Project description:BackgroundWe indirectly compared the effects of immune checkpoint inhibitors alone (ICI) and ICI-combined chemotherapy (chemo-ICI) in patients with non-small cell lung cancer who had high programmed death-ligand 1 (PD-L1) expression (defined as tumour proportion score ≥50% or TC3/IC3) through network meta-analyses.MethodsThrough literature searches, we shortlisted 22 randomised controlled trials encompassing 4289 patients, with objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) set as the primary outcomes. The dichotomous data for ORR and hazard ratios (HRs) and their 95% confidence intervals (CIs) for OS and PFS were extracted.ResultsWe found that chemo-ICI had significantly improved ORR (OR 1.7, 95% CI 1.1-2.5) and PFS (HR 0.59, 95% CI: 0.48-0.74) relative to ICI. Although no significant difference in OS was observed, the analyses revealed that the chemo-ICI patients tended to undergo fewer progression events than ICI patients (HR 0.82, 95% CI 0.6-1.1). In subgroup analysis, the non-squamous, PD-1 inhibitor and first-line treatment cohorts exhibited significant differences in ORR and PFS, but not in OS. However, in the squamous, PD-L1 inhibitor, and previously treated cohorts, PFS, OS and ORR were not different between chemo-ICI and ICI patients.ConclusionsIn conclusion, for non-squamous NSCLC patients, accepting PD-1 as the first-line treatment may be a relatively better option.
Project description:Blockade of the immunoinhibitory PD-1/PD-L1 pathway using monoclonal antibodies has shown impressive results with durable clinical antitumor responses. Anti-PD-1 and anti-PD-L1 antibodies have now been approved for the treatment of a number of tumor types, whereas the development of small molecules targeting immune checkpoints lags far behind. We characterized two classes of macrocyclic-peptide inhibitors directed at the PD-1/PD-L1 pathway. We show that these macrocyclic compounds act by directly binding to PD-L1 and that they are capable of antagonizing PD-L1 signaling and, similarly to antibodies, can restore the function of T-cells. We also provide the crystal structures of two of these small-molecule inhibitors bound to PD-L1. The structures provide a rationale for the checkpoint inhibition by these small molecules, and a description of their small molecule/PD-L1 interfaces provides a blueprint for the design of small-molecule inhibitors of the PD-1/PD-L1 pathway.
Project description:Non-small-cell lung cancer takes up the majority of lung carcinoma-caused deaths. It is reported that targeting PD-1/PD-L1, a well-known immune evasion checkpoint, can eradicate tumor. Checkpoint inhibitors, such as monoclonal antibodies, are actively employed in cancer treatment. Thus, this review aimed to assess the therapeutic and toxic effects of PD-1/PD-L1 inhibitors in treatment of NSCLC. So far, 6 monoclonal antibodies blocking PD-1/PD-L1 interaction are identified and used in clinical trials and randomized controlled trials for NSCLC therapy. These antibody-based therapies for NSCLC were collected by using search engine PubMed, and articles about the assessment of adverse events were collected by using Google search. Route of administration and dosage are critical parameters for efficient immunotherapy. Although antibodies can improve overall survival and are expected to be target-specific, they can cause systemic adverse effects in the host. Targeting certain biomarkers can limit the toxicity of adverse effects of the antibody-mediated therapy. Clinical experts with knowledge of adverse effects (AEs) of checkpoint inhibitors can help manage and reduce mortalities associated with antibody-based therapy of NSCLC.
