analyzed for the secretion of human Fas ligand, and cells were used to determine cell death and apoptosis, cell death receptor, and intracellular proteins expression. Cell death and apoptosis index were higher in uninfected THP-1 cells stimulated with supernatants of BeWo cells; however, apoptosis index was reduced by T. gondii infection. Macrophage migration inhibitory factor (MIF) and transforming growth factor (TGF)-β1, secreted by BeWo cells, altered the cell death and apoptosis rates in THP-1 cells. In infected THP-1 cells, the expression of Fas/CD95 and secretion of FasL was significantly higher; however, caspase 3 and phosphorylated extracellular-signal-regulated kinase (ERK1/2) were downregulated. Results suggest that soluble factors secreted by BeWo cells induce cell death and apoptosis in THP-1 cells, and Fas/CD95 can be involved in this process. On the other hand, T. gondii interferes in the mechanism of cell death and inhibits THP-1 cell apoptosis, which can be associated with active caspase 3 and phosphorylated ERK1/2. In conclusion, our results showed that human BeWo trophoblast cells and T. gondii infection modulate cell death in human THP-1 monocyte cells.

PD-1/PD-L1 Inhibitors versus Chemotherapy for Previously Treated Advanced Gastroesophageal Cancer: A Meta-Analysis of Randomized Controlled Trials.

Patients with advanced gastroesophageal cancer refractory to the previous regimen of chemotherapy suffered from poor prognosis without many effective treatment options. Immune checkpoint inhibitors (ICIs) provide promising efficacy, but the relevant clinical trials have offered controversial data. We performed this meta-analysis to compare the efficacy and safety of inhibitors against programmed cell death receptor 1 (PD-1) and its ligand PD-L1 versus chemotherapy as second or third-line therapy in patients with advanced gastroesophageal cancer. Six randomized controlled trials (RCTs) including 2,648 patients were included. The meta-analysis results indicated that both ORR (RR = 1.39, 95% CI: 0.85∼2.25, P = 0.188) and PFS (HR = 1.14, 95% CI: 0.88∼1.46, P = 0.316) were not significantly improved by ICIs compared with chemotherapy. However, the OS was significantly prolonged (HR = 0.85, 95% CI: 0.75–0.97, P = 0.018) in the ICIs group compared with chemotherapy. Subgroup analysis showed that ICIs provide statistically significant OS benefits over chemotherapy in PD-L1-positive, squamous cell carcinoma, Asia origin, esophageal cancer, second-line treatment, male, and aged 65 or older patients. Compared with chemotherapy, the TRAEs risk of ICIs was reduced by 33% (RR = 0.67, 95% CI: 0.62–0.73, P ≤ 0.001). And the risk of grades 3–5 of TRAEs was reduced by 60% (RR = 0.40, 95% CI: 0.33–0.49, P ≤ 0.001). Compared to chemotherapy, ICIs appeared to improve OS and were better tolerated in previously treated patients with advanced esophageal cancer. We recommend PD-1/PD-L1 inhibitors as an optimal treatment option for positive PD-L1 expression, squamous cell carcinoma, Asia origin, esophageal cancer, second-line treatment, male, and ≥65 years of age patients.

PD-L1 regulation revisited: impact on immunotherapeutic strategies.

A particularly promising cancer treatment is the use of monoclonal antibodies (mAbs) against immune checkpoints (i.e., immune checkpoint inhibitors; ICIs). However, many patients experience relapse and severe adverse events. To overcome these negative issues and improve efficiency, current approaches rely on combinatorial treatments, including some modulating the expression of programmed cell death receptor 1 (PD-1)/programmed death ligand 1 (PD-L1) immune checkpoints directly. In this review, we examine the recently discovered pathways involved in PD-L1 expression and highlight the relevant druggable strategies that are being developed to both improve the response rate and avoid the onset of resistance. Altogether, these new strategies will pave the way for effective treatment combinations in future oncology clinical trials.

