Pediatric hereditary angioedema

Clinical profile and management of pediatric hereditary angioedema in resource-constrained settings: our experience from a single centre in North India

Hereditary angioedema (HAE) is a rare genetic disorder. The pattern of HAE is different in children as compared to adults. There is limited literature from developing countries where all first-line treatments are either unavailable or not easily accessible. Data of children with HAE were retrieved from medical records of patients registered in the Pediatric Immunodeficiency Clinic at our institute. Of the 206 patients with HAE, 61 were diagnosed before the age of 18 years. Male: female ratio was 1.1:1. Median age at onset of symptoms and diagnosis were 6.2 years (range 1-17 years) and 10.7 years (range 1.5-18 years) respectively. Median delay in diagnosis was 4.9 years (range 0-16 years). The commonest presentation was facial swelling (51/61) followed by swelling of extremities (47/61). Laryngeal edema and abdominal symptoms were reported in 28/61 and 31/61 patients respectively. Abdominal attacks were found to be less common in children as compared to adults. Most patients in our cohort received fresh-frozen plasma (n = 5/61) as on-demand therapy. Long-term prophylaxis included attenuated androgens (n = 25/61) and tranexamic acid (n = 23/61). Median duration of follow-up was 2242 patient months. One patient died on follow-up in this cohort. This is the largest single-centre cohort of pediatric HAE from resource-constrained settings. Facial attacks were more common, and there were significant delays in diagnosis when the age of onset of symptoms was younger. Gastrointestinal symptoms were less common in children than adults. HIGHLIGHTS: One of the largest single-centre cohorts of pediatric HAE and the only one from resource-constrained settings. There were significant delays in diagnosis when the age of onset of symptoms was younger. Abdominal attacks were found to be less common in children as compared to adults.

Garadacimab for hereditary angioedema attack prevention: long-term efficacy, quality of life, and safety data from a phase 2, randomised, open-label extension study

BACKGROUND

Garadacimab is a fully human immunoglobulin G4 monoclonal antibody targeting activated factor XII. This study evaluated long-term efficacy, health-related quality of life (HRQoL), and safety data for garadacimab in adults with hereditary angioedema.

METHODS

This global phase 2 study comprised a treatment period 1 (TP1: 12 weeks, double-blind, placebo-controlled) and a treatment period 2 (TP2: ≥44-week open-label extension). Patients aged 18-65 years with clinically confirmed hereditary angioedema were eligible. In TP1, 32 patients were randomly assigned (1:1:1:1) to receive subcutaneous garadacimab (75 mg, 200 mg, or 600 mg) or placebo every 4 weeks (once monthly). Randomisation was done using interactive response technology via block randomisation (block sizes 1-4). Subsequently, six additional patients in TP1 were assigned to open-label garadacimab 400 mg every 2 weeks. At the start of TP2, patients were re-randomised (if receiving placebo, garadacimab 75 mg, or garadacimab 400 mg) or continued to receive garadacimab 200 mg or garadacimab 600 mg once monthly. After a protocol amendment on March 20, 2020, patients originally assigned to the 600 mg dose were down-titrated to 200 mg at their next visit. The primary endpoint (published previously) was monthly attack rate for patients receiving 200 mg or 600 mg garadacimab in TP1 in the intention-to-treat population. Here, we assessed the impact of garadacimab on patient-reported and investigator-reported outcomes and HRQoL as well as long-term efficacy and safety. This trial is registered with ClinicalTrials.gov, NCT03712228, and is completed.

FINDINGS

Of 54 patients screened between Oct 29, 2018, and Aug 28, 2019, 32 randomised and six open-label patients completed TP1 and entered TP2 (20 in the garadacimab 200 mg group; 18 in the garadacimab 600 mg group; total 38 patients). Median age was 39·0 years (IQR 27·0-53·0), and 21 patients (55%) were female and 17 (45%) were male. In TP2, the median garadacimab exposure was 87·9 weeks (IQR 50·0-106·6) in the garadacimab 200 mg group and 44·1 weeks (24·1-56·1) in the garadacimab 600 mg group. Median monthly attack rates were 0·0 (IQR 0·0-0·1) in the garadacimab 200 mg group and 0·1 (0·0-0·4) in the garadacimb 600 mg group. Median reduction in monthly attack rate versus run-in was 100% (IQR 98-100) with garadacimab 200 mg. HRQoL improvements observed during TP1 with garadacimab were sustained throughout TP2. TP2 safety signals were consistent with TP1. Two patients experienced serious adverse events of diverticular perforation and asthma (not garadacimab-related). Treatment-emergent adverse events were mostly mild or moderate in severity. The most common adverse events were headache (nine of 38, 24%) and abdominal pain (seven of 38, 18%). There were no treatment-related deaths.

