An evidence based therapeutic approach to hereditary and acquired angioedema

A Case of Refractory Angioedema

Angioedema is an acute disorder that affects mucous membranes and the deepest layers of the skin along with underlying tissue, marked by rapid swelling, large welts, and pain. There are 3 major subtypes of angioedema: mast-cell mediated, bradykinin-mediated, and multifactorial or unclear mechanism subtype. The most common subtype of bradykinin-mediated angioedema is ACE-inhibitor induced, which disproportionately affects African-Americans. It is most often self-limiting and usually responds to the withdrawal of the offending agent. The prolonged duration of angioedema is uncommon in the absence of a persistent stimulus, though it is more likely when there is an abnormality of the metabolic pathways, such as in hereditary angioedema or other gene polymorphisms affecting the complement system. We present a case of severe angioedema that persisted for over a month and required a tracheostomy to manage the airway.

Evaluation and Management of Angioedema in the Emergency Department

Angioedema is defined by non-dependent, non-pitting edema that affects several different sites and is potentially life-threatening due to laryngeal edema. This narrative review provides emergency physicians with a focused overview of the evaluation and management of angioedema. Two primary forms include histamine-mediated and bradykinin-mediated angioedema. Histamine-mediated forms present similarly to anaphylaxis, while bradykinin-mediated angioedema presents with greater face and oropharyngeal involvement and higher risk of progression. Initial evaluation and management should focus on evaluation of the airway, followed by obtaining relevant historical features, including family history, medications, and prior episodes. Histamine-mediated angioedema should be treated with epinephrine intramuscularly, antihistaminergic medications, and steroids. These medications are not effective for bradykinin-mediated forms. Other medications include C1-INH protein replacement, kallikrein inhibitor, and bradykinin receptor antagonists. Evidence is controversial concerning the efficacy of these medications in an acute episode, and airway management is the most important intervention when indicated. Airway intervention may require fiberoptic or video laryngoscopy, with preparation for cricothyrotomy. Disposition is dependent on patient's airway and respiratory status, as well as the sites involved.

Angioedema due to acquired C1-inhibitor deficiency: spectrum and treatment with C1-inhibitor concentrate

Background

Acquired angioedema due to C1-inhibitor (C1-INH) deficiency (AAE-C1-INH) is a serious condition that may result in life-threatening asphyxiation due to laryngeal edema. It is associated with malignant B-cell lymphoma and other disorders. The purpose of this study was to describe the characteristics and associated disorders of patients with AAE-C1-INH and assess the efficacy of plasma-derived C1-INH concentrate (pdC1-INH) in the treatment of AAE-C1-INH. Forty-four patients with AAE-C1-INH from the Angioedema Outpatient Service of Mainz were assessed for associated disorders. In 32 of these patients, the duration of swelling attacks was measured before and after treatment with pdC1-INH (Berinert® (CSL Behring, Marburg, Germany)). The time between injection and complete resolution of symptoms and treatment effectiveness was provided by the patients.

Results

The following underlying disorders were present: monoclonal gammopathy of undetermined significance (47.7%), non-Hodgkin lymphoma (27.3%), anti-C1-INH autoantibodies alone (11.4%), and other conditions (4.5%). In 9.1% patients, no associated disorder could be found. AAE-C1-INH led to the detection of lymphoma in 75% of patients with the malignancy. Treatment with pdC1-INH shortened attacks by an average (SD) 54.4 (± 32.8) hours (P < 0.0001). The earlier the attack was treated, the shorter the time between injection and resolution of symptoms (P = 0.0149). A total of 3553 (97.7%) of the 3636 attacks were effectively treated with pdC1-INH as assessed by the patient. The mean (SD) dose per-attack was 787 (± 442) U. pdC1-INH was effective in 1246 (93.8%) of 1329 attacks in 8 patients with anti-C1-INH autoantibodies and in 344 (99.4%) of 346 attacks in 6 patients without autoantibodies. The average (SD) dose per effectively treated attack was 1238.4 (± 578.2) U in patients with anti-C1-INH autoantibodies and 510.2 (± 69.1) U in patients without autoantibodies.