PD-L1 expression, EGFR and KRAS mutations and survival among stage III unresected non-small cell lung cancer patients: a Danish cohort study

Programmed cell death receptor ligand-1 (PD-L1) expression, KRAS (KRASm) and EGFR (EGFRm) mutations may influence non-small cell lung cancer (NSCLC) prognosis. We aimed to evaluate PD-L1 expression, KRASm, and EGFRm and survival among stage III unresected NSCLC patients. Using Danish registries, we collected data on stage III unresected NSCLC patients diagnosed 2001–2012 and paraffin-embedded tumor tissue from pathology archives. We assessed PD-L1 expression in tumors and tumor-infiltrating immune cells (ICs) by immunohistochemistry (ge 1% threshold for PD-L1+). We genotyped KRAS and EGFR. Follow-up extended from 120 days post-diagnosis to death, emigration, or 31/12/2014. We computed median survival using Kaplan–Meier methods, and hazard ratios (HRs) using Cox regression associating the biomarkers with death, adjusting for confounders. Among 305 patients, 48% had adenocarcinoma; 38% squamous cell carcinoma. Forty-nine percent had PD-L1+ tumors—51% stage IIIA and 26% KRASm. Few (2%) patients had EGFRm. Median survival in months was 14.7 (95% CI = 11.8–17.9) and 13.4 (95% CI = 9.5–16.3) in PD-L1+ and PD-L1− tumors, respectively. KRASm was not associated with death (HR = 1.06, 95% CI = 0.74–1.51 versus wildtype). PD-L1+ tumors yielded a HR = 0.83 (95% CI = 0.63–1.10); PD-L1+ ICs a HR = 0.51 (95% CI = 0.39–0.68). Tumor expression of PD-L1 did not influence survival. PD-L1+ ICs may confer survival benefit in stage III unresected NSCLC patients.

Clinical Response to Immunotherapy Targeting Programmed Cell Death Receptor 1/Programmed Cell Death Ligand 1 in Patients With Treatment-Resistant Microsatellite Stable Colorectal Cancer With and Without Liver Metastases

Microsatellite stable (MSS) metastatic colorectal cancer has been historically characterized as resistant to immunotherapy. Recent studies have demonstrated limited clinical activity of programmed cell death receptor 1/programmed death ligand 1 (PD-1/PD-L1) targeting in MSS metastatic colorectal cancer. The association of metastatic disease in the liver with treatment response has not been fully investigated. To investigate the association of liver metastases with response to PD-1/PD-L1-targeting therapy in MSS metastatic colorectal cancer. This single-center retrospective cohort study evaluated clinical responses to PD-1- or PD-L1-targeting therapy, with or without other investigational agents, in patients with MSS metastatic colorectal cancer and disease progression after standard of care therapy from January 1, 2014, to December 31, 2020. Objective response rate (ORR) and progression-free survival (PFS), measured from initiation of PD-1/PD-L1-targeting therapy. Ninety-five patients with MSS metastatic colorectal cancer were identified (54 men [56.8%]; median age, 55 [interquartile range (IQR), 49-64] years). The overall ORR was 8.4% (8 of 95 patients). Eight of 41 patients without liver metastases achieved an ORR of 19.5%, and no response was observed in 54 patients with liver metastases. The disease control rate was 58.5% (24 of 41) in patients without liver metastasis and 1.9% (1 of 54) in patients with liver metastasis. Patients without liver metastases at the time of PD-1/PD-L1-targeting treatment had a superior median PFS compared with patients with liver metastases (4.0 [IQR, 2.0-7.5] vs 1.5 [IQR, 1.0-2.0] months; P < .001). In addition, median PFS was 5.5 (IQR, 2.0-11.5) months for patients without any prior or current liver involvement at the time of PD-1/PD-L1-targeting treatment initiation. Using a multivariate Cox regression model correcting for Eastern Cooperative Oncology Group status, primary tumor location, RAS and BRAF status, tumor mutation burden, and metastatic sites, liver metastases was the variable with the most significant association with faster progression after PD-1/PD-L1 treatment inhibition (hazard ratio, 7.00; 95% CI, 3.18-15.42; P < .001). Findings of this cohort study suggest that patients with MSS metastatic colorectal cancer and without liver metastases may derive clinical benefits from checkpoint inhibitors, whereas the presence of liver metastases was associated with resistance. Further prospective studies are needed to investigate PD-1/PD-L1 inhibitors in patients with MSS metastatic colorectal cancer without liver metastases.

