Fostamatinib for the treatment of chronic immune thrombocytopenia

New insights into SYK targeting in solid tumors

Spleen tyrosine kinase (SYK) is predominantly expressed in hematopoietic cells and has been extensively studied for its pivotal role in B cell malignancies and autoimmune diseases. In epithelial solid tumors, SYK shows a paradoxical role, acting as a tumor suppressor in some cancers while driving tumor growth in others. Recent preclinical studies have identified the role of SYK in the tumor microenvironment (TME), revealing that SYK signaling in immune cells, especially B cells, and myeloid cells, promote immunosuppression, tumor growth, and metastasis across various solid tumors. This review explores the emerging roles of SYK in solid tumors, the mechanisms of SYK activation, and findings from preclinical and clinical studies of SYK inhibitors as either standalone treatments or in combination with immunotherapy or chemotherapy for solid tumors.

Novel treatments for immune thrombocytopenia: targeting platelet autoantibodies

INTRODUCTION

Immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by low platelets and an increased risk of bleeding. Platelet autoantibodies target major platelet glycoproteins and cause Fc-mediated platelet destruction in the spleen and reticuloendothelial systems. As mechanisms of disease, platelet autoantibodies are important therapeutic targets. Neonatal Fc receptor (FcRn) antagonists are a new class of therapeutics that reduce the half-life of immunoglobulin G including pathogenic platelet autoantibodies. Spleen tyrosine kinase (Syk) inhibitors interfere with Fc-mediated platelet clearance. Bruton's tyrosine kinase (BTK) inhibitors and B-cell activating factor (BAFF) inhibitors reduce antibody production. The efficacy of these targeted therapies provides new support for the role of platelet autoantibodies in pathogenesis of ITP even these antibodies can be difficult to detect.

AREAS COVERED

This review includes an in-depth exploration of the pathophysiologic mechanisms of ITP, focusing on autoantibodies. Treatments outlined in this review include a) FcRn antagonists, b) complement inhibitors, c) B-cell directed therapies such as BTK inhibitors, and anti-BAFF agents, d) Syk inhibitors, e) plasma-cell directed therapies, and f) novel cellular therapeutic products.

EXPERT OPINION

Platelet autoantibodies are often elusive in ITP, yet novel treatments targeting this pathway reinforce their role in the pathogenesis of this autoimmune platelet disorder.

A pathological study on the efficacy of Syk inhibitors in a Candida albicans-induced aortic root vasculitis murine model

BACKGROUND

The activation of innate immunity may be involved in the development of Candida albicans-induced murine vasculitis, which resembles Kawasaki disease (KD) vasculitis. This study aimed to histologically clarify the time course of the development of vasculitis in this model in detail and to estimate the potential role of spleen tyrosine kinase (Syk) inhibitors in KD vasculitis.

METHODS AND RESULTS

DBA/2 male mice were intraperitoneally injected with a vasculitis-inducing substance and treated with a Syk inhibitor (R788 or GS-9973). Systemic vasculitis, especially in the aortic annulus area, was histologically evaluated. Regarding lesions in the aortic annulus area, some mice in the untreated control group already showed initiation of vasculitis 1 day after the final injection of a vasculitis-inducing substance. The vasculitis expanded over time. Inflammation occurred more frequently at the aortic root than at the coronary artery. The distribution of inflammatory cells was limited to the intima, intima plus adventitia, or all layers. In the Syk inhibitor-treated groups, only one mouse had vasculitis at all observation periods. The severity and area of the vasculitis were reduced by both Syk inhibitors.

CONCLUSION

Candida albicans-induced murine vasculitis may occur within 1 day after the injection of a vasculitis-inducing substance. Additionally, Syk inhibitors suppress murine vasculitis.

The Syk Inhibitor Entospletinib Abolishes Dermal-Epidermal Separation in a Fully Human Ex Vivo Model of Bullous Pemphigoid

Bullous pemphigoid (BP) is an autoantibody-mediated blistering skin disease characterized by local inflammation and dermal-epidermal separation, with no approved targeted therapy. The Syk tyrosine kinase is critical for various functions of the immune response. Second-generation Syk inhibitors such as entospletinib are currently being tested for hematological malignancies. Our aim was to test the effect of entospletinib in a fully human model system of BP. Incubating BP serum-treated human frozen skin sections with normal human granulocytes and fresh plasma triggered dermal-epidermal separation that was dependent on complement, NADPH oxidase, and protease activity. Entospletinib dramatically reduced dermal-epidermal separation with a half-maximal inhibitory concentration of ≈16 nM. Entospletinib also reduced ROS production, granule release, and spreading of human granulocytes plated on immobilized immune complexes consisting either of a generic antigen-antibody pair or of recombinant collagen type XVII (BPAg2) and BP serum components (supposedly autoantibodies). However, entospletinib did not affect the chemotactic migration of human granulocytes or their responses to nonphysiological stimulation by phorbol esters. Entospletinib had no effect on the survival of granulocytes either. Taken together, entospletinib abrogates dermal-epidermal separation, likely through inhibition of granulocyte responsiveness to deposited immune complexes. Entospletinib or other Syk inhibitors may provide therapeutic benefits in BP.

[Differential diagnosis and therapy of immune thrombocytopenia]

Immune thrombocytopenia is caused by autoantibodies against surface antigens on platelets. Since only about 50 % of cases will allow the identification of glycoprotein-specific antibodies, ITP remains a diagnosis of exclusion. Apart from EDTA-induced pseudo thrombocytopenia, other diseases like secondary thrombocytopenia due to medication, a large number of other disease and hereditary thrombocytopenias must be taken into account. The first-line therapy of ITP includes corticosteroids and intravenous immunoglobulins. The second line consists of thrombopoietin receptor agonists, rituximab, or splenectomy. For further lines of therapy, Fostamatinib and non-steroidal immunosuppressives are available.

Efficacy and safety of sovleplenib (HMPL-523) in adult patients with chronic primary immune thrombocytopenia in China (ESLIM-01): a randomised, double-blind, placebo-controlled, phase 3 study

BACKGROUND

Sovleplenib, a novel spleen tyrosine kinase (SYK) inhibitor, showed promising safety and activity in patients with primary immune thrombocytopenia in a phase 1b/2 trial. We aimed to evaluate the efficacy and safety of sovleplenib in patients with chronic primary immune thrombocytopenia.

METHODS

This randomised, double-blind, placebo-controlled, phase 3 trial (ESLIM-01) was done in 34 clinical centres in China. Eligible patients, aged 18-75 years, had chronic primary immune thrombocytopenia, an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1, and received one or more previous treatments. Patients were randomly assigned (2:1) to receive oral sovleplenib or placebo, 300 mg once daily, for 24 weeks. Randomisation was stratified by baseline platelet counts, previous splenectomy, and concomitant treatment for anti-immune thrombocytopenia at baseline. The primary endpoint was durable response rate (proportion of patients with a platelet count of ≥50 × 109/L on at least four of six scheduled visits between weeks 14 and 24, not affected by rescue treatment) assessed by intention-to-treat. The trial is registered with ClinicalTrials.gov, NCT05029635, and the extension, open-label phase is ongoing.

FINDINGS

Between Sept 29, 2021, and Dec 31, 2022, 188 patients were randomly assigned to receive sovleplenib (n=126) or placebo (n=62). 124 (66%) were female, 64 (34%) were male, and all were of Asian ethnicity. Median previous lines of immune thrombocytopenia therapy were 4·0, and 134 (71%) of 188 patients had received previous thrombopoietin or thrombopoietin receptor agonist. The primary endpoint was met; durable response rate was 48% (61/126) with sovleplenib compared with zero with placebo (difference 48% [95% CI 40-57]; p<0·0001). The median time to response was 8 days with sovleplenib compared with 30 days with placebo. 125 (99%) of 126 patients in the sovleplenib group and 53 (85%) of 62 in the placebo group reported treatment-emergent adverse events (TEAEs), and most events were mild or moderate. Frequent TEAEs of grade 3 or higher for sovleplenib versus placebo were platelet count decreased (7% [9/126] vs 10% [6/62]), neutrophil count decreased (3% [4/126] vs 0% [0/62]), and hypertension (3% [4/126] vs 0% [0/62]). Incidences of serious TEAEs were 21% (26/126) in the sovleplenib group and 18% (11/62) in the placebo group. There were no deaths in the study.

