The ABCs of preventing hyperprogressive disease after immunotherapy: awareness, biomarkers, and combination

Recent Advances in Perioperative Immunotherapies in Lung Cancer

Several clinical trials have been revolutionizing the perioperative treatment of early-stage non-small cell lung cancer (NSCLC). Many of these clinical trials involve cancer immunotherapies with antibody drugs that block the inhibitory immune checkpoints programmed death 1 (PD-1) and its ligand PD-L1. While these new treatments are expected to improve the treatment outcome of NSCLC patients after pulmonary resection, several major clinical questions remain, including the appropriate timing of immunotherapy (neoadjuvant, adjuvant, or both) and the identification of patients who should be treated with neoadjuvant and/or adjuvant immunotherapies, because some early-stage NSCLC patients are cured by surgical resection alone. In addition, immunotherapy may induce immune-related adverse events that will require permanent treatment in some patients. Based on this fact as well, it is desirable to select appropriate patients for neoadjuvant/adjuvant immunotherapies. So far, data from several important trials have been published, with findings demonstrating the efficacy of adjuvant atezolizumab (IMpower010 trial), neoadjuvant nivolumab plus platinum-doublet chemotherapy (CheckMate816 trial), and several perioperative (neoadjuvant plus adjuvant) immunotherapies (AEGEAN, KEYNOTE-671, NADIM II, and Neotorch trials). In addition to these key trials, numerous clinical trials have reported a wealth of data, although most of the above clinical questions have not been completely answered yet. Because there are so many ongoing clinical trials in this field, a comprehensive understanding of the results and/or contents of these trials is necessary to explore answers to the clinical questions above as well as to plan a new clinical trial. In this review, we comprehensively summarize the recent data obtained from clinical trials addressing such questions.

The combination of immune checkpoint inhibitors and chemotherapy in advanced non-small-cell lung cancer: the rational choice

Lung cancer is the second most common cancer worldwide and the leading cause of death among cancers. The progressive approvals of immunotherapy as first-line treatment options have helped improve cancer prognosis. However, longer follow-up has confirmed the possibility of acquired resistance to immune checkpoint inhibitors (ICIs) which can lead to late relapses. Chemotherapy can act as a priming therapy to increase a tumor's response to immunotherapy. We aim through this review to explain the mechanism behind ICI resistance and the value of chemotherapy in escaping this resistance. Finally, all US FDA approvals regarding the management of metastatic non-small-cell lung cancer using a combination of ICIs and chemotherapy are summarized.

Is Weak Acid Beneficial for Addressing Checkpoint Inhibitor-Triggered Cancer Hyper Progression in Anti-PD1/PD-L1 Immunotherapies?

Numerous cases of checkpoint inhibitor–triggered cancer hyperprogression have been documented. A previous hypothesis attributes cancer onset to the local buildup of hydrogen chloride, jointly mediated by hydrogen bond donors and acceptors and basic amino acids. The anti-PD1/PD-L1 immunotherapies may have caused a surge of protons or chloride ions for the effective treatment of neoplasm, thus giving rise to the local formation of hydrogen chloride and subsequently cancer hyperprogression in some susceptible individuals. It was postulated that the local strength of acidity is critical for tumor growth and metastasis, as the intake of weak organic acids reduces cancer risks. The anti-PD1/PD-L1 immunotherapies can be integrated with weak organic acids to reduce adverse reactions and generate better anticancer outcomes.

PD-1 Blockade Aggravates Epstein-Barr Virus+ Post-Transplant Lymphoproliferative Disorder in Humanized Mice Resulting in Central Nervous System Involvement and CD4+ T Cell Dysregulations

