Successful off-pump coronary artery bypass graft surgery in a patient with hereditary angioedema

Hereditary Angioedema: Management of Laryngeal Attacks

Background

Hereditary angioedema (HAE) patients suffering from laryngeal attacks in the United States faced severely limited treatment options until 2008. These potentially life-threatening episodes occur in over one-half of the patients affected by HAE during their lifetimes. Acute therapy had been relegated to supportive care, intubation, and consideration of fresh frozen plasma (FFP)–-the latter with the potential for actually accelerating the speed and severity of the swelling.

Methods

In this article we will review the recently approved and emerging HAE treatments that have evolved from the recognition that bradykinin generation is the fundamental abnormality leading to attacks of angioedema.

Results

Acute therapy for laryngeal attacks will be discussed including purified plasma–derived C1 inhibitor (C1INH), recombinant C1INH, an inhibitor of plasma kallikrein (ecallantide), and a B2 receptor antagonist (icatibant). Prophylactic care has also been transformed from a reliance on attenuated androgens with their attendant side effects to C1INH replacement.

Conclusion

The arrival of these novel therapies promises to transform the future management of HAE.

Recent developments in the treatment of acute abdominal and facial attacks of hereditary angioedema: focus on human C1 esterase inhibitor

Hereditary angioedema (HAE) is a potentially fatal genetic disorder typified by a deficiency (type I) or dysfunction (type II) of the C1-inhibitor (C1-INH) and characterized by swelling of the extremities, face, trunk, abdominal viscera, and upper airway. Type III is normal estrogen-sensitive C1-INH HAE. Bradykinin, the main mediator of HAE, binds to endothelial B2 receptors, increasing vascular permeability and resulting in edema. HAE management includes short- and long-term prophylaxis. For treating acute episodes, C1-INH concentrate is recommended with regression of symptoms achieved in 30-90 min. Infusions of 500-1000 U have been used in Europe for years. Two plasma-derived C1-INH concentrates have been licensed recently in the United States: Berinert(®) for treating acute attacks and Cinryze(®) for prophylaxis in adolescent/adult patients. A recombinant C1-INH that is being considered for approval (conestat alfa) exhibited significant superiority versus placebo. Ecallantide (Kalbitor(®)) is a selective kallikrein inhibitor recently licensed in the United States for treating acute attacks in patients aged >16 years. It is administered in three 10-mg subcutaneous injections with the risk of anaphylactic reactions. Icatibant (Firazyr(®)) is a bradykinin B2 receptor competitor. It is administered subcutaneously as a 30-mg injection and approved in Europe but not in the United States.

Successful C1 inhibitor short-term prophylaxis during redo mitral valve replacement in a patient with hereditary angioedema

Hereditary angioedema is characterized by sudden episodes of nonpitting edema that cause discomfort and pain. Typically the extremities, genitalia, trunk, gastrointestinal tract, face, and larynx are affected by attacks of swelling. Laryngeal swelling carries significant risk for asphyxiation. The disease results from mutations in the C1 esterase inhibitor gene that cause C1 esterase inhibitor deficiency. Attacks of hereditary angioedema result from contact, complement, and fibrinolytic plasma cascade activation, where C1 esterase inhibitor irreversibly binds substrates. Patients with hereditary angioedema cannot replenish C1 esterase inhibitor levels on pace with its binding. When C1 esterase inhibitor is depleted in these patients, vasoactive plasma cascade products cause swelling attacks. Trauma is a known trigger for hereditary angioedema attacks, and patients have been denied surgical procedures because of this risk. However, uncomplicated surgeries have been reported. Appropriate prophylaxis can reduce peri-operative morbidity in these patients, despite proteolytic cascade and complement activation during surgical trauma. We report a case of successful short-term prophylaxis with C1 esterase inhibitor in a 51-year-old man with hereditary angioedema who underwent redo mitral valve reconstructive surgery.

Summary of the International Multicenter Prospective Angioedema C1-inhibitor Trials 1 and 2 (IMPACT1 and 2)

Hereditary angioedema (HAE) is an autosomal dominant disease characterized by deficiency of C1 inhibitor (C1-INH) that commonly presents with recurrent swelling affecting different parts of the body. Supplementation with C1-INH is successfully used to treat HAE in selected countries, mostly in Europe. Berinert P (CSL Behring, Marburg, Germany), a human plasma-derived C1-INH, was studied in the International Multicenter Prospective Angioedema C1-inhibitor Trial 1 (IMPACT1) that was completed in 2007. It was the first safety and dose-finding study of C1-INH in patients with acute abdominal and facial angioedema. IMPACT2 was the extension of the first trial to study C1-INH efficacy and safety in multiple treatments of acute HAE attacks in various areas of the body. Berinert P has excellent potential to become a first-line therapy for treating patients with acute HAE attacks in the USA and other countries involved in the IMPACT trials. While final data from the IMPACT2 trial are not yet released, this article reviews currently available data from previous reports and abstract presentations.

HAE therapies: past present and future

Advances in understanding the pathophysiology and mechanism of swelling in hereditary angioedema (HAE) has resulted in the development of multiple new drugs for the acute and prophylactic treatment of patients with HAE. This review will recap the past treatment options, review the new current treatment options, and discuss potential future treatment options for patients with HAE.

