Novel pharmacotherapy of acute hereditary angioedema with bradykinin B2-receptor antagonist icatibant

Bas M, Bier H, Greve J, Kojda G, Hoffmann TK.
Allergy. 2006 Dec;61(12):1490–1492

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Hereditary angioedema: a current state-of-the-art review, VIII: current status of emerging therapies

Bernstein JA,
Ann Allergy Asthma Immunol. 2008; 100 (suppl2): S41-S46

Abstract

OBJECTIVE: To provide an overview on the current status of emerging therapies for hereditary angioedema (HAE) in the United States. DATA SOURCES: Summary statements were obtained from each pharmaceutical company regarding their agent. STUDY SELECTION: Each agent is undergoing or has completed phase 3, double-blind, placebo-controlled trials. RESULTS: Berinert P, a purified, virus-inactivated, human plasma-derived C1 inhibitor (C1-INH) concentrate, is being investigated in 2 international, multicenter, prospective trials. Experience with this agent in Europe and Canada indicates it is effective and safe. Cinryze is a nanofiltered C1-INH replacement therapy demonstrated to be effective and safe in acute and prophylactic arms of a phase 3, double-blind, placebo-controlled study. Rhucin, a recombinant human C1-INH replacement therapy from transgenic rabbits, has been shown to be effective and safe in phase 2 and phase 2/3 studies, with an additional phase 3 study ongoing. DX-88 or ecallantide, a potent and specific inhibitor of plasma kallikrein, achieved all primary and secondary efficacy end points in a placebo-controlled, double-blind, phase 3 study, with a second phase 3 study ongoing. Icatibant, a potent and specific peptidomimetic bradykinin 2 receptor antagonist, was studied in 2 phase 3 trials: FAST 1 (For Angioedema Subcutaneous Treatment) did not achieve statistical significance for the primary end point but did so for secondary end points, whereas FAST 2 achieved statistical significance for primary and secondary end points. CONCLUSIONS: The future treatment of HAE in the United States appears promising based on progress being made in drug development for this orphan disease.

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Symptoms, Course, and Complications of Abdominal Attacks in Hereditary Angioedema due to C1 Inhibitor Deficiency

Bork K, Staubach P, Eckardt MAJ, and Hardt J.
Am J Gastroenterol. 2006 Mar;101(3):619-27.

Abstract

OBJECTIVES: Recurrent abdominal attacks belong to the cardinal and most distressing symptoms of hereditary angioedema (HAE) due to C1 inhibitor deficiency. They are characterized by crampy pain, but may include vomiting, diarrhea, and other features. Detailed clinical data about the symptoms and course of abdominal attacks have not been reported.
METHODS: We retrospectively observed a total of 33,671 abdominal attacks in 153 patients with HAE including a prospectively examined subgroup of 23 patients. Symptoms, course, frequency of attacks, and complications were analyzed. RESULTS: The relation of mild, moderate, and severe attacks was 1:1.4:5.6 in the prospective part of the study. Extra-abdominal symptoms preceded the abdominal symptoms. The mean maximal pain score was 8.4 (range 1-10). Vomiting occurred in 73% (24,696) and diarrhea in 41% (13,682) of the attacks. Circulatory collapse accompanied 4.4% (1,468) of the attacks, with loss of consciousness (LOC) occurring in 2.2% (739). Nine patients could clearly distinguish two types of abdominal attacks: vomiting and diarrhea. Rare complications included tetany, hemorrhagic stools, and intussusception of the colon. In 28% (43) of the patients, recurrent abdominal attacks had started before the characteristic swelling of the skin had ever occurred. A model is proposed to classify the severity of the attacks and to describe the clinical course.
CONCLUSIONS: Abdominal attacks in HAE constitute a more disabling and complex syndrome than previously assumed. Our results add to the understanding of symptoms and course of HAE and may aid in the early recognition of an impending attack and improve clinical management.

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Treatment of acute edema attacks in hereditary angioedema with a bradykinin receptor-2 antagonist (Icatibant)

Bork K, Frank J, Grundt B, Schlattmann P, Nussberger J, Kreuz W.
J Allergy Clin Immunol. 2007 Jun;119(6):1497-503