INTERPRETATION

Sovleplenib showed a clinically meaningful sustained platelet response in patients with chronic primary immune thrombocytopenia, with a tolerable safety profile and improvement in quality of life. Sovleplenib could be a potential treatment option for patients with immune thrombocytopenia who received one or more previous therapy.

FUNDING

HUTCHMED and Science and Technology Commission of Shanghai Municipality.

Hypermethylation of the FOXP3 gene regulates Tregs immunodysregulation in chronic idiopathic thrombocytopenic purpura

BACKGROUND

Chronic idiopathic thrombocytopenic purpura (ITP) is an autoimmune disease characterized by a breakdown of immune tolerance; in ITP, the body's immune system mistakenly attacks and destroys platelets. This study aims to investigate the role and underlying mechanisms of FOXP3 in chronic ITP.

METHODS

Flow cytometry was used to detect the proportion of CD4+CD25+FOXP3+ regulatory T cells (Tregs) in CD4+CD25+ T lymphocytes from 20 patients with chronic ITP (CITP), 20 acute ITP (AITP) controls, and 20 healthy individuals.CD4+CD25+ Treg cells were isolated from peripheral blood of patients with CITP using magnetic beads and then treated with phosphate-buffered saline solution or decitabine (a methylation inhibitor) for 48 h. The levels of interleukin-2 (IL-2), IL-10, and transforming growth factor-beta1 (TGF-β1) in the plasma and CD4+CD25+ Treg cells were assessed by Enzyme-linked-immunosorbent serologic assay and quantitative real-time polymerase chain reaction (qRT-PCR). FOXP3 level was measured by qRT-PCR and Western blot analysis. Methylation-specific PCR (MS-PCR) was adopted to detect the status of FOXP3 methylation.

RESULTS

The number of Treg cells and the contents of IL-2, IL-10, and TGF-β1 decreased in patients with CITP, compared to the AITP control group and normal group. FOXP3 expression was reduced and FOXP3 methylation increased in patients with CITP, compared to the AITP control group and normal group. Hypermethylation of FOXP3 promoter led to decrease in FOXP3 level in Treg cells. Inhibition of FOXP3 promoter hypermethylation promoted the secretion of IL-2, IL-10, and TGF-β1 in Treg cells.

CONCLUSION

The number of Treg cells in CITP patients decreased, and the hypermethylation of FOXP3 promoter led to reduction of its expression in Treg cells, thus affecting the immune functioning of Treg cells.

Development of SYK NanoBRET Cellular Target Engagement Assays for Gain-of-Function Variants

Spleen tyrosine kinase (SYK) is a non-receptor tyrosine kinase that is activated by phosphorylation events downstream of FcR, B-cell and T-cell receptors, integrins, and C-type lectin receptors. When the tandem Src homology 2 (SH2) domains of SYK bind to phosphorylated immunoreceptor tyrosine-based activation motifs (pITAMs) contained within these immunoreceptors, or when SYK is phosphorylated in interdomain regions A and B, SYK is activated. SYK gain-of-function (GoF) variants were previously identified in six patients that had higher levels of phosphorylated SYK and phosphorylated downstream proteins JNK and ERK. Furthermore, the increased SYK activation resulted in the clinical manifestation of immune dysregulation, organ inflammation, and a predisposition for lymphoma. The knowledge that the SYK GoF variants have enhanced activity was leveraged to develop a SYK NanoBRET cellular target engagement assay in intact live cells with constructs for the SYK GoF variants. Herein, we developed a potent SYK-targeted NanoBRET tracer using a SYK donated chemical probe, MRL-SYKi, that enabled a NanoBRET cellular target engagement assay for SYK GoF variants, SYK(S550Y), SYK(S550F), and SYK(P342T). We determined that ATP-competitive SYK inhibitors bind potently to these SYK variants in intact live cells. Additionally, we demonstrated that MRL-SYKi can effectively reduce the catalytic activity of SYK variants, and the phosphorylation levels of SYK(S550Y) in an epithelial cell line (SW480) stably expressing SYK(S550Y).

Drug repurposing for personalized medicine

Personalized medicine has emerged as a revolutionary approach to healthcare in the 21st century. By understanding a patient's unique genetic and biological characteristics, it aims to tailor treatments specifically to the individual. This approach takes into account factors such as an individual's lifestyle, genetic makeup, and environmental factors to provide targeted therapies that have the potential to be more effective and lower the risk of side reactions or ineffective treatments. It is a paradigm shift from the traditional "one size fits all" approach in medicine, where patients with similar symptoms or diagnoses receive the same standard treatments regardless of their differences. It leads to improved clinical outcomes and more efficient use of healthcare resources. Drug repurposing is a strategy that uses existing drugs for new indications and aims to take advantage of the known safety profiles, pharmacokinetics, and mechanisms of action of these drugs to accelerate the development process. Precision medicine may undergo a revolutionary change as a result, enabling the rapid development of novel treatment plans utilizing drugs that traditional methods would not otherwise link to. In this chapter, we have focused on a few strategies wherein drug repurposing has shown great success for precision medicine. The approach is particularly useful in oncology as there are many variations induced in the genetic material of cancer patients, so tailored treatment approaches go a long way. We have discussed the cases of breast cancer, glioblastoma and hepatocellular carcinoma. Other than that, we have also looked at drug repurposing approaches in anxiety disorders and COVID-19.

Human Fc gamma receptor IIIA blockade inhibits platelet destruction in a humanized murine model of ITP

ABSTRACT

Fc gamma receptor (FcγR) IIIA is an important receptor for immunoglobulin G (IgG) and is involved in immune defense mechanisms as well as tissue destruction in some autoimmune diseases including immune thrombocytopenia (ITP). FcγRIIIA on macrophages can trigger phagocytosis of IgG-sensitized platelets, and prior pilot studies observed blockade of FcγRIIIA increased platelet counts in patients with ITP. Unfortunately, although blockade of FcγRIIIA in patients with ITP increased platelet counts, its engagement by the blocking antibody drove serious adverse inflammatory reactions. These adverse events were postulated to originate from the antibody's Fc and/or bivalent nature. The blockade of human FcγRIIIA in vivo with a monovalent construct lacking an active Fc region has not yet been achieved. To effectively block FcγRIIIA in vivo, we developed a high affinity monovalent single-chain variable fragment (scFv) that can bind and block human FcγRIIIA. This scFv (17C02) was expressed in 3 formats: a monovalent fusion protein with albumin, a 1-armed human IgG1 antibody, and a standard bivalent mouse (IgG2a) antibody. Both monovalent formats were effective in preventing phagocytosis of ITP serum-sensitized human platelets. In vivo studies using FcγR-humanized mice demonstrated that both monovalent therapeutics were also able to increase platelet counts. The monovalent albumin fusion protein did not have adverse event activity as assessed by changes in body temperature, whereas the 1-armed antibody induced some changes in body temperature even though the Fc region function was impaired by the Leu234Ala and Leu235Ala mutations. These data demonstrate that monovalent blockade of human FcγRIIIA in vivo can potentially be a therapeutic strategy for patients with ITP.

Primary Immune Thrombocytopenic Purpura (ITP) and ITP Associated with Systemic Lupus Erythematosus: A Review of Clinical Characteristics and Treatment Modalities

Immune thrombocytopenic purpura (ITP) is an immune-mediated disorder characterized by the destruction of platelets and megakaryocytes due to autoantibodies against the platelet surface proteins. ITP without any apparent cause of thrombocytopenia is defined as primary ITP, and ITP in the setting of SLE is secondary ITP, which can be diagnosed after excluding other causes of thrombocytopenia by history, physical examination, and laboratory testing. Patients with ITP associated with SLE have higher median platelet count and less bleeding manifestations compared to the patients with primary ITP. It can be very challenging to diagnose primary ITP in SLE patients as other causes of thrombocytopenia including drug-induced thrombocytopenia, antiphospholipid syndrome, and thrombotic microangiopathic process should be ruled out. Corticosteroids are the main modality of treatment. IVIG can be used in severe cases. Splenectomy was found to be less effective in ITP associated with SLE compared to primary ITP. Control of disease activity with immunosuppressive therapy can be helpful in some cases associated with active disease flares in SLE patients.

