Fenebrutinib in H(1) antihistamine-refractory chronic spontaneous urticaria: a randomized phase 2 trial

Chronic Spontaneous Urticaria: Current and Emerging Biologic Agents

Antihistamine refractory chronic spontaneous urticaria (CSU) has a prevalence of up to 50%. Anti-immunoglobulin E (IgE) therapies have revolutionized management of CSU, yet refractory cases persist, suggesting a role for biologic agents that impact alternative routes of mast cell stimulation independent of cross-linking at FcεR1. This review addresses anti-IgE and Th2-targeted therapies in the management of CSU. In addition, we explore novel treatments targeting alternative pathways of mast cell activation including MAS-related G protein-coupled receptor-X2 and sialic acid-binding immunoglobulin-like lectin-6, inhibiting intracellular signaling via Bruton's tyrosine kinase, and disrupting KIT activation by SCF.

Mast cell signaling and its role in urticaria

Chronic urticaria is a mast cell (MC)-driven disease characterized by the development of itching wheals and/or angioedema. In the last decades, outstanding progress has been made in defining the mechanisms involved in MC activation, and novel activating and inhibitory receptors expressed in MC surface were identified and characterized. Besides an IgE-mediated activation through high-affinity IgE receptor cross-linking, other activating receptors, including Mas-related G-protein-coupled receptor-X2, C5a receptor, and protease-activated receptors 1 and 2 are responsible for MC activation. This would partly explain the reason some subgroups of chronic spontaneous urticaria (CSU), the most frequent form of urticaria in the general population, do not respond to IgE target therapies, requiring other therapeutic approaches for improving the management of the disease. In this review, we shed some light on the current knowledge of the immunologic and nonimmunologic mechanisms regulating MC activation in CSU, considering the complex inflammatory scenario underlying CSU pathogenesis, and novel potential MC-targeted therapies, including surface receptors and cytoplasmic signaling proteins.

Treatment options in refractory chronic spontaneous urticaria

PURPOSE OF REVIEW

Chronic spontaneous urticaria (CSU) patients sometimes do not respond to second-generation antihistamine, and 10-50% patients do not even respond to four-fold the usual dose of nonsedating H1 antihistamine, which further leads to repeated courses of oral corticosteroids to abate the symptoms. There are third-line agents approved by EAACI guidelines, which include omalizumab and cyclosporine. Certain patients are even resistant to the third-line agents. In this review, various other treatment options will be discussed in patients of refractory CSU.

RECENT FINDINGS

Recently, we demonstrated azathioprine as a possible third-line option, which was found noninferior to cyclosporine in antihistamine refractory CSU. There have been trials, studies, case series and reports, which suggest other putative options for refractory CSU management.

SUMMARY

Studies on the management of refractory CSU are accumulating thereby expanding the armamentarium of dermatologists and allergologist against difficult-to-treat urticaria patients.

The future of targeted therapy in chronic spontaneous urticaria

Chronic urticaria can be divided into 2 subsets: chronic spontaneous urticaria (CSU) with skin lesions occurring without a specific trigger and chronic inducible urticaria, which has an identified specific stimulus. The annual prevalence of chronic urticaria is 0.5% to 2.3% globally. The CSU is a self-limited disorder in most cases, with an average duration of 2 to 5 years, but symptoms persist beyond 5 years in up to 30% of patients. The first line of treatment is a daily nonsedating, second-generation H1-antihistamine. The CSU guidelines recommend using oral nonsedating antihistamines up to 4 fold in patients with CSU unresponsive to standard doses as the next step in treatment. A meta-analysis found that the rate of response in patients with CSU who responded to updosing was 63.2%. Therefore, approximately 40% of patients continue to have persistent hives and itching requiring treatment with the biologic omalizumab, based on evidence from randomized controlled trials. Although omalizumab has been shown to markedly relieve symptoms of CSU, omalizumab is not effective in all patients and has not been shown to induce long-term disease remission. Thus, there is an unmet need for more effective treatments that can lead to cure or long-term remission. In this review, we will provide an overview of new treatment targets and biologics that are under investigation for the treatment of CSU.

Disease modification in chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is a debilitating, inflammatory skin condition characterized by infiltrating immune cells. Available treatments are limited to improving the signs and symptoms. There is an unmet need to develop therapies that target disease-driving pathways upstream of mast cell activation to inhibit or delay the progression of CSU and associated comorbidities. Here, we aim to define disease modification due to a treatment intervention and criteria that disease-modifying treatments (DMTs) must meet in CSU. We have defined disease modification in CSU as a favorable treatment-induced change in the underlying pathophysiology and, therefore, the disease course, which is clinically beneficial and enduring. A DMT must fulfil the following criteria: (1) prevents or delays the progression of CSU, (2) induces long-term, therapy-free clinical remission, which is the sustained absence of CSU signs and symptoms without the need for treatment, and (3) affects the underlying mechanism of CSU, as demonstrated by an effect on disease-driving signals and/or a biomarker. DMTs in CSU should slow disease progression, achieve long-lasting disease remission, target disease-driving mechanisms, reduce mast cell-activating IgE autoantibodies, target cytokine profile polarization, and normalize the gut microbiome and barrier. Treating CSU at the immune system level could provide valuable alternatives to pharmacotherapy in CSU management. Specific DMTs in CSU are yet to be developed, but some show potential benefits, such as inhibitors of Bruton's Tyrosine Kinase, IL-4 and IL-13. Future therapies could prevent CSU signs and symptoms, achieve long-term clinical benefits after discontinuing treatment, and prevent associated concomitant disorders.

The Effect of Placebo on Pruritus in Patients with Chronic Urticaria: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials

BACKGROUND

The anti-pruritic effect of placebo in patients with chronic urticaria has gained increasing attention in clinical research. However, the extent of placebo effect and its influencing factors in the treatment of chronic urticaria are not well understood.

OBJECTIVE

The objective of this systematic review and meta-analysis was to investigate the effect of placebo on pruritus in patients with chronic urticaria and to explore relevant influencing factors.

METHODS

PubMed, Embase, Web of Science, Cochrane Library, and PsycINFO were searched from inception to 10 July, 2024. Primary outcome included pruritus scores. The secondary outcomes focused on global symptoms and quality of life. Subgroup analyses and meta-regression analyses were conducted based on drug types, sample size, participants' age, and other variables. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system and a trial sequential analysis were employed to establish the reliability of evidence.

RESULTS

A total of 65 eligible publications (including 67 randomized controlled trials) involving 10,704 patients with chronic urticaria were included. The pruritus scores decreased following placebo treatment (moderate evidence). In addition, favorable results were observed in global symptoms (moderate evidence) and quality of life (low evidence) after placebo treatment. Subgroup analyses indicated that the type of active medication in intervention groups was an influencing factor of placebo effect of pruritus. Meta-regression analyses demonstrated that the anti-pruritic effect of placebo was inversely correlated with sample size and positively correlated with participants' age. A trial sequential analysis provided further support for the anti-pruritic effect of placebo.

CONCLUSIONS

A substantial improvement of pruritus after placebo treatment was observed in patients with chronic urticaria. The anti-pruritic effect of placebo varied with sample size, participants' age, and type of active medication used. Future research should further investigate the effect size of placebo and clarify the potential mechanism.

PROSPERO REGISTRATION

The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) as CRD42023482608.

