Population pharmacokinetics of recombinant human C1 inhibitor in patients with hereditary angioedema

Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema

Angioedema is a well-recognized and potentially lethal complication of angiotensin-converting enzyme inhibitor (ACEi) therapy. In ACEi-induced angioedema, bradykinin accumulates due to a decrease in its metabolism by ACE, the enzyme that is primarily responsible for this function. The action of bradykinin at bradykinin type 2 receptors leads to increased vascular permeability and the accumulation of fluid in the subcutaneous and submucosal space. Patients with ACEi-induced angioedema are at risk for airway compromise because of the tendency for the face, lips, tongue, and airway structures to be affected. The emergency physician should focus on airway evaluation and management when treating patients with ACEi-induced angioedema.

The international WAO/EAACI guideline for the management of hereditary angioedema - The 2021 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2), by providing guidance on common and important clinical issues, such as: 1) How should HAE be diagnosed? 2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? 3) What are the goals of treatment? 4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast feeding women? 5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2021 revision and update

Hereditary angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1 inhibitor (type 1) and HAE with dysfunctional C1 inhibitor (type 2), by providing guidance on common and important clinical issues, such as: (1) How should HAE be diagnosed? (2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? (3) What are the goals of treatment? (4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast-feeding women? and (5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema

Angioedema is a well-recognized and potentially lethal complication of angiotensin-converting enzyme inhibitor (ACEi) therapy. In ACEi-induced angioedema, bradykinin accumulates due to a decrease in its metabolism by ACE, the enzyme that is primarily responsible for this function. The action of bradykinin at bradykinin type 2 receptors leads to increased vascular permeability and the accumulation of fluid in the subcutaneous and submucosal space. Patients with ACEi-induced angioedema are at risk for airway compromise because of the tendency for the face, lips, tongue, and airway structures to be affected. The emergency physician should focus on airway evaluation and management when treating patients with ACEi-induced angioedema.

Therapeutic SERPINs: Improving on Nature

Serine proteases drive important physiological processes such as coagulation, fibrinolysis, inflammation and angiogenesis. These proteases are controlled by serine protease inhibitors (SERPINs) that neutralize their activity. Currently, over 1,500 SERPINs are known in nature, but only 37 SERPINs are found in humans. Thirty of these are functional protease inhibitors. The inhibitory potential of SERPINs is in perfect balance with the proteolytic activities of its targets to enable physiological protease activity. Hence, SERPIN deficiency (either qualitative or quantitative) can lead to disease. Several SERPIN resupplementation strategies have been developed to treat SERPIN deficiencies, including concentrates derived from plasma and recombinant SERPINs. SERPINs usually inhibit multiple proteases, but only in their active state. Over the past decades, considerable insights have been acquired in the identification of SERPIN biological functions, their inhibitory mechanisms and specificity determinants. This paves the way for the development of therapeutic SERPINs. Through rational design, the inhibitory properties (selectivity and inhibitory potential) of SERPINs can be reformed and optimized. This review explores the current state of SERPIN engineering with a focus on reactive center loop modifications and backbone stabilization. We will discuss the lessons learned from these recombinant SERPINs and explore novel techniques and strategies that will be essential for the creation and application of the future generation of therapeutic SERPINs.

Plasma-derived and recombinant C1 esterase inhibitor: Binding profiles and neuroprotective properties in brain ischemia/reperfusion injury