Post-transplant lymphoproliferative disorder (PTLD) is one of the most common malignancies after solid organ or allogeneic stem cell transplantation. Most PTLD cases are B cell neoplasias carrying Epstein-Barr virus (EBV). A therapeutic approach is reduction of immunosuppression to allow T cells to develop and combat EBV. If this is not effective, approaches include immunotherapies such as monoclonal antibodies targeting CD20 and adoptive T cells. Immune checkpoint inhibition (ICI) to treat EBV⁺ PTLD was not established clinically due to the risks of organ rejection and graft-versus-host disease. Previously, blockade of the programmed death receptor (PD)-1 by a monoclonal antibody (mAb) during ex vivo infection of mononuclear cells with the EBV/M81⁺ strain showed lower xenografted lymphoma development in mice. Subsequently, fully humanized mice infected with the EBV/B95-8 strain and treated in vivo with a PD-1 blocking mAb showed aggravation of PTLD and lymphoma development. Here, we evaluated vis-a-vis in fully humanized mice after EBV/B95-8 or EBV/M81 infections the effects of a clinically used PD-1 blocker. Fifteen to 17 weeks after human CD34⁺ stem cell transplantation, Nod.Rag.Gamma mice were infected with two types of EBV laboratory strains expressing firefly luciferase. Dynamic optical imaging analyses showed systemic EBV infections and this triggered vigorous human CD8⁺ T cell expansion. Pembrolizumab administered from 2 to 5 weeks post-infections significantly aggravated EBV systemic spread and, for the M81 model, significantly increased the mortality of mice. ICI promoted Ki67⁺CD30⁺CD20⁺EBER⁺PD-L1⁺ PTLD with central nervous system (CNS) involvement, mirroring EBV⁺ CNS PTLD in humans. PD-1 blockade was associated with lower frequencies of circulating T cells in blood and with a profound collapse of CD4⁺ T cells in lymphatic tissues. Mice treated with pembrolizumab showed an escalation of exhausted T cells expressing TIM-3, and LAG-3 in tissues, higher levels of several human cytokines in plasma and high densities of FoxP3⁺ regulatory CD4⁺ and CD8⁺ T cells in the tumor microenvironment. We conclude that PD-1 blockade during acute EBV infections driving strong CD8⁺ T cell priming decompensates T cell development towards immunosuppression. Given the variety of preclinical models available, our models conferred a cautionary note indicating that PD-1 blockade aggravated the progression of EBV⁺ PTLD.

Synergism between anti-angiogenic and immune checkpoint inhibitor drugs: A hypothesis

Hepatocellular cancer (HCC) and renal cell cancer (RCC) are singularly resistant to conventional chemotherapy drugs but therapies targeting the supporting stroma have significantly altered their management. Two recent trials combining anti-angiogenic (AA) agents with immune checkpoint inhibitors (ICIs)- the IMbrave150 and IMmotion151 - have reported impressive progress over targeted agents. It has been suggested that bevacizumab, by improving tissue perfusion, changes the immune suppressive tumour microenvironment to an immune stimulatory one where the ICIs can be more effective. This hypothesis proposes an alternative explanation: That bevacizumab, by increasing tissue hypoxia, amplifies the mutational burden of the tumour by stress-induced mutagenesis, creating a hypermutator profile, which is more vulnerable to the ICI drug, atezolizumab. Additionally, ICIs are known to cause hyperprogression in some tumours, and bevacizumab could provide further benefit by starving these rapidly proliferative tumours of blood supply and nutrients.

Hyperprogression Under Immune Checkpoint-Based Immunotherapy-Current Understanding, The Role of PD-1/PD-L1 Tumour-Intrinsic Signalling, Future Directions and a Potential Large Animal Model

Immune evasion is a major challenge for the development of successful cancer treatments. One of the known mechanisms is the expression of immune checkpoints (ICs)-proteins regulating the immune cells activation. The advent of immunotherapy using monoclonal antibodies (mAbs) to block the immune checkpoint receptor-ligand interaction brought about a landslide improvement in the treatment responses, leading to a prompt approval of such therapeutics. In recent years, it was discovered that a subset of patients receiving IC blockade treatment experienced a previously unknown pattern of treatment response called hyperprogression (HP), characterised by rapid deterioration on initialisation of the therapy. HP represents an urgent issue for clinicians and drug developers, while posing questions about the adequacy of the current clinical trial process. Here, we briefly summarise the state of knowledge and propose new directions for research into HP mechanisms, focusing on tumour-intrinsic signalling of IC proteins malignantly expressed by cancer. We also discuss the potential role of spontaneously occurring canine cancer in the assessment of immunotherapeutics, which can provide the missing link between murine and human studies.