Definition, acronyms, nomenclature, and classification of angioedema (DANCE): AAAAI, ACAAI, ACARE, and APAAACI DANCE consensus

Global frequency, diagnosis, and treatment of hereditary angioedema with normal C1 inhibitor

Background

Hereditary angioedema (HAE) is a rare genetic disease, most frequently associated with deficiency or dysfunction in the C1 inhibitor protein. HAE with normal C1 inhibitor (HAE-nC1INH) lacks standardized diagnostic tests, limiting precise prevalence estimates and development of specific treatment guidelines.

Objective

This study sought to describe the global frequency, diagnostic pathway, and current treatment patterns of HAE-nC1INH.

Methods

Board-certified HAE-treating physicians from accredited Angioedema Centers of Reference and Excellence (ACAREs) were invited to complete a 27-item online survey between December 2022 and April 2023.

Results

Thirty physicians from 30 ACAREs across 15 countries reported a mean of 71 (range, 11-148) patients with HAE assessed/treated within the previous 12 months. On average, physicians estimated 24% (range, 2-44%) of patients with HAE were diagnosed with HAE-nC1INH, most of whom were adults (88%). To diagnose HAE-nC1INH, physicians most commonly assessed family history and plasma C4 levels (90% each), and C1 function and quantitative levels (87% each). On-demand and prophylactic treatment patterns varied widely across countries, with an average (range) of 56% (33-100%) of patients receiving on-demand treatment only, and 37% (0-67%) receiving both on-demand and prophylactic treatment. Physicians identified the greatest unmet needs in HAE-nC1INH management as treatment specifically indicated for this patient population and availability of an oral treatment.

Conclusion

HAE-nC1INH may be more prevalent than previously reported. Importantly, our findings revealed varying diagnostic and treatment approaches. Validated, accessible diagnostic biomarkers and clinical outcomes derived from rigorous clinical trials assessing mechanistically based treatments would advance understanding and management of HAE-nC1INH.

A national survey of four decades of hereditary angioedema prophylaxis: Efficacy and safety of old and new drugs

BACKGROUND

Hereditary angioedema (HAE) imposes a significant burden on patients due to the unpredictability of attacks. Long-term prophylaxis (LTP) aims to prevent these episodes and improve quality of life. Over the past five decades, LTP options have evolved from non-specific treatments (fresh frozen plasma, attenuated androgens, antifibrinolytics) to more targeted therapies (intravenous or subcutaneous C1 inhibitor (C1INH), lanadelumab, berotralstat).

OBJECTIVE

To assess the use, efficacy, and safety of various LTP therapies among Hungarian HAE patients.

METHODS

Data from the Hungarian HAE Registry (1979-2023) were analysed, including LTP usage, attack rates, side effects, and laboratory parameters.

RESULTS

Danazol and tranexamic acid use increased over the first 30 years but has declined in the last decade. Conversely, the use of modern LTP therapies and the proportion of patients relying solely on on-demand medication have significantly increased over the past decade. Danazol and tranexamic acid reduced attack rates in 60 % of patients without significant changes in the laboratory parameters at the lowest effective doses. Furthermore, 100 % of patients on subcutaneous C1INH, lanadelumab, and berotralstat experienced fewer attacks and improved quality of life compared to pre-treatment periods, with no serious side effects or significant laboratory abnormalities.

CONCLUSION

Modern prophylaxis usage is increasing among Hungarian HAE-C1INH patients, following the global trends. Both modern and traditional LTP options proved safe and effective in our patient population when used with appropriate monitoring.

Very rare adverse reactions to intravascular contrast media: From Kounis to sweet syndrome

Intravascular administration of contrast media may inadvertently result in adverse drug reactions (ADR) including selected hypersensitivity reactions. This review highlights some very rare ADR, aiming to alert imaging physicians to these conditions and to prompt adequate management. This is particularly relevant for Kounis syndrome, an immediate hypersensitivity reaction involving the coronary arteries. The acute management of Kounis syndrome can be challenging, as it requires continued contrast media administration, while balancing the simultaneous coronary reperfusion that requires vasodilatation with anti-allergic treatment that may involve vasoconstrictor agents. For other adverse reactions, referral to a drug allergy specialist is highly recommended to assess causality and identify safe alternatives. CLINICAL RELEVANCE STATEMENT: Cardiologists and radiologists must recognize the key symptoms of these very rare adverse reactions to contrast media to promptly initiate the appropriate therapy and refer patients for allergological evaluation, ideally within 1-6 months after the reaction.

