Oral Sebetralstat for On-Demand Treatment of Hereditary Angioedema Attacks

Global frequency, diagnosis, and treatment of hereditary angioedema with normal C1 inhibitor

Background

Hereditary angioedema (HAE) is a rare genetic disease, most frequently associated with deficiency or dysfunction in the C1 inhibitor protein. HAE with normal C1 inhibitor (HAE-nC1INH) lacks standardized diagnostic tests, limiting precise prevalence estimates and development of specific treatment guidelines.

Objective

This study sought to describe the global frequency, diagnostic pathway, and current treatment patterns of HAE-nC1INH.

Methods

Board-certified HAE-treating physicians from accredited Angioedema Centers of Reference and Excellence (ACAREs) were invited to complete a 27-item online survey between December 2022 and April 2023.

Results

Thirty physicians from 30 ACAREs across 15 countries reported a mean of 71 (range, 11-148) patients with HAE assessed/treated within the previous 12 months. On average, physicians estimated 24% (range, 2-44%) of patients with HAE were diagnosed with HAE-nC1INH, most of whom were adults (88%). To diagnose HAE-nC1INH, physicians most commonly assessed family history and plasma C4 levels (90% each), and C1 function and quantitative levels (87% each). On-demand and prophylactic treatment patterns varied widely across countries, with an average (range) of 56% (33-100%) of patients receiving on-demand treatment only, and 37% (0-67%) receiving both on-demand and prophylactic treatment. Physicians identified the greatest unmet needs in HAE-nC1INH management as treatment specifically indicated for this patient population and availability of an oral treatment.

Conclusion

HAE-nC1INH may be more prevalent than previously reported. Importantly, our findings revealed varying diagnostic and treatment approaches. Validated, accessible diagnostic biomarkers and clinical outcomes derived from rigorous clinical trials assessing mechanistically based treatments would advance understanding and management of HAE-nC1INH.

An evaluation of sebetralstat as the first oral on-demand therapy for Hereditary Angioedema

INTRODUCTION

Hereditary Angioedema (HAE) is a rare genetic disease characterized by sudden episodes of edema that do not respond to conventional treatments. Modern therapies targeting the kallikrein-kinin system aim to alleviate HAE attacks, reduce their frequency and severity, and enhance patients' quality of life. Sebetralstat, a novel oral plasma kallikrein inhibitor, offers a promising option for rapid and effective on-demand treatment of HAE attacks.

AREAS COVERED

This article evaluates the pharmacokinetics, pharmacodynamics, efficacy, and tolerability of sebetralstat based on developmental studies. We reviewed and analyzed seven pertinent original studies focusing on sebetralstat trials.

EXPERT OPINION

Oral sebetralstat provides a convenient alternative to injectable treatments, allowing patients to take the drug at the first sign of an attack, improving management of acute symptoms by helping to resolve them quickly. Clinical trials demonstrated that sebetralstat exhibits rapid absorption, effective plasma kallikrein inhibition, and a favorable safety and efficacy profile. Its pharmacokinetic and pharmacodynamic properties suggest its potential for reliable control of HAE attacks.

cAMP response element-binding protein: A credible cancer drug target

Despite advancements in radiotherapy, chemotherapy, endocrine therapy, targeted therapy, and immunotherapy, resistance to therapy remains a pervasive challenge in oncology, in part owing to tumor heterogeneity. Identifying new therapeutic targets is key to addressing this challenge because it can both diversify and enhance existing treatment options, particularly through combination regimens. The cAMP response element-binding protein (CREB) is a transcription factor involved in various biological processes. It is aberrantly activated in several aggressive cancer types, including breast cancer. Clinically, high CREB expression is associated with increased breast tumor aggressiveness and poor prognosis. Functionally, CREB promotes breast cancer cell proliferation, survival, invasion, metastasis, as well as therapy resistance by deregulating genes related to apoptosis, cell cycle, and metabolism. Targeting CREB with small molecule inhibitors has demonstrated promise in preclinical studies. This review summarizes the current understanding of CREB mechanisms and their potential as a therapeutic target. SIGNIFICANCE STATEMENT: cAMP response element-binding protein (CREB) is a master regulator of multiple biological processes, including neurodevelopment, metabolic regulation, and immune response. CREB is a putative proto-oncogene in breast cancer that regulates the cell cycle, apoptosis, and cellular migration. Preclinical development of CREB-targeting small molecules is underway.