INTERPRETATION

Once-monthly garadacimab for more than 2 years in patients with hereditary angioedema was well tolerated and efficacious in reducing monthly attack rate and improving HRQoL. These results reveal the potential of long-term prophylactic treatment with 200 mg once-monthly garadacimab towards complete disease control of patients with hereditary angioedema.

FUNDING

CSL Behring.

Lanadelumab in Patients 2 to Less Than 12 Years Old With Hereditary Angioedema: Results From the Phase 3 SPRING Study

BACKGROUND

Symptoms of hereditary angioedema (HAE) often first occur during childhood, and HAE attacks in children can be severe and substantially affect health-related quality of life (HRQoL). However, there are no approved long-term prophylaxis treatments for children aged less than 6 years.

OBJECTIVE

The SPRING Study (NCT04070326) evaluated the safety, pharmacokinetics, and efficacy of lanadelumab and HRQoL in patients aged 2 to less than 12 years.

METHODS

Over 52 weeks of treatment, patients aged 2 to less than 6 years received lanadelumab 150 mg every 4 weeks (Q4W) and patients aged 6 to less than 12 years received 150 mg every 2 weeks (Q2W) but could switch to Q4W if they were attack-free for 26 weeks.

RESULTS

We enrolled 21 patients (aged 2 to less than 6 years: n = 4; aged 6 to less than 12 years: n = 17), 20 of whom completed the study. There were no reported serious treatment-emergent adverse events or discontinuations resulting from such events. Treatment-emergent adverse events were reported for 17 patients (81.0%). The most common TEAE was injection site pain. Overall systemic exposure was comparable for both age groups. The mean (SD) attack rate during treatment decreased by 94.8% from baseline (1.84 [1.53] to 0.08 [0.17] attacks/mo), and 16 (76.2%) patients were attack-free. The attack rate reduction in both age groups was similar during the first 26-week fixed-dosing treatment. Seven patients switched from Q2W to Q4W and remained attack-free. A large, clinically meaningful increase in the Pediatric Quality of Life Inventory Generic Core Scale Total Score and a large increase in the Pediatric Quality of Life Inventory Generic Core Scale-Family Impact Module Total Score from baseline to end of study (better HRQoL) were observed.

CONCLUSIONS

Findings support safety, efficacy, and improved HRQoL with lanadelumab 150 mg Q2W and Q4W regimens for the prevention of HAE attacks in patients aged 2 to less than 12 years.

Epidemiology and treatment of children with hereditary angioedema in Germany: A retrospective database study

BACKGROUND

Hereditary angioedema (HAE) is a potentially life-threatening inherited disease that causes recurrent, serious, and debilitating episodes of swelling. While evidence has improved in adult patients, data on the epidemiology and treatment of pediatric patients with HAE remain very limited. The aim of this study was to determine the incidence and prevalence of pediatric patients with HAE aged <12 years, as well as treatment patterns, co-medication, and specialties involved.

METHODS

In this retrospective study (2016-2021), the German IQVIATM pharmacy claims (LRx) database was used to analyze prescriptions of HAE-specific treatments and co-medications.

RESULTS

We found an HAE prevalence in pediatric patients aged <12 years of 2.51:100,000 and a 12-month prevalence of up to 1.02:100,000 between 2016 and 2021. Most HAE treatments were prescribed by outpatient clinics and pediatricians, with an increasing proportion of icatibant as an on-demand treatment and low rates of long-term prophylaxis (LTP). The prescription rate of analgesics as the most common co-medication decreased notably after HAE diagnosis.

CONCLUSION

Our findings provide insights into the epidemiology and current pediatric HAE treatment landscape in Germany. The obtained HAE prevalence in pediatric patients aged <12 years was even higher than the previously reported average of overall cohorts, whereas the LTP rate was low, which might indicate an unmet need for newer LTP treatment options in pediatric patients.