Current Status and Prospects of Camrelizumab, A Humanized Antibody Against Programmed Cell Death Receptor 1

Current Status and Prospects of Camrelizumab, A Humanized Antibody Against Programmed Cell Death Receptor 1

Abstract 1044: ONC201 as a novel anti-cancer therapeutic via modulation of inhibitors of apoptosis and up-regulation of DR5 in gastric adenocarcinoma

Abstract Gastric adenocarcinoma is commonly asymptomatic early in its course, leading to late-stage diagnosis at a time when patients are inoperable. Currently available chemotherapy options are non-targeted and highly toxic, leading to a poor 5-year survival of only 31.5%. ONC201 is a small molecule imipridone anti-cancer therapy discovered by our lab that induces cell death in a variety of malignant tumors via a multitude of mechanisms including activation of the integrated stress response (ISR) leading to up-regulation of TNF-related apoptosis-inducing ligand (TRAIL), which induces apoptosis after binding to the death receptor 5 (DR5). We investigated the ability of ONC201 to induce cell death in gastric adenocarcinoma cells when used in combination with recombinant human TRAIL (rhTRAIL), and its affect on DR5 cell surface expression and expression of inhibitors of apoptosis (IAP) in order to further establish mechanism of action. AGS (caspase 8, KRAS, PIK3CA mutant, HER2 amplified), SNU-1 (KRAS and MLH1 mutant, microsatellite instable), SNU-5 (p53 mutant) and SNU-16 (p53 mutant) gastric adenocarcinoma cell lines were treated with ONC201 and rhTRAIL and viability assays were performed to determine cell line sensitivities. All lines were then treated with combination therapy based on sensitivities and viability assays were performed in order to determine combination indices. Cell death was verified with sub-G1 analysis via flow cytometry and protein expression was established via western blotting. All cell lines exhibited strong synergy in response to dual therapy with ONC201 and rhTRAIL, with combination indices &amp;lt;0.6 at doses that did not induce cell death in normal fibroblast cells. Synergy was confirmed via flow cytometry analysis with increased cells in the sub-G1 phase of the cell cycle with dual therapy in excess of what would be expected from an additive effect. On western blot analysis, apoptosis was confirmed with increased cleavage of PARP, caspase 8 and caspase 3 after dual treatment with ONC201 and rhTRAIL. Flow cytometry revealed increased cell surface expression of DR5 with ONC201 therapy, and western blot analysis showed that ONC201 lead to up-regulation of ATF-4 and CHOP, indicating activation of the ISR, and down-regulation of anti-apoptotic CIAP-2 and XIAP in all cell lines except AGS, as well as FLIP in all cell lines except SNU-16. These in vitro results suggest that ONC201 in combination with rhTRAIL may be an effective and non-toxic option for the treatment of gastric adenocarcinoma by inducing apoptosis via activation of the ISR, increased cell surface expression of DR5 and down-regulation of inhibitors of apoptosis. We are currently applying this regimen to an organoid model, as well as a murine sub-cutaneous xenograft model using AGS and SNU-1 cells. Citation Format: Cassandra Susan Parker, Lanlan Zhou, Varun Prabhu, Josh Allen, Wafik El-Deiry. ONC201 as a novel anti-cancer therapeutic via modulation of inhibitors of apoptosis and up-regulation of DR5 in gastric adenocarcinoma [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 1044.

Long Noncoding RNA GAS5 in Breast Cancer: Epigenetic Mechanisms and Biological Functions.

Long noncoding RNAs (lncRNAs) have been identified as contributors to the development and progression of cancer through various functions and mechanisms. LncRNA GAS5 is downregulated in multiple cancers and acts as a tumor suppressor in breast cancer. GAS5 interacts with various proteins (e.g., E2F1, EZH2, and YAP), DNA (e.g., the insulin receptor promoter), and various microRNAs (miRNAs). In breast cancer, GAS5 binds with miR-21, miR-222, miR-221-3p, miR-196a-5p, and miR-378a-5p that indicates the presence of several elements for miRNA binding (MREs) in GAS5. Mediated by the listed miRNAs, GAS5 is involved in the upregulation of a number of mRNAs of suppressor proteins such as PTEN, PDCD4, DKK2, FOXO1, and SUFU. Furthermore, the aberrant promoter methylation is involved in the regulation of GAS5 gene expression in triple-negative breast cancer and some other carcinomas. GAS5 can stimulate apoptosis in breast cancer via diverse pathways, including cell death receptors and mitochondrial signaling pathways. GAS5 is also a key player in the regulation of some crucial signal pathways in breast cancer, such as PI3K/AKT/mTOR, Wnt/β-catenin, and NF-κB signaling. Through epigenetic and other mechanisms, GAS5 can increase sensitivity to multiple drugs and improve prognosis. GAS5 is thus a promising target in the treatment of breast cancer patients.