Indirect treatment comparison of oral sebetralstat and intravenous recombinant human C1 esterase inhibitor for on-demand treatment of hereditary angioedema attacks

BACKGROUND

The goal of on-demand treatment for hereditary angioedema attacks is to halt attack progression to minimize morbidity and mortality. Four on-demand treatments have been approved thus far (ecallantide, icatibant, recombinant human C1 esterase inhibitor [rhC1INH], and plasma-derived C1INH). Results from the sebetralstat phase 3 KONFIDENT trial (NCT05259917) have been reported. To put these results into context without head-to-head trials, an indirect treatment comparison (ITC) was conducted to facilitate comparisons of efficacy and safety across treatment options.

METHODS

Based on a systematic literature review and feasibility assessment, only the pivotal trial for intravenous rhC1INH (NCT01188564) reported necessary data for a comparable primary efficacy endpoint (time to beginning of symptom relief) to enable an ITC with oral sebetralstat. Bayesian fixed-effects network meta-analyses models were conducted to indirectly compare the efficacy and safety outcomes of sebetralstat and rhC1INH (NCT01188564, NCT00225147, NCT00262301). A matching-adjusted indirect comparison (MAIC) of efficacy was performed, adjusting for baseline attack severity and demographic characteristics.

RESULTS

The fixed-effects model found no significant differences in time to beginning of symptom relief between sebetralstat 300 mg and rhC1INH 50 IU/kg (hazard ratio [95% credible interval], 0.96 [0.42-2.15] to 1.19 [0.58-2.45]). After adjusting for baseline attack severity, the MAIC showed numerically favorable results with sebetralstat compared with rhC1INH, regardless of whether baseline demographics were matched. The fixed-effects model found no significant differences in treatment-related treatment-emergent adverse events. All sensitivity analyses returned consistent results.

CONCLUSIONS

This ITC found no significant differences in time to beginning of symptom relief and overall treatment-related treatment-emergent adverse events between sebetralstat and rhC1INH.

Interplay between on-demand treatment trials for hereditary angioedema and treatment guidelines

Over the past 2 decades, guidelines for the on-demand treatment of hereditary angioedema attacks have undergone significant evolution. Early treatment guidelines, such as the Canadian 2003 International Consensus Algorithm, often gated on-demand treatment by attack location and/or severity. Pivotal trials for on-demand injectable treatments (plasma-derived C1 esterase inhibitor, icatibant, ecallantide [United States only], and recombinant human C1 esterase inhibitor), which were approved in the United States and the European Union between 2008 and 2014, were designed accordingly. Subsequent post hoc analyses of clinical trial data alongside real-world evidence led to a paradigm shift. In 2013, the US Hereditary Angioedema Association guidelines recommended that all attacks, irrespective of location or severity, be considered for treatment as early as possible after onset to minimize morbidity and mortality. This approach remains the cornerstone of current treatment guidelines and has shaped the design of recent clinical trials, such as those for the investigational agents, oral plasma kallikrein inhibitor sebetralstat and oral bradykinin B2 receptor antagonist deucrictibant. This narrative review discusses the evolution of on-demand treatment guidelines, the clinical trial and real-world data that prompted significant revisions, and the subsequent changes to trial designs introduced to facilitate guideline compliance.

Exploring the management of recurrent angioedema caused by different mechanisms

PURPOSE OF REVIEW

We aim to explore the most recent insights into the pathogenesis of recurrent angioedema caused by different mechanisms and then focus on the management and treatment approaches available.

RECENT FINDINGS

The recently developed DANCE consensus classification identifies five types of angioedema: mast cell-mediated (AE-MC), bradykinin-mediated, because of intrinsic vascular endothelium dysfunction (AE-VE), drug-induced (AE-DI), and due to unknown mechanisms (AE-UNK). These subtypes require different management with treatment choices targeting the main pathogenetic pathways involved in each form. For AE-MC and AE-BK, the therapeutic landscape has been significantly widened in recent years. Conversely, there is a lack of consensus for the hereditary forms because of newly discovered mutations ( factor 12 , plasminogen, kininogen-1 , myoferlin, angiopoietin-1 , heparan sulfate 3-O-sulfotransferase 6 ) and AE-UNK.

SUMMARY

Recurrent angioedema can present with or without wheals. Angioedema without wheals may be driven by bradykinin and/or mast cell mediators. The different forms respond to specific drugs and require a different management. For its potentially life-threatening and disfiguring features, angioedema should be promptly recognized and effectively treated. For this reason, enhancing awareness about various angioedema subtypes and their management provide a useful tool for the clinical practice.