Conclusions

pdC1-INH is highly effective in treating AAE-C1-INH patients and is also effective in the vast majority of attacks in patients with anti-C1-INH autoantibodies. It is fast-acting and reduces attack duration.

Human tissue kallikrein in the treatment of acute ischemic stroke

Acute ischemic stroke (AIS) remains a major cause of death and disability throughout the world. The most severe form of stroke results from large vessel occlusion of the major branches of the Circle of Willis. The treatment strategies currently available in western countries for large vessel occlusion involve rapid restoration of blood flow through removal of the offending blood clot using mechanical or pharmacological means (e.g. tissue plasma activator; tPA). This review assesses prospects for a novel pharmacological approach to enhance the availability of the natural enzyme tissue kallikrein (KLK1), an important regulator of local blood flow. KLK1 is responsible for the generation of kinins (bradykinin and kallidin), which promote local vasodilation and long-term vascularization. Moreover, KLK1 has been used clinically as a direct treatment for multiple diseases associated with impaired local blood flow including AIS. A form of human KLK1 isolated from human urine is approved in the People's Republic of China for subacute treatment of AIS. Here we review the rationale for using KLK1 as an additional pharmacological treatment for AIS by providing the biochemical mechanism as well as the human clinical data that support this approach.

Angiotensin-converting Enzyme Inhibitors-induced Angioedema

Angiotensin-converting enzyme inhibitors (ACEI) are widely used drugs nowadays in treating patients diagnosed with cardiovascular disorders. We present two consecutive cases of acquired angioedema caused by the administration of enalapril and lisinopril in patients with indication for ACE-inhibitors therapy. Rigorous follow-up of side effects of ACEI is required, due to these possible life-threatening adverse reactions.

Omalizumab rapidly improves angioedema-related quality of life in adult patients with chronic spontaneous urticaria: X-ACT study data

Background

The X‐ACT study aimed to examine the effect of omalizumab treatment on quality of life (QoL) in chronic spontaneous urticaria (CSU) patients with angioedema refractory to high doses of H₁‐antihistamines.

Methods

In X‐ACT, a phase III, double‐blind, placebo‐controlled study, CSU patients (18‐75 years) with ≥4 angioedema episodes during the 6 months before inclusion were randomized (1:1) to receive omalizumab 300 mg or placebo every 4 weeks for 28 weeks. Angioedema‐related QoL, skin‐related QoL impairment, and psychological well‐being were assessed.

Results

Ninety‐one patients were randomized and 68 (omalizumab, n = 35; placebo, n = 33) completed the 28‐week treatment period. At baseline, the mean (SD) total Angioedema QoL (AE‐QoL; 56.2 [18.7] and 59.9 [19.2]) and Dermatology Life Quality Index (DLQI; 14.6 [5.7] and 16.6 [7.3]) score were high in the omalizumab and placebo group, respectively. At Week 4 (after the first treatment), the least squares mean difference in the AE‐QoL and DLQI score between groups was −17.6 (P < .001) and −7.2 (P < .001), respectively. Significant QoL improvements in the omalizumab vs placebo groups continued until Week 28, but returned to placebo levels at the follow‐up visit. The mean (SD) baseline 5‐item World Health Organization Well‐being Index was 10.0 (5.5, omalizumab) and 7.7 (5.3, placebo), which increased above the depression threshold (<13) from Week 4 and throughout with omalizumab but not placebo treatment. Compared to placebo, omalizumab was also associated with decreased fear of suffocation due to angioedema.

Conclusions

Our findings support omalizumab treatment in patients with severe H1‐antihistamine‐refractory CSU with angioedema.