C1 esterase inhibitor (C1INH) is known to exert its inhibitory effect by binding to several target proteases of the contact and complement systems. One of C1INH's targets comprise mannose-binding lectin (MBL), a critical player in post-stroke pathophysiology. We therefore explored the effects of recombinant human (rh) and plasma derived (pd) C1INH in C57BL/6J mice subjected to transient occlusion of the middle cerebral artery (tMCAo), receiving 15U/mouse of pd or rhC1INH intravenously, at reperfusion. We analyzed the compounds' (i)neuroprotective effects, (ii) plasma presence, (iii)effects on circulating and brain MBL, (iv)time course of endothelial deposition, and (v) effects on the formation of active complement products. rhC1INH-treated mice had neuroprotective effects, including reduced behavioral deficits and neuronal loss, associated with decreased MBL brain deposition and decreased formation of complement C4b active fragments. In contrast, pdC1INH did not show these neuroprotective effects despite its longer plasma residence time. We also analyzed the response to tMCAo in C1INH-deficient mice, observing a poorer ischemic outcome compared to the wild type mice, which could be partially prevented by rhC1INH administration. In conclusion, we show that rhC1INH exhibits stronger neuroprotective effects than the corresponding plasma-derived protein after experimental ischemia/reperfusion injury in the brain, placing it as a promising drug for stroke. Differential effects are likely related to more effective MBL inhibition which further confirms it as a useful pharmacological target for stroke.

Population pharmacokinetics of recombinant human C1 esterase inhibitor in children with hereditary angioedema

BACKGROUND

Recombinant human C1 esterase inhibitor (rhC1-INH) is indicated in the United States for the treatment of acute hereditary angioedema (HAE) attacks in adolescents and adults; it is also indicated in Europe for children aged 2 years and older. A need exists for further insight into potential pharmacokinetic (PK) differences in functional C1-INH levels by age (ie, children, adolescents, and adults).

OBJECTIVE

To perform population PK modeling to predict C1-INH levels by age after by age rhC1-INH administration.

METHODS

Data from a phase 2 pediatric trial (children aged 4-13 years at screening) were added to a database of 6 trials in adults and adolescents. An unpublished population PK model was refined and used to simulate C1-INH exposure.

RESULTS

Analysis included 153 individuals (14 healthy volunteers; 139 patients with HAE) and 1788 functional C1-INH measurements (59 from 20 patients in the pediatric trial). Bodyweight (population weight, 16-128 kg) was a key predictor of C1-INH volume of distribution. Age was not a predictor of C1-INH PK after the inclusion of bodyweight in the model. Simulations of the recommended rhC1-INH dosing regimen (bodyweight <84 kg, 50 U/kg; ≥84 kg, 4200 U) revealed that overall C1-INH exposure was comparable among age groups. Predicted peak functional C1-INH concentrations were at or above the lower level of normal (≥0.7 U/mL) for 99.8% of adults (≥18 years), 99.8% of adolescents (14-17 years), and 96.0% of children (2-13 years).

CONCLUSION

The analyses support the same weight-based rhC1-INH dosing for HAE attacks in children as currently recommended for adolescents and adults. These results support clinical trial data, which revealed similar safety and efficacy profiles across these age groups.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2017 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease. Early diagnosis and appropriate therapy are essential. This update and revision of the global guideline for HAE provides up-to-date consensus recommendations for the management of HAE. In the development of this update and revision of the guideline, an international expert panel reviewed the existing evidence and developed 20 recommendations that were discussed, finalized and consented during the guideline consensus conference in June 2016 in Vienna. The final version of this update and revision of the guideline incorporates the contributions of a board of expert reviewers and the endorsing societies. The goal of this guideline update and revision is to provide clinicians and their patients with guidance that will assist them in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2). The key clinical questions covered by these recommendations are: (1) How should HAE-1/2 be defined and classified?, (2) How should HAE-1/2 be diagnosed?, (3) Should HAE-1/2 patients receive prophylactic and/or on-demand treatment and what treatment options should be used?, (4) Should HAE-1/2 management be different for special HAE-1/2 patient groups such as pregnant/lactating women or children?, and (5) Should HAE-1/2 management incorporate self-administration of therapies and patient support measures?