Elevated level of circulating VEGF in Chinese patients with hereditary angioedema and its correlation with disease status

BACKGROUND

Hereditary angioedema (HAE) is a rare inherited disease characterized by recurrent, potentially life-threatening angioedema. The vascular endothelium dysfunction is reported to play a role in angioedema episodes. Here, we conducted a case-control study to explore the correlation between vascular endothelium growth factor (VEGF), a representative indicator for endothelium dysfunction, and HAE as well as its attack frequency, disease control and disease severity.

METHODS

Patients with HAE and non-hereditary angioedema in their attack-free period were prospectively recruited. Demographic and disease information were collected through questionnaires. Disease control of HAE was assessed with the angioedema control test (AECT) with a recall period of three months. The current severity of HAE was comprehensively assessed through frequency of angioedema episodes, occurrence of life-threatening angioedema, necessity for hospitalization or emergency department visits. The plasma VEGF level was measured by chemiluminescence microparticle immunoassay. We compared clinical characteristics between HAE and non-hereditary angioedema patients, as well as among HAE patients with different attack frequency, disease control and disease severity. We further performed several generalized linear models (GLMs) to examine the correlation between VEGF levels and the attack frequency, disease control and disease severity of HAE.

RESULTS

We enrolled 74 patients with HAE and 55 patients with non-hereditary angioedema. HAE patients exhibited higher VEGF levels in remission than controls (112 vs. 60 ng/ml, P < 0.001). VEGF levels further increased in HAE patients with more frequent angioedema attacks, poorer disease control and greater disease severity. Results of GLMs confirmed significant correlations between plasma VEGF concentrations and the attack frequency of angioedema, disease control status and disease severity of HAE.

CONCLUSION

Circulating VEGF level elevated in patients with HAE during attack-free periods, particularly among those with greater disease burden, suggesting the involvement of vascular endothelial dysfunction in the pathogenesis of HAE. VEGF may serve as a predictive biomarker for risk stratification and disease monitoring in HAE.

Natural History of Pediatric Idiopathic Histaminergic Angioedema: A Retrospective Monocentric Study

BACKGROUND

Idiopathic histaminergic angioedema (IH-AAE) is a pathological entity poorly described in the literature. It overlaps with some forms of chronic urticaria, especially in pediatrics.

OBJECTIVE

This study is a descriptive analysis of this form of angioedema's natural history and prognosis. The aim is to describe long-term data about the course of this clinical entity, including clinical presentation, recurrence, and response to therapy, emphasizing follow-up and outcome.

METHODS

We performed a retrospective monocentric descriptive study at the Allergy Unit, Department of Pediatrics of the Institute for Maternal and Child Health of Trieste, Italy. We selected pediatric patients (0-18 years old) visiting the outpatient clinic from January 2010 to December 2020 who received a diagnosis of IH-AAE. We analyzed the disease recurrence, the remission rate, the time and frequency of recurrences, and the body sites involved.

RESULTS

The median follow-up was 57 months. Among the 36 individuals examined at follow-up, 9 (25%) still had episodes of angioedema, while 27 (75%) reported the absence of attacks. Disease remission was established in 24 patients (66.6%). The median remission time was 13 months (IQR: 7-28). When comparing AE recurrence at onset and follow-up, in all children, the number of episodes decreased (in 4/9 patients) or remained unchanged over time (in 5/9 patients). Moreover, within this group, AE recurrence was recorded as high, intermediate, and low, respectively, in one (11.1%), two (22.2%), and six patients (66.7%). The median number of monthly episodes was one (IQR: 0.2-3), and eight was the maximum value. The initial recurrence of AE attacks has no impact on the time and rate of remission (p = 0.56). According to these data, 36% of the patients will go into remission in 1 year, 54% in 2 years, and 71% in 6.5 years, while 14% of the children will still present with AE after 8 years of disease.

CONCLUSIONS

IH-AAE is a benign and self-limiting condition that can sometimes last several years. Over time, the number of episodes per month decreases or, at most, remains unchanged. No patients reported disease worsening. The frequency of attacks at onset does not correlate with the possibility of recovery or the remission time.

