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.).

An investigational oral plasma kallikrein inhibitor for on-demand treatment of hereditary angioedema: a two-part, randomised, double-blind, placebo-controlled, crossover phase 2 trial.

BACKGROUND: Guidelines recommend effective on-demand therapy for all individuals with hereditary angioedema. We aimed to assess the novel oral plasma kallikrein inhibitor, sebetralstat, which is in development, for on-demand treatment of hereditary angioedema attacks. METHODS: In this two-part phase 2 trial, individuals with type 1 or 2 hereditary angioedema aged 18 years or older were recruited from 25 sites, consisting of specialty outpatient centres, across nine countries in Europe and the USA. Individuals were eligible if they had experienced at least three hereditary angioedema attacks in the past 93 days, were not on prophylactic therapy, and had access to and the ability to self-administer conventional attack treatment. In part 1 of the trial, participants were given a single 600 mg open-label oral dose of sebetralstat to assess safety, pharmacokinetics, and pharmacodynamics of the dose. Part 2 was a randomised, double-blind, placebo-controlled, two-sequence, two-period (2 × 2) crossover trial; participants were randomly assigned (1:1) to either sequence 1, in which they were given a single dose of 600 mg of sebetralstat to treat the first eligible attack and a second dose of placebo to treat the second eligible attack, or sequence 2, in which they were given placebo to treat the first eligible attack and then 600 mg of sebetralstat to treat the second eligible attack. Participants and investigators were masked to treatment assignment. The primary endpoint was time to use of conventional attack treatment within 12 h of study drug administration, which was assessed in all participants who were randomly assigned to treatment and who received study drug for two attacks during part 2 of the study. Safety was assessed in all participants who received at least one dose of study drug, starting in part 1. This study is registered with ClinicalTrials.gov, NCT04208412, and is completed. FINDINGS: Between July 2, 2019, and Dec 8, 2020, 84 individuals were screened and 68 were enrolled in part 1 and received sebetralstat (mean age 38·3 years [SD 13·2], 37 [54%] were female, 31 [46%] were male, 68 [100%] were White). 42 (62%) of 68 participants completed pharmacokinetic assessments. Sebetralstat was rapidly absorbed, with a geometric mean plasma concentration of 501 ng/mL at 15 min. In a subset of participants (n=6), plasma samples obtained from 15 min to 4 h after study drug administration had near-complete protection from ex vivo stimulated generation of plasma kallikrein and cleavage of high-molecular-weight kininogen. In part 2, all 68 participants were randomly assigned to sequence 1 (n=34) or sequence 2 (n=34). 53 (78%) of 68 participants treated two attacks (25 [74%] in the sequence 1 group and 28 [82%] in the sequence 2 group). Time to use of conventional treatment within 12 h of study drug administration was significantly longer with sebetralstat versus placebo (at quartile 1: >12 h [95% CI 9·6 to >12] vs 8·0 h [3·8 to >12]; p=0·0010). There were no serious adverse events or adverse event-related discontinuations. INTERPRETATION: Oral administration of sebetralstat was well tolerated and led to rapid suppression of plasma kallikrein activity, resulting in increased time to use of conventional attack treatment and faster symptom relief versus placebo. Based on these results, a phase 3 trial to evaluate the efficacy and safety of two dose levels of sebetralstat in adolescent and adult participants with hereditary angioedema has been initiated (NCT05259917). FUNDING: KalVista Pharmaceuticals.

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.

Hereditary Angioedema With Normal C1 Inhibitor: US Survey of Prevalence and Provider Practice Patterns.

BACKGROUND: Hereditary angioedema (HAE) with normal C1-INH (HAE-nl-C1INH) is phenotypically similar to HAE resulting from C1-INH deficiency (HAE-C1INH). Confirmatory diagnostic tests for HAE-nl-C1INH are limited and few clinical study data exist regarding management of the condition. Therefore, survey studies may provide initial estimates of prevalence, diagnosis, and management patterns of this condition. OBJECTIVE: To estimate the prevalence and describe current management patterns for HAE-nl-C1INH in the United States (US). METHODS: We conducted an Internet-based survey of US physicians to estimate the prevalence of the HAE-nl-C1INH population in the United States. Potential participating physicians were identified from the US Hereditary Angioedema Association database and IQVIA Xponent prescription database. Eligible physicians were invited to complete an online survey between June and September 2021. RESULTS: A total of 113 physicians provided data for the estimation of HAE-nl-C1INH prevalence and 81 physicians treating HAE-nl-C1INH patients provided data about treatment patterns. In bias-corrected analysis, we estimated 1,230 to 1,331 HAE-nl-C1INH patients within the United States between May 2019 and April 2020. Mean time to diagnosis for HAE-nl-C1INH was approximately 6 years (range, 2.4-13.5 years). Response to medication was commonly used to inform diagnosis (antihistamine response or nonresponse used by 73% of physician respondents, corticosteroids by 57%, or HAE-specific medications by 74%), and Factor XII genetic testing was used by 43%. CONCLUSIONS: These survey data provide estimates of HAE-nl-C1INH prevalence in the United States as well as current diagnosis and management strategies. Results may be useful for developing studies to assess treatment efficacy and safety, and potentially improve the diagnosis for and management of this patient population.

Evaluation of patient-reported outcome measures for on-demand treatment of hereditary angioedema attacks and design of KONFIDENT, a phase 3 trial of sebetralstat.