Angioedema: Clinical Presentations and Pharmacological Management

Angioedema (AE) is a unique clinical presentation of an unchecked release of bradykinin. The origin of this clinical presentation can be either genetic or acquired. The outcome within the patient is subcutaneous swelling of the lower layers of the epidermis. Symptoms are most often localized to the upper airway or the gastrointestinal tract. A typical course resolves in 5 to 7 days, but in some patients, the clinical manifestations exist up to 6 weeks. Hereditary AE is rare and genetically linked, and typically, the patient has episodes for many years before diagnosis. Episodes of acquired AE may be drug induced, triggered by a specific allergen, or idiopathic. Angioedema can elicit the need for critical care interventions, for advanced airway management, or unnecessary abdominal surgery. The treatment for these patients is evolving as new pharmacological agents are developed. This article addresses subtypes of AE, triggers, pharmacology, and information for interdisciplinary team planning of individualized case management.

Acquired C1 Inhibitor Deficiency

Acquired angioedema due to C1-INH deficiency (C1-INH-AAE) can occur when there are acquired (not inherited) deficiencies of C1-INH. A quantitative or functional C1-INH deficiency with negative family history and low C1q is diagnostic of C1-INH-AAE. The most common conditions associated with C1-INH-AAE are autoimmunity and B-cell lymphoproliferative disorders. A diagnosis of C1-INH-AAE can precede a diagnosis of lymphoproliferative disease and confers an increased risk for developing non-Hodgkin lymphoma. Treatment focuses on symptom control with therapies that regulate bradykinin activity (C1-INH concentrate, icatibant, ecallantide, tranexamic acid, androgens) and treatment of any underlying conditions.

Proteinases, Their Extracellular Targets, and Inflammatory Signaling

Given that over 2% of the human genome codes for proteolytic enzymes and their inhibitors, it is not surprising that proteinases serve many physiologic-pathophysiological roles. In this context, we provide an overview of proteolytic mechanisms regulating inflammation, with a focus on cell signaling stimulated by the generation of inflammatory peptides; activation of the proteinase-activated receptor (PAR) family of G protein-coupled receptors (GPCR), with a mechanism in common with adhesion-triggered GPCRs (ADGRs); and by proteolytic ion channel regulation. These mechanisms are considered in the much wider context that proteolytic mechanisms serve, including the processing of growth factors and their receptors, the regulation of matrix-integrin signaling, and the generation and release of membrane-tethered receptor ligands. These signaling mechanisms are relevant for inflammatory, neurodegenerative, and cardiovascular diseases as well as for cancer. We propose that the inflammation-triggering proteinases and their proteolytically generated substrates represent attractive therapeutic targets and we discuss appropriate targeting strategies.

Diagnosis and screening of patients with hereditary angioedema in primary care

Hereditary angioedema (HAE) is a rare autosomal dominant disease that commonly manifests with episodes of cutaneous or submucosal angioedema and intense abdominal pain. The condition usually presents due to a deficiency of C1 esterase inhibitor (C1-INH) that leads to the overproduction of bradykinin, causing an abrupt increase in vascular permeability. A less-understood and less-common form of the disease presents with normal C1-INH levels. Symptoms of angioedema may be confused initially with mast cell-mediated angioedema, such as allergic reactions, and may perplex physicians when epinephrine, antihistamine, or glucocorticoid therapies do not provide relief. Similarly, abdominal attacks may lead to unnecessary surgeries or opiate dependence. All affected individuals are at risk for a life-threatening episode of laryngeal angioedema, which continues to be a source of fatalities due to asphyxiation. Unfortunately, the diagnosis is delayed on average by almost a decade due to a misunderstanding of symptoms and general lack of awareness of the disease. Once physicians suspect HAE, however, diagnostic methods are reliable and available at most laboratories, and include testing for C4, C1-INH protein, and C1-INH functional levels. In patients with HAE, management consists of acute treatment of an attack as well as possible short- or long-term prophylaxis. Plasma-derived C1-INH, ecallantide, icatibant, and recombinant human C1-INH are new treatments that have been shown to be safe and effective in the treatment of HAE attacks. The current understanding of HAE has greatly improved in recent decades, leading to growing awareness, new treatments, improved management strategies, and better outcomes for patients.

