Clinical practice. Hereditary angioedema

Hereditary angioedema: Linking complement regulation to the coagulation system

Congenital deficiency of C1 inhibitor, the main inhibitor of the classic complement system pathway, leads to paroxysmal angioedema (hereditary angioedema) that can be debilitating or life-threatening for affected patients. In the past few years many new insights on the pathogenesis of angioedema formation in the presence of low levels of C1 inhibitor has been accumulated. There is a central role for bradykinin that is released upon activation of the kallikrein-kinin system that is insufficiently controlled by adequate levels of C1 inhibitor. As C1 inhibitor also possesses a central regulatory role of other plasma systems, including the contact activation system of coagulation and the plasminogen-plasmin system that governs endogenous fibrinolysis, it is interesting to observe the effects of C1 inhibitor deficiency on activation of these systems and relevance for hemostasis in vivo and thrombo-embolic disease. Interestingly, and despite significant activation of these pathways, C1 inhibitor deficiency is not at all associated with a hemorrhagic tendency or prothrombotic state. New therapeutic options for treatment of C1 inhibitor efficiency have become available in recent years, including various forms of C1 inhibitor concentrate. Restoration of C1 inhibitor levels in patients with hereditary angioedema has not resulted in thrombotic complications or any other relevant disorder associated with the hemostatic system.

Angioedema and emergency medicine: From pathophysiology to diagnosis and treatment

Angioedema is a self-limiting edema of the subcutaneous or submucosal tissues due to localised increase of microvascular permeability whose mediator may be histamine or bradykinin. Patients present to emergency department when angioedema involves oral cavity and larynx (life-threatening conditions) or gut (mimicking an acute abdomen). After initial evaluation of consciousness and vital signs to manage breathing and to support circulation if necessary, a simple approach can be applied for a correct diagnosis and treatment. Forms of edema such as anasarca, myxedema, superior vena cava syndrome and acute dermatitis should be ruled out. Then, effort should be done to differentiate histaminergic from non-histaminergic angioedema. Concomitant urticaria and pruritus suggest a histaminergic origin. Exposure to allergens and drugs (mainly ACE inhibitors and non steroidal anti-inflammatory drugs) should be investigated as well as a family history of similar symptoms. Allergic histaminergic angioedema has a rapid course (minutes) whereas non histaminergic angioedema is slower (hours). Since frequently the intervention needs to be immediate, the initial diagnosis is only clinical. However, laboratory tests can be subsequently confirmatory. Allergic angioedema is sensitive to standard therapies such as epinephrine, glucocorticoids and antihistamines whereas non histaminergic angioedema is often resistant to these drugs. Therapeutic options for angioedema due C1-inhibitor deficiencies are C1-inhibitor concentrates, icatibant and ecallantide. If these drugs are not available, fresh frozen plasma can be considered. All these medications have been used also in ACE inhibitor-induced angioedema with variable results thus they are not currently recommended whereas experts agree on the discontinuation of the causative drug.

Effect of Lanadelumab Compared With Placebo on Prevention of Hereditary Angioedema Attacks: A Randomized Clinical Trial

IMPORTANCE

Current treatments for long-term prophylaxis in hereditary angioedema have limitations.

OBJECTIVE

To assess the efficacy of lanadelumab, a fully human monoclonal antibody that selectively inhibits active plasma kallikrein, in preventing hereditary angioedema attacks.

DESIGN, SETTING, AND PARTICIPANTS

Phase 3, randomized, double-blind, parallel-group, placebo-controlled trial conducted at 41 sites in Canada, Europe, Jordan, and the United States. Patients were randomized between March 3, 2016, and September 9, 2016; last day of follow-up was April 13, 2017. Randomization was 2:1 lanadelumab to placebo; patients assigned to lanadelumab were further randomized 1:1:1 to 1 of the 3 dose regimens. Patients 12 years or older with hereditary angioedema type I or II underwent a 4-week run-in period and those with 1 or more hereditary angioedema attacks during run-in were randomized.

INTERVENTIONS

Twenty-six-week treatment with subcutaneous lanadelumab 150 mg every 4 weeks (n = 28), 300 mg every 4 weeks (n = 29), 300 mg every 2 weeks (n = 27), or placebo (n = 41). All patients received injections every 2 weeks, with those in the every-4-week group receiving placebo in between active treatments.

MAIN OUTCOME AND MEASURES

Primary efficacy end point was the number of investigator-confirmed attacks of hereditary angioedema over the treatment period.

RESULTS

Among 125 patients randomized (mean age, 40.7 years [SD, 14.7 years]; 88 females [70.4%]; 113 white [90.4%]), 113 (90.4%) completed the study. During the run-in period, the mean number of hereditary angioedema attacks per month in the placebo group was 4.0; for the lanadelumab groups, 3.2 for the every-4-week 150-mg group; 3.7 for the every-4-week 300-mg group; and 3.5 for the every-2-week 300-mg group. During the treatment period, the mean number of attacks per month for the placebo group was 1.97; for the lanadelumab groups, 0.48 for the every-4-week 150-mg group; 0.53 for the every-4-week 300-mg group; and 0.26 for the every-2-week 300-mg group. Compared with placebo, the mean differences in the attack rate per month were -1.49 (95% CI, -1.90 to -1.08; P < .001); -1.44 (95% CI, -1.84 to -1.04; P < .001); and -1.71 (95% CI, -2.09 to -1.33; P < .001). The most commonly occurring adverse events with greater frequency in the lanadelumab treatment groups were injection site reactions (34.1% placebo, 52.4% lanadelumab) and dizziness (0% placebo, 6.0% lanadelumab).

CONCLUSIONS AND RELEVANCE

Among patients with hereditary angioedema type I or II, treatment with subcutaneous lanadelumab for 26 weeks significantly reduced the attack rate compared with placebo. These findings support the use of lanadelumab as a prophylactic therapy for hereditary angioedema. Further research is needed to determine long-term safety and efficacy.

TRIAL REGISTRATION

EudraCT Identifier: 2015-003943-20; ClinicalTrials.gov Identifier: NCT02586805.

Suffocation due to Acute Airway Edema in a Patient with Hereditary Angioedema Highlighted the Need for Urgent Improvements in Treatment Availability in Japan

A 42-year-old Japanese man with hereditary angioedema suffered accidental trauma to his jaw in Shizuoka Prefecture, Japan, which gradually caused facial edema. Since plasma-derived human C1 inhibitor (pdh C1-INH) was unavailable, he had to be transferred to Juntendo University Hospital in Tokyo. Due to his severe edema, he suffered asphyxiation leading to cardiopulmonary arrest upon arrival. The patient was resuscitated and promptly treated with pdh C1-INH. In Japan, the self-administration of pdh C1-INH is not allowed, and every prefecture does not always possess stocks of pdh C1-INH. This case emphasizes the need for urgent improvements in treatment availability in Japan.

Practicalities of a reduced volume formulation of a C1-INH concentrate for the treatment of hereditary angioedema: real-life experience

Background

Hereditary angioedema (HAE) due to C1 esterase inhibitor (C1-INH) deficiency is characterized by recurrent swelling attacks that can be life-threatening if left untreated. Prompt treatment is vital during acute attacks; plasma-derived C1-INH (Berinert^®) is one treatment currently licensed for the intravenous treatment of acute HAE attacks in adults, adolescents and children. A new, volume-reduced formulation, of C1-INH is currently available which aims to reduce the time to treatment, and provide greater convenience to patients and healthcare professionals. Here we compare the clinical experience of the reduced volume 1500 IU vial with multiple 500 IU vials.

