Self-administered C1 esterase inhibitor concentrates for the management of hereditary angioedema: usability and patient acceptance

Figurate annulare erythemas

T. Colcott Fox (1849-1916) first introduced in 1889 the term "figurate erythemas." According to the clinical pattern, figurate erythemas are annular, circinate, concentric, polycyclic, or arciform. The most important figurate annulare erythemas are erythema annulare centrifugum, erythema marginatum, erythema gyratum repens, erythema migrans, erythema chronicum migrans, and the pediatric annular erythemas. Erythema annulare centrifugum might be due to fungal, bacterial, or viral infections or drugs. It tends to spread centrifugally while developing central clearing. The most common locations are the trunk and the proximal extremities. Individual lesions last from several days to weeks and may resolve spontaneously. Erythema marginatum is one of the criteria for the diagnosis of acute rheumatic fever, but it also might be seen as a symptom of other diseases such as hereditary angioedema with C1-inhibitor deficiency and psittacosis. The typical clinical picture is presented by serpiginous erythematous macules and plaques with central clearing and accentuated borders. Erythema gyratum repens is a figurate erythema associated with internal malignancy. It has been linked especially to lung, esophageal, and breast cancers. Erythema gyratum repens is characterized by multiple erythematous, rounded macules or papules, rapidly progressing and forming concentric bands with an unique wood-grained appearance with desquamation on the edges of the erythema. Erythema chronicum migrans is the most common sign of infection with Borrelia burgdorferi and other Borrelia species. It is characterized by a round or oval erythematous or livid macule with a central depressed or raised area on the spot of a previous tick bite. Erythema migrans grows centrifugally and slowly in a matter of days or weeks. Central clearing is observed in 60% of patients, thus forming a targetoid appearance of the lesion. Many other figurate erythemas can be observed in infancy (pediatric annular erythemas). To this group belong neonatal lupus, erythema gyratum atrophicans transiens neonatale, annular centrifugal erythema, familial annular erythema, annular erythema of infancy, eosinophilic annular erythema, and figurate neutrophilic erythema of infancy. The treatment of the various types of figurate erythemas should be etiologic, and when the underlying condition is addressed, the therapy usually is successful.

The international WAO/EAACI guideline for the management of hereditary angioedema – The 2021 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2), by providing guidance on common and important clinical issues, such as: 1) How should HAE be diagnosed? 2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? 3) What are the goals of treatment? 4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast feeding women? 5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2021 revision and update

Hereditary angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up-to-date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1 inhibitor (type 1) and HAE with dysfunctional C1 inhibitor (type 2), by providing guidance on common and important clinical issues, such as: (1) How should HAE be diagnosed? (2) When should HAE patients receive prophylactic on top of on-demand treatment and what treatments should be used? (3) What are the goals of treatment? (4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast-feeding women? and (5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

The importance of recognizing and managing a rare form of angioedema: hereditary angioedema due to C1-inhibitor deficiency

The majority of angioedema cases encountered in clinical practice are histamine-mediated (allergic); however, some cases are bradykinin-related (non-allergic) and do not respond to standard anti-allergy medications. Among bradykinin-related angioedema, hereditary angioedema (HAE) is a rare, but chronic and debilitating condition. The majority of HAE is caused by deficiency (type 1) or abnormal function (type 2) of the naturally occurring protein, C1-inhibitor (C1-INH)-a major inhibitor of proteases in the contact (kallikrein-bradykinin cascade), fibrinolytic pathway, and complement systems. Failure to recognize HAE and initiate appropriate intervention can lead to years of pain, disability, impaired quality of life (QoL) and, in cases of laryngeal involvement, it can be life-threatening. HAE must be considered in the differential diagnosis of non-urticarial angioedema, particularly for patients with a history of recurrent angioedema attacks, family history of HAE, symptom onset in childhood/adolescence, prodromal signs/symptoms before swellings, recurrent/painful abdominal symptoms, and upper airway edema. Management strategies for HAE include on-demand treatment for acute attacks, short-term prophylaxis prior to attack-triggering events/procedures, and long-term or routine prophylaxis for attack prevention. Patients should be evaluated at least annually to assess need for routine prophylaxis. HAE specific medications like plasma-derived and recombinant C1-INH products, kallikrein inhibitors, and bradykinin B2 receptor antagonists, have improved management of HAE. While the introduction of intravenous C1-INH represented a major breakthrough in routine HAE prophylaxis, some patients fail to achieve adequate control and others have psychological barriers or experience complications related to intravenous administration. Subcutaneous (SC) C1-INH, SC monoclonal antibody (mAb)-based therapies, and an oral kallikrein inhibitor offer effective alternatives for HAE attack prevention and may facilitate self-administration. HAE management should be individualized, with QoL improvement being a key goal. This can be achieved with broader availability of existing options for routine prophylaxis, including greater global availability of C1-INH(SC), mAb-based therapy, oral treatments, and multiple on-demand therapies.