Population Pharmacokinetic/Pharmacodynamic and Exposure-Response Modeling of Garadacimab in Healthy Volunteers and Patients With Hereditary Angioedema

Hereditary angioedema (HAE) is a rare genetic disease that manifests as recurrent, unpredictable, and potentially life-threatening attacks of angioedema. Garadacimab is a first-in-class, fully human, monoclonal antibody targeting activated factor XII (FXIIa) that is under clinical development for the long-term prophylaxis of HAE attacks. We developed population pharmacokinetic (PK)/pharmacodynamic (PD)/exposure-response (ER) models using pooled data across clinical studies to quantify the relationship between garadacimab concentration and the relative risk of HAE attacks and to support the rationale for 200 mg once-monthly dosing. The PK of garadacimab was adequately characterized by a two-compartment model with first-order absorption and elimination. The PD, as analyzed by FXIIa-mediated kallikrein activity, was adequately characterized by a direct inhibitory response model. PK/PD parameters were generally consistent across multiple covariates. ER analysis based on a repeated-time-to-event model showed that administration of garadacimab 200 mg subcutaneously (SC) once monthly results in 75% of patients reaching the target therapeutic threshold (90% reduction in relative risk of attack vs. run-in). Use of a loading dose (two 200 mg SC injections) as the first administration achieved steady-state PK exposures and PD response, with 85% of patients having exposures surpassing the therapeutic threshold. The models support the use of garadacimab 200 mg SC once-monthly dosing in patients aged ≥ 12 years, with no need for dose adjustments, and indicate that, due to the achievement of garadacimab steady-state exposures after the first administration, the use of a loading dose may facilitate the early onset of protection against HAE attacks, as observed in clinical studies.

Garadacimab improves long-term health-related quality of life in patients with hereditary angioedema

Background: Hereditary angioedema (HAE) attacks substantially impair health-related quality of life (HRQoL). Current World Allergy Organization and the European Academy of Allergy and Clinical Immunology guidelines goals include complete control and normalization of patients' lives. Garadacimab (anti-activated factor XII monoclonal antibody) reduced the mean attack rate after first administration in the pivotal phase III (VANGUARD; NCT04656418) and ongoing long-term phase III open-label extension (OLE) (NCT04739059) studies. Objective: To report exploratory HRQoL data from the interim analysis of the phase III OLE study (data cutoff February 13, 2023). Methods: Patients ages ≥12 years and with HAE received garadacimab 200 mg subcutaneously once monthly in the OLE study. The patient population comprised patients who were garadacimab naive (received placebo in the previous phase III study and newly enrolled patients) and patients who received garadacimab in previous phase II/III studies. The Angioedema Quality of Life (AE-QoL) questionnaire, Treatment Satisfaction Questionnaire for Medication version II (TSQM II), and Work Productivity and Activity Impairment: General Health (WPAI:GH) questionnaire were administered at baseline and every 3 months during the OLE study. AE-QoL and TSQM II scores were evaluated in comparison with minimal clinically important differences (MCID). Results: Overall, 90 patients who were garadacimab naive and 71 patients with previous garadacimab exposure received garadacimab in the phase III OLE study. The mean ± standard deviation AE-QoL total score improved by 34.2 ± 18.8 points in patients who were garadacimab naive and by 2.3 ± 13.1 points further to the reduction experienced in patients with previous garadacimab exposure. The AE-QoL MCID was met by 92.1% of patients who were garadacimab naive; 81.6% of patients with previous garadacimab exposure experienced stable AE-QoL scores or further improvements per MCID. TSQM II scores were improved from day 1 with garadacimab and sustained to month 12. Improvements in WPAI:GH scores were consistent with AE-QoL and TSQM II. Conclusion: Garadacimab elicited clinically meaningful long-term improvements in HRQoL, work productivity, and treatment satisfaction in patients with HAE, which brought them closer to complete disease control and normalization of life.Clinical trial NCT04739059, clinicaltrials.gov.

Prediction of hereditary angioedema during attacks in patients with recurrent angioedema: Awareness at a glance with the hereditary angioedema prediction score

BACKGROUND/AIM

Misdiagnosis of hereditary angioedema (HAE) leads to inappropriate management of the attacks. A scoring system that anticipates diagnosis can be beneficial for clinicians who are unfamiliar with angioedema. This study aims to develop a practical scoring system for use during acute attacks to predict HAE in patients with recurrent angioedema (RAE).

METHOD

To predict HAE, nine HAE experts unanimously identified five predictive items (PIs); absence of urticaria, presence of abdominal pain episodes, family history, early onset of attacks and previous unresponsiveness to anti-histaminergic treatments. The researchers questioned 106 patients with HAE and 155 patients with mast cell-mediated angioedema (MMAE) about PIs. A score was attributed to each significant PI based on OR values obtained through logistic regression analysis. The cut-off point for the prediction of HAE and its sensitivity and specificity were determined by ROC curve analysis.

RESULTS

In a univariate analysis, all items showed significant differences between HAE and MMAE patients. Regression analysis attributed scores as follows: 23 points for the absence of urticaria, 11 points for the abdominal pain episodes, 9 points for family history, and 53 points for unresponsiveness to antihistaminergic treatments. No score was attributed to early onset of age (p > 0.05). The ROC analysis revealed an area under the curve of 0.990, with a total score of ≥38 demonstrating the best sensitivity (96.4%) and specificity (96.1%).