Methods

HAE patients treated with C1-INH at the Royal London Hospital were selected to take part in this assessment. Included patients were aged 10–65 with moderate to severe HAE requiring high doses of C1-INH. The practicalities of the reduced 1500 IU vial compared with multiple 500 IU vials were assessed, including preparation and administration time, training to self-administer time and several quality of life aspects.

Results

Twenty-three patients participated in this study. Twenty-one patients were previously treated with C1-INH (Berinert^®) 500 IU for 1–14 years prior to switching to the 1500 IU vial format, two patients were naïve to C1-INH (Berinert^®). Preparation and administration of C1-INH (Berinert^®) 1500 IU was faster than an equivalent dose with multiple 500 IU vials (11 and 17 min, respectively) and also required less time to train to self-administer (45 and 55 min, respectively). Overall, patients rated the 1500 IU vial format higher in all assessed aspects than the 500 IU format, including preparation, administration, training, travel and storage. Nonetheless, reconstitution of the 1500 IU vial was noted more difficult, requiring gentle mixing to fully dissolve prior to intravenous injection. Patients remained stable on C1-INH (Berinert^®) 1500 IU; two patients switched back to multiple 500 IU vials due to headaches and preference for a larger volume.

Conclusions

The volume-reduced C1-INH concentrate (Berinert^®) 1500 IU is a practical and convenient alternative to multiple 500 IU vials for the treatment of HAE, which provides patients with more control and independence over their disease owing to a simpler to administer treatment.

Small Peptides as Modulators of Serine Proteases

Serine proteases play critical roles in many physiological and pathological processes, and are proven diagnostic and therapeutic targets in a number of clinical indications. Suppression of the aberrant proteolytic activities of these proteases has been clinically used for the treatments of relevant diseases. Polypeptides with 10-20 residues are of great interests as medicinal modulators of serine proteases, because these peptides demonstrate the characteristics of both small molecule drugs and macromolecular drugs. In this review, we summarized the recent development of peptide-based inhibitors against serine proteases with potent inhibitory and high specificity comparable to monoclonal antibodies. In addition, we also discussed the strategies of enhancing plasma half-life and bioavailability of peptides in vivo, which is the main hurdle that limits the clinical translation of peptide-based drugs. This review advocates new avenue for the development of effective serine protease inhibitors and highlights the prospect of the medicinal use of these inhibitors.

Treatment of Hereditary Angioedema Attacks with Icatibant and Recombinant C1 Inhibitor During Pregnancy

PURPOSE

Hereditary angioedema (HAE) is a rare disease caused by a C1 inhibitor (C1-INH) deficit. Clinically, HAE is manifested by repeated episodes of localized subcutaneous or submucosal oedema attacks. Managing HAE patients in pregnancy is challenging, since there are only limited data on the safety and efficacy of various therapeutic approaches.

METHODS

We present our clinical experience treating acute HAE attacks during pregnancy in six consecutive patients.

RESULTS

During the pregnancies, 79 HAE attacks occurred. The most frequent were abdominal 53 (67.1%) followed by peripheral 21 (26.6%), facial 10 (12.7%), and laryngeal 10 (12.7%) oedemas; 13 (16.5%) attacks were combined. Fifty (63.3%) attacks were treated with recombinant human C1-INH (rhC1-INH); 17 (21.5%) with plasma-derived, pasteurized, nanofiltered C1-INH (pnfC1-INH); 13 (16.5%) with icatibant; and 1 (1.3%) with plasma-derived, nanofiltered C1-INH (nfC1-INH). Treatment had to be repeated in 5 attacks (6.3%). All six deliveries (one caesarean section and five spontaneous vaginal deliveries) were complication free. All pregnancies went to the full term and the patients delivered healthy babies with a birth weight ranging from 2850 to 3690 g. No congenital abnormalities were detected in the neonates. No abortions occurred.

CONCLUSIONS

Our results show good C1-INH or icatibant treatment efficacy for HAE attacks in pregnancy. The treatment by the first drug used was effective in 93.7% of all attacks. In 6.3% of attacks, a second treatment had to be used. No adverse effects were observed.

Population pharmacokinetics of subcutaneous C1-inhibitor for prevention of attacks in patients with hereditary angioedema

BACKGROUND

Long-term prophylaxis with subcutaneous (SC) administration of a highly concentrated plasma-derived C1-esterase inhibitor (C1-INH) formulation was recently approved by the Food and Drug Administration for hereditary angioedema (HAE) attack prevention.

OBJECTIVE

To characterize the population pharmacokinetics of C1-INH (SC) (HAEGARDA^® ; CSL Behring) in healthy volunteers and HAE patients, and assess the variability and influence of covariates on pharmacokinetics.

METHODS

C1-INH functional activity data obtained after administration of various C1-INH (intravenous; IV) and C1-INH (SC) doses from 1 study in healthy volunteers (n = 16) and 2 studies in subjects with HAE (n = 108) were pooled to develop a population pharmacokinetic model (NONMEM v7.2). Pharmacokinetic parameters derived from steady-state simulations based on the final model were also evaluated.

RESULTS

C1-INH functional activity following C1-INH (SC) administration was described by a linear one-compartment model with first-order absorption and elimination, with inter-individual variability in all parameters tested. The mean population bioavailability of C1-INH (SC), and pharmacokinetic parameters for clearance (CL), volume of distribution, and absorption rate were estimated to be ~43%, 1.03 mL/hour/kg, 0.05 L/kg and 0.0146 hour^-1 , respectively. The effect of bodyweight on CL of C1-INH functional activity was included in the final model, estimated to be 0.74. Steady-state simulations of C1-INH functional activity vs time profiles in 1000 virtual HAE patients revealed higher minimum functional activity (C_trough ) levels after twice-weekly dosing with 40 IU/kg (~40%) and 60 IU/kg (~48%) compared with 1000 IU IV (~30%). Based on the population pharmacokinetic model, the median time to peak concentration was ~59 hours and the median apparent plasma half-life was ~69 hours.

CONCLUSIONS AND CLINICAL RELEVANCE

Twice-weekly bodyweight-adjusted dosing of C1-INH (SC) exhibits linear pharmacokinetics and dose-dependent increases in C_trough levels at each dosing interval. In this analysis, SC dosing led to maintenance of higher C_trough levels than IV dosing.

The complex alteration in the network of IL-17-type cytokines in patients with hereditary angioedema

Hereditary angioedema (HAE) is a rare autosomic-dominant disorder characterized by a deficiency of C1 esterase inhibitor which causes episodic swellings of subcutaneous tissues, bowel walls and upper airways that are disabling and potentially life-threatening. We evaluated n = 17 patients with confirmed HAE diagnosis during attack and remission state and n = 19 healthy subjects. The samples were tested for a panel of IL (Interleukin)-17-type cytokines (IL-1β, IL-6, IL-10, granulocyte-macrophage colony stimulating factor (GM-CSF), IL-17, IL-21, IL-22, IL-23) and transforming growth factor-beta (TGF-β) subtypes. Data indicate that there are variations of cytokine levels in HAE subjects comparing the condition during the crisis respect to the value in the remission phase, in particular type 17 signature cytokines are increased, whereas IL-23 is unmodified and TGF-β3 is significantly reduced. When comparing healthy and HAE subjects in the remission state, we found a significant difference for IL-17, GM-CSF, IL-21, TGF-β1 and TGF-β2 cytokines. These results confirm and extend our previous findings indicating that in HAE there is operating an inflammatory activation process, which involves also T helper 17 (Th17) cytokines and TGF-β isoforms, associated with localized angioedema attacks and characterized by elevated bradykinin levels.