A Novel C1-Esterase Inhibitor Oxygenator Coating Prevents FXII Activation in Human Blood

The limited hemocompatibility of currently used oxygenator membranes prevents long-term use of artificial lungs in patients with lung failure. To improve hemocompatibility, we developed a novel covalent C1-esterase inhibitor (C1-INH) coating. Besides complement inhibition, C1-INH also prevents FXII activation, a very early event of contact phase activation at the crossroads of coagulation and inflammation. Covalently coated heparin, as the current anticoagulation gold standard, served as control. Additionally, a combination of both coatings (C1-INH/heparin) was established. The coatings were tested for their hemocompatibility by dynamic incubation with freshly drawn human whole blood. The analysis of various blood and plasma parameters revealed that C1-INH-containing coatings were able to markedly reduce FXIIa activity compared to heparin coating. Combined C1-INH/heparin coatings yielded similarly low levels of thrombin-antithrombin III complex formation as heparin coating. In particular, adhesion of monocytes and platelets as well as the diminished formation of fibrin networks were observed for combined coatings. We could show for the first time that a covalent coating with complement inhibitor C1-INH was able to ameliorate hemocompatibility. Thus, the early inhibition of the coagulation cascade is likely to have far-reaching consequences for the other cross-reacting plasma protein pathways.

Modeling Cost-Effectiveness of On-Demand Treatment for Hereditary Angioedema Attacks

BACKGROUND

Hereditary angioedema (HAE) is a rare C1-inhibitor (C1-INH) deficiency disease. Low levels of functional C1-INH can lead to recurrent attacks of severe swelling occurring in areas such as the limbs, face, gastrointestinal tract, and throat. These attacks are both painful and disabling and, if not treated promptly and effectively, can result in hospitalization or death. Agents targeting the specific physiologic pathway of HAE attacks can offer improved outcomes with limited side effects compared with nonspecific therapies. However, these treatments display varying efficacy in HAE patients, including the need to redose or seek additional care if the treatment does not resolve symptoms effectively.

OBJECTIVE

To analyze the expected cost and utility per HAE attack when treated on-demand with HAE therapies indicated for the treatment of acute attacks.

METHODS

A decision-tree model was developed using TreeAge Pro software. Four on-demand HAE treatments were included: ecallantide, icatibant, plasma-derived (pd)C1-INH, and recombinant human (rh)C1-INH. The model uses probabilities for redosing, self-administration versus health care provider administration, and risk of hospitalization. Costs within the model consisted of the HAE treatments and associated health care system expenses. Nonattack baseline utility and attack utility were implemented for effectiveness calculations; time to attack resolution was considered as well. Effectiveness and overall costs per attack were calculated and used to estimate cost per quality-adjusted life-year (QALY). Variability and ranges in cost-effectiveness were determined using probabilistic sensitivity analyses. Finally, a budget impact model for a health plan with 1 million covered lives was also developed.

RESULTS

The base case model outputs show costs and calculated effectiveness per attack at $12,905 and 0.806 for rhC1-INH, $14,806 and 0.765 for icatibant, $14,668 and 0.769 for pdC1-INH, and $21,068 and 0.792 for ecallantide, respectively. Cost per QALY was calculated using 26.9 attacks per person-year, leading to results of $420,941 for rhC1-INH, $488,349 for icatibant, $483,892 for pdC1-INH, and $689,773 for ecallantide. Sensitivity analyses demonstrate that redose rates (from 3% for rhC1-INH to 44% for icatibant) are a primary driver of variability in cost-effectiveness. Annual health plan costs from the budget impact model are calculated as $6.94 million for rhC1-INH, $7.97 million for icatibant, $7.90 million for pdC1-INH, and $11.33 million for ecallantide.