The Lectin Pathway of Complement in Myocardial Ischemia/Reperfusion Injury-Review of Its Significance and the Potential Impact of Therapeutic Interference by C1 Esterase Inhibitor

Acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality in modern medicine. Early reperfusion accomplished by primary percutaneous coronary intervention is pivotal for reducing myocardial damage in ST elevation AMI. However, restoration of coronary blood flow may paradoxically trigger cardiomyocyte death secondary to a reperfusion-induced inflammatory process, which may account for a significant proportion of the final infarct size. Unfortunately, recent human trials targeting myocardial ischemia/reperfusion (I/R) injury have yielded disappointing results. In experimental models of myocardial I/R injury, the complement system, and in particular the lectin pathway, have been identified as major contributors. In line with this, C1 esterase inhibitor (C1INH), the natural inhibitor of the lectin pathway, was shown to significantly ameliorate myocardial I/R injury. However, the hypothesis of a considerable augmentation of myocardial I/R injury by activation of the lectin pathway has not yet been confirmed in humans, which questions the efficacy of a therapeutic strategy solely aimed at the inhibition of the lectin pathway after human AMI. Thus, as C1INH is a multiple-action inhibitor targeting several pathways and mediators simultaneously in addition to the lectin pathway, such as the contact and coagulation system and tissue leukocyte infiltration, this may be considered as being advantageous over exclusive inhibition of the lectin pathway. In this review, we summarize current concepts and evidence addressing the role of the lectin pathway as a potent mediator/modulator of myocardial I/R injury in animal models and in patients. In addition, we focus on the evidence and the potential advantages of using the natural inhibitor of the lectin pathway, C1INH, as a future therapeutic approach in AMI given its ability to interfere with several plasmatic cascades. Ameliorating myocardial I/R injury by targeting the complement system and other plasmatic cascades remains a valid option for future therapeutic interventions.

Pharmacological Management of Hereditary Angioedema with C1-Inhibitor Deficiency in Pediatric Patients

Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is a form of bradykinin-mediated angioedema. It is a rare disorder with an onset during childhood in most instances. Therefore, familiarity with the options for the management of pediatric cases is indispensable. The recurrent angioedematous episodes do not respond to conventional treatments and may evolve into a life-threatening condition. In view of the recommendations adopted by international consensus in 2016, patient management and follow-up should be guided by an individualized strategy. During the last decade, various medicinal products with novel modes of action and different posology have been developed for the treatment of C1-INH-HAE. These drugs either inhibit the release of bradykinin (plasma-derived C1-inhibitors, recombinant C1-inhibitors, kallikrein inhibitors) or prevent the released bradykinin from binding to its receptor (bradykinin B₂ receptor antagonists). This review summarizes the properties of the medicinal products currently available for the treatment of C1-INH-HAE, the indications for their use in pediatric patients, and the findings of the clinical trials conducted in this patient population. It is concluded by a brief outline of future therapeutic options.

Complete kinetic follow-up of symptoms and complement parameters during a hereditary angioedema attack

We studied the kinetics of C1-inhibitor (C1-INH) and other complement parameters in a self-limited edematous attack (EA) in a patient with hereditary angioedema due to C1-INH deficiency to better understand the pathomechanism of the evolution, course, and complete resolution of EAs. C1-INH concentration and functional activity (C1-INH_c+f ), C1(q,r,s), C3, C4, C3a, C4a, C5a, and SC5b-9 levels were measured in blood samples obtained during the 96-hour observation period. The highest C1-INH_c+f , C4, and C1(q,r,s) levels were measured at baseline, and their continuous decrease was observed during the entire observation period. C4 depletion started at prodromal phase, and C4 was lowest after the maximum severity peak. Compared to baseline, C4a level was four times higher 7 hours before the onset of the attack. C1-INH did not increase after resolution of the attack suggesting that factors other than C1-INH may be important in this process. C4a may be a useful biomarker for the prediction of EAs.

Investigational drugs in phase I and phase II clinical trials for hereditary angioedema

INTRODUCTION

Hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE) is a rare bradykinin-mediated disease characterized by recurrent subcutaneous and/or submucosal angioedematous attacks (HAE attacks), which occur unpredictably. The recurrent HAE attacks do not respond to conventional treatments, and may evolve into a life-threatening condition; therefore, special therapy is required.