Abstract

BACKGROUND: In hereditary angioedema, bradykinin is assumed to be the most important mediator of edema formation.
OBJECTIVE: To assess whether the selective bradykinin receptor-2 antagonist Icatibant is effective in acute edema attacks of hereditary angioedema.
METHODS: In this uncontrolled pilot study, 15 patients with 20 attacks were treated with Icatibant. The attacks were analyzed by using a standardized and validated visual analog scale measurement and compared with historical data of untreated attacks. Plasma bradykinin concentration was measured before and 4 hours after intravenous Icatibant treatment. RESULTS: Symptom intensity decreased within 4 hours after administration of Icatibant; the median time to onset of symptom relief was 1.50, 1.42, and 1.13 hours in the intravenous groups and 0.58 and 0.45 hours in the subcutaneous groups, respectively. The median difference in the 10-cm visual analog scale 4 hours after start of treatment was 4.11 cm (95% CI, 1.72-6.07). Compared with untreated attacks, Icatibant treatment reduced the mean (SD) time to onset of symptom relief by 97% from 42 +/- 14 to 1.16 +/- 0.95 hours (all groups combined). Median bradykinin concentration was 7-fold above the norm during acute attacks at 48.5 pmol/L and decreased to 18.0 pmol/L 4 hours after Icatibant infusion or injection. CONCLUSION: Icatibant was effective in treating acute attacks of hereditary angioedema.
CLINICAL IMPLICATIONS: This is the first report demonstrating the clinical usefulness of antagonizing bradykinin binding to bradykinin receptor-2 in hereditary angioedema.

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Hereditary angioedema: new findings concerning symptoms, affected organs, and course.

Bork, K, Meng G, Staubach P, Hardt J.
Am J Med. 2006 Mar;119(3):267-74

Abstract

Hereditary angioedema (HAE) due to C1 inhibitor deficiency is clinically characterized by relapsing skin swellings, abdominal pain attacks, and life-threatening upper airway obstruction. Our aim was to examine a temporal and spatial pattern of the edema episodes by evaluating the long-term course of hereditary angioedema in order to establish a specific swelling pattern. SUBJECTS AND METHODS: Data were generated from 221 patients with C1 inhibitor deficiency by asking them about symptoms they experienced during their edema episodes. Documentation was accomplished through the use of standardized questionnaires. RESULTS: A total of 131110 edema episodes were observed. Clinical symptoms started at a mean age of 11.2 (SD 7.7) years. During the following cumulative 5736 years, only 370 (6.5%) symptom-free years occurred. Skin swellings, including extremity, facial, genital, and trunk swellings, and abdominal attacks occurred in 97.4% of all edema episodes of the disease. The other episodes were laryngeal edema (0.9%); edema of the soft palate (0.6%); tongue swellings (0.3%); headache episodes (0.7%); episodes affecting urinary bladder (0.3%), chest (0.2%), muscles (0.4%), joints (0.1%), kidneys (0.1%), and esophagus (0.05%), and were partly combined with other edema episodes. The per-patient analysis and the per-episode analysis revealed markedly discrepant results. On average, women had a more severe course of the disease than men. Patients with early onset of clinical symptoms were affected more severely than those with late onset. CONCLUSION: The described swelling pattern is specific for HAE and allows a tentative diagnosis based on clinical symptoms and the course of the disease.

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Symptoms, course, and complications of abdominal attacks in hereditary angioedema due to C1 inhibitor deficiency.

Bork, K, Staubach P, Eckardt AJ, Hardt J.
Am J Gastroenterol. 2006 Mar;101(3):619-27

Abstract

Recurrent abdominal attacks belong to the cardinal and most distressing symptoms of hereditary angioedema (HAE) due to C1 inhibitor deficiency. They are characterized by crampy pain, but may include vomiting, diarrhea, and other features. Detailed clinical data about the symptoms and course of abdominal attacks have not been reported. METHODS: We retrospectively observed a total of 33,671 abdominal attacks in 153 patients with HAE including a prospectively examined subgroup of 23 patients. Symptoms, course, frequency of attacks, and complications were analyzed. RESULTS: The relation of mild, moderate, and severe attacks was 1:1.4:5.6 in the prospective part of the study. Extra-abdominal symptoms preceded the abdominal symptoms. The mean maximal pain score was 8.4 (range 1-10). Vomiting occurred in 73% (24,696) and diarrhea in 41% (13,682) of the attacks. Circulatory collapse accompanied 4.4% (1,468) of the attacks, with loss of consciousness (LOC) occurring in 2.2% (739). Nine patients could clearly distinguish two types of abdominal attacks: vomiting and diarrhea. Rare complications included tetany, hemorrhagic stools, and intussusception of the colon. In 28% (43) of the patients, recurrent abdominal attacks had started before the characteristic swelling of the skin had ever occurred. A model is proposed to classify the severity of the attacks and to describe the clinical course. CONCLUSIONS: Abdominal attacks in HAE constitute a more disabling and complex syndrome than previously assumed. Our results add to the understanding of symptoms and course of HAE and may aid in the early recognition of an impending attack and improve clinical management.


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Canadian 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema

Bowen T; Cicardi M; Bork K; Zuraw B; Frank M, et al.
Annals of allergy, asthma & immunology 2007; 100:30-40

Abstract

Background: We published the Canadian 2003 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema (HAE; C1 inhibitor [C1-INH] deficiency) in 2004.

