Recombinant human C1 esterase inhibitor treatment for hereditary angioedema attacks in children.

BACKGROUND: Attacks of hereditary angioedema (HAE) due to C1 esterase inhibitor deficiency (C1-INH-HAE) usually begin during childhood or adolescence. However, limited data are available regarding indications and modalities of treatment of children. This study evaluated recombinant human C1-INH (rhC1-INH) for HAE attacks in children. METHODS: This open-label, phase 2 study included children aged 2-13 years with C1-INH-HAE. Eligible HAE attacks were treated intravenously with rhC1-INH 50 IU/kg body weight (maximum, 4200 IU). The primary end-point was time to beginning of symptom relief (TOSR; ≥20 mm decrease from baseline in visual analog scale [VAS] score, persisting for two consecutive assessments); secondary end-point was time to minimal symptoms (TTMS; <20 mm VAS score for all anatomic locations). RESULTS: Twenty children (aged 5-14 years; 73 HAE attacks) were treated with rhC1-INH. Seventy (95.9%) of the attacks were treated with a single dose of rhC1-INH. Seven (35.0%) children were treated for four or more attacks. Overall, median TOSR was 60.0 minutes (95% confidence interval [CI], 60.0-65.0); data were consistent across attacks. Median TTMS was 122.5 minutes (95% CI, 120.0-126.0); data were consistent across attacks. No children withdrew from the study due to adverse events. No treatment-related serious adverse events or hypersensitivity reactions were reported; no neutralizing antibodies were detected. CONCLUSIONS: Recombinant human C1-INH was efficacious, safe, and well tolerated in children. Data support use of the same dosing regimen for HAE attacks in children (50 IU/kg; up to 4200 IU, followed by an additional dose, if needed) as is currently recommended for adolescents and adults.

A randomized trial of human C1 inhibitor prophylaxis in children with hereditary angioedema.

BACKGROUND: Patients with hereditary angioedema with C1 inhibitor deficiency or dysfunction have burdensome recurrent angioedema attacks. The safety, efficacy, and health-related quality of life (HRQoL) outcomes of C1 inhibitor (C1-INH) prophylaxis (intravenously administered) in patients aged 6-11 years were investigated. METHODS: Eligible patients were enrolled in a randomized, single-blind, crossover, phase 3 trial. After a 12-week baseline observation period (BOP), patients received 500 or 1000 U C1-INH, twice weekly, for 12 weeks before crossing over to the alternate dose for 12 weeks. The primary efficacy end-point was the monthly normalized number of angioedema attacks (NNA). HRQoL was assessed using the EuroQoL 5-dimensional descriptive system youth version and visual analog scale (EQ-VAS). RESULTS: Twelve randomized patients had a median (range) age of 10.0 (7-11) years. Mean (SD) percentage reduction in monthly NNA from BOP was 71.1% (27.1%) with 500 U and 84.5% (20.0%) with 1000 U C1-INH. Mean (SD) within-patient difference (-0.4 [0.58]) for monthly NNA with both doses was significant (P = 0.035 [90% CI, -0.706 to -0.102]). Cumulative attack severity, cumulative daily severity, and number of acute attacks treated were reduced. No serious adverse events or discontinuations occurred. Mean EQ-VAS change from BOP to week 9 of treatment (500 U C1-INH, 10.4; 1000 U C1-INH, 21.6) was greater than the minimal important difference, indicating a meaningful HRQoL change. CONCLUSIONS: C1-INH prophylaxis was effective, safe, and well tolerated in children aged 6-11 years experiencing recurrent angioedema attacks. A post hoc analysis indicated a meaningful improvement in HRQoL with C1-INH. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02052141.

Recombinant human C1 esterase inhibitor for prophylaxis of hereditary angio-oedema: a phase 2, multicentre, randomised, double-blind, placebo-controlled crossover trial.