AREAS COVERED

The agents used so far for the acute management of HAE attacks act by blocking the release of bradykinin, or its binding to its receptor. By contrast, the investigational medicinal products under evaluation in Phase I and II clinical trials are targeted at the prevention of HAE attacks. Chemically, these new drugs are small synthetic molecules, oligonucleotides, or antibodies, which inhibit either kallikrein, or Factor XII.

EXPERT OPINION

The key considerations for the development of new medicinal products include more straightforward dosing, self-administration, longer duration of action, and keeping the patient attack-free. This review summarizes the status and the findings of the currently ongoing Phase I and Phase II clinical trials of C1-INH-HAE.

Recombinant Human C1-Esterase Inhibitor to Treat Acute Hereditary Angioedema Attacks in Adolescents

BACKGROUND

Recombinant human C1-esterase inhibitor (rhC1-INH) is efficacious and well tolerated for managing hereditary angioedema (HAE) attacks in adults. However, there are insufficient data on its efficacy and safety in adolescents.

OBJECTIVE

To evaluate the efficacy and safety profiles of rhC1-INH for acute HAE attacks in adolescents.

METHODS

Adolescents (aged 12-18 y) with HAE enrolled in 2 randomized controlled trials and 2 open-label extension trials were included and received intravenous rhC1-INH for acute attacks. Times to the beginning of sustained symptom relief (visual analog scale change from baseline ≥20 mm) and minimal symptoms (visual analog scale score of <20 mm across locations) were assessed. Safety parameters included hypersensitivity reactions, anti-rhC1-INH antibodies, and host-related impurities.

RESULTS

Sixteen adolescents (50 attacks, aged 14-18 y) received rhC1-INH. Attacks were managed with single-dose rhC1-INH 50 U/kg (46.0%) and single-dose rhC1-INH 2100 U (16%), and 32.0% were treated with additional doses after receiving an initial rhC1-INH 2100 U dose (total dose, 4200-6300 U). Most attacks (88.0%) occurred at a single location; 59.1% (26 of 44) were abdominal. Across the first 5 attacks, median times to the beginning of symptom relief ranged from 19.0 to 78.5 minutes; median times to minimal symptoms ranged from 120 to 190 minutes. Pharmacokinetics showed that rhC1-INH restored functional plasma C1-esterase inhibitor levels to the normal (>70%) range for almost all evaluable patients. No severe or drug-related adverse events or hypersensitivity reactions occurred. No treatment-emergent antibodies to rhC1-INH or host-related impurities were observed.

CONCLUSIONS

rhC1-INH is efficacious and well tolerated among adolescents with HAE.

Inhibition of complement improves graft outcome in a pig model of kidney autotransplantation

BACKGROUND

Ischemia reperfusion injury (IRI) induced immune response is a critical issue in transplantation. Complement and contact system activation are among its key mechanisms.

STUDY DESIGN

We investigated the benefits of pre-reperfusion treatment with recombinant human C1INH (rhC1INH), inhibitor of both complement and contact activation, in a pig model of kidney autotransplantation, subjecting the organ to 60 min warm ischemia prior to 24 h static preservation to maximize damage.

RESULTS

Serum creatinine measurement showed that treated animals recovered glomerular function quicker than the Vehicle group. However, no difference was observed in tubular function recovery, and elevated level of urinary NGal (Neutrophil gelatinase-associated lipocalin) and plasma AST (Aspartate Aminotransferase) were detected, indicating that treatment did not influence IRI-mediated tubular cell necrosis. Regarding chronic graft outcome, rhC1INH significantly prevented fibrosis development and improved function. Immunohistochemistry and western blot showed decreased invasion by macrophages and T lymphocytes, and reduction of epithelial to mesenchymal transition. We determined the effect of treatment on complement activation with immunofluorescence analyses at 30 min post reperfusion, showing an inhibition of C4d deposition and MBL staining in treated animals.