Quantification of human C1 esterase inhibitor protein using an automated turbidimetric immunoassay

Background

Impaired levels or function of C1 inhibitor (C1‐INH) results in angioedema due to increased bradykinin. It is important to distinguish between angioedema related to C1‐INH deficiency and that caused by other mechanisms, as treatment options are different. In hereditary (HAE) and acquired (AAE) angioedema, C1‐INH concentration is measured to aid patient diagnosis. Here, we describe an automated turbidimetric assay to measure C1‐INH concentration on the Optilite^® analyzer.

Methods

Linearity, precision, and interference were established over a range of C1‐INH concentrations. The 95th percentile reference interval was generated from 120 healthy adult donors. To compare the Optilite C1‐INH assay with a predicate assay used in a clinical laboratory, samples sent for C1‐INH investigation were used. The predicate results were provided to allow comparison.

Results

The Optilite C1‐INH assay was linear across the measuring range at the standard sample dilution. Intra and interassay variability was <6%. The 95th percentile adult reference interval for the assay was 0.21‐0.38 g/L. There was a strong correlation between the Optilite concentrations and those generated with the predicate assay (R² = 0.94, P < 0.0001, slope y = 0.83x). All patients with Type I HAE (n = 24) and AAE (n = 3) tested had concentrations below the measuring range in both assays, while all patients with unspecified angioedema (UAE), not diagnosed with HAE or AAE had values within the reference range.

Conclusion

The Optilite assay allows the automated and precise quantification of C1‐INH concentrations in patient samples. It could therefore be used as a tool to aid the investigation of patients with angioedema.

Oral Plasma Kallikrein Inhibitor for Prophylaxis in Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a life-threatening illness caused by mutations in the gene encoding C1 inhibitor (also called C1 esterase inhibitor) that lead to overactivation of the kallikrein-bradykinin cascade. BCX7353 is a potent oral small-molecule inhibitor of plasma kallikrein with a pharmacokinetic and pharmacodynamic profile that may help prevent angioedema attacks.

METHODS

In this international, three-part, dose-ranging, placebo-controlled trial, we evaluated four doses of BCX7353 (62.5 mg, 125 mg, 250 mg, and 350 mg once daily) for the prevention of angioedema attacks over a 28-day period. Patients with type I or II hereditary angioedema with a history of at least two angioedema attacks per month were randomly assigned to BCX7353 or placebo. The primary efficacy end point was the number of confirmed angioedema attacks. Key secondary end points included angioedema attacks according to anatomical location and quality of life.

RESULTS

A total of 77 patients underwent randomization, 75 received BCX7353 or placebo, and 72 completed the trial. The rate of confirmed angioedema attacks was significantly lower among patients who received BCX7353 at daily doses of 125 mg or more than among those who received placebo, with a 73.8% difference at 125 mg (P<0.001). Significant benefits with respect to quality-of-life scores were observed in the 125-mg and 250-mg dose groups (P<0.05). Gastrointestinal adverse events, predominantly of grade 1, were the most commonly reported adverse events, particularly in the two highest BCX7353 dose groups.

CONCLUSIONS

Once-daily oral administration of BCX7353 at a dose of 125 mg or more resulted in a significantly lower rate of attacks of hereditary angioedema than placebo. Mild gastrointestinal symptoms were the principal side effect. (Funded by BioCryst Pharmaceuticals; APeX-1 ClinicalTrials.gov number, NCT02870972 .).

Secreted Phospholipases A2 in Hereditary Angioedema With C1-Inhibitor Deficiency

Background

Hereditary angioedema (HAE) caused by deficiency (type I) or dysfunction (type II) of the C1 inhibitor protein (C1-INH-HAE) is a disabling, potentially fatal condition characterized by recurrent episodes of swelling. We have recently found that patients with C1-INH-HAE have increased plasma levels of vascular endothelial growth factors and angiopoietins (Angs), which have been associated with vascular permeability in several diseases. Among these and other factors, blood endothelial cells and vascular permeability can be modulated by extracellular or secreted phospholipases A₂ (sPLA₂s).

Objective

We sought to investigate the enzymatic activity and biological functions of sPLA₂ in patients with C1-INH-HAE.

Methods

sPLA₂s enzymatic activity was evaluated in the plasma from 109 adult patients with C1-INH-HAE and 68 healthy donors in symptom-free period and attacks. Plasma level of group IIA sPLA₂ (hGIIA) protein was measured in selected samples. The effect of C1-INH-HAE plasma on endothelial permeability was examined in vitro using a vascular permeability assay. The role of hGIIA was determined using highly specific sPLA₂ indole inhibitors. The effect of recombinant hGIIA on C1-INH activity was examined in vitro by functional assay.

Results

Plasma sPLA₂ activity and hGIIA levels are increased in symptom-free C1-INH-HAE patients compared with controls. sPLA₂ activity negatively correlates with C1-INH protein level and function. C1-INH-HAE plasma increases endothelial permeability in vitro, and this effect is partially reverted by a specific hGIIA enzymatic inhibitor. Finally, recombinant hGIIA inhibits C1-INH activity in vitro.

Conclusion

sPLA₂ enzymatic activity (likely attributable to hGIIA), which is increased in C1-INH-HAE patients, can promote vascular permeability and impairs C1-INH activity. Our results may pave the way for investigating the functions of sPLA₂s (in particular, hGIIA) in the pathophysiology of C1-INH-HAE and may inform the development of new therapeutic targets.

Emotional processes and stress in children affected by hereditary angioedema with C1-inhibitor deficiency: a multicenter, prospective study

Background

Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is characterized by recurrent edema of unpredictable frequency and severity. Stress, anxiety, and low mood are among the triggering factors most frequently reported. Impaired regulation and processing of emotions, also known as alexithymia, may influence outcomes. The aim of this study was to confirm the presence of alexithymia and stress in children with C1-INH-HAE, to determine whether they are also present in children affected by other chronic diseases, and to investigate their relationship with C1-INH-HAE severity. Data from children with C1-INH-HAE (n = 28) from four reference centers in Italy were compared with data from children with type 1 diabetes (T1D; n = 23) and rheumatoid arthritis (RA; n = 25). Alexithymia was assessed using the Alexithymia Questionnaire for Children scale; perceived stress was assessed using the Coddington Life Event Scale for Children (CLES-C).

Results

Mean age (standard deviation [SD]) in the C1-INH-HAE, T1D, and RA groups was 11.8 (3.3), 11.7 (2.9), and 11.1 (2.6) years, respectively. Mean C1-INH-HAE severity score was 5.9 (2.1), indicating moderate disease. Alexithymia scores were similar among disease groups and suggestive of difficulties in identifying and describing emotions; CLES-C scores tended to be worse in C1-INH-HAE children. C1-INH-HAE severity was found to correlate significantly and positively with alexithymia (p = 0.046), but not with perceived stress. Alexithymia correlated positively with perceived stress.

Conclusions

Alexithymia is common in children with chronic diseases. In C1-INH-HAE, it may result in increased perceived stress and act as a trigger of edema attacks. Comprehensive management of C1-INH-HAE children should consider psychological factors.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0871-x) contains supplementary material, which is available to authorized users.

Canadian physician survey on the medical management of hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) is a rare disease that has significant morbidity and may be potentially fatal because of airway obstruction.

OBJECTIVE

To determine practice patterns in physicians treating HAE.

METHODS

A survey was designed to determine HAE practice patterns among Canadian physicians. These physicians were identified by sending the survey to members of 3 physician organizations (Canadian Hereditary Angioedema Network, Canadian Society of Clinical Immunology and Allergy, and Canadian Hematology Society).