Diagnostic and therapeutic management of hereditary angioedema due to C1-inhibitor deficiency: the Italian experience

PURPOSE OF REVIEW

Hereditary angioedema (HAE) due to C1-inhibitor (C1-INH) deficiency (C1-INH-HAE) is a rare disease, with a reported prevalence of about 1 : 50 000. C1-INH-HAE causes disabling symptoms, which may be life-threatening if swelling affects upper airways. Diagnostic procedures are now well established and the role of bradykinin as the main mediator of plasma outflow eliciting angioedema formation has been clearly elucidated.

RECENT FINDINGS

Increased understanding of the pathogenesis of C1-INH-HAE allowed in recent years the development of new drugs targeted to inhibit bradykinin synthesis (Ecallantide) or activity (Icatibant). At the same time, a recombinant C1-INH concentrate (Ruconest) was produced from the milk of transgenic rabbits and two plasma-derived C1-INHs (Berinert, Cinryze) underwent controlled trials to obtain marketing authorization. In 2012, an Italian network for C1-INH-HAE (ITACA) was established by physicians of 17 HAE reference centres to collect data from Italian patients and to homogenize and improve the diagnostic and therapeutic approach to the disease.

SUMMARY

Although there is a widespread agreement on therapeutic goals and treatment of C1-INH-HAE acute attacks, different approaches to prophylaxis are still present among HAE experts. The clinical experience of ITACA on a large population of C1-INH-HAE patients followed for several years may help in identifying the most effective strategies for the management of the disease.

An individualized diagnostic approach based on guidelines for chronic urticaria (CU)

Chronic urticaria (CU), defined as the spontaneous or inducible appearance of hives, angioedema or both for 6 weeks or more, presents with a number of subtypes which all substantially impair patients' quality of life (QoL). International urticaria guidelines give clear recommendations on workup and treatment but the occurrence of CU with multiple causes and triggers (sometimes with more than one subtype occurring in a single patient) presents challenges for an individualized assessment by physicians. This review summarizes recent guidance on the classification, diagnosis and assessment of CU subtypes and discusses how currently available patient assessment tools and laboratory tests can be used in clinical practice as part of an individualized patient management plan.

Overview of Laboratory Testing and Clinical Presentations of Complement Deficiencies and Dysregulation

Historically, complement disorders have been attributed to immunodeficiency associated with severe or frequent infection. More recently, however, complement has been recognized for its role in inflammation, autoimmune disorders, and vision loss. This paradigm shift requires a fundamental change in how complement testing is performed and interpreted. Here, we provide an overview of the complement pathways and summarize recent literature related to hereditary and acquired angioedema, infectious diseases, autoimmunity, and age-related macular degeneration. The impact of complement dysregulation in atypical hemolytic uremic syndrome, paroxysmal nocturnal hemoglobinuria, and C3 glomerulopathies is also described. The advent of therapeutics such as eculizumab and other complement inhibitors has driven the need to more fully understand complement to facilitate diagnosis and monitoring. In this report, we review analytical methods and discuss challenges for the clinical laboratory in measuring this complex biochemical system.

Complement, a target for therapy in inflammatory and degenerative diseases

Complement is a key component of immunity with crucial inflammatory and opsonic properties; inappropriate activation of complement triggers or exacerbates inflammatory disease.

Complement dysregulation is a core feature of some diseases and contributes to pathology in many others.

Approved agents have been developed for and are highly effective in some orphan applications, but their progress to use in more common diseases has been slow.

Numerous challenges, such as target concentration or high turnover, limit the efficacy of these agents in humans.

Numerous novel agents targeting different parts of the complement system in different ways are now emerging from pre-clinical studies and are entering Phase I/II trials; these agents bring the potential for more-effective and more-specific anti-complement therapies in disease.

Other agents, both biologic and small molecule, are in Phase II or III trials for both rare and common diseases — administration routes include localized (for example, intravitreal) and systemic routes.

There is an urgent need to develop biomarkers and imaging methods that enable monitoring of the effects and efficacy of anti-complement agents.