New drugs for the treatment of hereditary angioedema

INTRODUCTION

Revolutionary drugs have been developed and approved in the last 5 years for the treatment of hereditary angioedema (HAE). Increased knowledge of HAE pathophysiology has led to the development of innovative drugs for self-administered on-demand therapy and for short- and long-term prophylaxis (LTP). This has rendered possible a personalized approach for patients, allowing greater control of symptoms, better quality of life and reduction in the incidence of adverse effects linked to old treatments.

AREAS COVERED

In this review we have highlighted which treatments are currently approved for HAE and some of the promising future therapies under development.

EXPERT OPINION

While the first generation of approved treatments improved disease control for most patients, innovative therapies may allow individualized action plans and reduce complexity of treatment. Switching therapies due to insufficient efficacy, patient preference or adverse events is becoming progressively feasible and common. New LTPs may lead to the achievement of attack-free remission, allowing us to hopefully reach complete disease control for all patients and further improving their quality of life. In particular, LTPs with longer administration intervals, and on-demand therapies administered via the oral route will have a key role and will set more prominent targets for the upcoming drugs.

Hereditary angioedema in children: Review and practical perspective for clinical management

BACKGROUND

Hereditary angioedema (HAE) in children has specific features and requires multidisciplinary management.

METHODS

We performed a literature search and underwent in-depth discussions to provide practical tools for physicians.

RESULTS

HAE is a rare, life-threatening genetic disorder. Its epidemiology is poorly documented in children. Clinical manifestations usually appear during childhood or early adolescence. Classical signs, often preceded by prodromal symptoms, include transient, localized, non-pitting, non-pruritic swelling of deep dermal/subcutaneous or mucosal/submucosal tissues, leading to oedema of the extremities, face, lips, tongue, trunk and genitals, recurring gastrointestinal symptoms and laryngeal edema possibly causing asphyxiation and death. Diagnosis is often delayed due to low awareness in the medical community, and particularly challenging in case of isolated abdominal crises or atypical presentation and in neonates or infants. It relies on biological tests (measurement of serum/plasma levels of C1INH function, C1INH protein, and C4), genetic testing in selected cases, and imaging for differential diagnosis of acute abdominal crises. Main differential diagnosis for peripheral oedema is mast cell-mediated oedema that accounts for 95% of angioedema in clinical practice. Quality of life can be significantly impaired. Disease management includes treatment of attacks, short-term and long-term prophylaxis, psychological support, avoidance of triggers, patients' and parents' education and coordination of all stakeholders, ideally within a specialized healthcare network. New plasma kallikrein inhibitors, namely lanadelumab (subcutaneous route) and berotralstat (oral route) have facilitated long-term prophylaxis thanks to improved usability.

CONCLUSION

Diagnostic and treatment of HAE are particularly challenging in children and require specific management by multiple stakeholders.

Hereditary angioedema due to C1-inhibitor deficiency: current therapeutic approaches

PURPOSE OF REVIEW

For decades, treatment options for hereditary angioedema (HAE) were limited by major adverse effects, insufficient efficacy, and difficult routes of administration. However, the growing body of knowledge regarding HAE pathophysiology has led to the development of innovative drugs for self-administered, on-demand therapy and for short- and long-term prophylaxis. This review provides a comprehensive overview of the approved drugs and the development of HAE treatments.

RECENT FINDINGS

The implementation of new therapies will improve the application of individualized action plans based on the key goals of minimizing the number of attacks and meeting the complex needs of patients.

SUMMARY

HAE is a rare genetic disease with a high impact on patients' quality of life due to the unpredictability and variable severity of attacks. Advances in HAE research have allowed optimization of attack management and individualization of therapeutic approaches.

Recent and anticipated novel drug approvals (3Q 2024 through 2Q 2025)

PURPOSE

Health-system pharmacists play a crucial role in monitoring the pharmaceutical pipeline to manage formularies, allocate resources, and optimize clinical programs for new therapies. This article aims to support pharmacists by sharing new and anticipated novel drug approvals.

SUMMARY

Selected drug approvals anticipated in the 12-month period covering the third quarter of 2024 through the second quarter of 2025 are reviewed. The analysis emphasizes drugs expected to have significant clinical and financial impact in hospitals and clinics selected from 54 novel drugs awaiting US Food and Drug Administration approval. New cell therapies for treating cancers continue to enter the drug pipeline, while novel targeted therapies for biliary tract, gastric, pancreatic, and breast cancers, as well as 3 subcutaneous versions of already approved drugs given intravenously, are awaiting approval. Additionally, many novel drugs are being developed for treatment of rare and ultra-rare diseases such as hereditary angioedema, macular telangiectasia, congenital adrenal hyperplasia, and Barth syndrome. Two new subcutaneous drugs for hemophilia, a new oral medication for hereditary angioedema, a novel monoclonal antibody for atopic dermatitis, and the first oral penem antibiotic are also in the pipeline.