CONCLUSIONS

HAEps is a valuable tool for diagnosing HAE in patients with RAE. A score of 38 or more indicates the possible presence of HAE with substantial sensitivity and specificity.

An evaluation of sebetralstat as the first oral on-demand therapy for Hereditary Angioedema

INTRODUCTION

Hereditary Angioedema (HAE) is a rare genetic disease characterized by sudden episodes of edema that do not respond to conventional treatments. Modern therapies targeting the kallikrein-kinin system aim to alleviate HAE attacks, reduce their frequency and severity, and enhance patients' quality of life. Sebetralstat, a novel oral plasma kallikrein inhibitor, offers a promising option for rapid and effective on-demand treatment of HAE attacks.

AREAS COVERED

This article evaluates the pharmacokinetics, pharmacodynamics, efficacy, and tolerability of sebetralstat based on developmental studies. We reviewed and analyzed seven pertinent original studies focusing on sebetralstat trials.

EXPERT OPINION

Oral sebetralstat provides a convenient alternative to injectable treatments, allowing patients to take the drug at the first sign of an attack, improving management of acute symptoms by helping to resolve them quickly. Clinical trials demonstrated that sebetralstat exhibits rapid absorption, effective plasma kallikrein inhibition, and a favorable safety and efficacy profile. Its pharmacokinetic and pharmacodynamic properties suggest its potential for reliable control of HAE attacks.

Hereditary Angioedema with Normal C1 Inhibitor: an Updated International Consensus Paper on Diagnosis, Pathophysiology, and Treatment

Hereditary angioedema (HAE) has been recognized for almost 150 years. The newest form of HAE, where C1 inhibitor levels are normal (HAE-nC1INH), was first described in 2000. Over the last two decades, new types of apparent non-mast cell-mediated angioedema with normal quantity and activity of C1INH have been described, in some cases with proven genetic pathogenic variants that co-segregate with angioedema expression within families. Like HAE due to C1INH deficiency, HAE-nC1INH patients are at risk of serious morbidity and mortality. Therefore, proactive management and treatment of HAE-nC1INH patients after an expert physician diagnosis is critically important. The underlying pathophysiology responsible for the angioedema has also been clarified in some of the HAE-nC1INH types. While several clinical guidelines and practice parameters including HAE-nC1INH have been published, we have made substantial progress in our understanding encompassing diagnostic criteria, pathophysiology, and treatment outcomes. HAE International (HAEi) and the US HAE Association (HAEA) convened a symposium of global HAE-nC1INH experts to synthesize our current knowledge in the area. Given the paucity of high-level evidence in HAE-nC1INH, all recommendations are based on expert opinion. This review and expert opinion on the best practice approach to diagnosing and treating HAE-nC1INH will support physicians to better manage patients with HAE-nC1INH.

Whole Exome Sequencing in Drug-Induced Angioedema Caused by Angiotensin-Converting Enzyme Inhibitors: A Pilot Study in Five Patients

Background and Objectives: One of the most common causes of drug-induced angioedema (AE-DI) is related to reduced bradykinin breakdown after the use of certain medications. This is the case for forms of AE-DI due to the use of angiotensin-converting enzyme inhibitors (ACEi), which are used for the treatment of cardiovascular conditions. The causes of AE are not clear in these patients. Given the limited number of AE-ACEi genetic loci identified by genome-wide association studies, we opted to assess the utility of NGS of a panel of relevant genes to identify candidate genetic risk factors in severely affected patients. Methods: Five hypertensive patients from unrelated families with clinical AE-ACEi were included in the study. Whole-exome sequencing, variant calling, and annotation techniques were used. ANNOVAR v18.04.16 was used to annotate the variant calls. The resulting variants for each patient were assessed using the Hereditary Angioedema Database Annotation tool and Franklin genomic platform for variant prioritization and clinical impact interpretation. Results: The genetic variant rs6025 in the F5 gene was identified in all recruited samples, which has been associated with an increase in blood clotting in AE-ACEi patients. In two patients, a common synonymous genetic variant of the ACE gene was found (rs4343). Finally, we identified the ACE genetic variant rs142947404 in only one patient. This variant has not been assessed in AE-ACEi. Conclusions: More studies will be needed to clarify the genetics involved in AE-DI. In this way, we will be able to try to predict future episodes of angioedema due to the use of ACEi.

