Oral Sebetralstat for On-Demand Treatment of Hereditary Angioedema Attacks.

BACKGROUND: Approved on-demand treatments for hereditary angioedema attacks need to be administered parenterally, a route of administration that is associated with delays in treatment or withholding of therapy. METHODS: In this phase 3, double-blind, three-way crossover trial, we randomly assigned participants at least 12 years of age with type 1 or type 2 hereditary angioedema to take up to two oral doses of sebetralstat (300 mg or 600 mg) or placebo for an angioedema attack. The primary end point, assessed in a time-to-event analysis, was the beginning of symptom relief, defined as a rating of "a little better" on the Patient Global Impression of Change scale (ratings range from "much worse" to "much better") at two or more consecutive time points within 12 hours after the first administration of the trial agent. Key secondary end points, assessed in a time-to-event analysis, were a reduction in attack severity (an improved rating on the Patient Global Impression of Severity [PGI-S] scale, with ratings ranging from "none" to "very severe") at two or more consecutive time points within 12 hours and complete attack resolution (a rating of "none" on the PGI-S scale) within 24 hours. RESULTS: A total of 136 participants were assigned to one of six trial sequences, with 110 treating 264 attacks. The time to the beginning of symptom relief with the 300-mg dose and the 600-mg dose was faster than with placebo (P<0.001 and P = 0.001 for the two comparisons, respectively), with median times of 1.61 hours (interquartile range, 0.78 to 7.04), 1.79 hours (1.02 to 3.79), and 6.72 hours (1.34 to >12), respectively. The time to reduction in the attack severity with the 300-mg dose and the 600-mg dose was faster than with placebo (P = 0.004 and P = 0.003), with median times of 9.27 hours (interquartile range, 1.53 to >12), 7.75 hours (2.19 to >12), and more than 12 hours (6.23 to >12). The time to complete resolution was faster with the 300-mg and 600-mg doses than with placebo (P = 0.002 and P<0.001). The percentage of attacks with complete resolution within 24 hours was 42.5% with the 300-mg dose, 49.5% with the 600-mg dose, and 27.4% with placebo. Sebetralstat and placebo had similar safety profiles; no serious adverse events related to the trial agents were reported. CONCLUSIONS: Oral sebetralstat provided faster times to the beginning of symptom relief, reduction in attack severity, and complete attack resolution than placebo. (Funded by KalVista Pharmaceuticals; KONFIDENT ClinicalTrials.gov number, NCT05259917; EudraCT number, 2021-001226-21.).

The analysis of the effect of the COVID-19 pandemic on patients with hereditary angioedema type I and type II.

Due to the similarity between the pathomechanism of SARS-CoV-2 infections and hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE), a possibility emerged that C1-INH-HAE may worsen the course of the infection, or that the infection may influence the severity of angioedema (HAE) attacks in C1-INH-HAE patients. Our study aimed to evaluate the effects of the COVID-19 pandemic on the quality of life (QoL) of Hungarian C1-INH-HAE patients, and to survey the acute course of the infection, post COVID symptoms (PCS), vaccination coverage and the side effects of vaccines in this patient population. 93 patients completed our questionnaire between 1st July 2021 and 31st October 2021. In this same period and between March 2019 and March 2020, 63 patients completed the angioedema quality of life questionnaire (AE-QoL). Out of those patients infected with SARS-CoV-2 in the examined period (18/93 patients; 19%), 5% required hospitalization, 28% experienced HAE attacks in the acute phase of the infection, and 44% experienced PCS. A total number of 142 doses of vaccines were administered to the patients. Serious vaccine reactions did not occur in any case, 4 (5%) out of the 73 vaccinated patients experienced HAE attacks. No significant difference (p = 0.59) was found in the median of the AE-QoL total score, or in the number of HAE attacks prior and during the pandemic. Based on our study, HAE patients did not experience more serious SARS-CoV-2 infection, and it did not aggravate the course of HAE either. Changes in the QoL were not significant, and vaccines were safe in HAE patients.