Drug-Loaded Biomimetic Carriers for Non-Hodgkin's Lymphoma Therapy: Advances and Perspective

Chemotherapy remains the mainstay of treatment for the lymphoma patient population, despite its relatively poor therapeutic results, high toxicity, and low specificity. With the advancement of biotechnology, the significance of drug-loading biomimetic materials in the medical field has become increasingly evident, attracting extensive attention from the scientific community and the pharmaceutical industry. Given that they can cater to the particular requirements of lymphoma patients, drug-loading biomimetic materials have recently become a potent and promising delivery approach for various applications. This review mainly reviews the recent advancements in the treatment of tumors with biological drug carrier-loaded drugs, outlines the mechanisms of lymphoma development and the diverse treatment modalities currently available, and discusses the merits and limitations of biological drug carriers. What is more, the practical application of biocarriers in tumors is explored by providing examples, and the possibility of loading such organisms with antilymphoma drugs for the treatment of lymphoma is conceived.

Current Understanding of Immune Thrombocytopenia: A Review of Pathogenesis and Treatment Options

The management of immune thrombocytopenia (ITP) and the prediction of patient response to therapy still represent a significant and constant challenge in hematology. ITP is a heterogeneous disease with an unpredictable evolution. Although the pathogenesis of ITP is currently better known and its etiology has been extensively studied, up to 75% of adult patients with ITP may develop chronicity, which represents a significant burden on patients' quality of life. A major risk of ITP is bleeding, but knowledge on the exact relationship between the degree of thrombocytopenia and bleeding symptoms, especially at a lower platelet count, is lacking. The actual management of ITP is based on immune suppression (corticosteroids and intravenous immunoglobulins), or the use of thrombopoietin receptor agonists (TPO-RAs), rituximab, or spleen tyrosine kinase (Syk) inhibitors. A better understanding of the underlying pathology has facilitated the development of a number of new targeted therapies (Bruton's tyrosine kinase inhibitors, neonatal Fc receptors, strategies targeting B and plasma cells, strategies targeting T cells, complement inhibitors, and newer TPO-RAs for improving megakaryopoiesis), which seem to be highly effective and well tolerated and result in a significant improvement in patients' quality of life. The disadvantage is that there is a lack of knowledge of the predictive factors of response to treatments, which would help in the development of an optimized treatment algorithm for selected patients.

Therapeutic strategies in FcγIIA receptor-dependent thrombosis and thromboinflammation as seen in heparin-induced thrombocytopenia (HIT) and vaccine-induced immune thrombocytopenia and thrombosis (VITT)

INTRODUCTION

Fcγ-receptors (FcγR) are membrane receptors expressed on a variety of immune cells, specialized in recognition of the Fc part of immunoglobulin G (IgG) antibodies. FcγRIIA-dependent platelet activation in platelet factor 4 (PF4) antibody-related disorders have gained major attention, when these antibodies were identified as the cause of the adverse vaccination event termed vaccine-induced immune thrombocytopenia and thrombosis (VITT) during the COVID-19 vaccination campaign. With the recognition of anti-PF4 antibodies as cause for severe spontaneous and sometimes recurrent thromboses independent of vaccination, their clinical relevance extended far beyond heparin-induced thrombocytopenia (HIT) and VITT.

AREAS COVERED

Patients developing these disorders show life-threatening thromboses, and the outcome is highly dependent on effective treatment. This narrative literature review summarizes treatment options for HIT and VITT that are currently available for clinical application and provides the perspective toward new developments.

EXPERT OPINION

Nearly all these novel approaches are based on in vitro, preclinical observations, or case reports with only limited implementation in clinical practice. The therapeutic potential of these approaches still needs to be proven in larger cohort studies to ensure treatment efficacy and long-term patient safety.

Transcriptomics analysis reveals distinct mechanism of breast cancer stem cells regulation in mammospheres from MCF-7 and T47D cells

Luminal A breast cancer, constituting 70 % of breast cancer cases, presents a challenge due to the development of resistance and recurrence caused by breast cancer stem cells (BCSC). Luminal breast tumors are characterized by TP53 expression, a tumor suppressor gene involved in maintaining stem cell attributes in cancer. Although a previous study successfully developed mammospheres (MS) from MCF-7 (with wild-type TP53) and T47D (with mutant TP53) luminal breast cancer cells for BCSC enrichment, their transcriptomic profiles remain unclear. We aimed to elucidate the transcriptomic disparities between MS of MCF-7 and T47D cells using bioinformatics analyses of differentially expressed genes (DEGs), including the KEGG pathway, Gene Ontology (GO), drug-gene association, disease-gene association, Gene Set Enrichment Analysis (GSEA), DNA methylation analysis, correlation analysis of DEGs with immune cell infiltration, and association analysis of genes and small-molecule compounds via the Connectivity Map (CMap). Upregulated DEGs were enriched in metabolism-related KEGG pathways, whereas downregulated DEGs were enriched in the MAPK signaling pathway. Drug-gene association analysis revealed that both upregulated and downregulated DEGs were associated with fostamatinib. The KEGG pathway GSEA results indicated that the DEGs were enriched for oxidative phosphorylation, whereas the downregulated DEGs were negatively enriched for the p53 signaling pathway. Examination of DNA methylation revealed a noticeable disparity in the expression patterns of the PKM2, ERO1L, SLC6A6, EPAS1, APLP2, RPL10L, and NEDD4 genes when comparing cohorts with low- and high-risk breast cancer. Furthermore, a significant positive correlation was identified between SLC6A6 expression and macrophage presence, as well as MSN, and AKR1B1 expression and neutrophil and dentritic cell infiltration. CMap analysis unveiled SA-83851 as a potential candidate to counteract the effects of DEGs, specifically in cells harbouring mutant TP53. Further research, including in vitro and in vivo validations, is warranted to develop drugs targeting BCSCs.

Signaling network analysis reveals fostamatinib as a potential drug to control platelet hyperactivation during SARS-CoV-2 infection

Introduction

Pro-thrombotic events are one of the prevalent causes of intensive care unit (ICU) admissions among COVID-19 patients, although the signaling events in the stimulated platelets are still unclear.

Methods

We conducted a comparative analysis of platelet transcriptome data from healthy donors, ICU, and non-ICU COVID-19 patients to elucidate these mechanisms. To surpass previous analyses, we constructed models of involved networks and control cascades by integrating a global human signaling network with transcriptome data. We investigated the control of platelet hyperactivation and the specific proteins involved.

Results

Our study revealed that control of the platelet network in ICU patients is significantly higher than in non-ICU patients. Non-ICU patients require control over fewer proteins for managing platelet hyperactivity compared to ICU patients. Identification of indispensable proteins highlighted key subnetworks, that are targetable for system control in COVID-19-related platelet hyperactivity. We scrutinized FDA-approved drugs targeting indispensable proteins and identified fostamatinib as a potent candidate for preventing thrombosis in COVID-19 patients.

Discussion

Our findings shed light on how SARS-CoV-2 efficiently affects host platelets by targeting indispensable and critical proteins involved in the control of platelet activity. We evaluated several drugs for specific control of platelet hyperactivity in ICU patients suffering from platelet hyperactivation. The focus of our approach is repurposing existing drugs for optimal control over the signaling network responsible for platelet hyperactivity in COVID-19 patients. Our study offers specific pharmacological recommendations, with drug prioritization tailored to the distinct network states observed in each patient condition. Interactive networks and detailed results can be accessed at https://fostamatinib.bioinfo-wuerz.eu/.