Adaptation and Linguistic Validation of Angioedema PROMs in Latvian for Assessing Recurrent Angioedema

Background: Angioedema (AE) is a localized, non-pitting swelling affecting subcutaneous and/or submucosal tissues. Despite varying underlying mechanisms, AE significantly impacts patients' quality of life (QoL), which is closely linked to disease activity and control. Objectives: This study aimed to translate and linguistically validate the angioedema activity score (AAS), angioedema control test (AECT), and angioedema quality of life (AE-QoL) questionnaires into Latvian, and to use these validated tools to assess disease activity, control, and quality of life within the study population. Methods: PROMs, including the AECT, AAS, and AE-QoL, underwent a standardized linguistic validation process. Patients with hereditary angioedema (HAE), mast cell-mediated angioedema (AE-MC), and angioedema of unknown origin (AE-UNK) were recruited from two separate studies conducted at Riga Stradiņš University. Results: We enrolled 41 participants (90.2% women) with a mean age of 46.3 years. AE-MC was the most common (63.4%), followed by HAE (19.5%) and AE-UNK (17.1%). The mean AAS score was 15.8, with no significant differences regarding AE type, gender, or age. The mean AECT score was 8.29, revealing significant gender differences (women: 7, men: 13.5). The AE-QoL total score was 45.5, with significant gender differences in most domains. Strong correlations were found between AE-QoL scores and both AAS and AECT, highlighting the impact of both disease activity and control on QoL. Conclusions: The Latvian adaptation of the AAS, AECT, and AE-QoL questionnaires effectively assesses AE activity, control, and disease-related QoL. Our study reveals poor disease control, underscoring the need for tailored interventions and regular PROM evaluations, with the Latvian version of the AE-QoL questionnaire identifying five distinct domains compared to four in the original version.

De Novo or inherited: gonosomal mosaicism in hereditary angioedema due to C1 inhibitor deficiency

Hereditary angioedema (HAE) is a rare genetic disease, characterized by transient and self-limiting episodes of subcutaneous or submucosal swelling that spontaneously resolve within two to five days. The most common form of HAE, HAE-C1-INH, is caused by deleterious mutations in the SERPING1 gene, encoding the C1-Inhibitor protein, and its diagnosis is confirmed by decreased C1-INH function. Distinctively from other genetic forms of HAE, up to 15-20% of HAE-C1-INH cases are sporadic caused by de novo mutations. Here, we report a patient with apparently sporadic HAE-C1-INH. The patient had compatible clinical symptoms and a markedly low C1-INH function, and the parents showed normal values of C4 and normal C1-INH function. In the patient, we identified a novel splice site mutation in SERPING1 (c.890-1G>C) and, by cDNA analysis, we confirmed its pathogenicity. Despite normal C1-INH function in the parents, we found that the mother was, unexpectedly, a mutation carrier. The inverted profile of the Sanger peaks compared with the patient, strongly suggested the presence of gonosomal mosaicism in the mother. We confirmed and quantified the mosaicism in different tissues by high depth NGS-based deep amplicon sequencing, showing a similar frequency of the variant ranging from 17 to 23%. In this study, we present the first case of gonosomal mosaicism in a family with a single child affected with HAE-C1-INH from unaffected parents. Our results underscore the importance of parental genetic testing in all patients, regardless of whether the parents are affected, and highlights the implications of gonosomal mosaicism for genetic counseling.

Exploring the management of recurrent angioedema caused by different mechanisms

PURPOSE OF REVIEW

We aim to explore the most recent insights into the pathogenesis of recurrent angioedema caused by different mechanisms and then focus on the management and treatment approaches available.

RECENT FINDINGS

The recently developed DANCE consensus classification identifies five types of angioedema: mast cell-mediated (AE-MC), bradykinin-mediated, because of intrinsic vascular endothelium dysfunction (AE-VE), drug-induced (AE-DI), and due to unknown mechanisms (AE-UNK). These subtypes require different management with treatment choices targeting the main pathogenetic pathways involved in each form. For AE-MC and AE-BK, the therapeutic landscape has been significantly widened in recent years. Conversely, there is a lack of consensus for the hereditary forms because of newly discovered mutations ( factor 12 , plasminogen, kininogen-1 , myoferlin, angiopoietin-1 , heparan sulfate 3-O-sulfotransferase 6 ) and AE-UNK.

SUMMARY

Recurrent angioedema can present with or without wheals. Angioedema without wheals may be driven by bradykinin and/or mast cell mediators. The different forms respond to specific drugs and require a different management. For its potentially life-threatening and disfiguring features, angioedema should be promptly recognized and effectively treated. For this reason, enhancing awareness about various angioedema subtypes and their management provide a useful tool for the clinical practice.

