Physician and patient perspectives on the management of hereditary angioedema: a survey on treatment burden and needs

Targeting factor XIIa for therapeutic interference with hereditary angioedema

Hereditary angioedema (HAE) is a rare, potentially life-threatening genetic disorder characterized by recurrent attacks of swelling. Local vasodilation and vascular leakage are stimulated by the vasoactive peptide bradykinin, which is excessively produced due to dysregulation of the activated factor XII (FXIIa)-driven kallikrein-kinin system. There is a need for novel treatments for HAE that provide greater efficacy, improved quality of life, minimal adverse effects, and reduced treatment burden over current first-line therapies. FXIIa is emerging as an attractive therapeutic target for interference with HAE attacks. In this review, we draw on preclinical, experimental animal, and in vitro studies, providing an overview on targeting FXIIa as the basis for pharmacologic interference in HAE. We highlight that there is a range of FXIIa inhibitors in development for different therapeutic areas. Of these, garadacimab, an FXIIa-targeted inhibitory monoclonal antibody, is the most advanced and has shown potential as a novel long-term prophylactic treatment for patients with HAE in clinical trials. The evidence from these trials is summarized and discussed, and we propose areas for future research where targeting FXIIa may have therapeutic potential beyond HAE.

The future of therapeutic options for hereditary angioedema

Hereditary angioedema (HAE) is a rare genetic condition causing unpredictable and severe episodes of angioedema that are debilitating and life-threatening. Moreover, HAE can be classified into HAE due to C1-esterase inhibitor deficiency (HAE-C1INH) or HAE with normal C1INH. Moreover, HAE-C1INH is subcategorized as types I and II based on deficient or dysfunctional circulating C1INH protein resulting from inherited or spontaneous mutations in the SERPING1 gene leading to uncontrolled factor XII/plasma kallikrein activation and excessive bradykinin production. Bradykinin-2 receptor activation leads to vasodilation, increased vascular permeability, and smooth muscle contractions, resulting in subcutaneous or submucosal fluid extravasation that can affect the face, extremities, airway, and gastrointestinal and genitourinary systems. Furthermore, HAE with normal C1INH is caused by either a known or unknown genetic mutation, and the mechanisms are less well-established but most forms are thought to be related to bradykinin signaling with a similar presentation as HAE-C1INH despite normal levels of C1INH protein and function. Current HAE management strategies include on-demand and prophylactic treatments which replace C1INH, reduce kallikrein activity, or block bradykinin binding to the bradykinin B2 receptor. With the advent of additional small molecule inhibitors, monoclonal antibodies, RNA-targeted therapies, gene therapies, and gene modification approaches, preclinical studies and human clinical trials are underway to further expand therapeutic options in HAE. This review article will briefly summarize current HAE treatments and provide an overview of potential future therapies for HAE.

Androgen transition and management of hereditary angioedema long-term prophylaxis in real life: a single-center case series

BACKGROUND

Hereditary angioedema (HAE) is a rare and potentially life-threatening disease that manifests clinically as recurrent episodes of swelling affecting multiple anatomical locations. Long-term prophylaxis (LTP) aims to control the disease by preventing HAE attacks. Previously, treatments such as attenuated androgens have been used for LTP, but they have an unfavorable adverse effect profile. Today, these limitations may be overcome by patients transitioning to newer, targeted therapies including oral berotralstat and subcutaneous lanadelumab. This case series reports the transition process between different prophylactic therapies in a family with HAE in a real-world setting.

RESULTS

Four adult patient cases from the same family who underwent transitions in HAE prophylaxis are presented. Three were female and one male. Two patients who transitioned to berotralstat were initially prescribed attenuated androgens. Two patients were not taking LTP at the time of initiating targeted treatment but had previously been prescribed tranexamic acid. The length of transition varied between the patients, with the longest time taken to stabilize on new therapy being 26 months. All patients received regular follow-up in person or by telephone and all four required an adjustment from their initial treatment plan.

CONCLUSIONS

Transitioning between LTP in HAE may help improve control of attacks, avoid unwanted adverse effects, or better cater to individual patient preferences. Newer targeted therapies have been shown to be effective and should be discussed with patients. Shared decision-making is a tool that can aid these discussions. The transition journey between LTP therapies in HAE may not be straightforward and is specific to each patient. Physicians should consider complicating factors such as patient anxieties around changing treatment, adverse effects, preferred routes of administration, and speed of transition. Following patients closely during the transition period helps identify any issues, including difficulties with treatment adherence, and may allow the transition plan to be adapted when necessary.