Evaluation of the efficacy and safety of home treatment with the recombinant human C1-inhibitor in hereditary angioedema resulting from C1-inhibitor deficiency.

OBJECTIVE: Conestat alpha, a C1-inhibitor produced by recombinant technology (rhC1-INH) is an acute treatment for edematous attacks occurring in hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE). Our study evaluated the efficacy and safety of rhC1-INH administered during HAE attacks, and for short-term prophylaxis (STP). MATERIALS & METHOD: Our prospective study analyzed the course of 544 HAE attacks experienced by the 21 C1-INH-HAE patients treated, as well as the outcome of 97 instances of STP implemented with rhC1-INH. Using a purpose-designed questionnaire, the patients recorded relevant, treatment-related information. RESULTS: Time to the administration of rhC1-INH was 90.0 min (median) after the onset of HAE attacks. The symptoms started to improve as early as 60 min after the injection of rhC1-INH, and the attack resolved 730.0 min after treatment. The interval between the onset of the HAE attack and the administration of rhC1-INH correlated with time until the onset of improvement (R = 0.2053 p < 0.0001), and with time to the complete resolution of symptoms (R = 0.2805, p < 0.0001). Nine patients received STP with rhC1-INH in 97 instances. STP successfully prevented the HAE attack within 72 h of the event on 93/97 occasions. No local and serious systemic adverse events/effects were observed. CONCLUSIONS: Treatment with rhC1-INH is effective and safe both for acute management, and for STP. Following the onset of an HAE attack, early administration of rhC1-INH may reduce time to the improvement and to the complete resolution of symptoms. Repeated administration of rhC1-INH does not impair its efficacy.

Hereditary angioedema: an update on causes, manifestations and treatment.

Hereditary angioedema is a rare genetic disorder caused by deficiency of C1 esterase inhibitor (C1-INH) and characterized by recurrent episodes of severe swelling that affect the limbs, face, intestinal tract and airway. Since laryngeal oedema can be life-threatening as a result of asphyxiation, correct diagnosis and management of hereditary angioedema is vital. Hereditary angioedema attacks are mediated by bradykinin, the production of which is regulated by C1-INH. Hereditary angioedema therapy relies on treatment of acute attacks, and short- and long-term prophylaxis. Acute treatment options include C1-INH concentrate, icatibant and ecallantide. Self-administration of treatment is recommended and is associated with increased quality of life of patients with hereditary angioedema. Advances in diagnosis and management have improved the outcomes and quality of life of patients with hereditary angioedema.

Cost-Effectiveness of Prophylactic Medications for the Treatment of Hereditary Angioedema Due to C1 Inhibitor Deficiency: A Real-World U.S. Perspective.

DISCLOSURES: No funding supported the writing of this commentary. The author reports personal fees from BioCryst, CSL Behring, Shire, and Pharming and grants from Ionis. He is chair of the US HAEA Medical Advisory Board and scientific advisor for HAE International.

Update on the Use of C1-Esterase Inhibitor Replacement Therapy in the Acute and Prophylactic Treatment of Hereditary Angioedema.

In the vast majority of patients with hereditary angioedema (HAE), angioedema attacks are due to the quantitative or functional deficiency of C1-esterase inhibitor (C1-INH), which leads to increased vascular permeability and unregulated release of bradykinin. Exogenous administration of C1-INH is a rational way to restore the concentration and functional activity of this protein, regulate the release of bradykinin, and attenuate or prevent subcutaneous and submucosal edema associated with HAE. Recent international guidelines for the management of HAE include C1-INH as an option for acute treatment of HAE. In addition, these guidelines recommend C1-INH as first-line treatment for long-term prophylaxis and as the therapy of choice for short-term/preprocedural prophylaxis. Several C1-INH products are available, with approved indications varying across regions. For the acute treatment of HAE, both plasma-derived and recombinant C1-INH formulations have been shown to be effective and well tolerated in adolescents and adults with HAE, with onset of relief within 30 min to a few hours. Plasma-derived C1-INH is approved for use in children, and recombinant C1-INH is being evaluated in this population. Intravenous (IV) and subcutaneous (SC) formulations of C1-INH have been approved for routine prophylaxis to prevent HAE attacks in adolescents and adults. Both formulations when administered twice weekly have been shown to reduce the frequency and severity of HAE attacks. The SC formulation of C1-INH obviates the need for repeated venous access and may facilitate self-administration of HAE prophylaxis at home, as recommended in HAE treatment guidelines. As with most rare diseases, the costs of HAE treatment are high; however, the development of additional acute and prophylactic medications for HAE may result in competitive pricing and help drive down the costs of HAE treatment.