RESULTS

Thirty-six physicians responded to the survey. Thirty-four physicians were included in the analysis. Most referrals to HAE-treating physicians were from family and emergency department physicians. The most common sites of swelling reported by patients to physicians were facial, peripheral, and abdominal. A mean of 53.9% of patients with type 1 and 2 HAE and 53.4% of patients with HAE with normal C1 esterase inhibitor were undergoing long-term prophylaxis. A mean of 41.9%, 19.4%, and 93.5% of respondents had some patients taking danazol, tranexamic acid, and C1-esterase inhibitor, respectively. Most physicians believed that severity and frequency of attacks were the most important determinants in deciding when to use prophylaxis. A mean of 88.2% of physicians used C1-esterase inhibitor to treat acute attacks and 79.4% used icatibant. All respondents were aware of HAE guidelines.

CONCLUSION

Physicians are using guidelines to support their practice and using agents suggested by guidelines with confidence. C1 inhibitor is being used widely for prophylaxis and treatment of acute attacks along with icatibant. However, certain special patient populations may require additional focus in future guidelines.

Factor XII Deficiency Mimicking Bleeding Diathesis: A Unique Presentation and Diagnostic Pitfall

Factor XII (FXII), also known as Hageman factor, is a coagulation protein that is necessary for the functioning of the intrinsic coagulation cascade and fibrin formation. When deficient, it results in a significant prolongation of activated partial thromboplastin time (aPTT), mimicking a bleeding disorder. However, it does not result in clinical bleeding tendency. We report a case of an elderly male who was found to have prolonged aPTT, discovered during preoperative evaluation for operative repair of hip fracture. Although laboratory investigation was suggestive of bleeding tendency, he was diagnosed with factor XII deficiency and had no bleeding complications intra-operatively or in the post-operative period.

Hereditary angioedema due to C1-inhibitor deficiency in Macedonia: clinical characteristics, novel SERPING1 mutations and genetic factors modifying the clinical phenotype

OBJECTIVE

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare disease, characterized by swellings. We aimed to characterize on a clinical and molecular basis C1-INH-HAE patients in the Republic of Macedonia.

RESULTS

All 15 patients from six unrelated families were diagnosed with C1-INH-HAE type I, with a mean age of symptom onset of 11 years and an average delay of diagnosis of seven years. Patients reported on average 31 angioedema attacks/year, with a median clinical severity score (CSS) of 7. We identified three known mutations and two new mutations (c.813_818delCAACAA and c.1488T > G) that were reported for the first time. To address the genotype-phenotype association, a pooled analysis including 78 C1-INH-HAE south-eastern European patients was performed, with additional analysis of F12-46C/T and KLKB1-428G/A polymorphisms. We demonstrated that patients with nonsense and frameshift mutations, large deletions/insertions, splicing defects and mutations at Arg444 exhibited an increased CSS compared with missense mutations, excluding mutations at Arg444. In addition, the CC F12-46C/T polymorphism was suggestive of earlier disease onset.

DISCUSSION

Genetic analysis helped identify the molecular basis of C1-INH-HAE given that causative mutations in SERPING1 were detected in all patients, including an infant before the appearance of clinical symptoms. We identified two novel mutations and further corroborated the genotype-phenotype relationship, wherein mutations with a clear effect on C1-INH function predispose patients to a more severe disease phenotype and CC F12-46C/T predisposes patients to earlier disease onset. KEY MESSAGES • In the present nationwide study, we aimed to characterize on a clinical and molecular basis patients with hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) in the Republic of Macedonia.   • Causative mutations in SERPING1 were detected in all 15 C1-INH-HAE patients from six Macedonian families, including an infant, before the appearance of clinical symptoms.   • We identified three known mutations and two novel mutations (c.813_818delCAACAA and c.1488T > G). These findings further corroborated the genotype-phenotype relationship, wherein mutations with a clear effect on C1-INH function predispose patients to a more severe disease phenotype and the CC F12-46C/T polymorphism predisposes patients to earlier disease onset.

The Complex Interaction Between Polycystic Ovary Syndrome and Hereditary Angioedema: Case Reports and Review of the Literature

Importance

Hereditary angioedema (HAE) is a rare but severe disease, with high risk of death, and attacks have been associated to high estrogen levels. Polycystic ovary syndrome (PCOS) is a common hyperandrogenic condition, which is frequently treated with combined oral contraceptives.

Objective

The aim of this study was to describe 2 clinical cases of young women diagnosed as having PCOS who developed HAE attacks after the introduction of combined estrogen-progestin pills to treat PCOS symptoms.

Evidence Acquisition

Literature review of sex hormones' role in genesis of HAE attacks and possible mechanisms involved.

Results

In the cases reported, after initiation of combined contraceptives, patients presented with facial swelling with airway involvement (laryngeal edema) and abdominal pain. They had a familial history of angioedema and normal C1 inhibitor (C1-INH) levels, leading to the diagnosis of HAE with normal C1-INH (HAEnC1-INH) or HAE type III. After suspension of exogenous estrogen, patients remained asymptomatic from HAE.

Conclusions and Relevance

HAEnC1-INH is an estrogen-dependent form of HAE. It is well established that exogenous estrogen triggers attacks of all types of HAE. However, this is the first description of the association between PCOS and HAE, in which PCOS could be masking HAE symptoms. We propose that PCOS might have a protective role regarding HAE attacks, because of its particular hormonal features, that is, hyperandrogenism and relative stable levels of estradiol. The use of combined estrogen-progestin compounds in women with PCOS and HAE must be avoided, and treatment must be individualized.

Angiotensin-converting Enzyme Inhibitor and Other Drug-associated Angioedema

Nonsteroidal antiinflammatory agents, β-lactam antibiotics, non-β lactam antibiotics, and angiotensin-converting enzyme inhibitors are the most common classes of drugs that cause angioedema. Drug-induced angioedema is known to occur via mechanisms mediated by histamine, bradykinin, or leukotriene, and an understanding of these mechanisms is crucial in guiding therapeutic decisions. Nonallergic angioedema occurs in patients with genetic variants that affect metabolism or synthesis of bradykinin, substance P, prostaglandins, or leukotrienes, or when patients are taking drugs that have synergistic mechanisms. The mainstay in treatment of nonallergic drug-induced angioedema is cessation of the offending agents.

Burden of Illness and Quality-of-Life Measures in Angioedema Conditions

Burden of illness studies and evaluation of health-related quality of life using validated questionnaires have become an important task in the comprehensive management of angioedema conditions, mainly angioedema associated with chronic spontaneous urticaria and hereditary angioedema caused by C1-inhibitor deficiency. A review of the principal tools and studies is presented. Both diseases present a higher proportion of psychiatric disorders, impair work and studies productivity, and produce high direct and indirect costs. These assessments also have been useful to evaluate the positive impact of new drugs and interventions. More studies are desirable, especially in other types of angioedema disorders, such as hereditary angioedema with normal C1 inhibitor.