Once-Daily Oral Berotralstat for Long-Term Prophylaxis of Hereditary Angioedema: The Open-Label Extension of the APeX-2 Randomized Trial

BACKGROUND

Berotralstat is a first-line, once-daily oral plasma kallikrein inhibitor approved for prophylaxis of hereditary angioedema (HAE) attacks in patients 12 years or older.

OBJECTIVE

This analysis examined the safety and effectiveness of long-term prophylaxis with berotralstat.

METHODS

APeX-2 was a phase 3, parallel-group, multicenter trial in patients with HAE caused by C1-inhibitor deficiency (NCT03485911). Part 1 was a randomized, double-blind, placebo-controlled evaluation of 150 and 110 mg of berotralstat over 24 weeks. In part 2, berotralstat-treated patients continued the same treatment, and placebo-treated patients were re-randomized to 150 or 110 mg of berotralstat for 24 weeks. In part 3, all patients were treated with open-label berotralstat at 150 mg, which could be continued for up to an additional 4 years. In part 3, the primary endpoint was long-term safety and tolerability. Secondary endpoints included HAE attack rates and quality of life (QoL).

RESULTS

Eighty-one patients entered part 3. Treatment-emergent adverse events (TEAEs) occurred in 82.7% of patients, with most being mild or moderate in severity. The most common TEAEs were nasopharyngitis, urinary tract infection, abdominal pain, arthralgia, coronavirus infection, and diarrhea. Drug-related TEAEs occurred in 14.8% of patients, but none were serious. For patients who completed 96 weeks of berotralstat treatment (n = 70), the mean (standard error) change in attack rate from baseline was -2.21 (0.20) attacks/mo. Clinically meaningful improvements in QoL were also observed, with the largest improvements in the functioning domain.

CONCLUSION

Berotralstat was generally well tolerated, provided rapid and sustained reductions in HAE attacks and improved QoL over 96 weeks.

Real-world reporting rates of administration-site reactions with on-demand treatment of hereditary angioedema attacks

Background: Hereditary angioedema (HAE) is characterized by recurrent and unpredictable episodes of subcutaneous and/or submucosal swelling. Objective: To characterize the real-world treatment burden associated with existing on-demand therapies, we analyzed administration-site adverse drug reactions (ADR) associated with approved on-demand HAE therapies reported in the U.S. Food and Drug Administration's (FDA) Adverse Event Reporting System (FAERS). Methods: We searched the FAERS database from October 1, 2009, to March 31, 2022, for reports of all FDA-approved on-demand therapies for HAE: plasma-derived C1-inhibitor (pdC1-INH), ecallantide, icatibant, and recombinant C1-inhibitor (rhC1-INH). ADRs in which the drug was listed as the "primary suspect" were recorded for each drug. ADR preferred terms were grouped into 18 ADR domains based on semantic and/or clinical similarity, and the number of reports for each drug was calculated per year from the time of approval through March 2022, and descriptive results were presented. Preferred terms associated with administration-site ADRs identified from clinical trials and denoted on approved HAE drug U.S. package inserts were examined in a complementary analysis. Results: The highest reported rates of administration-site ADRs per year were site pain (17.9 reports per year), site erythema (7.4 per year), and site swelling (6.7 per year). RhC1-INH was the only drug for which access-site complications and/or malfunctions were reported (9.5 per year). PdC1-INH had the highest rate of incorrect route of product administration (3.7 per year). PdC1-INH showed statistically significant elevated reporting rate of injection-site reactions (reporting odds ratio [ROR] 3.59 [2.36-5.46]; empirical Bayesian geometric mean [EBGM] 1.97 [1.39]). Icatibant and rhC1-INH showed a statistical trend toward an increased reporting rate of administration-site reactions. Conclusion: Real-world data from FAERS were generally consistent with adverse events reported in clinical trials and suggest that patients experience substantial treatment burden associated with FDA-approved parenteral on-demand therapies for HAE attacks. It should be noted that ADR rates are not exposure adjusted and are based on spontaneous reporting.

Patient-physician interactions in hereditary angioedema-Key learnings from the coronavirus disease 2019 pandemic

BACKGROUND

The coronavirus disease pandemic and its containing measures have caused concerns for patients with hereditary angioedema (HAE) and their treating physicians. Both faced challenges surrounding interaction, and communication had to adapt to facilitate appropriate management. Specifically, the pandemic resulted in reduced in-person contact in clinics. Where possible, telemedicine appointments were offered and treatment outside the hospital setting was encouraged. BODY: The pandemic markedly affected patient-physician communication, which is essential to maintain partnerships and optimize care. Although patients with HAE are often experts in their condition, guidance by their physicians is essential, especially with the recent shift toward patient-centered management for rare diseases and shared decision-making (SDM). SDM enables patients to take control of their disease and allows the risks and benefits of treatment to be discussed with their physicians. This review explores perspectives from patients and physicians in the HAE clinical setting, particularly regarding their experiences with communication throughout the pandemic. We discuss the importance of SDM in rare diseases such as HAE, factors that impact effective communication, and potential solutions.