CONCLUSIONS

In this model, the inhibition of complement activation by rhC1INH at reperfusion, while not completely counteracting IRI, limited immune system activation, significantly improving graft outcome on the short and long term.

Recombinant human C1 esterase inhibitor in the management of hereditary angioedema

Hereditary angioedema (HAE), a rare autosomal dominant genetic disorder, is caused by a deficiency in functional C1 esterase inhibitor (C1-INH). This potentially life-threatening condition manifests as recurrent attacks of subcutaneous and submucosal swelling of the skin, gastrointestinal tract and larynx. The management of HAE includes treatment of acute episodes, short-term prophylaxis in preparation for exposure to known triggers and long-term prophylaxis to decrease the incidence and severity of HAE attacks. Four products are approved in the USA for the treatment of acute attacks of HAE, including one human plasma-derived C1-INH therapy, a recombinant human C1-INH product (rhC1-INH), a plasma kallikrein inhibitor and a bradykinin B2 receptor antagonist. In addition, one human plasma-derived C1-INH therapy and danazol are approved for prophylaxis of HAE attacks. rhC1-INH, extracted from the milk of transgenic rabbits, is a glycoprotein of 478 amino acids with an identical amino acid sequence to the endogenous human C1-INH protein. Population pharmacokinetic analysis of rhC1-INH supports an intravenous dosing strategy of 50 U/kg (maximum 4200 U). The safety and efficacy of rhC1-INH in the treatment of acute attacks in patients with HAE were demonstrated in three randomized, double-blind, placebo-controlled studies and two open-label extension studies. In a pilot prophylaxis study, weekly administration of rhC1-INH 50 U/kg for 8 weeks reduced the incidence of HAE attacks and was well tolerated. Administration of rhC1-INH has not been associated with the development of anti-drug antibodies or antibodies to anti-host-related impurities.

Recombinant replacement therapy for hereditary angioedema due to C1 inhibitor deficiency

Hereditary angioedema is a rare genetic condition transmitted as an autosomal dominant trait and characterized most commonly by the production of either inadequate or nonfunctioning C1 esterase inhibitor (C1-INH), a blood protein that regulates proteases in the complement, fibrinolytic and contact systems. Patients with hereditary angioedema suffer from episodic, unpredictable manifestations of edema affecting multiple anatomical locations, including the GI tract, facial tissue, the upper airway, oropharynx, urogenital region and/or the arms and legs. A rational approach to treatment is replacement of C1-INH protein, to normalize the levels of C1-INH activity and halt the progression of the biochemical activation processes underlying the edema formation. Ruconest is a highly purified recombinant human C1-INH. This article will focus on the results of ten clinical studies demonstrating the efficacy and safety of Ruconest® (Pharming Group NV, Leiden, the Netherlands), which is now approved for use in Europe, Israel and the USA.

Elevated D-dimers in attacks of hereditary angioedema are not associated with increased thrombotic risk

Background

Recommended management of attacks of hereditary angioedema (HAE) due to C1 esterase inhibitor (C1-INH) deficiency (C1-INH-HAE) includes therapy with exogenous C1INH. Thrombotic/thromboembolic events (TEE) have been reported with plasma-derived C1INH, but so far none with recombinant human C1INH (rhC1INH). This phase III, randomized, placebo (saline)-controlled study evaluated the safety of rhC1INH 50 IU/kg for the treatment of acute attacks in 74 patients with C1-INH-HAE.

Methods

Monitoring for TEE and assessment of risk of deep vein thrombosis (DVT) by the Wells prediction rule were performed, and levels of fibrin degradation products (plasma D-dimers) were assessed before study drug administration (baseline), 2 h, and 7 days posttreatment.