Optimum Use of Acute Treatments for Hereditary Angioedema: Evidence-Based Expert Consensus

Acute treatment of hereditary angioedema due to C1 inhibitor deficiency has become available in the last 10 years and has greatly improved patients’ quality of life. Two plasma-derived C1 inhibitors (Berinert and Cinryze), a recombinant C1 inhibitor (Ruconest/Conestat alpha), a kallikrein inhibitor (Ecallantide), and a bradykinin B2 receptor inhibitor (Icatibant) are all effective. Durably good response is maintained over repeated treatments and several years. All currently available prophylactic agents are associated with breakthrough attacks, therefore an acute treatment plan is essential for every patient. Experience has shown that higher doses of C1 inhibitor than previously recommended may be desirable, although only recombinant C1 inhibitor has been subject to full dose–response evaluation. Treatment of early symptoms of an attack, with any licensed therapy, results in milder symptoms, more rapid resolution and shorter duration of attack, compared with later treatment. All therapies have been shown to be well-tolerated, with low risk of serious adverse events. Plasma-derived C1 inhibitors have a reassuring safety record regarding lack of transmission of virus or other infection. Thrombosis has been reported in association with plasma-derived C1 inhibitor in some case series. Ruconest was associated with anaphylaxis in a single rabbit-allergic volunteer, but no further anaphylaxis has been reported in those not allergic to rabbits despite, in a few cases, prior IgE sensitization to rabbit or milk protein. Icatibant is associated with high incidence of local reactions but not with systemic effects. Ecallantide may cause anaphylactoid reactions and is given under supervision. For children and pregnant women, plasma-derived C1 inhibitor has the best evidence of safety and currently remains first-line treatment.

Specialist Advice Support for Management of Severe Hereditary Angioedema Attacks: A Multicenter Cluster-Randomized Controlled Trial

STUDY OBJECTIVE

Hereditary angioedema is a rare disease associated with unpredictable, recurrent attacks of potentially life-threatening edema. Management of severe attacks is currently suboptimal because emergency medical teams are often unaware of new specific treatments. The objective of this trial is to test whether a dedicated national telephone care-management strategy would reduce resource use during severe hereditary angioedema attacks.

METHODS

We conducted a cluster-randomized multicenter prospective trial of patients with a documented diagnosis of hereditary angioedema (type I, II or FXII hereditary angioedema). Participants were enrolled between March 2013 and June 2014 at 8 participating reference centers. The randomized units were the reference centers (clusters). Patients in the intervention arm were given a national free telephone number to call in the event of a severe attack. Emergency physicians in the SOS-hereditary angiœdema (SOS-HAE) call center were trained to advise or prescribe specific treatments. The primary outcome was number of admissions for angioedema attacks. Economic evaluation was also performed.

RESULTS

We included 100 patients in the SOS-HAE group and 100 in the control group. During the 2 years, there were 2,368 hereditary angioedema attacks among 169 patients (85%). Mean number of hospital admissions per patient in the 2-year period was significantly greater in the usual-practice group (mean 0.16 [range 0 to 2] versus 0.03 [range 0 to 1]); patient risk difference was significant: -0.13 (95% confidence interval -0.22 to -0.04; P=.02). Probabilistic sensitivity graphic analysis indicated a trend toward increased quality-adjusted life-years in the SOS-HAE group.

CONCLUSION

A national dedicated call center for management of severe hereditary angioedema attacks is associated with a decrease in hospital admissions and may be cost-effective if facilities and staff are available to deliver the intervention alongside existing services.

Hereditary Angioedema: The Economics of Treatment of an Orphan Disease

This review will discuss the cost burden of hereditary angioedema on patients, healthcare systems, and society. The impact of availability of and access to novel and specific therapies on morbidity, mortality, and the overall burden of disease will be explored along with potential changes in treatment paradigms to improve effectiveness and reduce cost of treatment. The prevalence of orphan diseases, legislative incentives to encourage development of orphan disease therapies and the impact of orphan disease treatment on healthcare payment systems will be discussed.

Clinical Features of Hereditary and Mast Cell-mediated Angioedema Focusing on the Differential Diagnosis in Japanese Patients

Objective The present study was designed to identify the clinical characteristics that permit the differential diagnosis of hereditary angioedema (HAE) and mast cell-mediated angioedema (Mast-AE) during the first consultation. Methods The medical histories and laboratory data of 46 patients with HAE and 41 patients with Mast-AE were compared. Results The average age of onset in the HAE group (19.8±9.0 years) was significantly lower than that in the Mast-AE group (35.2±12.0 years). The incidence of familial angioedema (AE) in the HAE group (73.9%) was significantly higher than that in the Mast-AE group (9.7%). The frequency of history of AE in the extremities, larynx, or gastrointestinal tract was significantly higher in the HAE group. The frequency of AE episodes of the lips and eyelids was significantly lower in the HAE group. The serum C4 concentration and CH50 titer were lower than the normal limit in 91.3% and 45.6% of the patients in the HAE group, respectively; in Mast-AE group the serum C4 concentration and CH50 titer were significantly lower than the normal limit in 4.8% and 0% of the patients, the difference between the two groups was statistically significant. A C1-inhibitor (C1-INH) activity level of <50% was observed in all of the HAE patients, but none of the Mast-AE patients. The mean serum IgE titer in the HAE group (120.8±130.5 IU/mL) was significantly lower than that in the Mast-AE group (262.2±314.9 IU/mL). Conclusion The parameters within the patients' medical histories, such as the age at the onset of AE, a family history of AE, and the locations of past AE episodes are critical for the successful diagnosis of the disease. Measurements of the C4 and C1-INH activity are very useful for differential diagnosis of HAE from Mast-AE.

An adolescent with acute abdominal pain and bowel wall thickening

: A 15-year-old girl was admitted with acute crampy abdominal pain and repeated vomiting over the preceding 2 hours; no fever, diarrhoea or abdominal trauma was reported. She had started oestrogen-progestin contraception 3 months ago. She had sought medical advice twice in the previous weeks for self-limiting episodes of right hand swelling, without urticaria. On examination, she was unwell and in pain, with severe tenderness in the right lower quadrant, without guarding or rebound tenderness. Bowel sounds were diminished. Blood tests were unremarkable. Two hours after admission, an abdominal ultrasound scanning showed an impressive wall thickening (>1 cm) of the terminal ileum, caecum and ascending colon (figure 1). Abundant free intraperitoneal fluids in the pelvis and in the hepatorenal recess were present.edpract;103/1/22/EDPRACT2016311823F1F1EDPRACT2016311823F1Figure 1Marked caecal wall thickening evidenced at the ultrasound scanning.

QUESTIONS

Which of the following is the most likely diagnosis in this patient? Ileocolic intussusceptionGastrointestinal manifestation of Henoch-Schönlein purpuraAbdominal attack of hereditary angioedema (HAE)Acute pancreatitisWhich of the following blood tests may help to confirm the diagnosis? Erythrocyte sedimentation rateC4Serum amylase: 36 IU/LC1-inhibitorHow should this patient be evaluated and treated?Answers are on page ▪▪▪.

Health-Related Quality of Life with Subcutaneous C1-Inhibitor for Prevention of Attacks of Hereditary Angioedema

BACKGROUND

Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) impairs health-related quality of life (HRQoL).

OBJECTIVE

The objective of this study was to assess HRQoL outcomes in patients self-administering subcutaneous C1-INH (C1-INH[SC]; HAEGARDA) for routine prevention of HAE attacks.

METHODS

Post hoc analysis of data from the placebo-controlled, crossover phase III COMPACT study (Clinical Studies for Optimal Management of Preventing Angioedema with Low-Volume Subcutaneous C1-Inhibitor Replacement Therapy). Ninety patients with C1-INH-HAE were randomized to 1 of 4 treatment sequences: C1-INH(SC) 40 or 60 IU/kg twice weekly for 16 weeks, preceded or followed by 16 weeks of twice weekly placebo injections. All HAE attacks were treated with open-label on-demand treatment as necessary. HRQoL assessments at week 14 (last visit) included the European Quality of Life-5 Dimensions Questionnaire (EQ-5D-3L), the Hospital Anxiety and Depression Scale (HADS), the Work Productivity and Activity Impairment Questionnaire (WPAI), and the Treatment Satisfaction Questionnaire for Medication (TSQM).