A Comprehensive Management Approach in Pediatric and Adolescent Patients With Hereditary Angioedema

Hereditary angioedema (HAE) is a rare autosomal-dominant disorder; most cases are characterized by low plasma levels of C1 esterase inhibitor (C1-INH). Clinical manifestations of HAE due to C1-INH deficiency include unpredictable, acute, recurrent episodes of nonpruritic swelling that can affect the face, trunk, limbs, and the respiratory, gastrointestinal, and genitourinary tracts. Attacks can be disfiguring, disabling, painful, and even life-threatening if laryngeal swelling occurs. Symptoms of HAE generally manifest in childhood. Effective medications are available and approved to treat HAE in children. However, evidence informing use of these medications in pediatric clinical practice is limited. Hereditary angioedema management plans are critical to optimize outcomes and should address on-demand treatment for acute attacks and plans to prevent potentially fatal laryngeal attacks. The plan should also comprise a holistic approach to address nonclinical aspects of HAE, including quality of life (QoL) and psychological issues. This article provides an overview of HAE management principles that health care providers can apply to treat pediatric patients to improve their QoL.

Short-term prophylaxis for children and adolescents with hereditary angioedema

Background: Hereditary Angioedema (HAE) is a rare, autosomal dominant, life threatening disease, secondary to the deficiency of C1-inhibitor, dysfunction of C1-inhibitor or inadequate control of the contact pathway. Presentation includes recurrent swelling of the skin, upper airway and the abdomen. Trauma can precipitate attacks, which in the airway can lead to asphyxia. For this reason, short term prophylaxis (STP) may be indicated before medical, surgical and dental procedures. The goal of the manuscript is to review short term prophylaxis for children of all ages. Methods: We searched the following search words: children, pediatric, adolescent, plasma derived C1-inhibitor, recombinant C1-inhibitor, surgery, medical procedures, prophylaxis, dental, Hereditary Angioedema, tranexamic acid, androgens, fresh frozen plasma, short term prophylaxis, lanadelumab, subcutaneous C1-inhibitor in Google Scholar and in PubMed to develop our results. Results: STP should be discussed at every visit. Plans should be individualized based upon the procedure, therapies available and shared decision making with patient/parent. For high risk procedures plasma derived C1-inhibitor should be used at 20 units/kg just prior to the procedure. Alternative agents for STP include recombinant C1-inhibitor, fresh frozen plasma, androgens, or tranexamic acid. In all cases, with or without the use of STP, 2 doses of on-demand therapy should be available in case of an attack. Conclusion: Herein, we review the published data on STP for pediatric patients with HAE and discuss first-line options, and off label use of medications, as well as review the guidelines pertaining to short term prophylaxis.

Novel SERPING1 gene mutations and clinical experience of type 1 hereditary angioedema from North India

BACKGROUND

There is paucity of literature on long-term follow-up of patients with hereditary angioedema (HAE) from developing countries.

OBJECTIVE

This study was carried out to analyze the clinical manifestations, laboratory features, and genetic profile of 32 patients (21 male and 11 female) from 23 families diagnosed with HAE between January 1996 and December 2019.

METHODS

Data were retrieved from medical records of Paediatric Immunodeficiency Clinic, Postgraduate Institute of Medical Education and Research, Chandigarh, India.

RESULTS

Median age at onset of symptoms was 6.25 years (range 1-25 years), and median age at diagnosis was 12 years (range 2-43 years). Serum complement C4 level was decreased in all patients. All patients had low C1-esterase inhibitor (C1-INH) quantitative level (type 1 HAE). SERPING1 gene sequencing could be carried out in 20 families. Of these, 11 were identified to have a pathogenic disease-causing variant in the SERPING1 gene. While 2 of these families had a previously reported mutation, remaining 9 families had novel pathogenic variants in SERPING1 gene. Because of non-availability of C1-INH therapy in India, all patients were given long-term prophylaxis (attenuated androgens or tranexamic acid (TA) or a combination of the 2). Life-threatening episodes of laryngeal edema were managed with fresh-frozen plasma (FPP) infusions. We recorded one disease-related mortality in our cohort. This happened in spite of long-term prophylaxis with stanozolol and TA.