Project description:PurposeBlocking the interaction between the programmed cell death (PD)-1 protein and one of its ligands, PD-L1, has been reported to have impressive antitumor responses. Therapeutics targeting this pathway are currently in clinical trials. Pembrolizumab and nivolumab are the first of this anti-PD-1 pathway family of checkpoint inhibitors to gain accelerated approval from the US Food and Drug Administration (FDA) for the treatment of ipilimumab-refractory melanoma. Nivolumab has been associated with improved overall survival compared with dacarbazine in patients with previously untreated wild-type serine/threonine-protein kinase B-raf proto-oncogene BRAF melanoma. Although the most mature data are in the treatment of melanoma, the FDA has granted approval of nivolumab for squamous cell lung cancer and the breakthrough therapy designation to immune- checkpoint inhibitors for use in other cancers: nivolumab, an anti-PD-1 monoclonal antibody, for Hodgkin lymphoma, and MPDL-3280A, an anti-PD-L1 monoclonal antibody, for bladder cancer and non-small cell lung cancer. Here we review the literature on PD-1 and PD-L1 blockade and focus on the reported clinical studies that have included patients with melanoma.MethodsPubMed was searched to identify relevant clinical studies of PD-1/PD-L1-targeted therapies in melanoma. A review of data from the current trials on clinicaltrial.gov was incorporated, as well as data presented in abstracts at the 2014 annual meeting of the American Society of Clinical Oncology, given the limited number of published clinical trials on this topic.FindingsThe anti-PD-1 and anti-PD-L1 agents have been reported to have impressive antitumor effects in several malignancies, including melanoma. The greatest clinical activity in unselected patients has been seen in melanoma. Tumor expression of PD-L1 is a suggestive, but inadequate, biomarker predictive of response to immune-checkpoint blockade. However, tumors expressing little or no PD-L1 are less likely to respond to PD-1 pathway blockade. Combination checkpoint blockade with PD-1 plus cytotoxic T-lymphocyte antigen (CTLA)-4 blockade appears to improve response rates in patients who are less likely to respond to single-checkpoint blockade. Toxicity with PD-1 blocking agents is less than the toxicity with previous immunotherapies (eg, interleukin 2, CTLA-4 blockade). Certain adverse events can be severe and potentially life threatening, but most can be prevented or reversed with close monitoring and appropriate management.ImplicationsThis family of immune-checkpoint inhibitors benefits not only patients with metastatic melanoma but also those with historically less responsive tumor types. Although a subset of patients responds to single-agent blockade, the initial trial of checkpoint-inhibitor combinations has reported a potential to improve response rates. Combination therapies appear to be a means of increasing response rates, albeit with increased immune-related adverse events. As these treatments become available to patients, education regarding the recognition and management of immune-related effects of immune-checkpoint blockade will be essential for maximizing clinical benefit.
Project description:Programmed death 1 ligand (PD-L1), an important immune checkpoint molecule, is mainly expressed on cancer cells and has been shown to exert an immunosuppressive effect on T-cell function by binding to programmed cell death 1 (PD-1) expressed on T-cells. Recently, immune checkpoint inhibitors using antibody drugs such as nivolumab and atezolizumab have attracted attention. However, clinical challenges, including limitations to the scope of their application, are yet to be addressed. In this study, we developed a novel immune checkpoint inhibitor that targets PD-L1 using lipid-siRNA conjugates (lipid-siPDL1s). The inhibitory effect of lipid-siPDL1s on PD-L1 expression was evaluated and found to strongly suppress mRNA expression. Notably, lipid-siPDL1s exerted a significantly stronger effect than unmodified siPDL1. Interestingly, lipid-siPDL1s strongly inhibited PD-L1 expression despite cancer cell stimulation by interferon-gamma, which induced the overexpression of PD-L1 genes. These results strongly suggest that lipid-siPDL1s could be used as novel immune checkpoint inhibitors.