Results

Plasma D-dimer levels were elevated in 80% of the patients (median [25th–75th percentiles]: 2149 [480–5105] μg/l; normal ≤250 μg/l) and were higher in patients with submucosal (abdominal, oropharyngeal–laryngeal) attacks (3095 [890–10000] μg/l; n = 29) compared with subcutaneous (peripheral, facial) attacks (960 [450–4060] μg/l; n = 35). Median plasma D-dimer levels were comparable across treatment groups at baseline (1874 [475–4568] μg/l rhC1INH; 2259 [586–7533] μg/l saline) and 2 h postinfusion (2389 [760–4974] μg/l rhC1INH; 2550 [310–8410] μg/l saline); median plasma D-dimer levels were decreased by Day 7 in both groups (425 [232–3240] μg/l rhC1INH; 418 [246–2318] μg/l saline). No increased risk of DVT was identified, nor any TEE reported in rhC1INH treated or controls.

Conclusion

Elevated plasma D-dimer levels were associated with acute C1-INH-HAE attacks, particularly with submucosal involvement. However, rhC1INH therapy was not associated with thrombotic events.

Recombinant human-C1 inhibitor is effective and safe for repeat hereditary angioedema attacks

BACKGROUND

Hereditary angioedema (HAE) caused by a deficiency in functional C1 esterase inhibitor (C1INH) is characterized by recurrent episodes of cutaneous and/or mucosal/submucosal tissue swelling affecting multiple anatomic locations. Previous studies demonstrated efficacy of recombinant human C1INH (rhC1INH) for acute HAE attacks.

OBJECTIVE

This study evaluated the efficacy and safety of rhC1INH (50 IU/kg) for the treatment of multiple HAE attacks in an open-label extension study.

METHODS

Time to onset of symptom relief and time to minimal symptoms were assessed using a Treatment Effect Questionnaire (TEQ), a visual analog scale, and a 6-point ordinal scale Investigator Score.

RESULTS

Forty-four patients received rhC1INH, and a single dose was administered for 215 of 224 (96%) attacks. Median time to beginning of symptom relief based on TEQ for the first 5 attacks was 75.0 (95% CI, 69-89) minutes, ranging from 62.5 (95% CI, 48-90) to 134.0 (95% CI, 32-119) minutes. Median time to minimal symptoms using TEQ for the first 3 attacks was 303.0 (95% CI, 211-367) minutes. rhC1INH was well tolerated. There were no discontinuations due to adverse events. No thrombotic or anaphylactic events were reported, and repeat rhC1INH treatments were not associated with neutralizing anti-C1INH antibodies.

CONCLUSIONS

A single 50-IU/kg dose rhC1INH was effective for improving symptoms of an HAE attack with sustained efficacy for treatment of subsequent attacks. rhC1INH had a positive safety profile throughout the study. This study supports repeated use of rhC1INH over time in patients with HAE attacks.

Effect of C1-Esterase-inhibitor in angiotensin-converting enzyme inhibitor-induced angioedema

OBJECTIVES/HYPOTHESIS

The study objective was to generate pilot data to evaluate the effectiveness and safety of C1-esterase-inhibitor concentrate (C1-INH) compared to standard treatment in patients with angiotensin-converting enzyme inhibitor (ACEi)-induced angioedema affecting the upper aerodigestive tract.

STUDY DESIGN

Proof-of-concept case series with historical control.

METHODS

Adult patients with angioedema in the upper aerodigestive tract presenting to the emergency department were included. After establishing the diagnosis of ACEi-induced angioedema based on patient history and thorough clinical examination, all patients were administered 1,000 international units (IU) of C1-INH intravenously. A historical control group consisting of adult patients with ACEi-induced angioedema who had been treated with intravenous corticosteroids and antihistamines at the same institution over the past 8 years was used for comparison. The most important parameters assessed were the time to complete resolution of symptoms and the need for intubation or tracheotomy.

RESULTS

Ten patients were included in the C1-INH group and 47 in the corticosteroid/antihistamine group. The time to complete resolution of symptoms was considerably longer in the historical control group (33.1 ± 19.4 hours) than in the C1-INH group (10.1 ± 3.0 hours). No intubation or tracheotomy was needed in the C1-INH group (0/10 patients), whereas three out of the 47 historical controls required tracheotomy and two were intubated (5/47).