CRISPR-Based Therapy for Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a rare genetic disease characterized by severe and unpredictable swelling attacks. NTLA-2002 is an in vivo gene-editing therapy that is based on clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9. NTLA-2002 targets the gene encoding kallikrein B1 (KLKB1). A single dose of NTLA-2002 may provide lifelong control of angioedema attacks.

METHODS

In this phase 2 portion of a phase 1-2 trial, we randomly assigned adults with hereditary angioedema in a 2:2:1 ratio to receive NTLA-2002 in a single dose of 25 mg or 50 mg or placebo. The primary end point was the number of angioedema attacks per month (the monthly attack rate) from week 1 through week 16. Secondary end points included safety, pharmacokinetics, and pharmacodynamics (i.e., the change from baseline in total plasma kallikrein protein level); exploratory end points included patient-reported outcomes.

RESULTS

Of the 27 patients who underwent randomization, 10 received 25 mg of NTLA-2002, 11 received 50 mg, and 6 received placebo. From week 1 through week 16, the estimated mean monthly attack rate was 0.70 (95% confidence interval [CI], 0.25 to 1.98) with 25 mg of NTLA-2002, 0.65 (95% CI, 0.24 to 1.76) with 50 mg, and 2.82 (95% CI, 0.80 to 9.89) with placebo; the difference in the estimated mean attack rate with NTLA-2002 as compared with placebo was -75% with 25 mg and -77% with 50 mg. Among patients who received NTLA-2002, 4 of the 10 patients who received 25 mg (40%) and 8 of the 11 who received 50 mg (73%) were attack-free with no additional treatment during the period from week 1 through week 16. The most common adverse events among patients who received NTLA-2002 were headache, fatigue, and nasopharyngitis. The mean percent change in total plasma kallikrein protein levels from baseline to week 16 was -55% with 25 mg and -86% with 50 mg; levels remained unchanged with placebo.

CONCLUSIONS

NTLA-2002 administered in a single dose of 25 mg or 50 mg reduced angioedema attacks and led to robust and sustained reduction in total plasma kallikrein levels in patients with hereditary angioedema. These results support continued investigation in a larger phase 3 trial. (Funded by Intellia Therapeutics; ClinicalTrials.gov number, NCT05120830; EudraCT number, 2021-001693-33.).

Hereditary angioedema in children: Review and practical perspective for clinical management

BACKGROUND

Hereditary angioedema (HAE) in children has specific features and requires multidisciplinary management.

METHODS

We performed a literature search and underwent in-depth discussions to provide practical tools for physicians.

RESULTS

HAE is a rare, life-threatening genetic disorder. Its epidemiology is poorly documented in children. Clinical manifestations usually appear during childhood or early adolescence. Classical signs, often preceded by prodromal symptoms, include transient, localized, non-pitting, non-pruritic swelling of deep dermal/subcutaneous or mucosal/submucosal tissues, leading to oedema of the extremities, face, lips, tongue, trunk and genitals, recurring gastrointestinal symptoms and laryngeal edema possibly causing asphyxiation and death. Diagnosis is often delayed due to low awareness in the medical community, and particularly challenging in case of isolated abdominal crises or atypical presentation and in neonates or infants. It relies on biological tests (measurement of serum/plasma levels of C1INH function, C1INH protein, and C4), genetic testing in selected cases, and imaging for differential diagnosis of acute abdominal crises. Main differential diagnosis for peripheral oedema is mast cell-mediated oedema that accounts for 95% of angioedema in clinical practice. Quality of life can be significantly impaired. Disease management includes treatment of attacks, short-term and long-term prophylaxis, psychological support, avoidance of triggers, patients' and parents' education and coordination of all stakeholders, ideally within a specialized healthcare network. New plasma kallikrein inhibitors, namely lanadelumab (subcutaneous route) and berotralstat (oral route) have facilitated long-term prophylaxis thanks to improved usability.

CONCLUSION

Diagnostic and treatment of HAE are particularly challenging in children and require specific management by multiple stakeholders.

Chronic Spontaneous Urticaria: A Review

Importance

Chronic spontaneous urticaria affects approximately 1% of the general population worldwide, including approximately 3 million people in the US, impairs patients' quality of life, and is associated with multiple comorbidities.