Targeting Bruton's tyrosine kinase (BTK) as a signaling pathway in immune-mediated diseases: from molecular mechanisms to leading treatments

Bruton's tyrosine kinase (BTK), a nonreceptor tyrosine kinase, plays a remarkable role in the transmission and amplification of extracellular signals to intracellular signaling pathways. Various types of cells use the BTK pathway to communicate, including hematopoietic cells particularly B cells and T cells. The BTK pathway plays a role in controlling the proliferation, survival, and functions of B cells as well as other myeloid cells. First, second, and third-generation BTK inhibitors are currently being evaluated for the treatment of immune-mediated diseases in addition to B cell malignancies. In this article, the available evidence on the action mechanisms of BTK inhibitors is reviewed. Then, the most recent data obtained from preclinical studies and ongoing clinical trials for the treatment of autoimmune diseases, such as pemphigus vulgaris, pemphigus foliaceus, bullous pemphigoid, systemic lupus erythematosus, Sjögren's disease, rheumatoid arthritis, systemic sclerosis, multiple sclerosis, myasthenia gravis, and inflammatory diseases such as psoriasis, chronic spontaneous urticaria, atopic dermatitis, and asthma are discussed. In addition, adverse effects and complications associated with BTK inhibitors as well as factors predisposing patients to BTK inhibitors complications are discussed.

The potential of Bruton's tyrosine kinase (BTK) inhibitors in the pharmacotherapeutic management of immune and dermatological disease

INTRODUCTION

The review article explores the evolving role of Bruton's tyrosine kinase (BTK) inhibitors in immune-mediated dermatological conditions, addressing significant gaps in current treatment approaches.

AREAS COVERED

The review comprehensively discusses the mechanisms of action of BTK inhibitors, including irreversible and reversible inhibitors. Clinical applications of BTK inhibitors in dermatological diseases such as pemphigus, chronic spontaneous urticaria (CSU), hidradenitis suppurativa (HS), systemic lupus erythematosus (SLE), and atopic dermatitis are explored, highlighting recent advancements and ongoing clinical trials. Potential advantages of BTK inhibitors over existing therapies and challenges in translating preclinical findings to clinical outcomes are discussed.

EXPERT OPINION/COMMENTARY

BTK inhibitors represent a promising therapeutic avenue for immune-mediated dermatological conditions, offering oral administration, targeted pathway inhibition, and a favorable safety profile compared to biologic therapies. Ongoing research and clinical trials hold the potential to address unmet needs and reshape the therapeutic landscape in dermatology.

Emerging Therapeutics in Chronic Urticaria

Chronic urticaria (CU) is a common and long-lasting mast cell-mediated skin disease associated with psychiatric and autoimmune comorbidities, high economic costs, and considerable impact on quality of life. Available therapies show limited efficacy in many CU patients, which may be related to distinct underlying pathophysiology. Targeted and disease-modifying treatments with higher and broader efficacy are needed and are under development for CU. These novel drugs, small molecules, and monoclonal antibodies target mast cells and their receptors, signaling pathways, or mediators and other immune cells. In this article, the authors focus on the most promising emerging therapeutics in advanced development and discuss their potential place in future management of CU.

Chronic urticaria: unmet needs, emerging drugs, and new perspectives on personalised treatment

Chronic urticaria is a common and debilitating mast cell-driven skin disease presenting with itchy wheals, angio-oedema, or both. Chronic urticaria is classified as spontaneous (without definite triggers) and inducible (with definite and subtype-specific triggers; eg, cold or pressure). Current management guidelines recommend step-up administration of second-generation H1-antihistamines to four-fold the approved dose, followed by omalizumab and ciclosporin. However, in many patients, chronic urticaria does not respond to this linear approach due to heterogeneous underlying mechanisms. A personalised endotype-based approach is emerging based on the identification of autoantibodies and other drivers of urticaria pathogenesis. Over the past decade, clinical trials have presented promising options for targeted treatment of chronic urticaria with the potential for disease modification, including Bruton's tyrosine kinase inhibitors, anti-cytokine therapies, and mast cell depletion. This Therapeutics article focuses on the evidence for these novel drugs and their role in addressing an unmet need for personalised management of patients with chronic urticaria.

Bruton's tyrosine kinase inhibition for the treatment of allergic disorders

IgE signaling through its high-affinity receptor FcεRI is central to the pathogenesis of numerous allergic disorders. Oral inhibitors of Bruton's tyrosine kinase (BTKis), which are currently Food and Drug Administration-approved for treating B cell malignancies, broadly inhibit the FcεRI pathway in human mast cells and basophils, and therefore may be effective allergen-independent therapies for a variety of allergic diseases. The application of these drugs to the allergy space was previously limited by the low kinase selectivity and subsequent toxicities of early-generation compounds. Fortunately, next-generation, highly selective BTKis in clinical development appear to have more favorable risk-benefit profiles, and their likelihood of being Food and Drug Administration-approved for an allergy indication is increasing. Recent clinical trials have indicated the remarkable and rapid efficacy of the second-generation BTKi acalabrutinib in preventing clinical reactivity to peanut ingestion in adults with peanut allergy. In addition, next-generation BTKis including remibrutinib effectively reduce disease activity in patients with antihistamine-refractory chronic spontaneous urticaria. Finally, several BTKis are currently under investigation in early clinical trials for atopic dermatitis and asthma. In this review, we summarize recent data supporting the use of these drugs as novel therapies in food allergy, anaphylaxis, urticaria, and other allergic disorders. We also discuss safety data derived from trials using both short-term and chronic dosing of BTKis.

Spinal histamine H4 receptor mediates chronic pruritus via p-ERK in acetone-ether-water (AEW)-induced dry skin mice

Dry skin is common to many pruritic diseases and is difficult to improve with oral traditional antihistamines. Recently, increasing evidence indicated that histamine H4 receptor (H4R) plays an important role in the occurrence and development of pruritus. Extracellular signal-regulated kinase (ERK) phosphorylation activation in the spinal cord mediates histamine-induced acute and choric itch. However, whether the histamine H4 receptor regulates ERK activation in the dry skin itch remains unclear. In the study, we explore the role of the histamine H4 receptor and p-ERK in the spinal cord in a dry skin mouse model induced by acetone-ether-water (AEW). q-PCR, Western blot, pharmacology and immunofluorescence  were applied in the study. We established a dry skin itch model by repeated application of AEW on the nape of neck in mice. The AEW mice showed typically dry skin histological change and persistent spontaneous scratching behaviour. Histamine H4 receptor, instead of histamine H1 receptor, mediated spontaneous scratching behaviour in AEW mice. Moreover, c-Fos and p-ERK expression in the spinal cord neurons were increased and co-labelled with GRPR-positive neurons in AEW mice. Furthermore, H4R agonist 4-methyhistamine dihydrochloride (4-MH)induced itch. Both 4-MH-induced itch and the spontaneous itch in AEW mice were blocked by p-ERK inhibitor U0126. Finally, intrathecal H4R receptor antagonist JNJ7777120 inhibited spinal p-ERK expression in AEW mice. Our results indicated that spinal H4R mediates itch via ERK activation in the AEW-induced dry skin mice.

Molecular docking based comparative study of antiviral compounds on SARS-CoV-2 spike protein

The urgent need for effective therapeutic interventions against SARS-CoV-2 has prompted extensive exploration of potential drug candidates. Among the viral proteins, the spike (S) protein presents an attractive target due to its critical role in viral entry and infection. In this study, we employed molecular docking techniques to investigate the binding affinities and interaction profiles of a panel of active compounds against the SARS-CoV-2 spike protein. Utilising computational simulations, we assessed the binding properties of these compounds within the receptor-binding domain (RBD) and other key regions of the spike protein. Our comparative analysis elucidates the differential binding patterns and identifies promising lead compounds with high binding affinity and favourable interaction profiles. Furthermore, we discuss the implications of these findings for the development of potential therapeutics targeting the SARS-CoV-2 spike protein. Using molecular docking and the Lipinski five rule, this study illustrates possible compounds with strong binding affinities, their molecular interactions, for both naturally occurring and man-made drugs. Computational approach is applied, and it is concluded that, drugs like Withanolide, Dihydroergocristine, Fenebrutinib, and Ergotamine shows binding energies between -8.3 and -9.1 kcal/mol, and are possible candidate for anti covid drug.