RESULTS

Compared with placebo (on-demand treatment alone), treatment with twice weekly C1-INH(SC) (both doses combined) was associated with better EQ-5D visual analog scale general health, less HADS anxiety, less WPAI presenteeism, work productivity loss, and activity impairment, and greater TSQM effectiveness and overall treatment satisfaction. More patients self-reported a "good/excellent" response during routine prevention with C1-INH(SC) compared with on-demand only (placebo prophylaxis) management. For each HRQoL measure, a greater proportion of patients had a clinically meaningful improvement during C1-INH(SC) treatment compared with placebo.

CONCLUSIONS

In patients with frequent HAE attacks, a treatment strategy of routine prevention with self-administered twice weekly C1-INH(SC) had a greater impact on improving multiple HAE-related HRQoL impairments, most notably anxiety and work productivity, compared with on-demand treatment alone (placebo prophylaxis).

Intermittent C1-Inhibitor Deficiency Associated with Recessive Inheritance: Functional and Structural Insight

C1-inhibitor is a serine protease inhibitor (serpin) controlling complement and contact system activation. Gene mutations result in reduced C1-inhibitor functional plasma level causing hereditary angioedema, a life-threatening disorder. Despite a stable defect, the clinical expression of hereditary angioedema is unpredictable, and the molecular mechanism underlying this variability remains undisclosed. Here we report functional and structural studies on the Arg378Cys C1-inhibitor mutant found in a patient presenting reduced C1-inhibitor levels, episodically undergoing normalization. Expression studies resulted in a drop in mutant C1-innhibitor secretion compared to wild-type. Notwithstanding, the purified proteins had similar features. Thermal denaturation experiments showed a comparable denaturation profile, but the mutant thermal stability decays when tested in conditions reproducing intracellular crowding.Our findings suggest that once correctly folded, the Arg378Cys C1-inhibitor is secreted as an active, although quite unstable, monomer. However, it could bear a folding defect, occasionally promoting protein oligomerization and interfering with the secretion process, thus accounting for its plasma level variability. This defect is exacerbated by the nature of the mutation since the acquired cysteine leads to the formation of non-functional homodimers through inter-molecular disulphide bonding. All the proposed phenomena could be modulated by specific environmental conditions, rendering this mutant exceptionally vulnerable to mild stress.

Exposure-Response Model of Subcutaneous C1-Inhibitor Concentrate to Estimate the Risk of Attacks in Patients With Hereditary Angioedema

Subcutaneous C1‐inhibitor (HAEGARDA, CSL Behring), is a US Food and Drug Administration (FDA)‐approved, highly concentrated formulation of a plasma‐derived C1‐esterase inhibitor (C1‐INH), which, in the phase III Clinical Studies for Optimal Management in Preventing Angioedema with Low‐Volume Subcutaneous C1‐inhibitor Replacement Therapy (COMPACT) trial, reduced the incidence of hereditary angioedema (HAE) attacks when given prophylactically. Data from the COMPACT trial were used to develop a repeated time‐to‐event model to characterize the timing and frequency of HAE attacks as a function of C1‐INH activity, and then develop an exposure–response model to assess the relationship between C1‐INH functional activity levels (C1‐INH(f)) and the risk of an attack. The C1‐INH(f) values of 33.1%, 40.3%, and 63.1% were predicted to correspond with 50%, 70%, and 90% reductions in the HAE attack risk, respectively, relative to no therapy. Based on trough C1‐INH(f) values for the 40 IU/kg (40.2%) and 60 IU/kg (48.0%) C1‐INH (SC) doses, the model predicted that 50% and 67% of the population, respectively, would see at least a 70% decrease in the risk of an attack.

Disease Severity, Activity, Impact, and Control and How to Assess Them in Patients with Hereditary Angioedema

Hereditary angioedema (HAE) is a group of rare, potentially life-threatening, and frequently debilitating diseases characterized by recurrent, and often with an unpredictable onset, of swelling attacks. HAE is heterogeneous, with considerable differences between its subtypes, patients, and even within the same patient over time. During the past few years, several new on demand and prophylactic therapies have become available for HAE, allowing for individualized treatment. Therefore, to optimize HAE management, it is important to determine in all patients, the severity of their attacks, their disease activity, its therapeutic control, and its impact on their quality of life. In this manuscript, we review the existing tools to assess these aspects of HAE management, many of which are patient-reported outcome instruments. Also, we outline the current gaps of knowledge and what tools are still missing to allow for a comprehensive assessment of all patients with HAE including children.

Hereditary angioedema: a bradykinin-mediated swelling disorder

Edema is tissue swelling and is a common symptom in a variety of diseases. Edema form due to accumulation of fluids, either through reduced drainage or increased vascular permeability. There are multiple vascular signalling pathways that regulate vessel permeability. An important mediator that increases vascular leak is the peptide hormone bradykinin, which is the principal agent in the swelling disorder hereditary angioedema. The disease is autosomal dominant inherited and presents clinically with recurrent episodes of acute swelling that can be life-threatening involving the skin, the oropharyngeal, laryngeal, and gastrointestinal mucosa. Three different types of hereditary angiodema exist in patients. The review summarises current knowledge on the pathophysiology of hereditary angiodema and focuses on recent experimental and pharmacological findings that have led to a better understanding and new treatments for the disease.

The Search for Biomarkers in Hereditary Angioedema

The unpredictable nature of attacks of tissue swelling in hereditary angioedema requires the identification of reliable biomarkers to monitor disease activity as well as response to therapy. At present, one can assess a C4 level (by ELISA) to assist in diagnosis but neither C4 nor C1 inhibitor levels reflect clinical course or prognosis. We will here review a collection of plasma proteins involved in blood coagulation, fibrinolysis, and innate immunity (Figure 1). A main focus is those proteins that are key to the formation of bradykinin (BK); namely, factor XII, plasma prekallikrein/kallikrein, high-molecular weight kininogen, and BK itself since overproduction of BK is key to the disease. Considerations include new approaches to measurement of active enzymes, ELISA methods that may supersede SDS gel analysis of bond cleavages, and examples of changes outside the BK cascade that may reflect when, where, and how an attack of swelling is initiated. We will discuss their usefulness as biomarker candidates, with pros and cons, and compare the analytical methods that are being developed to measure their levels or activity.

In vivo activation and functions of the protease factor XII

Combinations of proinflammatory and procoagulant reactions are the unifying principle for a variety of disorders affecting the cardiovascular system. Factor XII (FXII, Hageman factor) is a plasma protease that initiates the contact system. The biochemistry of the contact system in vitro is well understood; however, its in vivo functions are just beginning to emerge. The current review concentrates on activators and functions of the FXII-driven contact system in vivo. Elucidating its physiologic activities offers the exciting opportunity to develop strategies for the safe interference with both thrombotic and inflammatory diseases.

Diminished capacity of opsonization and immune complex solubilization, and detection of anti-C1q antibodies in sera from patients with hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) is an autosomal dominant disease caused by deficiency of C1 esterase inhibitor. Symptoms of HAE include edema, which can potentially cause suffocation. Some patients with HAE exhibit immunological abnormalities, which could prevent an accurate diagnosis. Low levels of complement components are characteristic of HAE and in other settings are thought to reduce elimination of apoptotic cells and immune complex (IC). Thus, we aimed to experimentally clarify the mechanism of immunological abnormalities using sera from HAE patients.

METHODS

Serum samples from 18 patients with HAE were collected when free from angioedema attack and compared with normal human pooled sera (NHPS) from 20 healthy volunteers. Opsonization was measured as the rate of phagocytosis of apoptotic Jurkat cells by macrophages differentiated from THP-1 cells incubated with serum. IC solubilization in serum was analyzed by quantifying peroxidase released from a synthetic IC composed of peroxidase and anti-peroxidase antibodies. Anti-C1q antibody levels were detected using an enzyme-linked immunosorbent assay.