CONCLUSIONS

We report largest single-center cohort of patients with HAE from India. Attenuated androgens, fibrinolytic agents, and FPP may be used for management of HAE in resource-limited settings.

A hereditary angioedema screening in two villages, based on an index case, and identification of a novel mutation, "1033G>T", at the SERPING1 gene

Introduction

Hereditary angioedema (HAE) may be fatal and diagnosis can be delayed up to 10 years. We aimed to screen HAE in two villages based on an index case of HAE and to investigate for the mutation of the C1 esterase inhibitor (C1-INH) gene.

Material and methods

A total of 124 people were screened in two villages. The frequency and severity of symptoms were scored. C4, C1-INH levels and C1-INH activity were measured. We investigated for mutations of the C1-INH gene.

Results

Thirty-five cases of type I HAE and 7 cases of type II HAE were determined. Thirty-one (73.8%) patients diagnosed with HAE were 18 years old or younger. There was a positive correlation between C4 levels, C1-INH levels (p < 0.0001, r = 0.81), and C1-INH activity levels (p < 0.0001, r = 0.631) and between the age at diagnosis and severity score (p < 0.0001, r = 0.651). A positive correlation was found between the age at first symptom onset and C4 levels (p = 0.002, r = 0.774), and C1-INH levels (p = 0.006, r = 0.714). A marginally significant negative correlation was found between C1-INH activity levels and severity scores (p = 0.1, r = -0.515). We identified a novel heterozygous 1033G>T missense variant of the C1-INH gene, SERPING1, in patients with type I HAE.

Conclusions

There are long delay periods in the diagnosis of HAE and when the index case is present, family screening may be very important and even life-saving, in particular, in paediatric patients without symptoms. Furthermore, the present study provides evidence to link a novel mutation, c.1033G>T, to the development of HAE in a large HAE family from Turkey.

The Diagnosis of Hereditary Angioedema: Family Caregivers' Experiences

The aim of this study was to understand the experiences of family caregivers in the process of diagnosing hereditary angioedema. An interpretive and qualitative research methodology based on Gadamer's philosophical hermeneutics was carried out. Data collection took place between May 2015 and August 2016 and included a focus group and in-depth interviews with 16 family caregivers. Two themes define the experiences of family caregivers: "Family life focuses on identifying the problem" and "Discovering and coping with a complex diagnosis." The process of diagnosis generates fear, anxiety, uncertainty, and incomprehension. Family caregivers are the main support for patients diagnosed with hereditary angioedema. As they share in the patients' suffering, they need a diagnosis to be established to be able to cope with the disease and offer support. Family health nurses can contribute to improving the coping process in this phase of the disease.

C1-esterase inhibitor (Cinryze®) use in the treatment of pediatric hereditary angioedema

Hereditary angioedema (HAE) is a rare genetic disease resulting in unpredictable and potentially life-threatening subcutaneous and submucosal attacks mediated by the vasoactive peptide, bradykinin. HAE often presents within the first or second decade of life, with attacks increasing in both frequency and severity over time. First-line therapies exert their action by replacing C1 inhibitor (C1-INH) or via blocking the production or function of bradykinin. Cinryze® is a nanofiltered C1-INH, approved in Europe for the acute treatment, preprocedure prevention and routine prophylaxis of HAE attacks, and for routine prophylaxis of attacks in the USA. Of the current C1-INH preparations available, Cinryze shows particular promise in the safe and effective treatment and prophylaxis of HAE attacks in pediatric age patients.

Pediatric hereditary angioedema: an update

Hereditary angioedema (HAE) with C1-inhibitor (C1-Inh) deficiency (C1-Inh-HAE) is a rare, life-threatening, and disabling genetic disorder characterized by self-limited tissue swelling caused by deficiency or dysfunction of C1-Inh. Our aim in this update is to discuss new advances in HAE therapy, focusing mainly on the various treatment options that have become available recently and also drugs that are under trial for prophylaxis to prevent attacks. There is a paradigm shift to where the treatment of HAE is headed, focusing now on prophylactic treatment rather than abortive management.