Observations

Chronic spontaneous urticaria affects patients of any age but is most common in females aged 30 to 50 years. Diagnosis is based on clinical presentation, ie, spontaneously recurring wheals, angioedema, or both. Chronic spontaneous urticaria persists for more than 1 year in most patients (1 or repeated episodes) and may present with comorbidities including chronic inducible urticaria (>10%), autoimmune thyroiditis (approximately 20%), metabolic syndrome (6%-20%), and anxiety (10%-31%) and depression (7%-29%). Known autoimmune endotypes (subtypes of urticaria defined by distinct pathogenesis) of chronic spontaneous urticaria are mediated by mast cell-activating IgE and/or IgG autoantibodies (>50%). Approximately 40% of patients with chronic spontaneous urticaria have a Dermatology Life Quality Index of more than 10, corresponding to a very large or extremely large negative effect on quality of life. Second-generation H1 antihistamines are first-line treatment; partial or complete response, defined as a reduction in urticaria symptoms of greater than 50%, is observed in approximately 40% of patients. The 2022 international urticaria guideline recommends the monoclonal anti-IgE antibody omalizumab as second-line treatment for antihistamine-refractory chronic spontaneous urticaria. However, at least 30% of patients have an insufficient response to omalizumab, especially those with IgG-mediated autoimmune urticaria. Cyclosporine, used off-label, can improve symptoms in approximately 54% to 73% of patients, especially those with autoimmune chronic spontaneous urticaria and nonresponse to omalizumab, but has adverse effects such as kidney dysfunction and hypertension.

Conclusions and Relevance

Chronic spontaneous urticaria is an inflammatory skin disease associated with medical and psychiatric comorbidities and impaired quality of life. Second-generation H1 antihistamines are first-line treatment, omalizumab is second-line treatment, and cyclosporine is third-line treatment for chronic spontaneous urticaria.

Targeting factor XIIa for therapeutic interference with hereditary angioedema

Hereditary angioedema (HAE) is a rare, potentially life-threatening genetic disorder characterized by recurrent attacks of swelling. Local vasodilation and vascular leakage are stimulated by the vasoactive peptide bradykinin, which is excessively produced due to dysregulation of the activated factor XII (FXIIa)-driven kallikrein-kinin system. There is a need for novel treatments for HAE that provide greater efficacy, improved quality of life, minimal adverse effects, and reduced treatment burden over current first-line therapies. FXIIa is emerging as an attractive therapeutic target for interference with HAE attacks. In this review, we draw on preclinical, experimental animal, and in vitro studies, providing an overview on targeting FXIIa as the basis for pharmacologic interference in HAE. We highlight that there is a range of FXIIa inhibitors in development for different therapeutic areas. Of these, garadacimab, an FXIIa-targeted inhibitory monoclonal antibody, is the most advanced and has shown potential as a novel long-term prophylactic treatment for patients with HAE in clinical trials. The evidence from these trials is summarized and discussed, and we propose areas for future research where targeting FXIIa may have therapeutic potential beyond HAE.

Real-world outcomes of patients with hereditary angioedema with normal C1-inhibitor function and patients with idiopathic angioedema of unknown etiology in Canada

BACKGROUND

Hereditary angioedema with normal C1-inhibitor function (HAE nC1-INH) and idiopathic angioedema of unknown etiology (AE-UNK) are rare conditions that cause recurrent subcutaneous and submucosal swelling. The characteristics and clinical outcomes of patients with these conditions in Canada have not been studied.

METHODS

The aim of this study was to extract real-world evidence from the electronic health records of patients with HAE nC1-INH or AE-UNK who were managed in selected practices of Canadian HAE-treating specialist physicians between 01-Jan-2012 and 01-Jan-2022, to examine case numbers, treatment, clinical outcomes, and healthcare utilization.

RESULTS

Of 60 patients (37 with HAE nC1-INH, 23 with AE-UNK), median (range) age at symptom onset was 21.5 (5.0-57.0) and 23.0 (10.0-54.0) years, respectively. Time to diagnosis from onset of symptoms was 7.0 (0.0-43.0) and 2.0 (- 10.0 to 50.0) years. Significant differences were observed in terms of the predominant triggers for angioedema attacks between patients with HAE nC1-INH and AE-UNK: stress (65% vs. 26%, p = 0.007) and estrogen therapy (35% vs. 9%, p = 0.031). Before diagnosis, most patients received antihistamines (50% of HAE nC1-INH and 61% of AE-UNK patients). Post-diagnosis, 73% and 74% of HAE nC1-INH and AE-UNK patients received long-term prophylaxis (LTP), with the most common LTP treatments being subcutaneous pdC1-INH (43% of HAE nC1-INH patients and 39% of AE-UNK patients) and tranexamic acid (41% of HAE nC1-INH patients and 35% of AE-UNK patients). Of patients with HAE nC1-INH, and patients with AE-UNK, 22% and 13%, respectively, were taking more than one LTP treatment concurrently. Before HAE treatment initiation, significantly fewer patients with AE-UNK compared to patients with HAE nC1-INH had angioedema attacks affecting their extremities (13% vs. 38%, p = 0.045) and GI system (22% vs. 57%, p = 0.015). In the three months following treatment initiation, patients with AE-UNK experienced significantly fewer angioedema attacks compared to patients with HAE nC1-INH (median 2.0 attacks [0.0-48.0] vs. 6.0 attacks [0.0-60.0], p = 0.044). Additionally, fewer patients with AE-UNK compared to HAE nC1-INH experienced attacks affecting their GI system (26% vs. 57%, p = 0.032). Attack duration and frequency significantly decreased for patients with HAE nC1-INH from a median of 1.00 day (range: 0.00-7.00) to 0.29 day (range: 0.02-4.00; p = 0.001) and from 10.50 attacks (range: 0.00-90.00) to 6.00 attacks (range: 0.00-60.00; p = 0.004) in the three months following HAE treatment initiation.