Flow-mediated vasodilation assay indicates no endothelial dysfunction in hereditary angioedema patients with C1-inhibitor deficiency.

BACKGROUND: Hereditary angioedema with C1 inhibitor deficiency (C1-INH-HAE) is a rare, potentially life-threatening disorder characterized by recurrent edematous attacks. The edema formation is the consequence of interaction of bradykinin and various vasoactive peptides with endothelium. Besides these agents, danazol, a modified testosterone derivative used in these patients to prevent edematous attacks, can also affect the function of the endothelium, because it shifts the blood lipid profile to a pro-atherogenic phenotype. OBJECTIVE: To assess the endothelial function in C1-INH-HAE patients and in healthy matched controls. METHODS: To evaluate the endothelial function, we used the flow-mediated dilation method measured in the region of the brachial artery in 33 C1-INH-HAE patients and in 30 healthy matched controls. Laboratory measurements of standard biochemical parameters were performed on computerized laboratory analyzers. RESULTS: No difference was found in endothelial function (reactive hyperemia, RH) between patients (median, 9.0; 25%-75% percentile, 6.3-12.9) and controls (median, 7.37; 25%-75% percentile, 4.52-9.93). Although we found elevated cardiovascular risk (high body mass index and low-density lipoprotein/high-density lipoprotein ratio) in danazol-treated C1-INH-HAE patients, RH values did not differ between danazol-treated and nontreated patients. Furthermore, risk factors correlated with the endothelial function only in healthy controls and patients not treated with danazol. CONCLUSION: In summary, our results did not indicate any signs of endothelial dysfunction in C1-INH-HAE patients. Moreover, the normal endothelial function in danazol-treated patients with pro-atherogenic lipid profile suggests that elevated bradykinin level or other factor(s) involved in the pathogenesis of edematous attacks may have a protective role against endothelial dysfunction and atherosclerosis.

Hereditary angioedema with C1 inhibitor (C1-INH) deficit: the strength of recognition (51 cases).

Hereditary angioedema (HAE) is a rare autosomal dominant disease due to C1 esterase inhibitor deficiency (C1-INH). The disease is characterized by subcutaneous and submucosal edema in the absence of urticaria due to the accumulation of bradykinin. This descriptive study aimed to evaluate the clinical characteristics of patients with a confirmed diagnosis of HAE referred to our Outpatient Clinic between December 2009 and November 2017. Fifty-one patients (38 F, 13 M) with a mean age of 32 years (range: 7-70 y) were included. Family history of HAE was reported in 70% (36/51) of the cases; 33/46 patients became symptomatic by 18 years of age. The median time between onset of symptoms and diagnosis was 13 years (3 mo-50 y). The most frequent triggering factors for attacks were stress (74.4%), trauma (56.4%), and hormonal variations (56%). The main symptoms were subcutaneous edema in 93.5% (43/46) of patients, gastrointestinal symptoms in 84.8% (39/46), and obstruction in the upper airways in 34.8% (16/46). Hospitalization occurred in 65.2%, of whom 13.3% had to be transferred to the Intensive Care Unit. Prophylactic treatment was instituted in 87% (40/46) of patients, and 56.5% (26/46) required additional treatment to control attacks. Owing to our data collection over a period of 8 years, a significant number of patients were identified by this HAE reference center. Despite early recognition and prophylactic treatment, a high percentage of patients were hospitalized. HAE is still diagnosed late, reinforcing the need for more reference centers specialized in diagnosis and educational projects for health professionals.