Noncanonical NF-κB Signaling Upregulation in Inflammatory Bowel Disease Patients is Associated With Loss of Response to Anti-TNF Agents.

Objectives: Targeting tumor necrosis factor (TNF) with biologic agents, such as infliximab and adalimumab, is a widely used and effective therapeutic strategy in inflammatory bowel disease (IBD). Unfortunately, a significant number of patients fail to respond or lose response over time to these agents. Previous studies have defined multiple complex roles for canonical NF-κB signaling in the pathogenesis of IBD. However, preliminary evidence suggests that the lesser defined noncanonical NF-κB signaling pathway also contributes to disease pathogenesis and response to anti-TNF agents. The objective of this study was to evaluate this hypothesis in Crohn’s disease (CD) and ulcerative colitis (UC) patients. Design: A total of 27 subjects with IBD (19 with CD and 8 with UC) and 15 control subjects were tested. Clinical criteria, patient history, and endoscopic disease activity were factors used to categorize patients and define therapeutic response. Biopsy specimens were collected during colonoscopy and expression was determined for 88 target genes known to be associated with noncanonical NF-κB signaling and IBD. Results: Noncanonical NF-κB signaling was significantly upregulated in IBD patients and was associated with increased gastrointestinal inflammation, epithelial cell death, lymphocyte migration, and Nod-like receptor signaling. Furthermore, noncanonical NF-κB signaling was further upregulated in patients unresponsive to anti-TNF agents and was suppressed in responsive patients. MAP3K14, NFKB2, CCL19, CXCL12, and CXCL13 were significantly dysregulated, as were genes that encode pathway regulators, such as CYLD, NLRP12, and BIRC2/3. Conclusion: Our study identifies a previously uncharacterized role for the understudied noncanonical NF-κB signaling pathway in the pathogenesis of IBD and anti-TNF therapy responsiveness. The genes and pathways identified may ultimately prove useful in IBD management and could potentially be used as biomarkers of drug response.

The benefits and risks of CTLA4 inhibitor plus PD1/PDL1 inhibitor in stage IIIB/IV non-small cell lung cancer: A systematic analysis and meta-analysis based on randomized controlled trials.

Although immune checkpoint inhibitors (ICIs) have shown clinical benefit for patients with non-small cell lung cancer (NSCLC), the efficacy of the combination of ICIs targeting different pathways is still unclear. We performed this meta-analysis to explore the efficacy of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitor plus programmed cell death 1 receptor (PD-1)/programmed cell death receptor ligand 1 (PD-L1) inhibitor therapy (CP) for NSCLC IIIB/IV patients. We systematically searched the main databases for relevant studies. The main outcomes were overall survival (OS) and progression-free survival (PFS). We identified 3526 articles, including 5 randomized controlled trials (RCTs) (4377 patients), in our meta-analysis. We conducted two comparisons of CP versus chemotherapy or PD1/PDL1 inhibitor (P). Compared with chemotherapy, CP was more effective, with better OS (hazard ratio [HR]: 0.77, 95% CI [confidence interval]: 0.66-0.91; p=0.001), better PFS (HR: 0.77, 95% CI: 0.70-0.85; p<0.00001) and comparable objective response rate (ORR) (risk ratio [RR]: 1.27, 95% CI: 0.98-1.65; p=0.07); in terms of toxicity, CP was comparable to chemotherapy across all-grade adverse events (AEs) (RR: 0.87, 95% CI: 0.73-1.03; p=0.11) and grade 3-5 AEs (RR: 0.85, 95% CI: 0.63-1.14; p=0.27). Compared with P, CP had no superiority in efficacy in terms of the OS (HR: 1.04, 95%CI: 0.86-1.24; p=0.70), PFS (HR: 0.95, 95%CI: 0.75-1.22; p=0.70) and the ORR (RR: 1.07, 95% CI: 0.95-1.21; p=0.27) but CP was more effective than P when PD-L1 expression was <1% (RR: 0.77,95%CI: 0.60-0.98; p=0.04); in terms of toxicity, CP was associated with increased all-grade AEs (RR:1.07, 95% CI: 0.97-1.19; p=0.18) and grade 3-5 AEs (RR:1.58, 95% CI: 1.21-2.07; p=0.0008). CP is a beneficial therapeutic schedule with longer PFS and OS than chemotherapy and has an acceptable, manageable grade 3-4 AE rate in IIIB/IV NSCLC. However, compared with P, CP results in better OS only in patients with PD-L1 expression <1%.