BACKGROUND: Hereditary angio-oedema is a recurrent, oedematous disorder caused by deficiency of functional C1 inhibitor. Infusions of plasma-derived C1 esterase inhibitor deter attacks of hereditary angio-oedema, but the prophylactic effect of recombinant human C1 esterase inhibitor has not been rigorously studied. We aimed to assess the efficacy of recombinant human C1 esterase inhibitor for prophylaxis of hereditary angio-oedema. METHODS: We conducted this phase 2, multicentre, randomised, double-blind, placebo-controlled crossover trial at ten centres in Canada, the Czech Republic, Israel, Italy, Macedonia, Romania, Serbia, and the USA. We enrolled patients aged 13 years or older with functional C1-inhibitor concentrations of less than 50% of normal and a history of four or more attacks of hereditary angio-oedema per month for at least 3 months before study initiation. Patients were randomly assigned centrally (1:1:1:1:1:1), via an interactive response technology system with fixed allocation, to receive one of six treatment sequences. During each sequence, patients received intravenous recombinant human C1 esterase inhibitor (50 IU/kg; maximum 4200 IU) twice weekly, recombinant human C1 esterase inhibitor once weekly and placebo once weekly, and placebo twice weekly, each for 4 weeks with a 1 week washout period between crossover. All patients, investigators, and study personnel who participated in patient care were masked to group allocation during the study. The primary efficacy endpoint was the number of attacks of hereditary angio-oedema observed in each 4 week treatment period. Attack symptoms were recorded daily. The primary efficacy analysis was done in the intention-to-treat population. Safety was assessed in all patients who received at least one injection of study medication. This study is registered with ClinicalTrials.gov, number NCT02247739. FINDINGS: Between Dec 29, 2014, and May 3, 2016, we enrolled 35 patients, of whom 32 (91%) underwent randomisation (intention-to-treat population) and 26 (81%) completed the study. The mean number of attacks of hereditary angio-oedema over 4 weeks was significantly reduced with recombinant human C1 esterase inhibitor twice weekly (2·7 attacks [SD 2·4]) and once weekly (4·4 attacks [3·2]) versus placebo (7·2 attacks [3·6]), with mean differences of -4·4 attacks (p<0·0001) and -2·8 attacks (p=0·0004), respectively. We recorded adverse events in ten (34%) of 29 patients given twice-weekly recombinant human C1 esterase inhibitor, 13 (45%) of 29 patients given the once-weekly regimen, and eight (29%) of 28 patients given placebo. Headache (twice-weekly treatment) and nasopharyngitis (once-weekly treatment) were the most common adverse events. Two (7%) adverse events (fatigue and headache) were deemed possibly related to treatment with recombinant human C1 esterase inhibitor, but both resolved without additional treatment. No thrombotic or thromboembolic events, systemic allergic reactions (including anaphylaxis), or neutralising antibodies were reported. INTERPRETATION: Prophylaxis with recombinant human C1 esterase inhibitor provided clinically relevant reductions in frequency of hereditary angio-oedema attacks and was well tolerated. In view of the pharmacokinetic profile of recombinant human C1 esterase inhibitor, our results suggest that efficacy of C1-inhibitor replacement therapy might not be a direct function of plasma trough concentrations of C1 inhibitor. FUNDING: Pharming Technologies.

Preventing Hereditary Angioedema Attacks in Children Using Cinryze®: Interim Efficacy and Safety Phase 3 Findings.

BACKGROUND: Hereditary angioedema (HAE) is a rare genetic disease causing unpredictable and potentially life-threatening subcutaneous and submucosal edematous attacks. Cinryze® (Shire ViroPharma Inc., Lexington, MA, USA), a nanofiltered C1 inhibitor (C1-INH), is approved in Europe for the treatment, preprocedure prevention, and routine prophylaxis of HAE attacks, and for the routine prophylaxis of attacks in the USA. This phase 3 study assessed the safety and efficacy of 2 C1-INH doses in preventing attacks in children aged 6-11 years. METHODS: A randomized single-blind crossover study was initiated in March 2014. Results for the first 6 patients completing the study are reported here. After a 12-week qualifying observation period, patients were randomly assigned to 1 of 2 C1-INH doses, 500 or 1,000 U, every 3-4 days for 12 weeks and crossed over to the alternative dose for a second 12-week period. The primary efficacy endpoint was the number of angioedema attacks per month. RESULTS: Six females with HAE type I and a median age of 10.5 years received 2 doses of C1-INH (500 and 1,000 U). The mean (SD) difference in the number of monthly angioedema attacks between the baseline observation period and the treatment period was -1.89 (1.31) with 500 U and -1.89 (1.11) with 1,000 U. During the treatment periods, cumulative attack severity, cumulative daily severity, and the number of attacks needing acute treatment were lower. No serious adverse events or study drug discontinuations occurred. CONCLUSIONS: Interim findings from this study indicate that routine prevention with intravenous administration of C1-INH is efficacious, safe, and well tolerated in children ≥6 years of age.