Review and prospects of targeted therapies for Spleen tyrosine kinase (SYK)

Spleen tyrosine kinase (SYK) is a non-receptor tyrosine kinase. The dysregulation of SYK is closely related to the occurrence and development of allergic diseases, autoimmune diseases and cancer. SYK has become an attractive target for drug discovery due to its important biological functions. This article reviews the biological function of SYK, the relationship between SYK and disease, and therapies targeting SYK. In addition, inspired by new technologies such as proteolysis targeting chimeras (PROTACs) and phosphatase recruiting chimeras (PHORCs), we propose the development of new therapeutic approaches for targeting SYK, such as SYK PROTACs and SYK PHORCs, which may overcome deficiencies of existing methods.

Emerging Treatments and the Clinical Trial Landscape for Hidradenitis Suppurativa Part I: Topical and Systemic Medical Therapies

Hidradenitis suppurativa (HS) is an oftentimes debilitating condition that presents with painful nodules, abscesses, and sinus tracts. This condition is challenging to treat, in part because the pathogenesis of the condition is incompletely understood but also because there are limited therapeutic options. HS research is undergoing explosive growth with multiple new molecular pathways under study, which will hopefully lead to improved disease control for patients. Part I of this review will provide an overview of the emerging topical and systemic therapies under investigation for HS.

Characterisation of tyrosine kinase inhibitor-receptor interactions at VEGFR2 using sunitinib-red and nanoBRET

Vascular endothelial growth factor (VEGF) is an important mediator of angiogenesis, proliferation and migration of vascular endothelial cells. It is well known that cardiovascular safety liability for a wide range of small molecule tyrosine kinase inhibitors (TKIs) can result from interference with the VEGFR2 signalling system. In this study we have developed a ligand-binding assay using a fluorescent analogue of sunitinib (sunitinib-red) and full length VEGFR2 tagged on its C-terminus with the bioluminescent protein nanoluciferase to monitor ligand-binding to VEGFR2 using bioluminescence resonance energy transfer (BRET). This NanoBRET assay is a proximity-based assay (requiring the fluorescent and bioluminescent components to be within 10nm of each other) that can monitor the binding of ligands to the kinase domain of VEGFR2. Sunitinib-red was not membrane permeable but was able to monitor the binding affinity and kinetics of a range of TKIs in cell lysates. Kinetic studies showed that sunitinib-red bound rapidly to VEGFR2 at 25 °C and that cediranib had slower binding kinetics with an average residence time of 112 min. Comparison between the log K_i values for inhibition of binding of sunitinib-red and log IC₅₀ values for attenuation of VEGF₁₆₅a-stimulated NFAT responses showed very similar values for compounds that inhibited sunitinib-red binding. However, two compounds that failed to inhibit sunitinib-red binding (dasatinib and entospletinib) were still able to attenuate VEGFR2-mediated NFAT signalling through inhibition of downstream signalling events. These results suggest that these compounds may still exhibit cardiovascular liabilities as a result of interference with downstream VEGFR2 signalling.

Discovery of 3-(1H-benzo[d]imidazole-2-yl)-1H-pyrazol-4 -amine derivatives as novel and potent syk inhibitors for the treatment of hematological malignancies

Spleen tyrosine kinase (Syk) is an important oncogene and signal transduction mediator that is mainly expressed in hematopoietic cells. Syk plays a key role in the B cell receptor (BCR) signaling pathway. Abnormal activation of Syk is closely related to the occurrence and development of hematological malignancies. Therefore, Syk is a potential target for the treatment of various hematologic cancers. Starting from compound 6(Syk, IC₅₀ = 15.8 μM), we performed fragment-based rational drug design for structural optimization based on the specific solvent-accessible region, hydrophobic region, and ribose region of Syk. This resulted in the discovery of a series of novel 3-(1H-benzo [d]imidazole-2-yl)-1H-pyrazol-4-amine Syk inhibitors, which led to the identification of 19q, a highly potent Syk inhibitor that exhibited excellent inhibitory activity on Syk enzyme (IC₅₀ = 0.52 nM) and showed potency against several other kinases. In addition, compound 19q effectively reduced phosphorylation of downstream PLCγ2 level in Romos cells. And it also exhibited antiproliferative activity in multiple hematological tumour cells. More gratifyingly, 19q showed impressive efficacy at a low dosage (1 mg/kg/day) in the MV4-11 mouse xenograft model without affecting the body weight of the mice. These findings suggest that 19q is a promising new Syk inhibitor for treating blood cancers.

Targeting macrophage Syk enhances responses to immune checkpoint blockade and radiotherapy in high-risk neuroblastoma

Background

Neuroblastoma (NB) is considered an immunologically cold tumor and is usually less responsive to immune checkpoint blockade (ICB). Tumor-associated macrophages (TAMs) are highly infiltrated in NB tumors and promote immune escape and resistance to ICB. Hence therapeutic strategies targeting immunosuppressive TAMs can improve responses to ICB in NB. We recently discovered that spleen tyrosine kinase (Syk) reprograms TAMs toward an immunostimulatory phenotype and enhances T-cell responses in the lung adenocarcinoma model. Here we investigated if Syk is an immune-oncology target in NB and tested whether a novel immunotherapeutic approach utilizing Syk inhibitor together with radiation and ICB could provide a durable anti-tumor immune response in an MYCN amplified murine model of NB.

Methods

Myeloid Syk KO mice and syngeneic MYCN-amplified cell lines were used to elucidate the effect of myeloid Syk on the NB tumor microenvironment (TME). In addition, the effect of Syk inhibitor, R788, on anti-tumor immunity alone or in combination with anti-PDL1 mAb and radiation was also determined in murine NB models. The underlying mechanism of action of this novel therapeutic combination was also investigated.

Results

Herein, we report that Syk is a marker of NB-associated macrophages and plays a crucial role in promoting immunosuppression in the NB TME. We found that the blockade of Syk in NB-bearing mice markedly impairs tumor growth. This effect is facilitated by macrophages that become immunogenic in the absence of Syk, skewing the suppressive TME towards immunostimulation and activating anti-tumor immune responses. Moreover, combining FDA-approved Syk inhibitor, R788 (fostamatinib) along with anti-PDL1 mAb provides a synergistic effect leading to complete tumor regression and durable anti-tumor immunity in mice bearing small tumors (50 mm3) but not larger tumors (250 mm3). However, combining radiation to R788 and anti-PDL1 mAb prolongs the survival of mice bearing large NB9464 tumors.

Conclusion

Collectively, our findings demonstrate the central role of macrophage Syk in NB progression and demonstrate that Syk blockade can "reeducate" TAMs towards immunostimulatory phenotype, leading to enhanced T cell responses. These findings further support the clinical evaluation of fostamatinib alone or with radiation and ICB, as a novel therapeutic intervention in neuroblastoma.

Cost-Effectiveness of Thrombopoietin Mimetics in Patients with Thrombocytopenia: A Systematic Review

OBJECTIVES

Thrombopoietin (TPO) mimetics are a potential alternative to platelet transfusion to minimize blood loss in patients with thrombocytopenia. This systematic review aimed to evaluate the cost-effectiveness of TPO mimetics, compared with not using TPO mimetics, in adult patients with thrombocytopenia.

METHODS

Eight databases and registries were searched for full economic evaluations (EEs) and randomized controlled trials (RCTs). Incremental cost-effectiveness ratios (ICERs) were synthesized as cost per quality-adjusted life year gained (QALY) or as cost per health outcome (e.g. bleeding event avoided). Included studies were critically appraised using the Philips reporting checklist.

RESULTS

Eighteen evaluations from nine different countries were included, evaluating the cost-effectiveness of TPO mimetics compared with no TPO, watch-and-rescue therapy, the standard of care, rituximab, splenectomy or platelet transfusion. ICERs varied from a dominant strategy (i.e. cost-saving and more effective), to an incremental cost per QALY/health outcome of EUR 25,000-50,000, EUR 75,000-750,000 and EUR > 1 million, to a dominated strategy (cost-increasing and less effective). Few evaluations (n = 2, 10%) addressed the four principal types of uncertainty (methodological, structural, heterogeneity and parameter). Parameter uncertainty was most frequently reported (80%), followed by heterogeneity (45%), structural uncertainty (43%) and methodological uncertainty (28%).