CONCLUSIONS

Accounting for patient well-being and additional cost components of HAE attacks generates a better estimation of cost-effectiveness than drug cost alone. Results from this model indicate that rhC1-INH is the dominant treatment option with lower expected costs and higher calculated effectiveness than comparators. Further analyses reinforce the idea that low redose rates contribute to improved cost-effectiveness.

DISCLOSURES

Funding support was contributed by Pharming Healthcare. Relan and Adams are employed by Pharming Healthcare. Tyson and Magar are employed by AHRM, which received fees to perform the analysis and develop the manuscript. Bernstein reports grants, personal fees, and nonfinancial support from Shire, CSL Behring, and Pharming Healthcare; grants and personal fees from Biocryst; and nonfinancial support from HAEA, unrelated to this study.

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.

Training patients for self-administration of a new subcutaneous C1-inhibitor concentrate for hereditary angioedema

AIMS

The aim of this study was to provide recommendations for training patients with hereditary angioedema, based on nursing clinical trial experience, to self-administer subcutaneous C1-INH (C1-INH[SC]) used as routine prophylaxis.

BACKGROUND

A volume-reduced, subcutaneous C1-INH concentrate (C1-INH(SC); HAEGARDA®; CSL Behring) was recently FDA-approved for the routine prevention of hereditary angioedema attacks. Nurses will play an important role in patient training.

DESIGN

Review of a phase 3, randomized, placebo-controlled, double-blind, crossover trial of C1-INH(SC) (COMPACT) and summary of recommendations for training patients based on nurses' "hands-on experience."

METHODS

A panel of nurses with clinical trial experience provided recommendations for patient training.

RESULTS

Practical suggestions and guidelines were compiled regarding patient selection, product reconstitution and administration and patient follow-up. Successful patient self-administration of C1-INH(SC) can be greatly facilitated by qualified nursing intervention. The information provided in this paper will be useful to nurses anywhere who have an opportunity to interact with patients dealing with hereditary angioedema.

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 international WAO/EAACI guideline for the management of hereditary angioedema-The 2017 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease. Early diagnosis and appropriate therapy are essential. This update and revision of the global guideline for HAE provides up-to-date consensus recommendations for the management of HAE. In the development of this update and revision of the guideline, an international expert panel reviewed the existing evidence and developed 20 recommendations that were discussed, finalized and consented during the guideline consensus conference in June 2016 in Vienna. The final version of this update and revision of the guideline incorporates the contributions of a board of expert reviewers and the endorsing societies. The goal of this guideline update and revision is to provide clinicians and their patients with guidance that will assist them in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2). The key clinical questions covered by these recommendations are: (1) How should HAE-1/2 be defined and classified?, (2) How should HAE-1/2 be diagnosed?, (3) Should HAE-1/2 patients receive prophylactic and/or on-demand treatment and what treatment options should be used?, (4) Should HAE-1/2 management be different for special HAE-1/2 patient groups such as pregnant/lactating women or children?, and (5) Should HAE-1/2 management incorporate self-administration of therapies and patient support measures?

Safety, effectiveness, and impact on quality of life of self-administration with plasma-derived nanofiltered C1 inhibitor (Berinert®) in patients with hereditary angioedema: the SABHA study

BACKGROUND

Hereditary angioedema with C1 inhibitor deficiency is a disabling, potentially fatal condition characterized by recurrent episodes of swelling. Self-treatment is recommended, in order to reduce admissions to the Emergency Room and the time between the onset of the attack and the treatment, resulting in a better treatment outcome and an improved quality of life (QoL). The purpose of this study is to assess the safety, tolerability, and effect on QoL of self-administration of pnf C1-INH for IV use (Berinert®).