BTK signaling-a crucial link in the pathophysiology of chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is an inflammatory skin disorder that manifests with itchy wheals, angioedema, or both for more than 6 weeks. Mast cells and basophils are the key pathogenic drivers of CSU; their activation results in histamine and cytokine release with subsequent dermal inflammation. Two overlapping mechanisms of mast cell and basophil activation have been proposed in CSU: type I autoimmunity, also called autoallergy, which is mediated via IgE against various autoallergens, and type IIb autoimmunity, which is mediated predominantly via IgG directed against the IgE receptor FcεRI or FcεRI-bound IgE. Both mechanisms involve cross-linking of FcεRI and activation of downstream signaling pathways, and they may co-occur in the same patient. In addition, B-cell receptor signaling has been postulated to play a key role in CSU by generating autoreactive B cells and autoantibody production. A cornerstone of FcεRI and B-cell receptor signaling is Bruton tyrosine kinase (BTK), making BTK inhibition a clear therapeutic target in CSU. The potential application of early-generation BTK inhibitors, including ibrutinib, in allergic and autoimmune diseases is limited owing to their unfavorable benefit-risk profile. However, novel BTK inhibitors with improved selectivity and safety profiles have been developed and are under clinical investigation in autoimmune diseases, including CSU. In phase 2 trials, the BTK inhibitors remibrutinib and fenebrutinib have demonstrated rapid and sustained improvements in CSU disease activity. With phase 3 studies of remibrutinib ongoing, it is hoped that BTK inhibitors will present an effective, well-tolerated option for patients with antihistamine-refractory CSU, a phenotype that presents a considerable clinical challenge.

Mapping the intellectual structure of the research of omalizumab in chronic spontaneous urticaria: A bibliometric analysis

Background

The guidelines for treating chronic spontaneous urticaria (CSU) recommend using the IgE-targeted biologic omalizumab in patients with antihistamine-refractory disease.

Objective

Our aim was to present a bibliometric review of publications related to omalizumab and CSU over the past 2 decades.

Methods

Relevant publications from 2003 to 2022 were extracted from the Science Citation Index-Expanded (SCI-EXPANDED) database in the Web of Science Core Collection database as of January 8, 2023. We utilized CiteSpace (version 6.1.R3), VOSviewer (version 1.6.18), and the R package (version 4.2.1) to analyze and visualize the data. The R package bibliometrix (version 4.2.1) was also used.

Results

Between 2003 and 2022, a total of 566 articles on omalizumab and CSU were published. Since 2014, there has been a rapid increase in publication output. According to the collaboration network, the most influential country, institute, and scholar were the United States, Charité Universitätsmedizin Berlin, and Marcus Maurer, respectively. The study identified the Journal of Allergy and Clinical Immunology: In Practice as the most productive journal and the Journal of Allergy and Clinical Immunology as the most cocited journal. The analysis of key words revealed the presence of high-frequency terms such as angioedema, IgE, treatment, anti-IgE, asthma, and atopic dermatitis. Moreover, recent studies in this area have concentrated mainly on biomarkers, dupilumab, and coronavirus 2019 (COVID-19).

Conclusion

There has been a growing interest in the use of omalizumab in CSU in recent years. The current trending topics in this research are the identification of biomarkers and the development of new mAbs for the treatment of CSU.

A review of Bruton's tyrosine kinase inhibitors in multiple sclerosis

Bruton's tyrosine kinase (BTK) inhibitors are an emerging class of therapeutics in multiple sclerosis (MS). BTK is expressed in B-cells and myeloid cells, key progenitors of which include dendritic cells, microglia and macrophages, integral effectors of MS pathogenesis, along with mast cells, establishing the relevance of BTK inhibitors to diverse autoimmune conditions. First-generation BTK inhibitors are currently utilized in the treatment of B-cell malignancies and show efficacy in B-cell modulation. B-cell depleting therapies have shown success as disease-modifying treatments (DMTs) in MS, highlighting the potential of BTK inhibitors for this indication; however, first-generation BTK inhibitors exhibit a challenging safety profile that is unsuitable for chronic use, as required for MS DMTs. A second generation of highly selective BTK inhibitors has shown efficacy in modulating MS-relevant mechanisms of pathogenesis in preclinical as well as clinical studies. Six of these BTK inhibitors are undergoing clinical development for MS, three of which are also under investigation for chronic spontaneous urticaria (CSU), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Phase II trials of selected BTK inhibitors for MS showed reductions in new gadolinium-enhancing lesions on magnetic resonance imaging scans; however, the safety profile is yet to be ascertained in chronic use. Understanding of the safety profile is developing by combining safety insights from the ongoing phase II and III trials of second-generation BTK inhibitors for MS, CSU, RA and SLE. This narrative review investigates the potential of BTK inhibitors as an MS DMT, the improved selectivity of second-generation inhibitors, comparative safety insights established thus far through clinical development programmes and proposed implications in female reproductive health and in long-term administration.

Mast cell silencing: A novel therapeutic approach for urticaria and other mast cell-mediated diseases

Chronic urticaria (CU) is a mast cell (MC)-dependent disease with limited therapeutic options. Current management strategies are directed at inhibiting IgE-mediated activation of MCs and antagonizing effects of released mediators. Due to the complexity and heterogeneity of CU and other MC diseases and mechanisms of MC activation-including multiple activating receptors and ligands, diverse signaling pathways, and a menagerie of mediators-strategies of MC depletion or MC silencing (i.e., inhibition of MC activation via binding of inhibitory receptors) have been developed to overcome limitations of singularly targeted agents. MC silencers, such as agonist monoclonal antibodies that engage inhibitory receptors (e.g., sialic acid-binding immunoglobulin-like lectin8 -[Siglec-8] [lirentelimab/AK002], Siglec-6 [AK006], and CD200R [LY3454738]), have reached preclinical and clinical stages of development. In this review, we (1) describe the role of MCs in the pathogenesis of CU, highlighting similarities with other MC diseases in disease mechanisms and response to treatment; (2) explore current therapeutic strategies, categorized by nonspecific immunosuppression, targeted inhibition of MC activation or mediators, and targeted modulation of MC activity; and (3) introduce the concept of MC silencing as an emerging strategy that could selectively block activation of MCs without eliciting or exacerbating on- or off-target, immunosuppressive adverse effects.

Applications of oxetanes in drug discovery and medicinal chemistry

The compact and versatile oxetane motifs have gained significant attention in drug discovery and medicinal chemistry campaigns. This review presents an overview of the diverse applications of oxetanes in clinical and preclinical drug candidates targeting various human diseases, including cancer, viral infections, autoimmune disorders, neurodegenerative conditions, metabolic disorders, and others. Special attention is given to biologically active oxetane-containing compounds and their disease-related targets, such as kinases, epigenetic and non-epigenetic enzymes, and receptors. The review also details the effect of the oxetane motif on important properties, including aqueous solubility, lipophilicity, pKa, P-glycoprotein (P-gp) efflux, metabolic stability, conformational preferences, toxicity profiles (e.g., cytochrome P450 (CYP) suppression and human ether-a-go-go related gene (hERG) inhibition), pharmacokinetic (PK) properties, potency, and target selectivity. We anticipate that this work will provide valuable insights that can drive future discoveries of novel bioactive oxetane-containing small molecules, enabling their effective application in combating a wide range of human diseases.