CONCLUSIONS

Cost-effectiveness of TPO mimetics in adult patients with thrombocytopenia ranged from a dominant strategy to a significant incremental cost per QALY/health outcome or a strategy that is clinically inferior and has increased costs. Future validation and tackling the uncertainty of these models with country-specific cost data and up-to-date efficacy and safety data are needed to increase the generalizability.

Knowledge mapping of immune thrombocytopenia: a bibliometric study

Background

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by isolated thrombocytopenia. Recently, the pathophysiology and novel drugs of ITP have been the focus of researchers with plenty of publications emerging. Bibliometrics is the process of extracting measurable data through statistical analysis of published research studies to provide an insight into the trends and hotspots.

Objective

This study aimed to provide an insight into developing trends and hotspots in the field of ITP by bibliometric analysis.

Methods

By using three bibliometric mapping tools (bibliometrix R package, VOSviewer, CiteSpace), we summarized the overview information of retrieved publications, as well as the analysis of keyword co-occurrence and reference co-citation.

Results

A total of 3299 publications with 78066 citations on ITP research were included in the analysis. The keyword co-occurrence network identified 4 clusters relating to the diagnosis, pathophysiology, and treatment of ITP respectively. Then the reference co-citation analysis produced 12 clusters with a well-structured and highly credible clustering model, and they can be divided into 5 trends: second-line treatment, chronic ITP, novel therapy and pathogenesis, COVID-19 vaccine. Treg cells, spleen tyrosine kinase, and mesenchymal stem cells were the latest hotspots with strong burstness.

Conclusion

This bibliometric analysis provided a comprehensive insight into research hotspots and trends on ITP, which would enrich the review of the ITP research.

Plasma proteomics of SARS-CoV-2 infection and severity reveals impact on Alzheimer's and coronary disease pathways

Identification of proteins dysregulated by COVID-19 infection is critically important for better understanding of its pathophysiology, building prognostic models, and identifying new targets. Plasma proteomic profiling of 4,301 proteins was performed in two independent datasets and tested for the association for three COVID-19 outcomes (infection, ventilation, and death). We identified 1,449 proteins consistently associated in both datasets with any of these three outcomes. We subsequently created highly accurate models that distinctively predict infection, ventilation, and death. These proteins were enriched in specific biological processes including cytokine signaling, Alzheimer's disease, and coronary artery disease. Mendelian randomization and gene network analyses identified eight causal proteins and 141 highly connected hub proteins including 35 with known drug targets. Our findings provide distinctive prognostic biomarkers for two severe COVID-19 outcomes, reveal their relationship to Alzheimer's disease and coronary artery disease, and identify potential therapeutic targets for COVID-19 outcomes.

Sovleplenib (HMPL-523), a novel Syk inhibitor, for patients with primary immune thrombocytopenia in China: a randomised, double-blind, placebo-controlled, phase 1b/2 study

BACKGROUND

Spleen tyrosine kinase (Syk) inhibitor is a treatment option for primary immune thrombocytopenia. We aimed to evaluate the safety, tolerability, pharmacokinetics, preliminary activity, and recommended phase 2 dose of sovleplenib in patients with primary immune thrombocytopenia.

METHODS

This randomised, double-blind, placebo-controlled, phase 1b/2 study was conducted at nine hospitals in China. Eligible patients were aged 18-75 years, had an ECOG performance score of 0-1, had primary immune thrombocytopenia for more than 6 months, and did not respond or relapsed after previous first-line treatment or had poor response or postoperative relapse after a splenectomy. Dose-escalation (100 mg, 200 mg, or 300 mg given orally once a day) and dose-expansion phases (recommended phase 2 dose) each consisted of an 8-week, double-blind, placebo-controlled period in which patients were randomly assigned (3:1) to receive sovleplenib or placebo with an interactive web response system followed by a 16-week, open-label period with sovleplenib. Patients, investigators, and the sponsor were masked to treatment allocation during the first 8 weeks. The main efficacy endpoint was the proportion of patients whose platelet count reached 30 × 10⁹ platelets per L or higher and was double of the baseline at two consecutive visits during 0-8 weeks without rescue therapy. Efficacy was evaluated by intention-to-treat. This study is registered with ClinicalTrials.gov, NCT03951623.

FINDINGS

Between May 30, 2019, and April 22, 2021, 62 patients were assessed for eligibility and 45 (73%) were randomly assigned. Patients received at least one dose of the study drug during the 8-week double-blind period (placebo [n=11] and sovleplenib 100 mg [n=6], 200 mg [n=6], 300 mg [n=16], and 400 mg [n=6]; this group was added following the observation of no protocol-specified safety events at the previous doses). All participants were Asian; 18 (40%) of 45 were male and 27 (60%) were female. The median age was 40·0 years (IQR 33·0-50·0). Ten (29%) of 34 patients in sovleplenib groups versus five (45%) of 11 in the placebo group received concomitant anti-primary immune thrombocytopenia therapy. The recommended phase 2 dose was determined as 300 mg once a day. The proportion of patients who met the main efficacy endpoint were three (50%; 95% CI 12-88) in the 100 mg group, three (50%; 12-88) in the 200 mg group, ten (63%; 35-85) in the 300 mg group, and two (33%; 4-78) in the 400 mg group compared with one (9%; 0-41) in the placebo group. The overall response rate in the 300 mg group was 80% (16 of 20 who received continuous sovleplenib plus those who crossed over from placebo) and the durable response rate was 31% (11-59; five of 16) in the continuous sovleplenib 300 mg and 75% (19-99; three of four) crossed from placebo to sovleplenib during 0-24 weeks. During the 28-day safety evaluation period, two grade 2 or worse treatment-related treatment-emergent adverse events occurred in the sovleplenib groups (hypertriglyceridaemia and anaemia). During 0-8 weeks, the most frequent treatment-emergent adverse events were an increase in blood lactate dehydrogenase, haematuria, and urinary tract infection (seven [21%] of 34 in sovleplenib groups vs one [9%] of 11 in the placebo group); and occult blood-positive and hyperuricaemia (four [12%] vs three [27%] for each). No fatal treatment-emergent adverse events were recorded.

INTERPRETATION

Sovleplenib was well tolerated, and the recommended phase 2 dose showed a promising durable response in patients with primary immune thrombocytopenia, which provides evidence for future investigations. A phase 3 trial is ongoing (NCT05029635) to confirm the efficacy and safety of sovleplenib in patients with primary immune thrombocytopenia.

FUNDING

HUTCHMED.

Mitigating Serious Adverse Events in Gene Therapy with AAV Vectors: Vector Dose and Immunosuppression

Gene transfer with high doses of adeno-associated viral (AAV) vectors has resulted in serious adverse events and even death of the recipients. Toxicity could most likely be circumvented by repeated injections of lower and less toxic doses of vectors. This has not been pursued as AAV vectors induce potent neutralizing antibodies, which prevent cell transduction upon reinjection of the same vector. This review discusses different types of immune responses against AAV vectors and how they offer targets for the elimination or inhibition of vector-specific neutralizing antibodies. Such antibodies can be circumvented by using different virus serotypes for sequential injections, they can be removed by plasmapheresis, or they can be destroyed by enzymatic degradation. Antibody producing cells can be eliminated by proteasome inhibitors. Drugs that inhibit T-cell responses, B-cell signaling, or presentation of the vector's antigens to B cells can prevent or reduce induction of AAV-specific antibodies. Combinations of different approaches and drugs are likely needed to suppress or eliminate neutralizing antibodies, which would then allow for repeated dosing. Alternatively, novel AAV vectors with higher transduction efficacy are being developed and may allow for a dose reduction, although it remains unknown if this will completely address the problem of high-dose adverse events.