BACKGROUND: Hereditary angioedema (HAE) with C1-inhibitor deficiency (HAE-C1-INH) is characterized by recurrent, debilitating episodes of swelling. Sebetralstat, an investigational oral plasma kallikrein inhibitor, demonstrated promising efficacy for on-demand treatment of HAE-C1-INH in a phase 2 trial. We describe the multipronged approach informing the design of KONFIDENT, a phase 3 randomized, placebo-controlled, three-way crossover trial evaluating the efficacy and safety of sebetralstat in patients aged ≥12 years with HAE-C1-INH. METHODS: To determine an optimal endpoint to measure the beginning of symptom relief in KONFIDENT, we engaged patients with HAE on clinical outcome measures and subsequently conducted analyses of phase 2 outcomes. Sample size was determined via a simulation-based approach using phase 2 data. RESULTS: Patient interviews revealed a strong preference (71%) for the Patient Global Impression of Change (PGI-C) over other measures and indicated a rating of "A Little Better" as a clinically meaningful milestone. In phase 2, a rating of "A Little Better" demonstrated agreement with attack severity improvement and resolution on the Patient Global Impression of Severity and had better sensitivity than "Better." Simulations indicated that 84 patients completing treatment would ensure at least 90% power for assessing the primary endpoint of time to beginning of symptom relief defined as a PGI-C rating of at least "A Little Better" for two time points in a row. CONCLUSIONS: Patient feedback and phase 2 data support PGI-C as the primary outcome measure in the phase 3 KONFIDENT trial evaluating sebetralstat, which has the potential to be the first oral on-demand treatment for HAE-C1-INH attacks.

Tezacaftor/ivacaftor in people with cystic fibrosis who stopped lumacaftor/ivacaftor due to respiratory adverse events.

BACKGROUND: Increased rates of respiratory adverse events have been observed in people ≥12 years of age with cystic fibrosis homozygous for the Phe508del-CFTR mutation treated with lumacaftor/ivacaftor, particularly in those with percent predicted forced expiratory volume in 1 s (ppFEV1) of <40%. We evaluated the safety, tolerability, and efficacy of tezacaftor/ivacaftor in people with cystic fibrosis homozygous for Phe508del-CFTR who discontinued lumacaftor/ivacaftor due to treatment-related respiratory signs or symptoms. METHODS: Participants ≥12 years of age with cystic fibrosis homozygous for Phe508del-CFTR with ppFEV1 of ≥25% and ≤90% were randomized 1:1 and treated with tezacaftor/ivacaftor or placebo for 56 days. RESULTS: Of 97 participants, 94 (96.9%) completed the study. The primary endpoint was incidence of predefined respiratory adverse events of special interest (chest discomfort, dyspnea, respiration abnormal, asthma, bronchial hyperreactivity, bronchospasm, and wheezing): tezacaftor/ivacaftor, 14.0%; placebo, 21.3%. The adverse events were mild or moderate in severity. None were serious or led to treatment interruption or discontinuation. Overall, the discontinuation rate was similar between groups. The mean (SD) ppFEV1 at baseline was 44.6% (16.1%) with tezacaftor/ivacaftor and 48.0% (18.1%) with placebo. The posterior mean difference in absolute change in ppFEV1 from baseline to the average value of days 28 and 56 was 2.7 percentage points with tezacaftor/ivacaftor vs placebo. CONCLUSIONS: Tezacaftor/ivacaftor was generally safe, well tolerated, and efficacious in people ≥12 years of age with cystic fibrosis homozygous for Phe508del-CFTR with ppFEV1 of ≥25% and ≤90% who previously discontinued lumacaftor/ivacaftor due to treatment-related respiratory signs or symptoms.

Darbepoetin alfa administration to achieve and maintain target hemoglobin levels for 1 year in patients with chronic kidney disease.

OBJECTIVE: To assess the efficacy and safety of every-other-week darbepoetin alfa therapy in treating anemia and maintaining hemoglobin levels for 1 year in patients with chronic kidney disease (CKD) who were not undergoing dialysis and who had not previously received erythropolesis-stimulating proteins (ESPs). PATIENTS AND METHODS: This multicenter 52-week study (evaluation period, weeks 20-32), a subanalysis of the Simplify the Treatment of Anemia with Aranesp study, enrolled patients with CKD who were not receiving dialysis (creatinine clearance < or =70 mL/min or estimated glomerular filtration rate [GFR] < or =60 mL/min). Patients evaluated in this analysis were not receiving ESPs, had hemoglobin concentrations less than 11 g/dL, and had transferrin saturation of 20% or higher during screening. Patients Initiated every-other-week darbepoetin alfa therapy at 0.75 microg/kg, with the dose subsequently titrated to maintain hemoglobin levels not to exceed 12 g/dL. The first study participant was enrolled on February 4, 2002, and the last participant completed the study on March 31, 2004. RESULTS: The analysis included 911 patients (mean [SD] age, 66.4 [14.2] years; 54.3% female; 55.3% white). The least squares mean evaluation hemoglobin concentration was 11.54 g/dL (95% confidence interval, 11.47-11.61 g/dL), and the change from baseline was 1.6 g/dL (95% confidence interval, 1.5-1.7 g/dL). The mean (SD) every-other-week darbepoetin alfa dose during evaluation was 44.5 (33.7) microg. Iron supplementation was administered to 573 patients (62.9%) during the study. Darbepoetin alfa was well tolerated throughout the study period. CONCLUSION: Darbepoetin alfa initiated every other week safely and effectively treated anemia and maintained hemoglobin for 1 year in patients with CKD who were not undergoing dialysis and who were not receiving prior ESP therapy.