The 7-day recall period version of the Urticaria Control Test-UCT7

BACKGROUND

The Urticaria Control Test (UCT) is a well-established, very easy to use and calculate 4-item patient-reported outcome measure to assess chronic urticaria disease control during the previous 4 weeks. Clinical trials and practice may benefit from the use of a UCT version with a shorter recall period, but this does not exist.

OBJECTIVES

We sought to develop and validate a UCT version with a 7-day recall period, the UCT7.

METHODS

The UCT7 was developed, based on the UCT, and tested, in 152 patients with chronic urticaria (spontaneous: n = 101, inducible: n = 51) for its reliability, validity and screening accuracy, and clinimetric properties, in other words, the cutoff for well-controlled disease and the minimal clinically important difference.

RESULTS

The UCT7 showed excellent internal consistency reliability with a Cronbach αvalue of 0.91 and test-retest reliability with an intraclass correlation coefficient of 0.83. Convergent validity was high and strongly correlated with anchors of disease control, wheal and angioedema frequency, and urticaria-related quality of life impairment. The UCT7 showed excellent sensitivity to change; however, changes in angioedema activity and impact did not correlate well with changes in UCT7. Based on receiver-operating characteristic curve analysis, the proportion of correctly classified patients, and patients' assessment of treatment efficacy, we recommend a cutoff value of 12 points for identifying patients with well-controlled disease. The UCT7 minimal clinically important difference for improvement was estimated to be 2 points.

CONCLUSIONS

The UCT7 is a validated 7-day recall period version of the UCT. It is ideal for the assessment of disease control at short intervals in patients with chronic urticaria in clinical studies and practice.

Evidence-based use of antihistamines for treatment of allergic conditions

Available since the 1940s, H1 antihistamines are mainstay treatments for allergic conditions such as allergic rhinitis and urticaria. They function as inverse agonists that bind to the H1 receptor to inhibit histamine-induced inflammation. The older, first-generation drugs are no longer recommended for patient use because of their well-documented negative adverse effect profile. Evidence has been accumulating to support a newer generation of H1 antihistamines in oral and intranasal formulations, including in combination with intranasal corticosteroids. The literature is replete with large meta-analyses and systematic reviews establishing the safety and efficacy of second-generation H1 antihistamines in adult and pediatric allergic rhinitis populations, including combination nasal spray agents (eg, MP29-02 or MP-AzeFlu). Although intraclass differences do exist, patient preference, access, and costs should be the priority. Robust data on the regular, not as needed use of H1 antihistamines for urticaria have been published, including in the management of children and pregnant or lactating women. In addition, H1 antihistamines can be used in other related allergic conditions, such as the secondary symptoms of anaphylaxis, to provide patients with greater comfort, including in allergic asthma, depending on the individual.

Chronic spontaneous urticaria: new evidences on the role of autoimmunity

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of the recent advancements and relevance of the autoimmune theories in chronic spontaneous urticaria (CSU).

RECENT FINDINGS

Two primary types of autoimmunity, Type I and Type IIb, have emerged as major contributors to CSU, characterized by immunoglobulin E (IgE) and immunoglobulin G (IgG) autoantibodies, respectively. Genetic evidence supports the notion that CSU shares more similarities with other autoimmune diseases rather than atopic diseases. Novel autoallergens such as FcεRI and tissue transglutaminase have been identified, contributed to our understanding of autoimmune mechanisms. Furthermore, the potential overlap between Type I and Type IIb autoimmunity has been recognized. Evaluating the autoimmune status of CSU patients through biomarkers and understanding their clinical implications is vital for effective management. For instance, CSU patients with Type IIb autoimmunity, with or without coexisting Type I autoimmunity, may exhibit resistance to H1-antihistamines and omalizumab treatment but could potentially respond well to cyclosporine or Bruton's tyrosine kinase inhibitors.

SUMMARY

Further investigations are needed to explore new autoallergens and autoantibodies in CSU, establishing their connection to the development of autoimmunity. The efficacy of novel drugs targeting different mechanisms should be examined to determine their responses in both autoimmune CSU and nonautoimmunity-related CSU.

Type 2 chronic inflammatory diseases: targets, therapies and unmet needs

Over the past two decades, significant progress in understanding of the pathogenesis of type 2 chronic inflammatory diseases has enabled the identification of compounds for more than 20 novel targets, which are approved or at various stages of development, finally facilitating a more targeted approach for the treatment of these disorders. Most of these newly identified pathogenic drivers of type 2 inflammation and their corresponding treatments are related to mast cells, eosinophils, T cells, B cells, epithelial cells and sensory nerves. Epithelial barrier defects and dysbiotic microbiomes represent exciting future drug targets for chronic type 2 inflammatory conditions. Here, we review common targets, current treatments and emerging therapies for the treatment of five major type 2 chronic inflammatory diseases - atopic dermatitis, chronic prurigo, chronic urticaria, asthma and chronic rhinosinusitis with nasal polyps - with a high need for targeted therapies. Unmet needs and future directions in the field are discussed.

Siglecs as potential targets of therapy in human mast cell- and/or eosinophil-associated diseases

Siglecs (sialic acid-binding immunoglobulin-like lectins) are a family of vertebrate glycan-binding cell-surface proteins. The majority mediate cellular inhibitory activity once engaged by specific ligands or ligand-mimicking molecules. As a result, Siglec engagement is now of interest as a strategy to therapeutically dampen unwanted cellular responses. When considering allergic inflammation, human eosinophils and mast cells express overlapping but distinct patterns of Siglecs. For example, Siglec-6 is selectively and prominently expressed on mast cells while Siglec-8 is highly specific for both eosinophils and mast cells. This review will focus on a subset of Siglecs and their various endogenous or synthetic sialoside ligands that regulate eosinophil and mast cell function and survival. It will also summarize how certain Siglecs have become the focus of novel therapies for allergic and other eosinophil- and mast cell-related diseases.

Pleckstrin Homology [PH] domain, structure, mechanism, and contribution to human disease

The pleckstrin homology [PH] domain is a structural fold found in more than 250 proteins making it the 11th most common domain in the human proteome. 25% of family members have more than one PH domain and some PH domains are split by one, or several other, protein domains although still folding to give functioning PH domains. We review mechanisms of PH domain activity, the role PH domain mutation plays in human disease including cancer, hyperproliferation, neurodegeneration, inflammation, and infection, and discuss pharmacotherapeutic approaches to regulate PH domain activity for the treatment of human disease. Almost half PH domain family members bind phosphatidylinositols [PIs] that attach the host protein to cell membranes where they interact with other membrane proteins to give signaling complexes or cytoskeleton scaffold platforms. A PH domain in its native state may fold over other protein domains thereby preventing substrate access to a catalytic site or binding with other proteins. The resulting autoinhibition can be released by PI binding to the PH domain, or by protein phosphorylation thus providing fine tuning of the cellular control of PH domain protein activity. For many years the PH domain was thought to be undruggable until high-resolution structures of human PH domains allowed structure-based design of novel inhibitors that selectively bind the PH domain. Allosteric inhibitors of the Akt1 PH domain have already been tested in cancer patients and for proteus syndrome, with several other PH domain inhibitors in preclinical development for treatment of other human diseases.