Fostamatinib for the treatment of Japanese patients with primary immune thrombocytopenia: A phase 3, placebo-controlled, double-blind, parallel-group study

Fostamatinib, a spleen tyrosine kinase inhibitor, has been approved for the treatment of chronic primary immune thrombocytopenia (ITP) in the United States, Canada and some European countries. We conducted a phase 3, placebo-controlled, double-blind, parallel-group study to evaluate the efficacy and safety of fostamatinib in Japanese patients with primary ITP. Thirty-four patients were randomised to fostamatinib (n = 22) or placebo (n = 12) at 100-150 mg twice a day for 24 weeks. Stable responses (platelet ≥50 000/μl at ≥4 of the 6 visits from weeks 14 to 24) were observed in eight (36%) patients on fostamatinib and in none of the patients on placebo (p = 0.030). Overall responses (platelet ≥50 000/μl at ≥1 of the 6 visits from weeks 2 to 12) were seen in 10 (45%) patients on fostamatinib and in none of the patients on placebo (p = 0.006). Patients on fostamatinib required rescue medication less often and experienced fewer bleeding symptoms than patients on placebo. Adverse events observed were mild or moderate and were manageable. No new safety signals were identified in Japanese patients with ITP.

ASGARD is A Single-cell Guided Pipeline to Aid Repurposing of Drugs

Single-cell RNA sequencing technology has enabled in-depth analysis of intercellular heterogeneity in various diseases. However, its full potential for precision medicine has yet to be reached. Towards this, we propose A Single-cell Guided Pipeline to Aid Repurposing of Drugs (ASGARD) that defines a drug score to recommend drugs by considering all cell clusters to address the intercellular heterogeneity within each patient. ASGARD shows significantly better average accuracy on single-drug therapy compared to two bulk-cell-based drug repurposing methods. We also demonstrated that it performs considerably better than other cell cluster-level predicting methods. In addition, we validate ASGARD using the drug response prediction method TRANSACT with Triple-Negative-Breast-Cancer patient samples. We find that many top-ranked drugs are either approved by the Food and Drug Administration or in clinical trials treating corresponding diseases. In conclusion, ASGARD is a promising drug repurposing recommendation tool guided by single-cell RNA-seq for personalized medicine. ASGARD is free for educational use at https://github.com/lanagarmire/ASGARD .

The NEK family of serine/threonine kinases as a biomarker for cancer

Cancer is defined by unrestrained cell proliferation due to impaired protein activity. Cell cycle-related proteins are likely to play a role in human cancers, including proliferation, invasion, and therapeutic resistance. The serine/threonine NEK kinases are the part of Never In Mitosis A Kinases (NIMA) family, which are less explored kinase family involved in the cell cycle, checkpoint regulation, and cilia biology. They comprise of eleven members, namely NEK1, NEK2, NEK3, NEK4, NEK5, NEK6, NEK7, NEK8, NEK9, NEK10, and NEK11, located in different cellular regions. Recent research has shown the role of NEK family in various cancers by perversely expressing. Therefore, this review aimed to provide a systematic account of our understanding of NEK kinases; structural details; and its role in the cell cycle regulation. Furthermore, we have comprehensively reviewed the NEK kinases in terms of their expression and regulation in different cancers. Lastly, we have emphasized on some of the potential NEK inhibitors reported so far.

Intramuscular Anti-D treatment for immune thrombocytopenia: A single centre experience

Intravenous Anti-Rhesus-D immunoglobulin (Anti-D) is a first-line treatment option for immune thrombocytopenia in non-splenectomised and RhD-positive patients. In this report, we retrospectively review our experience with intramuscular (IM) Anti-D treatment in 74 adult patients between 1990 and 2018. We found that 73% of patients showed a response; almost all of them had complete responses (68.9%), and 26% achieved complete responses sustained at least 6 months after treatment discontinuation. [Correction added on 02 December 2022, after first online publication: In the preceding sentence, '(68.89%)' has been corrected to '(68.9%)' in this version.] No significant side effects were observed with no cases of acute haemolysis or anaemia reported. We conclude from this study that IM Anti-D is an effective and safe treatment for immune thrombocytopenia.

Safety and Efficacy of Tyrosine Kinase Inhibitors in Immune Thrombocytopenic Purpura: A Systematic Review of Clinical Trials

Immune thrombocytopenic purpura (ITP) is an acquired antibody or cell-mediated platelet damage or decreased platelet production. Steroids, IV immunoglobulins (IVIG), and Rho-anti-D antibodies are the commonly used initial treatments for ITP. However, many ITP patients either do not respond or do not maintain a response to initial therapy. Splenectomy, rituximab, and thrombomimetics are the commonly used second-line treatment. More treatment options include tyrosine kinases inhibitors (TKI), including spleen tyrosine kinase (Syk) and Bruton's tyrosine kinase (BTK) inhibitors. This review aims to assess the safety and efficacy of TKIs. Methods: Literature was searched on PubMed, Embase, WOS, and clinicaltrials.gov using keywords, "tyrosine kinase" and "idiopathic thrombocytopenic purpura". PRISMA guidelines were followed. Results: In total, 4 clinical trials were included with 255 adult patients with relapsed/refractory ITP. In all, 101 (39.6%) patients were treated with fostamatinib, 60 (23%) patients with rilzabrutinib, and 34 (13%) with HMPL-523. Patients treated with fostamatinib achieved a stable response (SR) and overall response (OR) in 18/101 (17.8%) and 43/101 (42.5%) of the patients, respectively, while SR and OR were achieved in 1/49 (2%) and 7/49 (14%) of the patients, respectively, in the placebo group. Patients treated with HMPL-523 (300 mg dose expansion) achieved an SR and OR in 5/20 (25%) and 11/20 (55%) of the patients, respectively, while SR and OR were achieved in 1/11 (9%) of the patients treated with the placebo. Patients treated with rilzabrutinib achieved an SR in 17/60 (28%) patients. Dizziness (1%), hypertension (2%), diarrhea (1%), and neutropenia (1%) were serious adverse events in fostamatinib patients. Rilzabrutinib or HMPL-523 patients did not require a dose reduction due to drug-related adverse effects. Conclusions: Rilzabrutinib, fostamatinib, and HMPL-523 were safe and effective in the treatment of relapsed/refractory ITP.

Small Molecule Drugs That Inhibit Phagocytosis

In our initial publication on the in vitro testing of more than 200 compounds, we demonstrated that small molecules can inhibit phagocytosis. We therefore theorized that a small molecule drug discovery-based approach to the treatment of immune cytopenias (ITP, AIHA, HTR, DHTR) is feasible. Those earlier studies showed that small molecules with anti-phagocytic groups, such as the pyrazole core, are good models for producing efficacious phagocytosis inhibitors with low toxicity. We recently screened a chemical library of 80 compounds containing pyrazole/isoxazole/pyrrole core structures and found four hit molecules for further follow-up, all having the pyrazole core structure. Subsequent evaluation via MTT viability, LDH release, and apoptosis, led to the selection of two lead compounds with negligible toxicity and high efficacy. In an in vitro assay for inhibition of phagocytosis, their IC₅₀ values were 2-4 µM. The rational development of these discoveries from hit to lead molecule stage, viz. independent synthesis/scale up of hit molecules, and in vivo activities in mouse models of autoimmune disease, will result in the selection of a lead compound(s) for further pre-clinical evaluation.

A multi-phenotype analysis reveals 19 susceptibility loci for basal cell carcinoma and 15 for squamous cell carcinoma

Basal cell carcinoma and squamous cell carcinoma are the most common skin cancers, and have genetic overlap with melanoma, pigmentation traits, autoimmune diseases, and blood biochemistry biomarkers. In this multi-trait genetic analysis of over 300,000 participants from Europe, Australia and the United States, we reveal 78 risk loci for basal cell carcinoma (19 previously unknown and replicated) and 69 for squamous cell carcinoma (15 previously unknown and replicated). The previously unknown risk loci are implicated in cancer development and progression (e.g. CDKL1), pigmentation (e.g. TPCN2), cardiometabolic (e.g. FADS2), and immune-regulatory pathways for innate immunity (e.g. IFIH1), and HIV-1 viral load modulation (e.g. CCR5). We also report an optimised polygenic risk score for effective risk stratification for keratinocyte cancer in the Canadian Longitudinal Study of Aging (794 cases and 18139 controls), which could facilitate skin cancer surveillance e.g. in high risk subpopulations such as transplantees.

