A systematic review of interleukin-2-based immunotherapies in clinical trials for cancer and autoimmune diseases

BACKGROUND The cytokine interleukin-2 (IL-2) can stimulate both effector immune cells and regulatory T (Treg) cells. The ability of selectively engaging either of these effects has spurred interest in using IL-2 for immunotherapy of cancer and autoimmune diseases. Thus, numerous IL-2-based biologic agents with improved bias or delivery towards effector immune cells or Treg cells have been developed. This study systematically reviews clinical results of improved IL-2-based compounds. METHODS We searched the ClinicalTrials.gov database for registered trials using improved IL-2-based agents and different databases for available results of these studies. FINDINGS From 576 registered clinical trials we extracted 36 studies on different improved IL-2-based compounds. Adding another nine agents reported in recent literature reviews and based on our knowledge totalled in 45 compounds. A secondary search for registered clinical trials of each of these 45 compounds resulted in 141 clinical trials included in this review, with 41 trials reporting results. INTERPRETATION So far, none of the improved IL-2-based compounds has gained regulatory approval for the treatment of cancer or autoimmune diseases. NKTR-214 is the only compound completing phase 3 studies. The PIVOT IO-001 trial testing the combination of NKTR-214 plus Pembrolizumab compared to Pembrolizumab monotherapy in metastatic melanoma missed its primary endpoints. Also the PIVOT-09 study, combining NKTR-214 with Nivolumab compared to Sunitinib or Cabozantinib in advanced renal cell carcinoma, missed its primary endpoint. Trials in autoimmune diseases are currently in early stages, thus not allowing definite conclusions on efficacy. FUNDING This work was supported by public funding agencies

Adaptive Immunosuppression in Lung Transplant Recipients Applying Complementary Biomarkers: The Zurich Protocol

Achieving adequate immunosuppression for lung transplant recipients in the first year after lung transplantation is a key challenge. Prophylaxis of allograft rejection must be balanced with the adverse events associated with immunosuppressive drugs, for example infection, renal failure, and diabetes. A triple immunosuppressive combination is standard, including a steroid, a calcineurin inhibitor, and an antiproliferative compound beginning with the highest levels of immunosuppression and a subsequent tapering of the dose, usually guided by therapeutic drug monitoring and considering clinical results, bronchoscopy sampling results, and additional biomarkers such as serum viral replication or donor-specific antibodies. Balancing the net immunosuppression level required to prevent rejection without overly increasing the risk of infection and other complications during the tapering phase is not well standardized and requires repeated assessments for dose-adjustments. In our adaptive immunosuppression approach, we additionally consider results from the white blood cell counts, in particular lymphocytes and eosinophils, as biomarkers for monitoring the level of immunosuppression and additionally use them as therapeutic targets to fine-tune the immunosuppressive strategy over time. The concept and its rationale are outlined, and areas of future research mentioned

IL-4 receptor engagement in human neutrophils impairs their migration and extracellular trap formation

Background Type 2 immunity serves to resist parasitic helminths, venoms, and toxins, but the role and regulation of neutrophils during type 2 immune responses are controversial. Helminth models suggested a contribution of neutrophils to type 2 immunity, whereas neutrophils are associated with increased disease severity during type 2 inflammatory disorders, such as asthma. Objective We sought to evaluate the effect of the prototypic type 2 cytokines IL-4 and IL-13 on human neutrophils. Methods Human neutrophils from peripheral blood were assessed without or with IL-4 or IL-13 for (1) expression of IL-4 receptor subunits, (2) neutrophil extracellular trap (NET) formation, (3) migration toward CXCL8 in vitro and in humanized mice, and (4) CXCR1, CXCR2, and CXCR4 expression, as well as (5) in nonallergic versus allergic subjects. Results Human neutrophils expressed both types of IL-4 receptors, and their stimulation through IL-4 or IL-13 diminished their ability to form NETs and migrate toward CXCL8 in vitro. Likewise, in vivo chemotaxis in NOD-scid-Il2rg−/− mice was reduced in IL-4–stimulated human neutrophils compared with control values. These effects were accompanied by downregulation of the CXCL8-binding chemokine receptors CXCR1 and CXCR2 on human neutrophils on IL-4 or IL-13 stimulation in vitro. Ex vivo analysis of neutrophils from allergic patients or exposure of neutrophils from nonallergic subjects to allergic donor serum in vitro impaired their NET formation and migration toward CXCL8, thereby mirroring IL-4/IL-13–stimulated neutrophils. Conclusion IL-4 receptor signaling in human neutrophils affects several neutrophil effector functions, which bears important implications for immunity in type 2 inflammatory disorders

Signature of long-lived memory CD8+ T cells in acute SARS-CoV-2 infection

Immunological memory is a hallmark of adaptive immunity and facilitates an accelerated and enhanced immune response upon re-infection with the same pathogen$^{1,2}$. Since the outbreak of the ongoing COVID-19 pandemic, a key question has focused on which SARS-CoV-2-specific T cells stimulated during acute infection give rise to long-lived memory T cells$^{3}$. Here, using spectral flow cytometry combined with cellular indexing of transcriptomes and T cell receptor sequencing, we longitudinally characterized individual SARS-CoV-2-specific CD8$^{+}$ T cells of patients with COVID-19 from acute infection to 1 year into recovery and found a distinct signature identifying long-lived memory CD8$^{+}$ T cells. SARS-CoV-2-specific memory CD8$^{+}$ T cells persisting 1 year after acute infection express CD45RA, IL-7 receptor-α and T cell factor 1, but they maintain low expression of CCR7, thus resembling CD45RA$^{+}$ effector memory T cells. Tracking individual clones of SARS-CoV-2-specific CD8$^{+}$ T cells, we reveal that an interferon signature marks clones that give rise to long-lived cells, whereas prolonged proliferation and mechanistic target of rapamycin signalling are associated with clonal disappearance from the blood. Collectively, we describe a transcriptional signature that marks long-lived, circulating human memory CD8$^{+}$ T cells following an acute viral infection

