Summary and future of medicine for hereditary angioedema

Hereditary angioedema (HAE) is a rare autosomal genetic disease for which there are currently nine FDA-approved drugs. This review summarizes drug treatments for HAE based on four therapeutic pathways: inhibiting the contact system, inhibiting bradykinin binding to B2 receptors, supplying missing C1 inhibitors, and inhibiting plasminogen conversion. The review generalizes the clinical use, pharmacological effects and mechanisms of HAE drugs, and it also discusses possible development directions and targets to enhance understanding of HAE and help researchers.

Sebetralstat (KVD900): A Potent and Selective Small Molecule Plasma Kallikrein Inhibitor Featuring a Novel P1 Group as a Potential Oral On-Demand Treatment for Hereditary Angioedema

Hereditary angioedema (HAE) is a rare genetic disorder in which patients experience sudden onset of swelling in various locations of the body. HAE is associated with uncontrolled plasma kallikrein (PKa) enzyme activity and generation of the potent inflammatory mediator, bradykinin, resulting in episodic attacks of angioedema. Herein, we disclose the discovery and optimization of novel small molecule PKa inhibitors. Starting from molecules containing highly basic P1 groups, which typically bind to an aspartic acid residue (Asp189) in the serine protease S1 pocket, we identified novel P1 binding groups likely to have greater potential for oral-drug-like properties. The optimization of P4 and the central core together with the particularly favorable properties of 3-fluoro-4-methoxypyridine P1 led to the development of sebetralstat, a potent, selective, orally bioavailable PKa inhibitor in phase 3 for on-demand treatment of HAE attacks.

Antisense Inhibition of Prekallikrein to Control Hereditary Angioedema

Hereditary angioedema is characterized by recurrent and unpredictable episodes of subcutaneous and mucosal swelling that can be life threatening. IONIS-PKK-L_Rx is a ligand-conjugated antisense oligonucleotide designed for receptor-mediated delivery to hepatocytes. In a compassionate-use pilot study, two patients with severe bradykinin-mediated angioedema were initially administered weekly subcutaneous injections of the unconjugated parent drug, IONIS-PKK_Rx, for 12 to 16 weeks, after which they received IONIS-PKK-L_Rx at a dose of 80 mg every 3 to 4 weeks for 7 to 8 months. Treatment was accompanied by a reduction in the angioedema attack rate. (Funded by Amsterdam UMC.).

Hereditary angioedema therapies in the United States: movement toward an international treatment consensus

BACKGROUND

Hereditary angioedema (HAE) is a rare, potentially life-threatening autosomal dominant disease characterized by recurrent angioedema attacks that affect the skin, gastrointestinal tract, and airway, including the larynx. Pharmacologic developments in HAE treatment have culminated in the recent introduction of 4 new HAE-specific therapies in the United States.

OBJECTIVES

In light of these new therapeutic options, this commentary outlines historical US HAE therapy choices, discusses the potential effect of the 4 recently approved HAE treatments, and considers strategies for optimizing their use in line with international treatment recommendations.

DISCUSSION

Treatment options for HAE in the United States have been limited to attenuated androgens and antifibrinolytic agents for long-term prophylaxis and FFP and supportive therapy for the management of acute attacks. The 4 new therapies that have recently become available (ie, 2 plasma-derived C1 esterase inhibitor (C1-INH) concentrates, the kallikrein inhibitor ecallantide, and the bradykinin β(2)-antagonist icatibant) have provided an opportunity to change routine HAE treatment. In 2009, despite the availability of 2 of the new treatments (ie, the plasma-derived C1-INH concentrates), a large survey of US physicians suggested that wide variability still existed in the treatment of patients with HAE. Since this survey was undertaken, clinical experience with all 4 new treatments has increased significantly, and because 3 of these agents (ie, 2 plasma-derived C1-INH concentrates and icatibant) can be self-administered by trained patients, physicians can now provide individualized care that is proven effective and more aligned with international guidance.

[Hereditary angioedema]

Hereditary angioedema (HAE) is a rare autosomal dominant disease characterized by episodic swelling of the face, extremities, larynx, gastrointestinal tract or genitals. Three different subtypes have been identified so far. Type I and II HAE are caused by mutations in the C1 inhibitor gene leading to decreased or dysfunctional C1 inhibitor, respectively. Type III is caused by a mutation in the coagulation factor XII. In addition, acquired forms or forms with no known etiology exist. Increased bradykinin production leading to increased vessel permeability is common to all HAE types. Treatment of HAE has evolved dramatically during the last years as self-administration of C1 inhibitor concentrate and bradykinin-2 receptor antagonist icatibant have become available.

Possible disease-modifying factors: the mannan-binding lectin pathway and infections in hereditary angioedema of children and adults

Introduction

Hereditary angioedema (HAE) is caused by mutations in the C1inh gene, leading to dysfunction of the C1-esterase inhibitor (C1-INH). C1-INH interacts with MASP-1 and MASP-2 proteases, participating in the mannan-binding lectin (MBL) pathway of complement activation. The aim of the study was to investigate the contribution of possible changes in MBL/MASP-2 complex activity and Helicobacter pylori, hepatitis B virus (HBV), and hepatitis C virus (HCV) infections to the severity and frequency of clinical symptoms of HAE.

Materials and Methods

The study was performed in 65 patients with HAE and 113 healthy persons. The parameters measured were C1-INH, C4, MBL concentration and MBL/MASP-2 complex activity, and serological markers of H. pylori, HBV, and HCV infection. Scores for the frequency and severity of HAE symptoms were determined.

Results

HAE scores were significantly higher in patients whose C1-INH activity did not exceed 10% than in patients with activity of 10-52% (p=0.016). No significant differences were found in the median levels of MBL concentration and MBL/MASP-2 complex activity between patients and the control group. There was a slight association between contact with H. pylori in patients and HAE symptom score (p=0.052, not significant). Adult patients showed a 2.6-times higher frequency of anti-HBc than the general population. HBV DNA was negative in anti-HBc(+) patients.

Conclusions

These results suggest that the MBL complement activation pathway itself does not contribute to the frequency of angioedema attacks. Infections with H. pylori and HBV may slightly influence the disease score (not significant).