CONCLUSIONS

Using Canadian real-world evidence, these data demonstrate differing clinical trajectories between patients with HAE nC1-INH and AE-UNK, including diagnostic delays, varied attack characteristics, treatment responses and healthcare utilization. Despite treatment response, many patients still experienced frequent angioedema attacks. These results suggest an unmet need for treatment guidelines and therapies specifically for patients with HAE nC1-INH and AE-UNK and better understanding of the pathophysiology accounting for the reported differences between the two.

Lanadelumab in a kidney transplant patient with hereditary angioedema due to C1-inhibitor deficiency and high cardiovascular risk - a case report

Introduction

Cardiovascular pathologies represent the first cause of death in uremic patients and are among the leading causes of mortality in patients with hereditary angioedema due to C1-inhibitor deficiency (HAE-C1INH). Before 2020, the most common treatment for long-term prophylaxis in HAE-C1INH patients in Italy was attenuated androgen, which may increase cardiovascular risk by multiple mechanisms.

Case description

We present a case report of a 56-year-old patient with HAE-C1INH type I affected by IgA nephropathy with severe kidney impairment. The patient experienced a first kidney transplant and, after late rejection, underwent a second kidney transplant. Further comorbidities included obesity, hypertensive cardiomyopathy, HCV liver disease, and dyslipidemia. His prophylactic therapy to prevent angioedema attacks had consisted of attenuated androgens for about 40 years. Since 2020, new modern targeted therapy for LTP, particularly lanadelumab, has shown promising results. The majority of patients with attenuated androgens have been successfully switched to lanadelumab, including our patient. Since introducing lanadelumab (300 mg subcutaneously every two weeks; after a six-month attack-free period, the dosing interval of lanadelumab was extended to four weeks), the patient has not experienced any acute HAE attack and did not report any adverse events. Moreover, we observed decreased total cholesterol, C-LDL, and body mass index, reducing the Matsushita et al. score for ten years of cardiovascular risk from 13.2% to 9.3%.

Conclusion

lanadelumab is effective and safe in preventing hereditary angioedema attacks, as well as in reducing cardiovascular risk in an immunosuppressed patient with significant comorbidities. The successful outcomes of this case highlight the potential of lanadelumab as a promising prophylactic therapy.

A human centred innovative approach based on persona in hereditary angioedema

BACKGROUND

Hereditary Angioedema (HAE) due to C1-inhibitor deficiency (C1INH) is a rare condition, clinically characterised by recurrent swelling. The unpredictability of attacks affects the patients' quality of life (QoL). HAE patients and their families have vast unmet physical, psychological, and social needs. A human-centred design (HCD) approach to describing the needs of different user types is to utilise personas, a data-driven narrative tool for communicating user archetypes that capture the individuals' attitudes, goals, and behaviours. The aim of this study was to create and analyse personas based on HAE patients' and their caregivers' interviews. Semi-structured interviews were conducted through anthropological conversations with patients, patient-caregivers (double role of patient and caregiver), and non-affected caregivers. Qualitative and quantitative insights from analyses formed the basis to create personas.

RESULTS

We enrolled 17 subjects: 15 patients (6 of them were patient-caregivers) and 2 non-affected caregivers. The mean age of participants was 50.3 ± 14.4 years. Eight patients were on treatment with prophylactic therapy. The mean percentage score of Angioedema Quality of Life (AE-QoL) for HAE patients was 19.8 ± 12.0. Six personas were identified describing the participants' personal history, disease management, and needs: four personas referred to patients, one to patient-caregivers, and one non-affected caregiver personas were identified. Across patient personas, the most expressed needs were psychological support and better awareness amongst healthcare professionals. Caregivers, on their side, desired better information about the disease, including the latest therapies, and higher awareness within the community.

CONCLUSION

A Human Centred Innovative Approach Based on Persona extends beyond the physical symptoms to encompass the psychological and social aspects of the individual's well-being also including the family in the evaluation.