RESULTS

Serological immunological abnormalities were detected in 12 patients. Opsonization in serum samples from each patient with HAE was lower than that in NHPS (∼20% versus 70%, respectively). The rate of IC solubilization was lower in serum from HAE patients than NHPS. Some patients had high serum anti-C1q antibody levels with increased serum IC levels.

CONCLUSIONS

Sera from patients with HAE exhibit anti-C1q antibodies, with a lower capacity for opsonization and IC solubilization. This may be associated with immunological abnormalities and should be investigated further to facilitate accurate diagnosis of HAE.

Recombinant human C1 esterase inhibitor for prophylaxis of hereditary angio-oedema: a phase 2, multicentre, randomised, double-blind, placebo-controlled crossover trial

BACKGROUND

Hereditary angio-oedema is a recurrent, oedematous disorder caused by deficiency of functional C1 inhibitor. Infusions of plasma-derived C1 esterase inhibitor deter attacks of hereditary angio-oedema, but the prophylactic effect of recombinant human C1 esterase inhibitor has not been rigorously studied. We aimed to assess the efficacy of recombinant human C1 esterase inhibitor for prophylaxis of hereditary angio-oedema.

METHODS

We conducted this phase 2, multicentre, randomised, double-blind, placebo-controlled crossover trial at ten centres in Canada, the Czech Republic, Israel, Italy, Macedonia, Romania, Serbia, and the USA. We enrolled patients aged 13 years or older with functional C1-inhibitor concentrations of less than 50% of normal and a history of four or more attacks of hereditary angio-oedema per month for at least 3 months before study initiation. Patients were randomly assigned centrally (1:1:1:1:1:1), via an interactive response technology system with fixed allocation, to receive one of six treatment sequences. During each sequence, patients received intravenous recombinant human C1 esterase inhibitor (50 IU/kg; maximum 4200 IU) twice weekly, recombinant human C1 esterase inhibitor once weekly and placebo once weekly, and placebo twice weekly, each for 4 weeks with a 1 week washout period between crossover. All patients, investigators, and study personnel who participated in patient care were masked to group allocation during the study. The primary efficacy endpoint was the number of attacks of hereditary angio-oedema observed in each 4 week treatment period. Attack symptoms were recorded daily. The primary efficacy analysis was done in the intention-to-treat population. Safety was assessed in all patients who received at least one injection of study medication. This study is registered with ClinicalTrials.gov, number NCT02247739.

FINDINGS

Between Dec 29, 2014, and May 3, 2016, we enrolled 35 patients, of whom 32 (91%) underwent randomisation (intention-to-treat population) and 26 (81%) completed the study. The mean number of attacks of hereditary angio-oedema over 4 weeks was significantly reduced with recombinant human C1 esterase inhibitor twice weekly (2·7 attacks [SD 2·4]) and once weekly (4·4 attacks [3·2]) versus placebo (7·2 attacks [3·6]), with mean differences of -4·4 attacks (p<0·0001) and -2·8 attacks (p=0·0004), respectively. We recorded adverse events in ten (34%) of 29 patients given twice-weekly recombinant human C1 esterase inhibitor, 13 (45%) of 29 patients given the once-weekly regimen, and eight (29%) of 28 patients given placebo. Headache (twice-weekly treatment) and nasopharyngitis (once-weekly treatment) were the most common adverse events. Two (7%) adverse events (fatigue and headache) were deemed possibly related to treatment with recombinant human C1 esterase inhibitor, but both resolved without additional treatment. No thrombotic or thromboembolic events, systemic allergic reactions (including anaphylaxis), or neutralising antibodies were reported.

INTERPRETATION

Prophylaxis with recombinant human C1 esterase inhibitor provided clinically relevant reductions in frequency of hereditary angio-oedema attacks and was well tolerated. In view of the pharmacokinetic profile of recombinant human C1 esterase inhibitor, our results suggest that efficacy of C1-inhibitor replacement therapy might not be a direct function of plasma trough concentrations of C1 inhibitor.

FUNDING

Pharming Technologies.

Patient satisfaction and experience with intravenously administered C1-inhibitor concentrates in the United States

BACKGROUND

Hereditary angioedema (HAE) is a rare genetic disorder with substantial morbidity and mortality. Despite expanded choices for effective acute treatment, prophylactic options are more limited. Intravenous C1 esterase inhibitor (C1-INH[IV]) is licensed and used to prevent HAE symptoms.

OBJECTIVE

To better understand patient experiences with using C1-INH(IV), including level of satisfaction and types and frequency of complications.

METHODS

Fifty adult members (≥18 years of age) of the US HAE Association who had HAE type I or II completed a self-administered internet survey. Eligible participants were experiencing at least 1 HAE attack per month and must have been receiving treatment with C1-INH(IV) as prophylaxis or acute therapy.

RESULTS

Almost all respondents (n = 47; 94%) were using C1-INH(IV) for HAE prophylaxis. Most patients reported administration of C1-INH(IV) through a peripheral vein (n = 34) and 19 were currently (n = 17) or previously (n = 2) using a central venous port. Most respondents (62%) who used a peripheral vein to administer treatment reported having difficulty finding a usable vein or getting the infusion to work properly at least some of the time. Issues accessing veins, exhausted veins, and frequency of attacks were the main reasons physicians recommended ports to respondents. Although ports allow easier administration of therapy, 47% of respondents with ports experienced problems such as occlusion, thrombosis, and infection. Respondents using C1-INH prophylaxis reported a mean of 2.3 attacks per month during the previous 6 months.

CONCLUSION

The survey results identified clinical challenges with IV HAE medication use, including venous access issues and ongoing monthly attack occurrence despite prophylactic C1-INH(IV) administration.

The complement and contact activation systems: partnership in pathogenesis beyond angioedema

The blood plasma contains four biologically important proteolytic cascades, which probably evolved from the same ancestral gene. This in part may explain why each cascade has very similar "initiating trigger" followed by sequential and cascade-like downstream enzymatic activation pattern. The four cascades are: the complement system, the blood clotting cascade, the fibrinolytic system, and the kallikrein-kinin system. Although much has been written about the interplay between all these enzymatic cascades, the cross-talk between the complement and the kinin generating systems has become particularly relevant as this interaction results in the generation of nascent molecules that have significant impact in various inflammatory diseases including angioedema and cancer. In this review, we will focus on the consequences of the interplay between the two systems by highlighting the role of a novel molecular link called gC1qR. Although this protein was first identified as a receptor for C1q, it is now recognized as a multiligand binding cellular protein, which serves not only as C1q receptor, but also as high affinity (K_D  ≤ 0.8 nM) binding site for both high molecular weight kininogen (HK) and factor XII (FXII). At inflammatory sites, where atherogenic factors such as immune complexes and/or pathogens can activate the endothelial cell into a procoagulant and proinflammatory surface, the two pathways are activated to generate vasoactive peptides that contribute in various ways to the inflammatory processes associated with numerous diseases. More importantly, since recent observations strongly suggest an important role for both pathways in cancer, we will focus on how a growing tumor cluster can employ the byproducts derived from the two activation systems to ensure not only its survival and growth, but also its escape into distal sites of colonization.