Assessment of inhibitory antibodies in patients with hereditary angioedema treated with plasma-derived C1 inhibitor.

BACKGROUND: Limited data are available regarding C1 inhibitor (C1-INH) administration and anti-C1-INH antibodies. OBJECTIVE: To assess the incidence of antibody formation during treatment with pasteurized, nanofiltered plasma-derived C1-INH (pnfC1-INH) in patients with hereditary angioedema with C1-INH deficiency (C1-INH-HAE) and the comparative efficacy of pnfC1-INH in patients with and without antibodies. METHODS: In this multicenter, open-label study, patients with C1-INH-HAE (≥12 years of age) were given 20 IU/kg of pnfC1-INH per HAE attack that required treatment and followed up for 9 months. Blood samples were taken at baseline (day of first attack) and months 3, 6, and 9 and analyzed for inhibitory anti-C1-INH antibody (iC1-INH-Ab) and noninhibitory anti-C1-INH antibodies (niC1-INH-Abs). RESULTS: The study included 46 patients (69.6% female; mean age, 38.9 years; all white) who received 221 on-site pnfC1-INH infusions; most patients received 6 or fewer infusions. No patient tested positive (titer ≥1:50) for iC1-INH-Ab at any time during the study. Thirteen patients (28.2%) had detectable niC1-INH-Abs in 1 or more samples. Nine patients (19.6%) had detectable niC1-INH-Abs at baseline; 3 of these had no detectable antibodies after baseline. Of 10 patients (21.7%) with 1 or more detectable result for niC1-INH-Abs after baseline, 6 had detectable niC1-INH-Abs at baseline. Mean times to symptom relief onset and complete symptom resolution per patient were similar for those with or without anti-niC1-INH-Abs. CONCLUSION: Administration of pnfC1-INH was not associated with iC1-INH-Ab formation in this population. Noninhibitory antibodies were detected in some patients but fluctuated during the study independently of pnfC1-INH administration and appeared to have no effect on pnfC1-INH efficacy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01467947.

Icatibant for Multiple Hereditary Angioedema Attacks across the Controlled and Open-Label Extension Phases of FAST-3.

BACKGROUND: In randomized, controlled, double-blind, multicenter phase 3 studies, one icatibant injection was efficacious and generally well tolerated in patients with a single hereditary angioedema (HAE) attack. Here, the efficacy and safety of icatibant for multiple HAE attacks was evaluated across the controlled and open-label extension phases of the For Angioedema Subcutaneous Treatment (FAST)-3 study (NCT00912093). METHODS: In the controlled phase, adults with HAE type I or II were randomized (1:1) to receive a single subcutaneous injection of icatibant 30 mg or placebo within 6 h of an attack becoming mild (laryngeal) or moderate (cutaneous/abdominal). Open-label icatibant was administered for severe laryngeal symptoms. In the open-label extension phase, patients could receive up to three icatibant injections per attack. Efficacy and safety were analyzed for the first five icatibant-treated attacks at any location (prospective analysis) and laryngeal attacks (post hoc analysis) across both phases. Efficacy outcomes were based on patient-reported symptom severity (visual analog scale). RESULTS: In groups of patients with one to five icatibant-treated attacks at any location (n = 88), the median times to onset of symptom relief, onset of primary symptom relief and almost complete symptom relief were 1.9-2.1, 1.5-2.0 and 3.5-19.7 h, respectively. The same outcomes for laryngeal attacks (n = 25) were 1.0-2.0, 1.0-2.0 and 1.5-8.1 h, respectively. The most frequently reported adverse events were a worsening or recurrence of HAE attack, headache and nasopharyngitis. Two serious adverse events (arrhythmia and noncardiac chest pain) were considered to be related to icatibant. CONCLUSIONS: Icatibant was efficacious and generally well tolerated across multiple HAE attacks, including laryngeal attacks.