Remibrutinib (LOU064) inhibits neuroinflammation driven by B cells and myeloid cells in preclinical models of multiple sclerosis

BACKGROUND

Bruton's tyrosine kinase (BTK) is a key signaling node in B cell receptor (BCR) and Fc receptor (FcR) signaling. BTK inhibitors (BTKi) are an emerging oral treatment option for patients suffering from multiple sclerosis (MS). Remibrutinib (LOU064) is a potent, highly selective covalent BTKi with a promising preclinical and clinical profile for MS and other autoimmune or autoallergic indications.

METHODS

The efficacy and mechanism of action of remibrutinib was assessed in two different experimental autoimmune encephalomyelitis (EAE) mouse models for MS. The impact of remibrutinib on B cell-driven EAE pathology was determined after immunization with human myelin oligodendrocyte glycoprotein (HuMOG). The efficacy on myeloid cell and microglia driven neuroinflammation was determined in the RatMOG EAE. In addition, we assessed the relationship of efficacy to BTK occupancy in tissue, ex vivo T cell response, as well as single cell RNA-sequencing (scRNA-seq) in brain and spinal cord tissue.

RESULTS

Remibrutinib inhibited B cell-dependent HuMOG EAE in dose-dependent manner and strongly reduced neurological symptoms. At the efficacious oral dose of 30 mg/kg, remibrutinib showed strong BTK occupancy in the peripheral immune organs and in the brain of EAE mice. Ex vivo MOG-specific T cell recall response was reduced, but not polyclonal T cell response, indicating absence of non-specific T cell inhibition. Remibrutinib also inhibited RatMOG EAE, suggesting that myeloid cell and microglia inhibition contribute to its efficacy in EAE. Remibrutinib did not reduce B cells, total Ig levels nor MOG-specific antibody response. In brain and spinal cord tissue a clear anti-inflammatory effect in microglia was detected by scRNA-seq. Finally, remibrutinib showed potent inhibition of in vitro immune complex-driven inflammatory response in human microglia.

CONCLUSION

Remibrutinib inhibited EAE models by a two-pronged mechanism based on inhibition of pathogenic B cell autoreactivity, as well as direct anti-inflammatory effects in microglia. Remibrutinib showed efficacy in both models in absence of direct B cell depletion, broad T cell inhibition or reduction of total Ig levels. These findings support the view that remibrutinib may represent a novel treatment option for patients with MS.

Research Advances in Mast Cell Biology and Their Translation Into Novel Therapies for Anaphylaxis

Anaphylaxis is an acute, potentially life-threatening systemic allergic reaction for which there are no known reliable preventative therapies. Its primary cell mediator, the mast cell, has several pathophysiologic roles and functions in IgE-mediated reactions that continue to be poorly understood. Recent advances in the understanding of allergic mechanisms have identified novel targets for inhibiting mast cell function and activation. The prevention of anaphylaxis is within reach with new drugs that could modulate immune tolerance, mast cell proliferation and differentiation, and IgE regulation and production. Several US Food and Drug Administration-approved drugs for chronic urticaria, mastocytosis, and cancer are also being repurposed to prevent anaphylaxis. New therapeutics have not only shown promise in potential efficacy for preventing IgE-mediated reactions, but in some cases, they are able to inform us about mast cell mechanisms in vivo. This review summarizes the most recent advances in the treatment of anaphylaxis that have arisen from new pharmacologic tools and our current understanding of mast cell biology.

Current and Emerging Therapies for Chronic Spontaneous Urticaria: A Narrative Review

Chronic spontaneous urticaria (CSU) is a condition in which wheals, angioedema, and pruritus occur spontaneously and recurrently for at least 6 weeks. The etiology of this disease is partially dependent on production of autoantibodies that activate and recruit inflammatory cells. Although the wheals can resolve within 24 h, symptoms have a significant detrimental impact on the quality of life of these patients. Standard therapy for CSU includes second-generation antihistamines and omalizumab. However, many patients tend to be refractory to these therapies. Available treatments such as cyclosporine, dapsone, dupilumab, and tumor necrosis factor alpha (TNFa) inhibitors have been used with success in some cases. Furthermore, various biologics and other novel drugs have emerged as potential treatments for this condition, and many more are currently under investigation in randomized clinical trials.

Chronic Spontaneous Urticaria: How to Measure It and the Need to Define Treatment Success

Chronic spontaneous urticaria (CSU) is a complex skin disease characterized by the spontaneous appearance of wheals, angioedema, or both, for more than 6 weeks. Many patients experience a relapsing-remitting disease course for years. Owing to the unpredictability of wheal recurrence and the severity of pruritis, patients suffer considerable impairment in their quality of life. Physicians face multiple challenges, not least of which is a lack of clear guidance on what constitutes "treatment success". There is a lack of awareness of which measures should be used to best assess the various aspects of CSU, including disease activity, disease control, and quality of life-which themselves each comprise multiple components-and how to apply the results of each score to treatment decision-making. Although the overarching aim of treatment is for patients to be completely free of signs and symptoms of CSU, a more realistic definition of "treatment success" is needed to guide ongoing, long-term disease management for each individual patient. In this review, we consider what lessons can be learned from the current evidence base to provide further direction toward a universal definition of "treatment success".

Aiming to IgE: Drug development in allergic diseases

The incidence of allergic disease significantly increases in recent decades, causing it become a major public health problem all over the world. The common allergic diseases such as allergic dermatitis, allergy rhinitis, allergic asthma and food allergy are mediated, at least in part, by immunoglobulin E (IgE), and so IgE acts as a central role in allergic diseases. IgE can interact with its high-affinity receptor (FcεRⅠ) which is primarily expressed on tissue-resident mast cells and circulating basophils, initiating intracellular signal transduction and then causing the activation and degranulation of mast cells and basophils. On the other hand, IgE interaction with its low-affinity receptor (CD23), can regulate various IgE-mediated immune responses including IgE-allergen complex presentation, IgE synthesis, the growth and differentiation of both B and T cells, and the secretion of pro-inflammatory mediators. With the deeper mechanism research for allergic diseases, new therapeutic strategies for interfering IgE are developed and receive a great attention. In this review, we summarize a current profile of therapeutic strategies for interfering IgE in allergic diseases. Besides, we suggest that targeting memory B cells (including long-lived plasma cells and (or) IgE⁺ memory B cells) may help to completely control allergic diseases, and highlight that the development of drugs synergistically aiming to multiple targets can be a better choice for improving treatment efficacy which results from allergic diseases as the systemic disorders caused by an impaired immune system.

Bruton's Tyrosine Kinase Inhibitors (BTKIs): Review of Preclinical Studies and Evaluation of Clinical Trials

In the last few decades, there has been a growing interest in Bruton's tyrosine kinase (BTK) and the compounds that target it. BTK is a downstream mediator of the B-cell receptor (BCR) signaling pathway and affects B-cell proliferation and differentiation. Evidence demonstrating the expression of BTK on the majority of hematological cells has led to the hypothesis that BTK inhibitors (BTKIs) such as ibrutinib can be an effective treatment for leukemias and lymphomas. However, a growing body of experimental and clinical data has demonstrated the significance of BTK, not just in B-cell malignancies, but also in solid tumors, such as breast, ovarian, colorectal, and prostate cancers. In addition, enhanced BTK activity is correlated with autoimmune disease. This gave rise to the hypothesis that BTK inhibitors can be beneficial in the therapy of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), Sjögren's syndrome (SS), allergies, and asthma. In this review article, we summarize the most recent findings regarding this kinase as well as the most advanced BTK inhibitors that have been developed to date and their clinical applications mainly in cancer and chronic inflammatory disease patients.