Project description:Over the last decade, the immune checkpoint blockade targeting the programmed death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) axis has improved progression-free and overall survival of advanced non-small cell lung cancer (NSCLC) patients. PD-L1 tumor expression, along with tumor mutational burden, is currently being explored as a predictive biomarker for responses to immune checkpoint inhibitors (ICIs). However, lung cancer patients may have insufficient tumor tissue samples and the high bleeding risk often prevents additional biopsies and, as a consequence, immunohistological evaluation of PD-L1 expression. In addition, PD-L1 shows a dynamic expression profile and can be influenced by intratumoral heterogeneity as well as the immune cell infiltrate in the tumor and its microenvironment, influencing the response rate to PD-1/PD-L1 axis ICIs. Therefore, to identify subgroups of patients with advanced NSCLC that will most likely benefit from ICI therapies, molecular characterization of PD-L1 expression in circulating tumor cells (CTCs) might be supportive. In this review, we highlight the use of CTCs as a complementary diagnostic tool for PD-L1 expression analysis in advanced NSCLC patients. In addition, we examine technical issues of PD-L1 measurement in tissue as well as in CTCs.
Project description:Gastrointestinal (GI) malignant neoplasms have a high global incidence and treatment prospects for patients with advanced GI tumors are dismal. PD-1/PD-L1 inhibitors emerged as a frontline treatment for several types of cancer. However, the shortcomings of PD-1/PD-L1 inhibitors have been observed, including low objective response rates and acquired tumor resistance, especially in patients receiving PD-1/PD-L1 inhibitors as a single treatment. Accumulating evidence from clinical trials increasingly suggests that combined immunotherapies enhance therapeutic responses in patients with malignances, especially for GI tumors which have a complex matrix, and significant molecular and immunological differences. Preclinical and clinical studies suggest there are advantages to combined immunological regimens, which represents the next logical step in this field, although further research is necessary. This literature review explores the current limitations of monotherapies, before critically discussing the rationale behind combination regimens. Then, we provide a summary of the clinical applications for gastrointestinal cancers.
Project description:Antibodies targeting the PD-1/PD-L1 immune checkpoint achieved spectacular success in anticancer therapy in the recent years. In contrast, no small molecules with cellular activity have been reported so far. Here we provide evidence that small molecules are capable of alleviating the PD-1/PD-L1 immune checkpoint-mediated exhaustion of Jurkat T-lymphocytes. The two optimized small-molecule inhibitors of the PD-1/PD-L1 interaction, BMS-1001 and BMS-1166, developed by Bristol-Myers Squibb, bind to human PD-L1 and block its interaction with PD-1, when tested on isolated proteins. The compounds present low toxicity towards tested cell lines and block the interaction of soluble PD-L1 with the cell surface-expressed PD-1. As a result, BMS-1001 and BMS-1166 alleviate the inhibitory effect of the soluble PD-L1 on the T-cell receptor-mediated activation of T-lymphocytes. Moreover, the compounds were effective in attenuating the inhibitory effect of the cell surface-associated PD-L1. We also determined the X-ray structures of the complexes of BMS-1001 and BMS-1166 with PD-L1, which revealed features that may be responsible for increased potency of the compounds compared to their predecessors. Further development may lead to the design of an anticancer therapy based on the orally delivered immune checkpoint inhibition.
Project description: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.
Project description:Immune checkpoint blockade is one of the most promising strategies of cancer immunotherapy. However, unlike classical targeted therapies, it is currently solely based on expensive monoclonal antibodies, which often inflict immune-related adverse events. Herein, we propose a novel small-molecule inhibitor targeted at the most clinically relevant immune checkpoint, PD-1/PD-L1. The compound is capable of disrupting the PD-1/PD-L1 complex by antagonizing PD-L1 and, therefore, restores activation of T cells similarly to the antibodies, while being cheap in production and possibly nonimmunogenic. The final compound is significantly smaller than others reported in the literature while being nontoxic to cells even at high concentrations. The scaffold was designed using a structure-activity relationship screening cascade based on a new antagonist-induced dissociation NMR assay, called the weak-AIDA-NMR. Weak-AIDA-NMR finds true inhibitors, as opposed to only binders to the target protein, in early steps of lead compound development, and this process makes it less time and cost consuming.