Recombinant human C1-esterase inhibitor relieves symptoms of hereditary angioedema attacks: phase 3, randomized, placebo-controlled trial.

BACKGROUND: Hereditary angioedema (HAE), caused by C1 inhibitor (C1INH) deficiency or dysfunction, is characterized by recurrent attacks of tissue swelling affecting multiple anatomic locations. Recombinant human C1INH (rhC1INH) has been shown effective for acute treatment of HAE attacks. OBJECTIVE: To evaluate the efficacy and safety of rhC1INH (50 IU/kg to maximum 4,200 IU/treatment) vs placebo in a larger HAE population. METHODS: Seventy-five patients experiencing peripheral, abdominal, facial, and/or oropharyngeal laryngeal attacks were randomized (3:2) to rhC1INH (n = 44) or placebo (saline; n = 31). Efficacy was assessed by patient responses on a Treatment Effect Questionnaire (TEQ) and visual analog scale (VAS). Safety also was evaluated. RESULTS: Median (95% confidence interval) time to beginning of symptom relief at the primary attack location was 90 minutes (61-150) in rhC1INH-treated patients vs 152 minutes (93, not estimable) in placebo-treated patients (P = .031) based on the TEQ and 75 minutes (60-105) vs 303 minutes (81-720, P = .003) based on a VAS decrease of at least 20 mm. Median time to minimal symptoms was 303 minutes (240-720) in rhC1INH-treated patients vs 483 minutes (300-1,440) in placebo-treated patients based on the TEQ (P = .078) and 240 minutes (177-270) vs 362 minutes (240, not estimable; P = .005), based on an overall VAS less than 20 mm. Overall, rhC1INH was safe and well tolerated; no thromboembolic events, anaphylaxis, or neutralizing antibodies were observed. CONCLUSION: Relief of symptoms of HAE attacks was achieved faster with rhC1INH compared with placebo as assessed by the TEQ and VAS, with a positive safety profile. Results are consistent with previous studies showing efficacy and safety of rhC1INH in patients with HAE.

C1-INH concentrate for treatment of acute hereditary angioedema: a pediatric cohort from the I.M.P.A.C.T. studies.

BACKGROUND: We analyzed the clinical response of pediatric and adolescent hereditary angioedema (HAE) patients to pdC1-INH in the International Multicenter Prospective Angioedema C1-INH Trials (I.M.P.A.C.T.) 1 and 2. METHODS: Patients included in this post hoc analysis of prospectively collected data were between 10 and 18 yr old with type I or II HAE and a documented history of abdominal or facial attacks. Patients received a single injection of pdC1-INH concentrate (Berinert(®) , CSL Behring, Marburg, Germany) 20 U/kg. Efficacy end-points were time from the administration of study drug to onset of symptom relief and time to complete relief of all symptoms. RESULTS: Seven pediatric patients were included in I.M.P.A.C.T.1 with only 1 attack analyzed per patient. Median time to onset of relief was 0.42 h and to complete resolution was 8.08 h. No patient experienced a worsening of symptoms during the 0-4-h assessment period. Nine patients who experienced a total of 115 attacks were included in the analysis of I.M.P.A.C.T.2. Abdominal attacks were rated as 'severe' more frequently than were other types of attacks. The number of attacks per patient ranged from 2 to 42, and study participation ranged from 1 to 38 months. Median times to onset of symptom relief and to complete symptom resolution were 0.49 h and 14.1 h, respectively. Of 4 treatment-emergent adverse events in both studies, only 2 were considered related to treatment. CONCLUSIONS: Study results showed that outcomes with pdC1-INH treatment of HAE in pediatric patients are comparable with outcomes in adults.