CONCLUSION

The results suggest a role for C1-INH as an effective and safe therapeutic option in patients with ACEi-induced angioedema, which needs to be confirmed by further larger and double-blinded studies.

LEVEL OF EVIDENCE

4.

Treatment of hereditary angioedema: a review (CME)

Hereditary angioedema (HAE) is a rare autosomal dominant disorder characterized by recurrent attacks of self-limiting tissue swelling. The management of HAE has transformed dramatically with recently approved therapies in the United States. However, there is lack of awareness among physicians about these new modalities. The aim of this review is to update the practicing physician about various therapeutic options available for HAE patients. An exhaustive literature search of PubMed and OVID was performed to develop this article. Management of HAE is traditionally classified into treatment of acute attacks or on-demand therapy, short-term (preprocedural) prophylaxis, and long-term prophylaxis. Newer therapies include C1 esterase inhibitor (C1-INH) and contact system modulators, namely, ecallantide and icatibant. Recombinant C1-INH, which is available in Europe, is awaiting approval in the United States. C1-INH concentrate is approved for prophylaxis as well as on-demand therapy while ecallantide and icatibant are approved for acute treatment only. Effective HAE management further includes patient education, reliable access to specific medications, and regular follow-up to monitor therapeutic response and safety.

Recombinant human C1-esterase inhibitor relieves symptoms of hereditary angioedema attacks: phase 3, randomized, placebo-controlled trial

BACKGROUND

Hereditary angioedema (HAE), caused by C1 inhibitor (C1INH) deficiency or dysfunction, is characterized by recurrent attacks of tissue swelling affecting multiple anatomic locations. Recombinant human C1INH (rhC1INH) has been shown effective for acute treatment of HAE attacks.

OBJECTIVE

To evaluate the efficacy and safety of rhC1INH (50 IU/kg to maximum 4,200 IU/treatment) vs placebo in a larger HAE population.

METHODS

Seventy-five patients experiencing peripheral, abdominal, facial, and/or oropharyngeal laryngeal attacks were randomized (3:2) to rhC1INH (n = 44) or placebo (saline; n = 31). Efficacy was assessed by patient responses on a Treatment Effect Questionnaire (TEQ) and visual analog scale (VAS). Safety also was evaluated.

RESULTS

Median (95% confidence interval) time to beginning of symptom relief at the primary attack location was 90 minutes (61-150) in rhC1INH-treated patients vs 152 minutes (93, not estimable) in placebo-treated patients (P = .031) based on the TEQ and 75 minutes (60-105) vs 303 minutes (81-720, P = .003) based on a VAS decrease of at least 20 mm. Median time to minimal symptoms was 303 minutes (240-720) in rhC1INH-treated patients vs 483 minutes (300-1,440) in placebo-treated patients based on the TEQ (P = .078) and 240 minutes (177-270) vs 362 minutes (240, not estimable; P = .005), based on an overall VAS less than 20 mm. Overall, rhC1INH was safe and well tolerated; no thromboembolic events, anaphylaxis, or neutralizing antibodies were observed.

CONCLUSION

Relief of symptoms of HAE attacks was achieved faster with rhC1INH compared with placebo as assessed by the TEQ and VAS, with a positive safety profile. Results are consistent with previous studies showing efficacy and safety of rhC1INH in patients with HAE.

On-demand therapy for hereditary angioedema

Consensus guidelines on hereditary angioedema (HAE) recommend that all patients have access to on-demand treatment of acute attacks. A recent patientcentric guideline recommended that at least 2 on-demand therapies be available because patients often have heterogeneous responses to different medications. Self-administration of therapeutic agents, or administration under supervision by a health care provider in the home setting, is the preferred treatment approach. Future studies are needed to show the benefits of acute on-demand therapies at improving quality of life and reducing morbidity and mortality in patients with HAE.