Consecutive injections of low-dose interleukin-2 improve symptoms and disease control in patients with chronic spontaneous urticaria

PURPOSE

To describe the effectiveness and tolerability of low-dose interleukin (IL)-2 in treating patients with chronic spontaneous urticaria (CSU) refractory to H₁-antihistamines.

METHODS

This retrospective study included CSU patients who received treatment with at least one cycle of IL-2, injected intramuscularly at a dose of 1.0 million international units daily for 7 consecutive days, after failing treatment with H₁-antihistamines. Patients were followed up for ≥12 weeks.

RESULTS

Of the 15 patients, 7 (46.7%) and 11 (73.3%) achieved complete response at Week 2 and Week 12, respectively. The mean change of urticaria control test (UCT) and weekly urticaria activity score (UAS7) from baseline was 6.6 (95% CI, 4.2 to 8.9) and - 16.9 (95% CI, -24.0 to -9.8), respectively, at Week 12. Local injection-site reactions were the most common adverse events. No serious adverse events were reported.

CONCLUSION

Low-dose IL-2 treatment improves symptoms and disease control for CSU patients refractory to H₁-antihistamines.

Drug delivery targets and strategies to address mast cell diseases

INTRODUCTION

Current and developing mast cell therapeutics are reliant on small molecule drugs and biologics, but few are truly selective for mast cells. Most have cellular and disease-specific limitations that require innovation to overcome longstanding challenges to selectively targeting and modulating mast cell behavior. This review is designed to serve as a frame of reference for new approaches that utilize nanotechnology or combine different drugs to increase mast cell selectivity and therapeutic efficacy.

AREAS COVERED

Mast cell diseases include allergy and related conditions as well as malignancies. Here, we discuss the targets of existing and developing therapies used to treat these disease pathologies, classifying them into cell surface, intracellular, and extracellular categories. For each target discussed, we discuss drugs that are either the current standard of care, under development, or have indications for potential use. Finally, we discuss how novel technologies and tools can be used to take existing therapeutics to a new level of selectivity and potency against mast cells.

EXPERT OPINION

There are many broadly and very few selectively targeted therapeutics for mast cells in allergy and malignant disease. Combining existing targeting strategies with technology like nanoparticles will provide novel platforms to treat mast cell disease more selectively.

Chronic spontaneous urticaria: Focus on pathophysiology to unlock treatment advances

Chronic spontaneous urticaria (CSU) is a debilitating skin disease characterized by intensely itchy wheals, angioedema, or both. Symptoms recur spontaneously, on a near-daily basis, over >6 weeks; many patients experience flare-ups over several years and, consequently, reduced quality of life. Differences between the inflammatory profiles of the skin of CSU patients (wheals and nonlesional sites) and healthy controls indicate that key drivers such as mast cells, eosinophils, and basophils interact, release vasoactive mediators, and prime the skin, leaving patients predisposed to symptoms. Many cytokines and chemokines involved in these inflammatory networks and their corresponding intracellular signaling cascades have been identified. These insights informed the development of therapies such as omalizumab, dupilumab, and Bruton's tyrosine kinase (BTK) inhibitors, marking a renewed focus on pathogenesis in CSU clinical research. Despite progress, current therapies provide symptomatic control but do not appear to redress the inflammatory balance in the skin permanently. A deeper understanding of CSU pathogenesis will permit a more targeted approach to developing novel treatments with curative intent. Here, we review what is known about the pathogenesis of CSU and consider how this can be used to identify rational targets to improve patient care further.

Discovery of structural diverse reversible BTK inhibitors utilized to develop a novel in vivo CD69 and CD86 PK/PD mouse model

For the past two decades, BTK a tyrosine kinase and member of the Tec family has been a drug target of significant interest due to its potential to selectively treat various B cell-mediated diseases such as CLL, MCL, RA, and MS. Owning to the challenges encountered in identifying drug candidates exhibiting the potency block B cell activation via BTK inhibition, the pharmaceutical industry has relied on the use of covalent/irreversible inhibitors to address this unmet medical need. Herein, we describe a medicinal chemistry campaign to identify structurally diverse reversible BTK inhibitors originating from HITS identified using a fragment base screen. The leads were optimized to improve the potency and in vivo ADME properties resulting in a structurally distinct chemical series used to develop and validate a novel in vivo CD69 and CD86 PD assay in rodents.

Repurposing MS immunotherapies for CIDP and other autoimmune neuropathies: unfulfilled promise or efficient strategy?

Despite advances in the treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and other common autoimmune neuropathies (AN), still-many patients with these diseases do not respond satisfactorily to the available treatments. Repurposing of disease-modifying therapies (DMTs) from other autoimmune conditions, particularly multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), is a promising strategy that may accelerate the establishment of novel treatment choices for AN. This approach appears attractive due to homologies in the pathogenesis of these diseases and the extensive post-marketing experience that has been gathered from treating MS and NMOSD patients. The idea is also strengthened by a number of studies that explored the efficacy of DMTs in animal models of AN but also in some CIDP patients. We here review the available preclinical and clinical data of approved MS therapeutics in terms of their applicability to AN, especially CIDP. Promising therapeutic approaches appear to be B cell-directed and complement-targeting strategies, such as anti-CD20/anti-CD19 agents, Bruton's tyrosine kinase inhibitors and anti-C5 agents, as they exert their effects in the periphery. This is a major advantage because, in contrast to MS, their action in the periphery is sufficient to exert significant immunomodulation.

Anaphylaxis: Advances in the Past 10 Years

In the past 10 years, anaphylaxis has grown into its own special area of study within Allergy-Immunology, both at the bench and at the bedside. This review focuses on some of the most clinically relevant advances over the past decade. These include simplified and more inclusive diagnostic criteria for adults and children, uniform definition of biphasic anaphylaxis, and improved systems for objective severity grading. Studies reported in the past decade have led to improved understanding of normal and abnormal regulation of mast cell function, translating into better diagnostic and therapeutic approaches to patients with anaphylaxis. Research has provided improved recognition and treatment of mast cell disorders and has identified a new condition, hereditary α-tryptasemia, that may impact anaphylactic syndromes. We have learned to recognize new causes (α-gal), new pathways (Mas-related G protein-coupled receptor-X2), and many risk factors for severe anaphylaxis. The stability of epinephrine in autoinjectors was reported to be very good for several years after the labeled expiry date, and it can tolerate freezing and thawing. Repeated and prolonged exposure to excessive heat leads to degradation of epinephrine activity. New treatments to prevent severe anaphylaxis have been described, using new ways to block the IgE receptor or modulate intracellular signaling pathways.

Acupuncture combined with pricking and cupping therapy is effective in patients with chronic spontaneous urticaria

OBJECTIVE

To determine the effects of acupuncture combined with pricking and cupping therapy on the balance of Th1/Th2 cytokines in patients with chronic spontaneous urticaria (CSU).

METHODS

The medical records of 75 patients with CSU treated in The First Affiliated Hospital of Hebei College of Traditional Chinese Medicine from January 10, 2021 to January 10, 2022 were collected and analyzed retrospectively. Among them, 35 patients treated with traditional therapy were assigned to a control group, and 40 patients treated with acupuncture combined with pricking and cupping therapy to an observation group. The clinical efficacy and adverse reactions in the two groups were compared after therapy. The two groups were also compared in terms of the levels of immunoglobulin (Ig)-E, interleukin (IL)-4 and interferon-γ (INF-γ) before and after therapy. In addition, the visual analogue scale (VAS) for pruritus was adopted for recording the pruritus degree of patients before and after therapy. The Dermatology Quality of Life Index (DLQI) was adopted to compare the quality of life between the two groups before and after therapy. The Hamilton anxiety scale (HAMA) and Hamilton depression rating scale (HAMD) were adopted for comparison of the anxiety and depression between the two groups before and after therapy. Moreover, the Pittsburgh sleep quality index (PSQI) was used to compare sleep quality between the two groups before and after therapy.