Small molecules in the treatment of COVID-19

The outbreak of COVID-19 has become a global crisis, and brought severe disruptions to societies and economies. Until now, effective therapeutics against COVID-19 are in high demand. Along with our improved understanding of the structure, function, and pathogenic process of SARS-CoV-2, many small molecules with potential anti-COVID-19 effects have been developed. So far, several antiviral strategies were explored. Besides directly inhibition of viral proteins such as RdRp and Mpro, interference of host enzymes including ACE2 and proteases, and blocking relevant immunoregulatory pathways represented by JAK/STAT, BTK, NF-κB, and NLRP3 pathways, are regarded feasible in drug development. The development of small molecules to treat COVID-19 has been achieved by several strategies, including computer-aided lead compound design and screening, natural product discovery, drug repurposing, and combination therapy. Several small molecules representative by remdesivir and paxlovid have been proved or authorized emergency use in many countries. And many candidates have entered clinical-trial stage. Nevertheless, due to the epidemiological features and variability issues of SARS-CoV-2, it is necessary to continue exploring novel strategies against COVID-19. This review discusses the current findings in the development of small molecules for COVID-19 treatment. Moreover, their detailed mechanism of action, chemical structures, and preclinical and clinical efficacies are discussed.

Repurposable Drugs That Interact with Steroid Responsive Gene Targets for Inner Ear Disease

Corticosteroids, oral or transtympanic, remain the mainstay for inner ear diseases characterized by hearing fluctuation or sudden changes in hearing, including sudden sensorineural hearing loss (SSNHL), Meniere's disease (MD), and autoimmune inner ear disease (AIED). Despite their use across these diseases, the rate of complete recovery remains low, and results across the literature demonstrates significant heterogeneity with respect to the effect of corticosteroids, suggesting a need to identify more efficacious treatment options. Previously, our group has cross-referenced steroid-responsive genes in the cochlea with published single-cell and single-nucleus transcriptome datasets to demonstrate that steroid-responsive differentially regulated genes are expressed in spiral ganglion neurons (SGN) and stria vascularis (SV) cell types. These differentially regulated genes represent potential druggable gene targets. We utilized multiple gene target databases (DrugBank, Pharos, and LINCS) to identify orally administered, FDA approved medications that potentially target these genes. We identified 42 candidate drugs that have been shown to interact with these genes, with an emphasis on safety profile, and tolerability. This study utilizes multiple databases to identify drugs that can target a number of druggable genes in otologic disorders that are commonly treated with steroids, providing a basis for establishing novel repurposing treatment trials.

Unusual complications in the management of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a common, indolent disease that typically presents with a proliferation of mature, immunologically dysfunctional CD5+ B-cells which preferentially occupy the bone marrow, peripheral blood and lymphoid organs. Immune dysfunction leads to an increase in autoimmune diseases which occur in approximately 10% of patients with CLL. Autoimmune cytopenias are the most common, but other organs may be affected as well. The treatment of these conditions typically depends on the extent of CLL and severity of symptoms, but generally consists of CLL-directed therapies, immunosuppression or both. CLL may also infiltrate extranodal sites in the body. Symptomatic extranodal CLL or extranodal disease which threatens normal organ function is an indication for initiation of CLL-directed therapy. The following review summarizes autoimmune and extranodal complications that can occur in patients with CLL and our suggested approach to their treatment.

Systemic lupus erythematosus-complicating immune thrombocytopenia: From pathogenesis to treatment

Immune thrombocytopenia (ITP) is a common hematological manifestation of systemic lupus erythematosus (SLE). The heterogeneity of its clinical characteristics and therapeutic responses reflects a complex pathogenesis. A better understanding of its pathophysiological mechanisms and employing an optimal treatment regimen is therefore important to improve the response rate and prognosis, and avoid unwanted outcomes. Besides glucocorticoids, traditional immunosuppressants (i.e. cyclosporine, mycophenolate mofetil) and intravenous immunoglobulins, new therapies are emerging and promising for the treatment of intractable SLE-ITP, such as thrombopoietin receptor agonists (TPO-RAs), platelet desialylation inhibitors(i.e. oseltamivir), B-cell targeting therapy(i.e. rituximab, belimumab), neonatal Fc receptor(FcRn) inhibitor, spleen tyrosine kinase(Syk) inhibitor and Bruton tyrosine kinase(BTK) inhibitor et al., although more rigorous randomized controlled trials are needed to substantiate their efficacy. In this review, we update our current knowledge on the pathogenesis and treatment of SLE-ITP.

Current therapeutic strategies and perspectives in refractory ITP: What have we learned recently?

Immune thrombocytopenia (ITP) is an acquired autoimmune bleeding disorder featured by increased platelet destruction and deficient megakaryocyte maturation. First-line treatments include corticosteroids, intravenous immunoglobulin and intravenous anti-D immunoglobulin. Second-line treatments consist of rituximab, thrombopoietin receptor agonists and splenectomy. Although most patients benefit from these treatments, an individualized treatment approach is warranted due to the large heterogeneity among ITP patients. In addition, ITP patients may relapse and there remains a subset of patients who become refractory to treatments. The management of these refractory patients is still a challenge. This review aims to summarize emerging therapeutic approaches for refractory ITP in several categories according to their different targets, including macrophages, platelets/megakaryocytes, T cells, B cells, and endothelial cells. Moreover, current management strategies and combination regimens of refractory ITP are also discussed.

Plasma proteomics of SARS-CoV-2 infection and severity reveals impact on Alzheimer and coronary disease pathways

Identification of the plasma proteomic changes of Coronavirus disease 2019 (COVID-19) is essential to understanding the pathophysiology of the disease and developing predictive models and novel therapeutics. We performed plasma deep proteomic profiling from 332 COVID-19 patients and 150 controls and pursued replication in an independent cohort (297 cases and 76 controls) to find potential biomarkers and causal proteins for three COVID-19 outcomes (infection, ventilation, and death). We identified and replicated 1,449 proteins associated with any of the three outcomes (841 for infection, 833 for ventilation, and 253 for death) that can be query on a web portal ( https://covid.proteomics.wustl.edu/ ). Using those proteins and machine learning approached we created and validated specific prediction models for ventilation (AUC>0.91), death (AUC>0.95) and either outcome (AUC>0.80). These proteins were also enriched in specific biological processes, including immune and cytokine signaling (FDR ≤ 3.72×10 -14 ), Alzheimer's disease (FDR ≤ 5.46×10 -10 ) and coronary artery disease (FDR ≤ 4.64×10 -2 ). Mendelian randomization using pQTL as instrumental variants nominated BCAT2 and GOLM1 as a causal proteins for COVID-19. Causal gene network analyses identified 141 highly connected key proteins, of which 35 have known drug targets with FDA-approved compounds. Our findings provide distinctive prognostic biomarkers for two severe COVID-19 outcomes (ventilation and death), reveal their relationship to Alzheimer's disease and coronary artery disease, and identify potential therapeutic targets for COVID-19 outcomes.

Evaluating fostamatinib disodium as a treatment option for immune thrombocytopenia in adult patients

INTRODUCTION

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by increased platelet destruction and decreased platelet production, leading to thrombocytopenia with or without bleeding manifestations. The majority of patients experiencing treatment need will eventually need secondary treatment following first line therapy with steroids. In 2018, the oral spleen tyrosine kinase inhibitor fostamatinib received US Food and Drug Administration approval for ITP patients with an insufficient response to a previous treatment.

AREAS COVERED

This review outlines pharmacological characteristics of fostamatinib and provides an overview of its efficacy and safety results in phase II and III trials, followed by the expert opinion of the authors.

EXPERT OPINION

Increasing knowledge on the role of different players and mechanisms in the pathophysiology of autoimmune disorders in general and of ITP in particular, has led to the development of several new treatment options, as illustrated by the introduction of fostamatinib in the treatment of ITP. However, lacking direct comparison with other recent treatment options (in particular thrombopoietin receptor agonists), its use should be evaluated critically taking into account the unique toxicity and potential drug-drug interaction profile.