Pediatric Hereditary Angioedema as a Cause of Acute Compartment Syndrome of the Hand and Forearm: A Case Report

BACKGROUND

Compartment syndrome of the upper extremity is a surgical emergency that, when left untreated, can have dire consequences. Its causes are numerous, one of which is the uncommon entity hereditary angioedema, an autosomal dominant disease resulting in edema in a variety of potential locations, including the extremities. This is only the second time hereditary angioedema has been mentioned in the literature as a cause of compartment syndrome.

METHODS

We present a case of hereditary angioedema leading to hand and forearm compartment syndrome in a 13-year-old pediatric patient. Diagnosis of hereditary angioedema was made by our Rheumatology colleagues with physical exam and a thorough history, and confirmed by laboratory studies.

RESULTS

Our patient presented with compartment syndrome of the hand and forearm and underwent hand and volar forearm fasciotomies. She was subsequently worked up for hereditary angioedema with laboratory results confirming the diagnosis. She was discharged after a 5-day hospitalization with prophylactic C1-inhibitor therapy.

CONCLUSIONS

Hereditary angioedema is a rare but known cause of compartment syndrome of the upper extremity, and must be considered when patients present with compartment syndrome of unknown etiology. This disease can be diagnosed by laboratory studies and symptoms can be controlled with medical therapy.

An Update on the Use of Immunomodulators in Primary Immunodeficiencies

The genomic revolution in the past decade fuelled by breathtaking advances in sequencing technologies has defined several new genetic diseases of the immune system. Many of these newly characterized diseases are a result of defects in genes involved in immune regulation. The discovery of these diseases has opened a vista of new therapeutic possibilities. Immunomodulatory agents, a hitherto unexplored therapeutic option in primary immunodeficiency diseases have been tried in a host of these newly described maladies. These agents have been shown conclusively to favorably modulate immune responses, resulting in abatement of clinical manifestations both in experimental models and patients. While some of the treatment options have been approved for therapeutic use or have been shown to be of merit in open-label trials, others have been shown to be efficacious in a handful of clinical cases, animal models, and cell lines. Interferon γ is approved for use in chronic granulomatous disease (CGD) to reduce the burden of infection and and has a good long-term efficacy. Recombinant human IL7 therapy has been shown increase the peripheral CD4 and CD8 T cell counts in patients with idiopathic CD4. Anti-IL1 agents are approved for the management of cryopyrin-related autoinflammatory syndrome, and their therapeutic efficacy is being increasingly recognized in other autoinflammatory syndromes and CGD. Mammalian target of rapamycin (mTOR) inhibitors have been proven useful in autoimmune lymphoproliferative syndrome (ALPS) and in IPEX syndrome. Therapies reported to be potential use in case reports include abatacept in CTLA4 haploinsufficiency and LRBA deficiency, ruxolitinib in gain-of-function STAT1, tocilizumab in gain-of-function STAT3 defect, mTOR inhibitors in PIK3CD activation, magnesium in XMEN syndrome, and pioglitazone in CGD. Treatment options of merit in human cell lines include interferon α and interferon β in TLR3 and UNC-93B deficiencies, anti-interferon therapy in SAVI, and Rho-kinase inhibitors in TTC7A deficiency. Anti-IL17 agents have show efficacy in animal models of leukocyte adhesion defect (LAD) and ALPS. This topical review explores the use of various immunomodulators and other biological agents in the context of primary immunodeficiency and autoinflammatory diseases.

International consensus on the diagnosis and management of pediatric patients with hereditary angioedema with C1 inhibitor deficiency

Background

The consensus documents published to date on hereditary angioedema with C1 inhibitor deficiency (C1‐INH‐HAE) have focused on adult patients. Many of the previous recommendations have not been adapted to pediatric patients. We intended to produce consensus recommendations for the diagnosis and management of pediatric patients with C1‐INH‐HAE.

Methods

During an expert panel meeting that took place during the 9th C1 Inhibitor Deficiency Workshop in Budapest, 2015 (www.haenet.hu), pediatric data were presented and discussed and a consensus was developed by voting.