RESULTS

The control group showed a significantly lower total response rate than the observation group (P<0.05). Compared with the control group, the observation group showed significantly lower levels of IgE and IL-4, and a higher IFN-γ level and had significantly lower pruritus-VAS, DLQI, HAMA, HAMD and PSQI scores (P<0.05). Additionally, the two groups were not greatly different in adverse reactions (nausea, sleepiness, ecchymosis and dizziness) (P>0.05).

CONCLUSION

Acupuncture combined with pricking and cupping therapy is highly effective in CSU, because it can significantly alleviate the symptoms as well as negative emotions, and improve the quality of life, sleep quality and the balance of Th1/Th2 cytokine in patients.

Unveiling chronic spontaneous urticaria pathophysiology through systems biology

BACKGROUND

Chronic spontaneous urticaria (CSU) is a rare, heterogeneous, severely debilitating, and often poorly controlled skin disease resulting in an itchy eruption that can be persistent. Antihistamines and omalizumab, an anti-IgE mAb, are the only licensed therapies. Although CSU pathogenesis is not yet fully understood, mast cell activation through the IgE:high-affinity IgE receptor (FcεRI) axis appears central to the disease process.

OBJECTIVE

We sought to model CSU pathophysiology and identify in silico the mechanism of action of different CSU therapeutic strategies currently in use or under development.

METHODS

Therapeutic performance mapping system technology, based on systems biology and machine learning, was used to create a CSU interactome validated with gene expression data from patients with CSU and a CSU model that was used to evaluate CSU pathophysiology and the mechanism of action of different therapeutic strategies.

RESULTS

Our models reflect the known role of mast cell activation as a central process of CSU pathophysiology, as well as recognized roles for different therapeutic strategies in this and other innate and adaptive immune processes. They also allow determining similarities and differences between them; anti-IgE and Bruton tyrosine kinase inhibitors play a more direct role in mast cell biology through abrogation of FcεRI signaling activity, whereas anti-interleukins and anti-Siglec-8 have a role in adaptive immunity modulation.

CONCLUSION

In silico CSU models reproduced known CSU and therapeutic strategies features. Our results could help advance understanding of therapeutic mechanisms of action and further advance treatment research by patient profile.

Biologicals in Treatment of Chronic Urticaria: A Narrative Review

Chronic urticaria is a common inflammatory skin disease affecting around 0.5-1% of the world's population. The disease has a chronic indolent course which significantly affects the patient's quality of life. Urticaria pathogenesis involves cross-linking of immunoglobulin E (IgE) on mast cells causing degranulation which occurs by various pathways which leads to development of wheals and angioedema. The first-line treatment for chronic urticaria is non-sedating second-generation H1 antihistamines (AHs). After the advent of anti-IgE monoclonal antibody omalizumab, the response rate in resistant urticaria has improved significantly without any major adverse events. Other biologicals such as anti-IgE, anti-IL-5, anti-IL-1, anti-IL-17, and anti-CD20 monoclonal antibodies are under trial. These biologicals have better efficacy and safety profile as compared to conventional immunosuppressants. Even with the advances in the last decade, recurrence after stopping the therapy is common, and there is a need for better understanding of the pathogenesis and the drugs acting on the key pathways involved in urticaria. In this review, we provide the role of several biologicals in the treatment of chronic urticaria.

Biologics for chronic spontaneous urticaria: toward a personalized treatment

INTRODUCTION

Chronic spontaneous urticaria (CSU) is characterized by the recurrent occurrence of short-lived wheals with or without angioedema for more than 6 weeks. Although its pathogenesis is not completely defined, several mechanisms seem involved, including autoimmunity and autoallergy with complement and coagulation activation. Various biologics are currently available or under investigation to counteract different CSU pathomechanisms.

AREAS COVERED

The recent literature dealing with biologics in the treatment of CSU was screened and analyzed; the different treatments were divided into anti-IgE and other than anti-IgE biologics. The latter were subdivided according to their target mechanisms.

EXPERT OPINION

Biologic drugs exert their effects in a very precise and specific manner. A majority of patients (arguably those with type I disease) respond to anti-IgE treatment. Others, possibly with type IIa disease, show a slow response to anti-IgE drugs. Things are much more complicated in anti-IgE-refractory patients. Some respond well to nonspecific immune suppressors, such as corticosteroids and cyclosporin suggesting that an immune-mediated pathogenic mechanism, not involving the high-affinity IgE receptor, is probably active. Several ongoing studies are evaluating biologics and small molecules counteracting other pathomechanisms, including anti-receptor biologics, Bruton tyrosine kinase (BTK) inhibitors, mast cell targets, and specific cytokines.

Existing and Investigational Medications for Refractory Chronic Spontaneous Urticaria: Safety, Adverse Effects, and Monitoring

Treatment of chronic spontaneous urticaria (CSU) is responsive to H1 antihistamines administered up to four times the recommended US Food and Drug Administration dose in approximately 50% of patients. However, when patients do not respond to these first-line agents, evidence-based guidelines using Grading of Recommendations, Assessment, Development, and Evaluations methodology have provided direction for second- and third-line treatments that can effectively treat patients with CSU. Some patients remain refractory to these advanced treatments; therefore, alternative treatments with a lower certainty of evidence may be necessary. Regardless of the therapies used to treat CSU patients, it is essential for clinicians to be knowledgeable about the mechanism of action, efficacy, and safety and monitoring recommendations of the treatments prescribed. This review provides a comprehensive review of the adverse effects and monitoring recommendations for agents in use for CSU treatment as well as those currently undergoing investigation for CSU treatment.

An update on anaphylaxis and urticaria

Notable scientific developments have taken place in the field of anaphylaxis and urticaria in recent years; they are highlighted in this review. Case-control studies, genome-wide association studies, and large omics analyses have promoted further insights into not only the underlying genetics but also the biomarkers of both anaphylaxis and urticaria. New evidence regarding IgE-dependent and non-IgE-dependent mechanisms of anaphylaxis and urticaria, including the Mas-related G protein-coupled receptor (MRGPR [formerly MRG]) signaling pathway, has been gained. Putative elicitors of anaphylactic reactions in the context of coronavirus disease 2019 (COVID-19) vaccination and impact of the COVID-19 pandemic on the management and course of chronic urticaria have been reported. Clinical progress has also been made regarding the severity grading and risk factors of anaphylaxis, as well as the distinction of phenotypes and elicitors of both diseases. Furthermore, novel treatment approaches for anaphylaxis and subtypes of urticaria have been assessed, with different outcome and potential for a better disease control or prevention.

Remibrutinib, a novel BTK inhibitor, demonstrates promising efficacy and safety in chronic spontaneous urticaria

BACKGROUND

Chronic spontaneous urticaria (CSU) is inadequately controlled in many patients and greatly affects quality of life. Remibrutinib, a highly selective, oral, novel covalent Bruton tyrosine kinase inhibitor, might be effective in CSU.

OBJECTIVE

This first-in-patient trial aimed to evaluate the efficacy and safety of remibrutinib in CSU treatment and characterize the dose-response.