Hereditary angioedema: current and emerging treatment options

Angioedema can result from allergic, hereditary, and acquired conditions. Hereditary angioedema (HAE) attacks are disabling at the time of occurrence and can be life threatening; they often result in hospitalization and intensive care unit admission. Although there are several variants of HAE, they share a final common pathway: unopposed activation of multiple kinins and mediators including kallikrein and bradykinin. This leads to increased vascular permeability, which in turn produces the edema after which the condition is named. Older treatment options licensed in the United States, anabolic steroids and antifibrinolytics, have troublesome side effect profiles and may not reverse a severe acute attack. In Europe, C1 esterase inhibitor (C1-INH) concentrates have been used since 1974 for both preventing and terminating attacks. Two of these have now been licensed in the United States for use in HAE patients, one for prophylaxis and the other for treating acute abdominal and facial HAE attacks. The first kinin pathway modulator, ecallantide, has also been licensed recently in the United States for treating HAE attacks. The objective of this article is to describe HAE and review the available options for managing patients, as well as different drugs currently under investigation. Specific attention is given to the perioperative management of patients with HAE.

New promise and hope for treating hereditary angioedema

BACKGROUND

While there is no approved effective therapy for the treatment of acute attacks of hereditary angioedema in the USA, four different drugs are completing or have recently completed Phase III clinical trials.

OBJECTIVE

To review the clinical status and future prospects of the new therapies under development for the treatment of hereditary angioedema.

METHODS

A review was carried out of the literature and presentations at meetings on the efficacy and safety of plasma-derived C1 inhibitor, recombinant human C1 inhibitor, the kallikrein inhibitor DX-88, and the B2 bradykinin receptor antagonist HOE-140.

RESULTS/CONCLUSION

Each of these drugs has been shown to be effective and safe for the treatment of hereditary angioedema; however, subtle differences in their mechanisms of action and delivery may influence how physicians and patients utilize the different drugs. The availability of effective therapy is expected to reshape the management of hereditary angioedema.

Novel therapies for hereditary angioedema

Advances in our understanding of the molecular mechanisms underlying hereditary angioedema (HAE) have led to the development of new treatment modalities. Five new drugs for the treatment of HAE are currently undergoing clinical testing in the United States. These novel therapeutics can be divided into two groups: drugs that replace C1 inhibitor (C1INH) functional activity and drugs that abrogate the bradykinin-mediated increase in vascular permeability associated with HAE attacks. The first group includes two plasma-derived C1INH concentrates as well as a recombinant transgenic human C1INH protein, and the second group includes an engineered plasma kallikrein inhibitor as well as a B2 bradykinin receptor antagonist. This article reviews the rationale, development, and potential use of these novel therapeutics.

Current and future therapy for hereditary angioedema

Hereditary angioedema (HAE) is an autosomal dominant disease characterized by recurrent episodes of potentially life-threatening angioedema. Attacks of angioedema in HAE patients typically last 3 or more days, begin during childhood, and continue to occur throughout life. Tragically, patients with HAE continue to die as a direct consequence of the disease. Minimizing the morbidity and mortality associated with HAE requires both effective treatment of acute attacks as well as strategies to prevent HAE attacks. While there is currently no effective therapy available in the United States for the treatment of acute attacks of HAE, several molecules have demonstrated impressive efficacy in this setting, and it is likely that one or more of these new drugs will become available in the United States soon. This article will review both the current and the future therapeutic options for the treatment of HAE.

Hereditary and acquired angioedema: problems and progress: proceedings of the third C1 esterase inhibitor deficiency workshop and beyond

Hereditary angioedema (HAE), a rare but life-threatening condition, manifests as acute attacks of facial, laryngeal, genital, or peripheral swelling or abdominal pain secondary to intra-abdominal edema. Resulting from mutations affecting C1 esterase inhibitor (C1-INH), inhibitor of the first complement system component, attacks are not histamine-mediated and do not respond to antihistamines or corticosteroids. Low awareness and resemblance to other disorders often delay diagnosis; despite availability of C1-INH replacement in some countries, no approved, safe acute attack therapy exists in the United States. The biennial C1 Esterase Inhibitor Deficiency Workshops resulted from a European initiative for better knowledge and treatment of HAE and related diseases. This supplement contains work presented at the third workshop and expanded content toward a definitive picture of angioedema in the absence of allergy. Most notably, it includes cumulative genetic investigations; multinational laboratory diagnosis recommendations; current pathogenesis hypotheses; suggested prophylaxis and acute attack treatment, including home treatment; future treatment options; and analysis of patient subpopulations, including pediatric patients and patients whose angioedema worsened during pregnancy or hormone administration. Causes and management of acquired angioedema and a new type of angioedema with normal C1-INH are also discussed. Collaborative patient and physician efforts, crucial in rare diseases, are emphasized. This supplement seeks to raise awareness and aid diagnosis of HAE, optimize treatment for all patients, and provide a platform for further research in this rare, partially understood disorder.

Safety and efficacy of pasteurized C1 inhibitor concentrate (Berinert P) in hereditary angioedema: a review. jean.de.serres@aventis.com

BACKGROUND

Hereditary angioedema caused by C1 inhibitor deficiency can be life threatening. Acute exacerbations are treated with intravenous purified, pasteurized C1 esterase inhibitor concentrate at doses of 500-1000 IU.

METHODS

We reviewed the literature about safety and efficacy of the C1 inhibitor concentrate used in Canada (Berinert P) or relevant to it.

RESULTS

Post-marketing experience since 1985 is reassuring. There were few adverse events and no transmission of infection with the pasteurized product. A number of case reports, retrospective studies and few randomized or non-randomized prospective studies have shown good efficacy measured as clinical resolution of symptoms or in time to resolution, time to relief or time to improvement.

CONCLUSIONS

There are numerous observational studies showing good efficacy and safety and a long post-marketing experience although few randomized placebo-controlled trials.