Icatibant for the treatment of hereditary angioedema with C1-inhibitor deficiency in adolescents and in children aged over 2 years.

INTRODUCTION: Hereditary angioedema (HAE) due to C1-inhibitor deficiency (C1-INH-HAE) is a rare disorder with life-threatening complications if untreated. It begins during childhood, and reduces the patient's quality of life. Therefore, the availability of an easily administered agent to relieve unpredictable HAE episodes is indispensable for this age group. Areas covered: Randomized, double-blind, placebo-controlled, open-label extensions and prospective observational studies have proven the safety and efficacy of the subcutaneously administered bradykinin B2 receptor antagonist, icatibant, in the acute treatment of HAE episodes in adult C1-INH-HAE patients. Recently, a Phase 3, multicenter, open-label, non-randomized, single-arm study demonstrated the efficacy, safety, and tolerability of icatibant as an acute treatment for pediatric patients aged 2 years to less than 18 years. Expert commentary: The clinical study in pediatric patients showed that icatibant undergoes rapid absorption, reaches a therapeutic level, and promptly relieves the symptoms. It is well tolerated, and the subcutaneous preparation, presented in a pre-filled syringe, ensures ease of use. It can be administered anytime, anywhere, and instantly - even by the patients themselves, or - in the case of children and adolescents - by a caregiver. Icatibant may greatly contribute to the improvement of the quality of life of pediatric patients.

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

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

Comparison of the Frequency of Angioedema Attack, before and during Pregnancy, in a Patient with Type I Hereditary Angioedema.

The patient was a 38-year-old Japanese woman who had been diagnosed with hereditary angioedema type I at 7 years of age based on her family history. She had undergone four pregnancies. She gave birth to a healthy baby girl after her first pregnancy and had reported few episodes of angioedema. However, she subsequently required abortions due to frequent angioedema episodes that occurred during her three subsequent pregnancies. Thus, our patient showed two clinical pregnancy courses. After treating her with C1-inhibitor concentrate, her symptoms of angioedema disappeared. The preventive use of C1 inhibitor concentrates should be considered in hereditary angioedema (HAE) patients with frequent angioedema attacks during pregnancy.

Hereditary angioedema with C1 inhibitor (C1-INH) deficit: the strength of recognition (51 cases)

Hereditary angioedema (HAE) is a rare autosomal dominant disease due to C1 esterase inhibitor deficiency (C1-INH). The disease is characterized by subcutaneous and submucosal edema in the absence of urticaria due to the accumulation of bradykinin. This descriptive study aimed to evaluate the clinical characteristics of patients with a confirmed diagnosis of HAE referred to our Outpatient Clinic between December 2009 and November 2017. Fifty-one patients (38 F, 13 M) with a mean age of 32 years (range: 7-70 y) were included. Family history of HAE was reported in 70% (36/51) of the cases; 33/46 patients became symptomatic by 18 years of age. The median time between onset of symptoms and diagnosis was 13 years (3 mo-50 y). The most frequent triggering factors for attacks were stress (74.4%), trauma (56.4%), and hormonal variations (56%). The main symptoms were subcutaneous edema in 93.5% (43/46) of patients, gastrointestinal symptoms in 84.8% (39/46), and obstruction in the upper airways in 34.8% (16/46). Hospitalization occurred in 65.2%, of whom 13.3% had to be transferred to the Intensive Care Unit. Prophylactic treatment was instituted in 87% (40/46) of patients, and 56.5% (26/46) required additional treatment to control attacks. Owing to our data collection over a period of 8 years, a significant number of patients were identified by this HAE reference center. Despite early recognition and prophylactic treatment, a high percentage of patients were hospitalized. HAE is still diagnosed late, reinforcing the need for more reference centers specialized in diagnosis and educational projects for health professionals.

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.

Anabolic androgen use in the management of hereditary angioedema: Not so cheap after all.