Preventing Hereditary Angioedema Attacks in Children Using Cinryze®: Interim Efficacy and Safety Phase 3 Findings

BACKGROUND

Hereditary angioedema (HAE) is a rare genetic disease causing unpredictable and potentially life-threatening subcutaneous and submucosal edematous attacks. Cinryze® (Shire ViroPharma Inc., Lexington, MA, USA), a nanofiltered C1 inhibitor (C1-INH), is approved in Europe for the treatment, preprocedure prevention, and routine prophylaxis of HAE attacks, and for the routine prophylaxis of attacks in the USA. This phase 3 study assessed the safety and efficacy of 2 C1-INH doses in preventing attacks in children aged 6-11 years.

METHODS

A randomized single-blind crossover study was initiated in March 2014. Results for the first 6 patients completing the study are reported here. After a 12-week qualifying observation period, patients were randomly assigned to 1 of 2 C1-INH doses, 500 or 1,000 U, every 3-4 days for 12 weeks and crossed over to the alternative dose for a second 12-week period. The primary efficacy endpoint was the number of angioedema attacks per month.

RESULTS

Six females with HAE type I and a median age of 10.5 years received 2 doses of C1-INH (500 and 1,000 U). The mean (SD) difference in the number of monthly angioedema attacks between the baseline observation period and the treatment period was -1.89 (1.31) with 500 U and -1.89 (1.11) with 1,000 U. During the treatment periods, cumulative attack severity, cumulative daily severity, and the number of attacks needing acute treatment were lower. No serious adverse events or study drug discontinuations occurred.

CONCLUSIONS

Interim findings from this study indicate that routine prevention with intravenous administration of C1-INH is efficacious, safe, and well tolerated in children ≥6 years of age.

The role of the complement system in hereditary angioedema

Hereditary angioedema (HAE) is a rare, but potentially life-threatening disorder, characterized by acute, recurring, and self-limiting edematous episodes of the face, extremities, trunk, genitals, upper airways, or the gastrointestinal tract. HAE may be caused by the deficiency of C1-inhibitor (C1-INH-HAE) but another type of the disease, hereditary angioedema with normal C1-INH function (nC1-INH-HAE) was also described. The patient population is quite heterogeneous as regards the location, frequency, and severity of edematous attacks, presenting large intra- and inter-individual variation. Here, we review the role of the complement system in the pathomechanism of HAE and also present an overview on the complement parameters having an importance in the diagnosis or in predicting the severity of HAE.

Health-related quality of life among children with hereditary angioedema

BACKGROUND

The clinical expressions of hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) and its related burden may negatively affect patient quality of life. This study aimed to assess health-related quality of life (HRQoL) in children with C1-INH-HAE.

METHODS

Children (N = 98: 34 C1-INH-HAE patients, 64 healthy controls) aged 3-18 years were recruited in Israel and Hungary. All individuals completed a demographic questionnaire, a disease activity and site questionnaire, and the Pediatric Quality of Life Inventory (PedsQL™) 4.0 Generic Core Scales (child self-report and maternal proxy report) to assess HRQoL.

RESULTS

Among C1-INH-HAE patients, nine (26.5%) had 1-5 attacks/year, six (17.6%) had 6-18 attacks/year, eight (23.5%) had 25-60 attacks/year, and 11 (32.4%) were asymptomatic over the previous year. Children with C1-INH-HAE attacks demonstrated lower HRQoL than healthy control children across the total score, school, and psychosocial dimensions of the PedsQL™. The number of C1-INH-HAE attacks negatively correlated with the total HRQoL score (r = -0.48, p = 0.008), school-related HRQoL (r = -0.39, p = 0.02), and psychosocial HRQoL (r = -0.43, p = 0.01). Patients with multisite laryngeal, abdominal, and peripheral C1-INH-HAE attacks had a lower HRQoL compared with those who experienced solely peripheral attacks across the total score (p = 0.04), physical (p = 0.04), and school (p = 0.02) domains. There was no significant difference between asymptomatic C1-INH-HAE patients and healthy controls.

CONCLUSIONS

Children with symptomatic C1-INH-HAE demonstrate impaired HRQoL compared with healthy controls. HRQoL was affected by the frequency and site of C1-INH-HAE attacks and mostly in the school and physical domains.

Pharmacoeconomics of Orphan Disease Treatment with a Focus on Hereditary Angioedema

This article discusses orphan diseases, their prevalence, legislative incentives to encourage development of therapies, and the impact of treatment on health care payment systems. Specifically, the cost burden of hereditary angioedema on patients, health care systems, and society is reviewed. The impact of availability of and access to novel and specific therapies on morbidity, mortality, and overall burden of disease is explored. Changes in treatment paradigms to improve effect and reduce cost of treatment are presented.

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.

Controversies and challenges in the management of chronic urticaria

This supplement reports proceedings of the second international Global Urticaria Forum, which was held in Berlin, Germany in November 2015. Despite the clear international guideline, there remain a number of controversies and challenges in the management of patients with chronic urticaria (CU). As a result of major advancements in urticaria over the past 4 years, the current EAACI/GA(2) LEN/EDF/WAO urticaria guideline treatment algorithm requires updating. Case studies from patients with chronic spontaneous urticaria (CSU) [also called chronic idiopathic urticaria (CIU)], chronic inducible urticaria (CIndU) or diseases and syndromes related to CU are useful in describing and exploring challenges in disease management. Case studies of specific CSU patient populations such as children with CU or patients with angio-edema but no hives also require consideration as potentially challenging groups with unmet needs. The current EAACI/GA(2) LEN/EDF/WAO urticaria guideline provides a general framework for the management of patients with CU but, as these cases highlight, a personalized approach based on the expert knowledge of the physician may be required.

Allergic Dermatoses

The purpose of this article is to review the current available material pertaining to atopic dermatitis, contact dermatitis, urticaria, and angioedema. This article focuses on each disease process's clinical presentation, diagnosis, and management. Although atopic dermatitis and contact dermatitis are similar, their development is different and can affect a patient's quality of life. Urticaria and angioedema are also similar, but the differentiation of the two processes is crucial in that they have significant morbidity and mortality, each with a different prognosis.

Sustained response of recombinant human C1 esterase inhibitor for acute treatment of hereditary angioedema attacks

BACKGROUND

Symptoms of hereditary angioedema (HAE) attacks can recur soon after initial treatment; the durability of response for recombinant human C1 esterase inhibitor (rhC1INH) treatment is unknown.

OBJECTIVE

To examine the efficacy and durability of rhC1INH for acute HAE attacks.

METHODS

In this pooled post hoc analysis of 2 trials, patients with type I or II HAE (functional C1INH levels <50% of normal) and a baseline visual analog scale score of at least 50 mm were included if they had received at least 1 intravenous dose of 50 IU/kg of rhC1INH. Response was defined as symptom relief within 4 hours after treatment with persistence (≥20-mm decrease in visual analog scale scores [0 mm {"no symptoms at all"} to 100 mm {"extremely disabling"}] at 2 consecutive time points) during the 4 hours. Durability was the response without an increase of at least 20 mm in the minimum post-treatment visual analog scale score up to 24 hours. Recurrence and new attack symptoms were determined for patients with 72-hour post-treatment data.

RESULTS

Data were analyzed for 127 patients treated with 50 IU/kg of rhC1INH in 2 studies. Most attacks (90.7%) responded within 4 hours, with differences in response rates among attack locations (61.5%-94.4%). The median time to the beginning of symptom relief was 75.0 minutes (95% confidence interval 65.0-80.0). No relapse occurred during 24 hours for attacks that initially responded. Only 7.1% of attacks were associated with symptom recurrence within 72 hours of initial rhC1INH treatment.

CONCLUSION

This integrated analysis supports the efficacy of rhC1INH for treatment of acute HAE across multiple attacks, with a sustained response for at least 3 days.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT00225147 and NCT00262301.