METHODS

This randomized, double-blind, placebo-controlled, phase 2b dose-finding trial evaluated remibrutinib (12 weeks) in patients inadequately controlled with second-generation H₁-antihistamines, with at least moderately active CSU, with or without prior anti-IgE treatment (NCT03926611). Patients received remibrutinib 10 mg once daily, 35 mg once daily, 100 mg once daily, 10 mg twice daily, 25 mg twice daily, 100 mg twice daily, or placebo (1:1:1:1:1:1:1 ratio). The main end points were weekly Urticaria Activity Score change from baseline at week 4 and safety.

RESULTS

Overall, 311 patients were randomized. Reduced symptom score was observed for all remibrutinib doses from week 1 until week 12, with weekly Urticaria Activity Score change from baseline at week 4: -19.1 (10 mg once daily), -19.1 (35 mg once daily), -14.7 (100 mg once daily), -16.0 (10 mg twice daily), -20.0 (25 mg twice daily), -18.1 (100 mg twice daily), and -5.4 for placebo (nominal P < .0001 for all doses vs placebo). Most adverse events were mild or moderate, with no dose-dependent pattern.

CONCLUSION

Remibrutinib was highly effective in the treatment of CSU over the entire dose range, with a rapid onset of action and a favorable safety profile.

Novel biologics for treatment of chronic spontaneous urticaria

Chronic idiopathic/spontaneous urticaria (CIU/CSU) causes significant impairments in quality of life and is often unresponsive to antihistamines. Although the anti-IgE mAb omalizumab has been an important addition to the therapeutic armamentarium for the management of patients with CSU, there are still a significant percentage of patients who do not respond to the combination of antihistamines and omalizumab. As a result, additional treatments are needed. With the expanding knowledge of the pathogenesis of CSU and the role of mast cells, novel therapeutic agents targeting unique pathways important in CSU are in development. This review focuses on the rationale behind, and results of, novel therapies trialed in CSU.

Evidence Gaps in Clinical Trials of Pharmacologic Treatment for H1-Antihistamine-Refractory Chronic Spontaneous Urticaria: A Systematic Review and Future Perspectives

No data addressing issues concerning disparities in participant and trial characteristics and trial outcome reporting have been established in clinical trials for H1-antihistamine-refractory chronic spontaneous urticaria (CSU). To better harmonize and compare the different treatment interventions, we systematically evaluated the overall landscape of pharmacological treatments for H1-antihistamine-refractory CSU clinical trials published between 2000 and 2021. This systematic review included 23 randomized clinical trials involving 2480 participants from 22 countries. We found significant increases in the number of globally published and newly tested drugs, especially biologic drugs. Regarding relatively small trials, we found that people living with H1-antihistamine-refractory CSU who were identified as members of minority groups (non-white population), populations of regions other than North America/Europe, and populations of low- to lower/upper-middle-income countries are underrepresented. Most trials were designed to evaluate treatment efficacy and safety profiles; however, less than half of the included trials reported the patient’s perspective in terms of patient-reported outcomes. Disparities in outcome reporting, including clinimetric tools for assessing treatment response and outcome sets, were observed. To close the evidence gap in H1-antihistamine-refractory CSU trials, strategies for improving trial and participant enrollment and standardizing core outcome sets for trial reporting are needed.

BTK inhibitors in the treatment of hematological malignancies and inflammatory diseases: mechanisms and clinical studies

Bruton's tyrosine kinase (BTK) is an essential component of multiple signaling pathways that regulate B cell and myeloid cell proliferation, survival, and functions, making it a promising therapeutic target for various B cell malignancies and inflammatory diseases. Five small molecule inhibitors have shown remarkable efficacy and have been approved to treat different types of hematological cancers, including ibrutinib, acalabrutinib, zanubrutinib, tirabrutinib, and orelabrutinib. The first-in-class agent, ibrutinib, has created a new era of chemotherapy-free treatment of B cell malignancies. Ibrutinib is so popular and became the fourth top-selling cancer drug worldwide in 2021. To reduce the off-target effects and overcome the acquired resistance of ibrutinib, significant efforts have been made in developing highly selective second- and third-generation BTK inhibitors and various combination approaches. Over the past few years, BTK inhibitors have also been repurposed for the treatment of inflammatory diseases. Promising data have been obtained from preclinical and early-phase clinical studies. In this review, we summarized current progress in applying BTK inhibitors in the treatment of hematological malignancies and inflammatory disorders, highlighting available results from clinical studies.

Efficacy of Fangfeng Tongsheng Granule Combined with Levocetirizine in the Treatment of Chronic Urticaria and Its Effect on Serum Complement, IL-4, IgE, and IFN-γ Levels in Patients

Objectives

To investigate the efficacy of Fangfeng Tongsheng granule combined with levocetirizine in the treatment of chronic urticaria and its effect on serum complement, interleukin (IL)-4, immunoglobulin E (IgE), and interferon-γ (IFN-γ) levels in patients.

Methods

A total of 98 patients with chronic urticaria who were admitted to our hospital from July 2021 to March 2022 were selected and divided into random odd-even numbers. The odd numbers were included in the observation group, with a total of 49 cases, and they were treated with Fangfeng Tongsheng granule combined with levocetirizine; the even numbers were included in the control group, with a total of 49 cases and were treated with levocetirizine alone. The two groups of patients were treated continuously for 4 weeks, and the clinical efficacy of the two groups was observed. Before treatment, 2 weeks and 4 weeks after treatment, evaluate the clinical symptom scores of patients such as itching, flushing, wheal, edema, observe the improvement of clinical symptoms of patients, and the changes in Dermatology Life Quality Index (DLQI). Serum complement C3, C4, T lymphocyte subsets CD₃⁺, CD₄⁺, CD₈⁺ levels and CD₄⁺/CD₈⁺ ratio, IL-4, IgE, and IFN-γ levels and the occurrence of adverse reactions in the two groups were calculated and observed. All patients were followed up for 2 months after treatment to observe the recurrence of patients.

Results

The scores of clinical symptoms such as wheal, itching, flushing, edema, and attack frequency in the observation group at each time point after treatment were lower than those in the control group (F times were 725.365, 851.521, 936.411, 3943.136, and 2226.147, all P < 0.05 (F between-group were 40.642, 102.124, 188.523, 259.291, and 23.92, P < 0.05); the total effective rate of the observation group was 93.88% (46/49), which was significantly higher than that of the control group, 73.47% (36/49) (χ² = 7.470, P=0.006). The DLQI scores of the observation group at each time point after treatment were lower than those of the control group (F time was 282.214, P < 0.05; F between-group was 6.546, P < 0.05). There was no significant difference in serum C4 levels between the two groups at each time point (F time was 1.225, P > 0.05; F between-group was 0.408, P > 0.05); serum complement C3, CD₃⁺, and CD₄⁺/the ratio of CD₈⁺ and IFN-γ were higher than those in the control group (F time was 407.352, 107.823, 32.941, and 2354.147, P < 0.05; F between-group was 40.941, 24.710, 54.982, and 264.921, P < 0.05); the observation group at each time after treatment the levels of IgE and IL-4 were lower than those of the control group (F time were 373.124 and 395.612, P < 0.05; F between-group were 21.802 and 62.591, P < 0.05). The incidence of adverse reactions in the observation group was 12.24% (6/49) compared with 10.20% (5/49) in the control group, which had no significant difference (χ² = 0.102, P=0.749). Both groups were followed up for 2 months after treatment. The recurrence rate in the observation group was 12.24% (6/49), which was lower than that in the control group, which was 32.65% (16/49) (χ² = 5.861, P=0.015).

Conclusion

The application of Fangfeng Tongsheng granules combined with levocetirizine in patients with chronic urticaria can effectively improve the clinical symptoms of patients, improve clinical efficacy, reduce the impact of the disease on life, improve the immune status of patients, and reduce the risk of recurrence.