CONCLUSION

New drugs with various indications for cancers and rare diseases continue to strengthen the drug pipeline.

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.

Advent of oral medications for the treatment of hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) is a rare genetic disorder characterized by unpredictable, debilitating episodes of submucosal and/or subcutaneous tissue swelling, which may be life-threatening depending on anatomic location. The two primary management strategies for HAE are ready access to effective on-demand treatment in all patients and the prevention of attacks (short-term prophylaxis [STP] and long-term prophylaxis [LTP]) in appropriate patients. All approved on-demand and most LTP medications require subcutaneous or intravenous administration. Injection-related challenges include trypanophobia (fear of needles), difficulty with self-administration, injection-site reactions (e.g., pain, erythema, bleeding, bruising), and anxiety-all contributing to poor compliance and administration delays. Oral HAE treatments may improve outcomes by reducing treatment barriers.

AIM

To review oral therapies, approved or in development, for on-demand treatment and/or prevention of HAE attacks.

MATERIALS AND METHODS

To provide a comprehensive review, data was obtained from publicly available resources through a targeted PubMed literature review and supplemented by information provided on company websites (search cutoff of May 31, 2024).

RESULTS

Berotralstat, an oral plasma kallikrein (PKa) inhibitor, is approved for LTP. Sebetralstat, another PKa inhibitor, is the investigational first oral on-demand HAE treatment to complete a phase 3 trial. Deucrictibant, an oral bradykinin B2 receptor antagonist, has completed phase 2 trials for on-demand therapy and LTP. Several other oral PKa inhibitors (ATN249, VE-4666, and VE-4062) are in early development for LTP.

CONCLUSION

Substantial advances have been made in the development of oral treatments for HAE. These treatments have the potential to improve and optimize clinical outcomes, satisfaction, and quality of life among patients with HAE.

Efficacy and Safety of Donidalorsen for Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a rare disorder characterized by episodic, potentially life-threatening swelling caused by kallikrein-kinin dysregulation. Long-term prophylaxis can stabilize this system. Donidalorsen, an antisense oligonucleotide, specifically reduces prekallikrein expression.

METHODS

In this phase 3, double-blind, randomized trial, we assigned patients with hereditary angioedema to receive donidalorsen (80 mg subcutaneously) or placebo once every 4 or 8 weeks. The primary end point was the time-normalized number of investigator-confirmed hereditary angioedema attacks per 4 weeks (attack rate) from week 1 to week 25.

RESULTS

A total of 90 patients received donidalorsen every 4 weeks (45 patients), donidalorsen every 8 weeks (23 patients), or placebo (22 patients). The least-squares mean time-normalized attack rate was 0.44 (95% CI, 0.27 to 0.73) in the 4-week group, 1.02 (95% CI, 0.65 to 1.59) in the 8-week group, and 2.26 (95% CI, 1.66 to 3.09) in the placebo group. The mean attack rate from week 1 to week 25 was 81% lower (95% CI, 65 to 89) in the 4-week group than in the placebo group (P<0.001) and 55% lower (95% CI, 22 to 74) in the 8-week group than in the placebo group (P = 0.004); the median reduction in the attack rate from baseline was 90% in the 4-week group, 83% in the 8-week group, and 16% in the placebo group. The mean attack rate during weeks 5 to 25 was 87% lower (95% CI, 72 to 94) in the 4-week group than in the placebo group (P<0.001) and 60% lower (95% CI, 25 to 79) in the 8-week group than in the placebo group. Donidalorsen administered every 4 weeks resulted in an improvement in the least-squares mean total score for the change at week 25 on the Angioedema Quality-of-Life Questionnaire (scores range from 0 to 100, with a score of 100 indicating the worst possible quality of life) that was 18.6 points (95% CI, 9.5 to 27.7) better than that with placebo (P<0.001). The most common adverse events were erythema at the injection site, headache, and nasopharyngitis; 98% of adverse events were mild or moderate in severity.

CONCLUSIONS

Donidalorsen treatment reduced the hereditary angioedema attack rate, a finding that supports potential prophylactic use for hereditary angioedema. (Funded by Ionis Pharmaceuticals; OASIS-HAE ClinicalTrials.gov number, NCT05139810.).