Human memory B cells show plasticity and adopt multiple fates upon recall response to SARS-CoV-2

The B cell response to different pathogens uses tailored effector mechanisms and results in functionally specialized memory B (B$_{m}$) cell subsets, including CD21$^{+}$ resting, CD21$^{–}$CD27$^{+}$ activated and CD21$^{–}$CD27$^{–}$ B$_{m}$ cells. The interrelatedness between these B$_{m}$ cell subsets remains unknown. Here we showed that single severe acute respiratory syndrome coronavirus 2-specific B$_{m}$ cell clones showed plasticity upon antigen rechallenge in previously exposed individuals. CD21$^{–}$ B$_{m}$ cells were the predominant subsets during acute infection and early after severe acute respiratory syndrome coronavirus 2-specific immunization. At months 6 and 12 post-infection, CD21$^{+}$ resting B$_{m}$ cells were the major B$_{m}$ cell subset in the circulation and were also detected in peripheral lymphoid organs, where they carried tissue residency markers. Tracking of individual B cell clones by B cell receptor sequencing revealed that previously fated B$_{m}$ cell clones could redifferentiate upon antigen rechallenge into other B$_{m}$ cell subsets, including CD21$^{–}$CD27$^{–}$ B$_{m}$ cells, demonstrating that single B$_{m}$ cell clones can adopt functionally different trajectories

The role of cytokines in T-cell memory in health and disease

Upon stimulation with their cognate antigen, naive T cells undergo proliferation and differentiation into effector cells, followed by apoptosis or survival as precursors of long-lived memory cells. These phases of a T-cell response and the ensuing maintenance of memory T cells are shaped by cytokines, most notably interleukin-2 (IL-2), IL-7, and IL-15 that share the common γ chain (γc ) cytokine receptor. Steady-state production of IL-7 and IL-15 is necessary for background proliferation and homeostatic survival of CD4+ and CD8+ memory T cells. During immune responses, augmented levels of IL-2, IL-15, IL-21, IL-12, IL-18, and type-I interferons determine the memory potential of antigen-specific effector CD8+ cells, while increased IL-2 and IL-15 cause bystander proliferation of heterologous CD4+ and CD8+ memory T cells. Limiting availability of γc cytokines, reduction in regulatory T cells or IL-10, and persistence of inflammation or cognate antigen can result in memory T cells, which fail to become cytokine-dependent long-lived cells. Conversely, increased IL-7 and IL-15 can expand memory T cells, including pathogenic tissue-resident memory T cells, as seen in lymphopenia and certain chronic-inflammatory disorders and malignancies. These abovementioned factors impact immunotherapy and vaccines directed at memory T cells in cancer and chronic infection

Interleukin-2–based therapies in cancer

Molecular insights into the mechanism of beneficial and adverse effects of interleukin-2 (IL-2) have resulted in the development of improved IL-2 formulations with IL-2 receptor bias and tissue-targeting properties. Several of these compounds are currently in clinical development and are ushering IL-2 therapy into the current era of cancer immunotherapy

Interleukin-2 signals converge in a lymphoid-dendritic cell pathway that promotes anticancer immunity.

Tumor-infiltrating dendritic cells (DCs) correlate with effective anticancer immunity and improved responsiveness to anti-PD-1 checkpoint immunotherapy. However, the drivers of DC expansion and intratumoral accumulation are ill-defined. We found that interleukin-2 (IL-2) stimulated DC formation through innate and adaptive lymphoid cells in mice and humans, and this increase in DCs improved anticancer immunity. Administration of IL-2 to humans within a clinical trial and of IL-2 receptor (IL-2R)-biased IL-2 to mice resulted in pronounced expansion of type 1 DCs, including migratory and cross-presenting subsets, and type 2 DCs, although neither DC precursors nor mature DCs had functional IL-2Rs. In mechanistic studies, IL-2 signals stimulated innate lymphoid cells, natural killer cells, and T cells to synthesize the cytokines FLT3L, CSF-2, and TNF. These cytokines redundantly caused DC expansion and activation, which resulted in improved antigen processing and correlated with favorable anticancer responses in mice and patients. Thus, IL-2 immunotherapy-mediated stimulation of DCs contributes to anticancer immunity by rendering tumors more immunogenic

Modulation of T cell responses by IL-2 and IL-2 complexes

Interleukin-2 (IL-2) is a cytokine centrally involved in the regulation of immune tolerance and activation by its effects on CD4+ T regulatory (Treg) cells and cytotoxic effector lymphocytes, respectively. Due to these properties IL-2 immunotherapy has been used, as low-dose IL-2, in the treatment of autoimmune and chronic-inflammatory disorders; conversely, at high doses, IL-2 has shown efficacy in a subset of patients with metastatic cancer. Recent advances have highlighted the possibility of using improved IL-2-based therapies, such IL-2-antibody complexes (IL-2 complexes), able to selectively and potently stimulate either Treg cells or cytotoxic effector cells. This article discusses the properties and clinical implications of IL-2 and IL-2 complexes