CONCLUSION

Since patient-centered care and SDM have particular relevance in rare diseases in general, we believe our findings could be transferrable and applicable in the management of other rare diseases.

Current challenges and future opportunities in patient-focused management of hereditary angioedema: A narrative review

Patients with hereditary angioedema (HAE) experience a high burden of disease due to unpredictable, painful, disfiguring, and potentially life-threatening HAE attacks. Multiple HAE-specific medications for the on-demand treatment, short-term and long-term prophylaxis of HAE attacks have entered the market in recent years; however, the availability and access to these medications may vary between different countries. For this review, PubMed and EMBASE databases were searched for guidelines, consensus statements, and other publications on HAE management as well as publications on quality of life in patients with HAE. The current guidelines and recent literature on HAE management in specific countries are summarized with the aim to highlight the similarities and differences between guideline recommendations and the country-specific clinical practice. Improvement in quality of life, which is a key goal in HAE management, is also discussed and the country-specific trends are highlighted. Finally, the ways to achieve a more patient-centric approach to HAE management within the framework set by the clinical management guidelines are examined.

Berotralstat (BCX7353): Structure-Guided Design of a Potent, Selective, and Oral Plasma Kallikrein Inhibitor to Prevent Attacks of Hereditary Angioedema (HAE)

Hereditary angioedema (HAE) is a rare and potentially life-threatening disease that affects an estimated 1 in 50 000 individuals worldwide. Until recently, prophylactic HAE treatment options were limited to injectables, a burdensome administration route that has driven the need for an oral treatment. A substantial body of evidence has shown that potent and selective plasma kallikrein inhibitors that block the generation of bradykinin represent a promising approach for the treatment of HAE. Berotralstat (BCX7353, discovered by BioCryst Pharmaceuticals using a structure-guided drug design strategy) is a synthetic plasma kallikrein inhibitor that is potent and highly selective over other structurally related serine proteases. This once-daily, small-molecule drug is the first orally bioavailable prophylactic treatment for HAE attacks, having successfully completed a Phase III clinical trial (meeting its primary end point) and recently receiving the U.S. Food and Drug Administration's approval for the prophylactic treatment of HAE attacks in patients 12 years and older.

Berotralstat (BCX7353) is a novel oral prophylactic treatment for hereditary angioedema: Review of phase II and III studies

Background: Hereditary angioedema (HAE) is a rare genetic disorder characterized by unpredictable and potentially life-threatening episodes of swelling in various parts of the body. These attacks can be painful and debilitating, and affect a patient's quality of life. Every patient who experiences an attack should be treated with on-demand medication to mitigate attack severity and duration. Many patients with HAE also receive long-term prophylaxis to reduce the frequency and severity of edema episodes. Although long-term prophylaxis reduces the disease burden for patients with HAE, available intravenous and subcutaneous treatments are accompanied by a significant treatment burden because of the logistical, emotional, and physical challenges posed by their long-term parenteral nature. Androgens are an effective oral prophylactic treatment; however, they are associated with significant adverse events and are not suitable for all patients. Thus, the HAE community has expressed interest in the development of alternative oral prophylactic therapies for preventing HAE attacks. Objective: Here, we review the phase II and III clinical data of berotralstat (BCX7353), which was approved by the U.S. Food and Drug Administration in December 2020. Results: Berotralstat is an oral, second-generation, synthetic, small-molecule plasma kallikrein inhibitor taken once daily for the prevention of HAE attacks in patients ages ≥ 12 years. Results from the APeX studies (APeX-1 NCT02870972, APeX-2 NCT03485911, APeX-S NCT03472040, APex-J NCT03873116) demonstrated the efficacy of berotralstat as long-term prophylaxis for patients with HAE, which showed a reduction in the attack rate and on-demand medication usage. Berotralstat was well tolerated, and gastrointestinal treatment-emergent adverse events were generally mild and self-limited. Conclusion: Oral berotralstat is an effective and safe long-term prophylactic treatment for patients with HAE that will provide patients unable to tolerate parenteral therapies with the option of disease control. Berotralstat may be associated with reduced treatment burden compared with injectable therapies, highlighting the importance of patient preference with regard to the administration route of their HAE prophylactic treatment.