Objective: To ensure that this consensus remains current.

Methods: In collaboration with the Canadian Network of Rare Blood Disorder Organizations, we held the second Canadian Consensus discussion with our international colleagues in Toronto, Ontario, on February 3, 2006, and reviewed its content at the Fifth C1 Inhibitor Deficiency Workshop in Budapest on June 2, 2007. Papers were presented by international investigators, and this consensus algorithm approach resulted.

Results: This consensus algorithm outlines the approach recommended for the diagnosis, therapy, and management of HAE, which was agreed on by the authors of this report. This document is only a consensus algorithm approach and continues to require validation. As such, participants agreed to make this a living 2007 algorithm, a work in progress, and to review its content at future international HAE meetings.

Conclusions: There is a paucity of double-blind, placebo-controlled trials on the treatment of HAE, making levels of evidence to support the algorithm less than optimal. Controlled trials currently under way will provide further insight into the management of HAE. As with our Canadian 2003 Consensus, this 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of HAE was formed through the meeting and agreement of patient care professionals along with patient group representatives and individual patients.

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Immunoregulatory disorders associated with hereditary angioedema. I. Clinical manifestations of autoimmune disease.

Brickman CM, Tsokos GC, Balow JE et al.
J Allergy Clin Immunol. 1986 May;77(5):749-57

Abstract

Occasional reports have appeared linking hereditary angioedema (HAE) with autoimmune diseases. We have systematically evaluated 157 patients for manifestations of autoimmunity. Nineteen of these patients (12%) had clinical immunoregulatory diseases including glomerulonephritis (five patients), Sjogren's syndrome (three), inflammatory bowel disease (three), thyroiditis (two), systemic lupus erythematosus (one), drug-induced lupus (one), rheumatoid arthritis (one), juvenile rheumatoid arthritis with IgA deficiency (one), incipient pernicious anemia (one), and sicca syndrome (one). All eight patients with HAE who developed an autoimmune disease with a known human histocompatibility antigen association developed a disease associated with their histocompatibility antigen haplotype (p = 0.014). Although only four patients developed Sjogren's syndrome or sicca syndrome, an additional nine manifested part of the sicca complex. We also found patients with HAE with features suggestive of an immune-based abnormality. These features included idiopathic pancreatitis (three patients), Raynaud's disease (two), partial lipodystrophy (one), chronic chorioretinitis (one), and alopecia universalis (one).

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Immunoregulatory disorders associated with hereditary angioedema. II. Serologic and cellular abnormalities.

Brickman CM, Tsokos GC, Chused TM et al.
J Allergy Clin Immunol. 1986 May;77(5):758-67

Abstract

Hereditary angioedema is defined biochemically by a deficiency in the functional activity of the inhibitor of Cl, Cl esterase inhibitor (Cl INH). Deficiency of this regulator of the early classic pathway of complement results in chronic activation of this cascade with a resultant deficiency of C4 and C2. Ninety-seven patients with either complicated (associated with autoimmune disorders) or uncomplicated hereditary angioedema were evaluated for laboratory evidence of immunoregulatory defects. Specific cellular and humoral abnormalities were found and included increased mean total lymphocyte counts, increased mean Leu 4+ (total) and Leu 3+ (helper) T cells, an increased mean Leu 3/Leu 2 (helper/suppressor T cell) ratio, polyclonal B cell activation, and evidence of circulating immune complexes. C4 functional titers were negatively correlated with percent Leu 3+ cells and absolute Leu 3+ cell numbers. We failed to detect any evidence of immune deficiency in this population, and yet a statistically significant number of patients demonstrated elevated levels of antibodies to Epstein-Barr virus antigens when patients were compared to a control group. Thus, early classic complement pathway activation and/or partial complement component deficiency may effect T cell subpopulations and B cell activation. However, additional predisposing factors (e.g., genetic or viral) appear necessary for the development of a particular autoimmune disease in hypocomplementemic patients.

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Angiotensin-converting enzyme inhibitor-associated angioedema.

Byrd JB, Adam A, Brown NJ
Immunol Allergy Clin North Am. 2006 Nov;26(4):725-37

Abstract

Angioedema, characterized by swelling of the lips, face, and tongue, occurs in anywhere from 0.1% to 6% of angiotensin-converting enzyme (ACE) inhibitor users. The incidence is more common in black Americans than in white Americans, in women than in men, and in smokers than in nonsmokers. The remitting and relapsing nature of ACE inhibitor-associated angioedema can confound clinical recognition of the adverse event but also provides clues to its causes. Defective degradation of vasoactive peptide substrates of ACE, such as bradykinin or substance P, may contribute via non-ACE pathways to the pathogenesis of ACE inhibitor-associated angioedema.

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