METHODS

An observational, monocenter, prospective study was designed. Patients referring to a center for angioedema that attended two sessions of self-infusion training course in the period March 2014-July 2015 were enrolled in the study. The primary endpoint was to monitor the safety and feasibility of pnf C1-INH self-infusion. The secondary endpoint was to evaluate the effect of self-infusion on the QoL, by means of the HAE-QoL questionnaire and the need for access to Emergency Room for infusion of Berinert®. Patients' medical history data were collected upon the first visit and questionnaires were filled after each attack treated with Berinert® (diary and Treatment Satisfaction Questionnaire for Medication) and upon the first visit and the follow-ups (HAE-QoL).

RESULTS

Twenty patients were enrolled (median age = 42, IQR: 39-49; 60% females). Fifteen patients completed the study. A total of 189 attacks were recorded (annual median rate of 4 attacks/patient). Patients waited a median of 2 h (IQR: 1-4) before self-administration, and the resolution of the attack occurred after a median of 6 h (IQR: 4-11). Most attacks were abdominal (39%) and peripheral (22%). 92% of the attacks were treated through self-/caregiver-administration. In most attacks no side effects were reported. The number of attacks with side effects decreased over time, from 37% to 13%. Global satisfaction grew over time during the study period, reaching statistical significance over the first 6 months. The median total HAE-QoL score at baseline was 86 (IQR: 76-103) and improved in a non-significant manner throughout the study period. 8% of the attacks treated with Berinert® required ER admission/healthcare professional help in the study period, compared with 100% in the 3 years before enrollment (p < 0.0001).

CONCLUSIONS

Self-administration of pnf C1-INH is safe, and increases patients' confidence in the treatment, showing also a trend towards an improvement in QoL. It reduces the need for ER admission/healthcare professionals help for the acute attacks, as well as the related costs.

An open-label study to evaluate the long-term safety and efficacy of lanadelumab for prevention of attacks in hereditary angioedema: design of the HELP study extension

BACKGROUND

Hereditary angioedema (HAE) is characterized by recurrent attacks of subcutaneous or submucosal edema. Attacks are unpredictable, debilitating, and have a significant impact on quality of life. Patients may be prescribed prophylactic therapy to prevent angioedema attacks. Current prophylactic treatments may be difficult to administer (i.e., intravenously), require frequent administrations or are not well tolerated, and breakthrough attacks may still occur frequently. Lanadelumab is a subcutaneously-administered monoclonal antibody inhibitor of plasma kallikrein in clinical development for prophylaxis of hereditary angioedema attacks. A Phase 1b study supported its efficacy in preventing attacks. A Phase 3, randomized, double-blind, placebo-controlled, parallel-arm study has been completed and an open-label extension is currently ongoing.

METHODS/DESIGN

The primary objective of the open-label extension is to evaluate the long-term safety of repeated subcutaneous administrations of lanadelumab in patients with type I/II HAE. Secondary objectives include evaluation of efficacy and time to first angioedema attack to determine outer bounds of the dosing interval. The study will also evaluate immunogenicity, pharmacokinetics/pharmacodynamics, quality of life, characteristics of breakthrough attacks, ease of self-administration, and safety/efficacy in patients who switch to lanadelumab from another prophylactic therapy. The open-label extension will enroll patients who completed the double-blind study ("rollover patients") and those who did not participate in the double-blind study ("non-rollover patients"), which includes patients who may or may not be currently using another prophylactic therapy. Rollover patients will receive a single 300 mg dose of lanadelumab on Day 0 and the second dose after the patient's first confirmed angioedema attack. Thereafter, lanadelumab will be administered every 2 weeks. Non-rollover patients will receive 300 mg lanadelumab every 2 weeks regardless of the first attack. All patients will receive their last dose on Day 350 (maximum of 26 doses), and will then undergo a 4-week follow-up.

DISCUSSION

Prevention of attacks can reduce the burden of illness associated with HAE. Prophylactic therapy requires extended, repeated dosing and the results of this study will provide important data on the long-term safety and efficacy of lanadelumab, a monoclonal antibody inhibitor of plasma kallikrein for subcutaneous administration for the treatment of HAE. Trial registration NCT02741596.