BACKGROUND: Hereditary angioedema due to C1 inhibitor deficiency (HAE) is a rare, life-threatening disease that imposes a significant burden on affected patients. 17α-alkylated androgens (anabolic androgens) decrease attack frequency and severity but carry the risk of potentially serious dose-related adverse effects. Despite the emergence of targeted therapies for HAE, continued anabolic androgen use has been driven in part by their low cost. OBJECTIVE: To examine the hidden cost of anabolic androgen use related to the risk of developing non-HAE comorbidities. METHODS: Patients with HAE were identified in the Southern California Kaiser Permanente database using clinical and laboratory findings compatible with HAE. These patients were stratified into anabolic androgen exposed and nonexposed groups. Matched controls were selected from the Kaiser database who did not have HAE or anabolic androgen exposure. Using multivariate analysis, we determined the number of non-HAE comorbidities linked to anabolic androgen use. We next determined the association between dosing and increasing exposure to anabolic androgens and the likelihood of having various comorbidities. RESULTS: Patients with HAE exposed to anabolic androgens had a 28% increase (P = .04) in non-HAE comorbidities when compared with their matched (nonexposed) controls. With each gram per month increase in exposure, a 12% increase in non-HAE comorbidities is observed (P < .01). The most commonly occurring non-HAE comorbidities were psychiatric, muscle cramps, obesity, and hyperlipidemia. CONCLUSION: Our data suggest that long-term anabolic androgen use enhances the risk of developing comorbid health conditions, thus amplifying the cost of care. Our report provides additional support for the preferred use of newer, targeted therapies for the management of HAE.

Hereditary angioedema (HAE): a cause for recurrent abdominal pain.

A 44-year-old Hispanic woman presented to the emergency room with a 2-day history of sudden onset of severe cramping left lower quadrant abdominal pain associated with ∼20 episodes diarrhoea. Abdominal CT scan exhibited bowel wall oedema and acute extensive colitis. On the basis of the preliminary diagnosis of acute abdomen, the patient was admitted under the surgical team and treated for acute colitis. Since her family history was significant for hereditary angioedema (HAE), complement studies were performed which revealed low complement C4 levels and abnormally low values of C1q esterase inhibitor. Thus, the diagnosis of HAE type I was established. This case report summarises that the symptoms of HAE are often non-specific, hence making the underlying cause difficult to diagnose.

Thyroid hormones and complement parameters in hereditary angioedema with C1-inhibitor deficiency.

BACKGROUND: Thyroid hormones control and up-regulate the synthesis of many plasma proteins. OBJECTIVE: To explore possible associations between thyroid hormone and complement levels in patients with hereditary angioedema resulting from the deficiency of the C1-inhibitor (C1-INH-HAE). METHODS: In this case-control study, serum thyrotropin, free triiodothyronine (FT3), and free thyroxine (FT4) levels, anti-thyroid peroxidase and antithyroglobulin antibody titers, and C1-INH concentrations were measured in 117 euthyroid patients with C1-INH-HAE and compared with their clinical properties. The control group comprised 150 healthy, age- and sex-matched, euthyroid individuals. RESULTS: The thyrotropin and antithyroglobulin levels were similar between the patients and the controls. Significantly lower FT3 (P < .001) and FT4 (P = .002) levels, as well as higher anti-thyroid peroxidase titers (P < .001), were seen in the patients with C1-INH-HAE. The proportion of patients with reduced C1-INH activity was greater among those with below-median FT4 levels than among those with above-median values (P = .02). Patients who experienced more edematous attacks per year had lower FT4 levels (within the normal range) than those afflicted by fewer episodes (P = .01). The FT3 and FT4 levels were significantly higher in patients undergoing long-term danazol therapy than in those who did not receive this drug (P = .01 and P = .02, respectively). The proportion of patients with FT4 levels in the below-median range was higher in the subset with increased d-dimer concentration (P = .009). CONCLUSION: Minor variations of the thyroid hormone levels (within the reference range) can influence the function of C1-INH in C1-INH-HAE. Our findings suggest a role for the endocrine system in the pathophysiology of C1-INH-HAE.