Results

The symptoms of C1‐INH‐HAE often present in childhood. Differential diagnosis can be difficult as abdominal pain is common in pediatric C1‐INH‐HAE, but also commonly occurs in the general pediatric population. The early onset of symptoms may predict a more severe subsequent course of the disease. Before the age of 1 year, C1‐INH levels may be lower than in adults; therefore, it is advisable to confirm the diagnosis after the age of one year. All neonates/infants with an affected C1‐INH‐HAE family member should be screened for C1‐INH deficiency. Pediatric patients should always carry a C1‐INH‐HAE information card and medicine for emergency use. The regulatory approval status of the drugs for prophylaxis and for acute treatment is different in each country. Plasma‐derived C1‐INH, recombinant C1‐INH, and ecallantide are the only agents licensed for the acute treatment of pediatric patients. Clinical trials are underway with additional drugs. It is recommended to follow up patients in an HAE comprehensive care center.

Conclusions

The pediatric‐focused international consensus for the diagnosis and management of C1‐INH‐HAE patients was created.

Treatment of allergic children - Where is the progress (for the practicing allergist)?

For any kind of therapeutic intervention in allergic diseases such as environmental control, pharmacological, or immunomodulating treatment including educational programs, children are addressed separately from adults. Health authorities like the Food and Drug Administration in the United States of America or the European Medicine Agency in Europe request a specific 'Pediatric investigational plan' with studies addressing dose-response relationship, safety, and efficacy for infants, children, and adolescents. During the last 2 years, promising advances have been reported for the treatment of a variety of allergic and immunologic disorders. This review summarizes the progress in the treatment of pediatric asthma and allergic diseases, based on publications of approximately the last 2.5 years (end of 2013 until May 2016) in and beyond this journal. Meanwhile, it highlights areas with promising novel therapeutic approaches, which are likely to change treatment for allergic children in the near future.

Management of Children With Hereditary Angioedema Due to C1 Inhibitor Deficiency

Hereditary angioedema (HAE) is a potentially life-threatening inherited disease characterized by attacks of skin swelling, severe abdominal pain, and upper airway swelling. Attacks typically begin in childhood, but the appropriate diagnosis is often missed. Attacks do not respond to epinephrine, antihistamines, or glucocorticoids. Recently, many effective drugs have been approved for treatment of adults with HAE, and the Medical Advisory Board of the HAE Patient's Association has developed and reported treatment recommendations for adults. Only 1 medication is approved for treatment of children <12 years of age, and there are no reported consensus recommendations for treatment of young children in the United States. The 11-member Medical Advisory Board, with extensive experience in the treatment of children, in concert with the leaders of the HAE Patient's Association, has developed these consensus recommendations to help in recognition, diagnosis, treatment of attacks, and prophylaxis of children with HAE.

Hereditary Angioedema Presenting as Recurrent Acute Pancreatitis

Hereditary angioedema (HAE) may manifest with swelling of the face, extremities, and upper airways. Gastrointestinal symptoms are also common and may include abdominal pain, vomiting, and diarrhea. However, pancreatic involvement is rare and has been reported only in a few adults with previously diagnosed HAE. We describe a 6-year-old boy who presented with recurrent severe abdominal pain accompanied by an elevation in pancreatic enzyme levels, without subcutaneous or cutaneous angioedema. His symptoms had begun 18 months earlier, and he was hospitalized several times before the present admission with a diagnosis of acute pancreatitis. More comprehensive analysis yielded low levels of C2, C4, CH50, and C1 esterase inhibitor, establishing the diagnosis of HAE. One year after diagnosis, swelling of the extremities appeared for the first time. This is the first report of a child in whom pancreatic disease was the presenting symptom of HAE. HAE should be included in the differential diagnosis of recurrent pancreatitis in children.

Plasma-derived C1-INH for managing hereditary angioedema in pediatric patients: A systematic review

Presently, medications approved for children with Hereditary Angioedema (HAE) are extremely limited. This is especially the case for children under 12 years of age. For this reason we reviewed and summarized the data on treatment of children with HAE. Available data indicate that plasma derived C1-inhibitor is a safe, effective treatment option for HAE in pediatric patients, including those below 12 years of age. Other therapies are also appear safe for the under 12 year of age, but less data are available. Importantly, home-based treatment of HAE in this age group appears to be safe and effective and can improve quality of life. These findings support current HAE consensus guidelines which strongly recommend the use of plasma derived C1-inhibitor as a first-line treatment in children and encourage home and self-treatment.