Development of New Drugs for Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia (AIHA) is a rare disorder characterized by the autoantibody-mediated destruction of red blood cells, and treatments for it still remain challenging. Traditional first-line immunosuppressive therapy, which includes corticosteroids and rituximab, is associated with adverse effects as well as treatment failures, and relapses are common. Subsequent lines of therapy are associated with higher rates of toxicity, and some patients remain refractory to currently available treatments. Novel therapies have become promising for this vulnerable population. In this review, we will discuss the mechanism of action, existing data, and ongoing clinical trials of current novel therapies for AIHA, including B-cell-directed therapy, phagocytosis inhibition, plasma cell-directed therapy, and complement inhibition.

Recent advances in treatments of adult immune thrombocytopenia

Immune thrombocytopenia (ITP) is isolated thrombocytopenia characterized by autoimmune-mediated disruption of platelet without other etiologies. Treatments for chronic ITP consist of corticosteroids, intravenous immunoglobulins, anti-D immunoglobulin, rituximab, thrombopoietin receptor agonists, immunosuppressants and splenectomy. Although current therapies are effective in over two-thirds of patients, some patients are refractory to therapies or fail to achieve long-term responses. Recently, great advance has been made in identifying various mechanisms involved in ITP pathogenesis, and new treatments targeting these pathways are being developed. Novel agents such as splenic tyrosine kinase inhibitor, Bruton kinase inhibitor, plasma cell targeting therapies, neonatal Fc receptor inhibitor, platelet desialylation inhibitor, and inhibition of the classical complement pathway are expected to be effective for ITP treatment. This review summarizes current strategies and emerging therapies of ITP.

Nanomedicines in B cell-targeting therapies

B cells play multiple roles in immune responses related to autoimmune diseases as well as different types of cancers. As such, strategies focused on B cell targeting attracted wide interest and developed intensively. There are several common mechanisms various B cell targeting therapies have relied on, including direct B cell depletion, modulation of B cell antigen receptor (BCR) signaling, targeting B cell survival factors, targeting the B cell and T cell costimulation, and immune checkpoint blockade. Nanocarriers, used as drug delivery vehicles, possess numerous advantages to low molecular weight drugs, reducing drug toxicity, enhancing blood circulation time, as well as augmenting targeting efficacy and improving therapeutic effect. Herein, we review the commonly used targets involved in B cell targeting approaches and the utilization of various nanocarriers as B cell-targeted delivery vehicles. STATEMENT OF SIGNIFICANCE: As B cells are engaged significantly in the development of many kinds of diseases, utilization of nanomedicines in B cell depletion therapies have been rapidly developed. Although numerous studies focused on B cell targeting have already been done, there are still various potential receptors awaiting further investigation. This review summarizes the most relevant studies that utilized nanotechnologies associated with different B cell depletion approaches, providing a useful tool for selection of receptors, agents and/or nanocarriers matching specific diseases. Along with uncovering new targets in the function map of B cells, there will be a growing number of candidates that can benefit from nanoscale drug delivery.

Fc receptors gone wrong: A comprehensive review of their roles in autoimmune and inflammatory diseases

Systemic autoimmune and inflammatory diseases have a complex and only partially known pathophysiology with various abnormalities involving all the components of the immune system. Among these components, antibodies, and especially autoantibodies are key elements contributing to autoimmunity. The interaction of antibody fragment crystallisable (Fc) and several distinct receptors, namely Fc receptors (FcRs), have gained much attention during the recent years, with possible major therapeutic perspectives for the future. The aim of this review is to comprehensively describe the known roles for FcRs (activating and inhibitory FcγRs, neonatal FcR [FcRn], FcαRI, FcεRs, Ro52/tripartite motif containing 21 [Ro52/TRIM21], FcδR, and the novel Fc receptor-like [FcRL] family) in systemic autoimmune and inflammatory disorders, namely rheumatoid arthritis, Sjögren's syndrome, systemic lupus erythematosus, systemic sclerosis, idiopathic inflammatory myopathies, mixed connective tissue disease, Crohn's disease, ulcerative colitis, immunoglobulin (Ig) A vasculitis, Behçet's disease, Kawasaki disease, IgG4-related disease, immune thrombocytopenia, autoimmune hemolytic anemia, antiphospholipid syndrome and heparin-induced thrombocytopenia.

Rapid response to mycophenolate mofetil in combination with romiplostim in a case of severe refractory immune thrombocytopenia post COVID-19 vaccination

Vaccine mediated immune mediated thrombocytopenia (ITP) is exceedingly rare. We present a case of a young female who developed severe refractory ITP with multiple bleeding sites post second dose of COVID-19 vaccination. She was treated with a combination of romiplostim and mycophenolate mofetil that resulted in rapid platelet count recovery.

New Insights into the Pathogenesis and Treatment Strategies in IgA Nephropathy

Background

Immunoglobulin A nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide. It is defined by mesangial IgA deposition, with consequent mesangial cell proliferation, inflammation, and tubulointerstitial fibrosis.

Summary

Approximately 30% of affected patients will progress to end-stage kidney disease within 20 years of diagnosis. Currently, there is no disease-specific treatment available and management recommendations are, in general, limited to optimization of lifestyle measures and use of renin-angiotensin-aldosterone system blockers. More recently, advances in the understanding of the pathogenesis of IgAN have informed the development of novel therapeutic strategies that are now being tested in clinical trials. These have focused on different areas that include modulating the production of poorly galactosylated IgA1, which is central to the development of IgAN, and inhibiting the downstream signaling pathways and complement activation that are triggered following mesangial IgA1 deposition. In this review, we will summarize important pathogenic mechanisms in IgAN and highlight important areas of interest where treatment strategies are being developed.

Key messages

IgAN is a common form of primary glomerulonephritis for which there is no current approved specific therapy. Recent advances in the understanding of its pathogenesis have led to the development of novel therapies, with the hope that new treatment options will be available soon to treat this condition.

Integrative Multi-omics Landscape of Non-structural Protein 3 of Severe Acute Respiratory Syndrome Coronaviruses

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is currently a global pandemic. Extensive investigations have been performed to study the clinical and cellular effects of SARS-CoV-2 infection. Mass spectrometry-based proteomics studies have revealed the cellular changes due to the infection and identified a plethora of interactors for all SARS-CoV-2 components, except for the longest non-structural protein 3 (NSP3). Here, we expressed the full-length NSP3 proteins of SARS-CoV and SARS-CoV-2 to investigate their unique and shared functions using multi-omics methods. We conducted interactome, phosphoproteome, ubiquitylome, transcriptome, and proteome analyses of NSP3-expressing cells. We found that NSP3 plays essential roles in cellular functions such as RNA metabolism and immune response (e.g., NF-κB signal transduction). Interestingly, we showed that SARS-CoV-2 NSP3 has both endoplasmic reticulum and mitochondrial localizations. In addition, SARS-CoV-2 NSP3 is more closely related to mitochondrial ribosomal proteins, whereas SARS-CoV NSP3 is related to the cytosolic ribosomal proteins. In summary, our integrative multi-omics study of NSP3 improves the understanding of the functions of NSP3 and offers potential targets for the development of anti-SARS strategies.

Targeting SARS-CoV-2-Platelet Interactions in COVID-19 and Vaccine-Related Thrombosis

It is clear that COVID-19 is more than a pneumonia and is associated with a coagulopathy and multi-organ failure. While the use of anti-coagulants does reduce the incidence of pulmonary emboli, it does not help with survival. This suggests that the coagulopathy is more likely to be platelet-driven rather than thrombin-driven. There is significant evidence to suggest that SARS-CoV-2 virions directly interact with platelets to trigger activation leading to thrombocytopenia and thrombosis. I propose a model of multiple interactions between SARS-CoV-2 and platelets that has many similarities to that with Staphylococcus aureus and Dengue virus. As platelet activation and thrombosis are major factors in poor prognosis, therapeutics that target the platelet-SARS-CoV-2 interaction have potential in treating COVID-19 and other virus infections.