The complement cascade, a key regulator of innate immunity, is a rich source of potential therapeutic targets for diseases including autoimmune, inflammatory and degenerative disorders. Morgan and Harris discuss the progress made in modulating the complement system and the existing challenges, including dosing, localization of the drug to the target and how to interfere with protein–protein interactions.

The complement system is a key innate immune defence against infection and an important driver of inflammation; however, these very properties can also cause harm. Inappropriate or uncontrolled activation of complement can cause local and/or systemic inflammation, tissue damage and disease. Complement provides numerous options for drug development as it is a proteolytic cascade that involves nine specific proteases, unique multimolecular activation and lytic complexes, an arsenal of natural inhibitors, and numerous receptors that bind to activation fragments. Drug design is facilitated by the increasingly detailed structural understanding of the molecules involved in the complement system. Only two anti-complement drugs are currently on the market, but many more are being developed for diseases that include infectious, inflammatory, degenerative, traumatic and neoplastic disorders. In this Review, we describe the history, current landscape and future directions for anti-complement therapies.

Patients perception of self-administrated medication in the treatment of hereditary angioedema

BACKGROUND

Early therapy of hereditary angioedema (HAE) decreases morbidity, improves outcomes, decreases absenteeism, and possibly decreases mortality. This can be accomplished best with self-therapy. Previously, the authors examined barriers to self-therapy from the perspective of the nurse and the physician, but data are lacking on what patients perceive as major barriers to self-administered therapy for HAE.

OBJECTIVE

To identify those barriers in a prospective fashion by patient interview.

METHODS

After approval from the institutional review board, a telephone survey was performed of patients with HAE from a database of patients who were recently seen in the clinic. The survey focused on anxiety, depression, stress, concerns regarding method of administration, the ability to inject themselves, and what they perceived as barriers to providing self-care.

RESULTS

Ninety-two patients were contacted and 59 agreed to participate. With 69% of those patients currently undergoing self-administered treatment, the results showed minimal depression and anxiety, a high satisfaction with treatment, and significant compliance with treatment. Most of those not yet on self-administered therapy wanted to start despite being satisfied with the care received in the emergency department. They also believed care at home would be optimal. The main concern of the 2 groups was not being able to treat themselves in the event of an HAE attack.

CONCLUSION

From these data, it is obvious that most patients are willing to self-treat. This suggests that physicians should encourage self-treatment of HAE to improve outcomes and quality of life of patients with HAE.

Current state of hereditary angioedema management: a patient survey

Hereditary angioedema (HAE) is a chronic disease with a high burden of disease that is poorly understood and often misdiagnosed. Availability of treatments, including C1 esterase inhibitor (C1INH) replacement, ecallantide, and icatibant, marks a significant advance for HAE patients. We aimed to better understand the current state of HAE care, from a patient perspective, after the introduction of several novel therapies. One session of the United States Hereditary Angioedema Association 2013 patient summit was devoted to data collection for this study. Patients attending the summit were self-selected, and HAE diagnosis was self-reported. Survey questions assessed patient characteristics, burden of disease, and treatment. Participant responses were captured using an audience response system. We surveyed 149 (80%) type I and II HAE (HAE-C1INH) and 37 (20%) HAE with normal C1INH (HAE-nlC1INH) patients. HAE-C1INH (72%) and HAE-nlCINH patients (76%) equally reported that HAE had a significant impact on quality of life (QOL). A third of HAE-C1INH patients were diagnosed within one year of their first HAE attack, but another third reported a delay of more than 10 years. Most HAE-C1INH (88%) and HAE-nlC1INH (76%) patients had on-demand treatment available. HAE-C1INH patients frequently had an individual treatment plan (76%) compared with 50% of HAE-nlC1INH patients. Most HAE-C1INH patients went to the emergency department (ED) or were hospitalized less than once every six months (80%). Our findings show that HAE management is improving with good access to on-demand and prophylactic treatment options. However, HAE patients still have a significant burden of disease and continued research and educational efforts are needed.