Randomized placebo-controlled trial of the bradykinin B2 receptor antagonist icatibant for the treatment of acute attacks of hereditary angioedema: the FAST-3 trial.

BACKGROUND: The For Angioedema Subcutaneous Treatment (FAST)-3 study was a phase III, randomized, double-blind, placebo-controlled study of icatibant (bradykinin B(2) receptor antagonist) in subjects with hereditary angioedema (HAE) resulting from C1-INH deficiency or dysfunction (type I/II). OBJECTIVE: To investigate icatibant efficacy and safety in subjects with acute HAE attacks. METHODS: Subjects with moderate to very severe cutaneous or abdominal symptoms received icatibant (n = 43) or placebo (n = 45). Five subjects with laryngeal (mild-to-moderate) first attacks received icatibant (n = 3) or placebo (n = 2), and 5 subjects with severe laryngeal first attacks received open-label icatibant. RESULTS: Cutaneous or abdominal attacks: icatibant significantly reduced median times (vs placebo) to 50% or more reduction in symptom severity (2.0 vs 19.8 hours; P < .001, primary endpoint), onset of primary symptom relief (1.5 vs 18.5 hours; P < .001, key secondary endpoint), or almost complete symptom relief (8.0 vs 36.0 hours; P = .012) and provided a shorter time to initial symptom relief (0.8 vs 3.5 hours; P < .001). For laryngeal attacks, median time to 50% or more reduction in symptom severity was 2.5 hours (icatibant) and 3.2 hours (placebo). No icatibant-treated subject required rescue medication before symptom relief occurred. The incidence of adverse events (AEs) was similar in icatibant- and placebo-treated subjects (41% and 52%, respectively). All icatibant-treated subjects experienced injection site reactions, but none reported clinically relevant changes in safety parameters or serious AEs. CONCLUSIONS: FAST-3 demonstrated that icatibant was effective and generally well tolerated in subjects with acute HAE attacks. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT00912093.

Hereditary angioedema: Validation of the end point time to onset of relief by correlation with symptom intensity.

Time to onset of symptom relief in hereditary angioedema (HAE) is a common primary end point in clinical studies but it has never been validated by correlation with the course of HAE symptoms. This study was designed as a retrospective validation of the primary end point for a placebo-controlled phase II/III study in patients with HAE. Ninety-eight abdominal attacks were treated with 10 or 20 U/kg of a highly purified C1 esterase inhibitor (C1-INH) concentrate or placebo. The primary end point was the time to onset of symptom relief, as determined by the patients. Patients assessed the intensity of the symptoms of pain, nausea, vomiting, cramps, and diarrhea over time. By Spearman rank correlation, the primary end point was compared with the time to first reduction of (1) any symptom intensity, (2) the sum of symptom intensity scores, and (3) the intensity of the last symptom present at baseline. The C1-INH, 20 U/kg, and placebo groups were compared by one-sided two-sample Wilcoxon tests. The time to first reduction in intensity of the last symptom present at baseline had the highest correlation with the primary end point (r = 0.77). The time to onset of symptom relief and the time to the first reduction in intensity of the last symptom were significantly shorter for the C1-INH, 20 U/kg, group compared with placebo (p = 0.009 and p = 0.0036, respectively). The association with the intensity of single symptoms confirmed that the time to onset of symptom relief is an appropriate end point for assessing the efficacy of C1-INH therapy.

Baseline level of functional C1-inhibitor correlates with disease severity scores in hereditary angioedema.

The diagnosis of hereditary angioedema (HAE) is based on complement tests. We studied for the first time the possible association between complement parameters measured at the time of diagnosis and disease severity in 115 patients with HAE. Serum levels of functional C1-inhibitor (C1-INH(f)), antigenic C1-inhibitor (C1-INH(a)), C4 and hemolytic activity of the classical pathway (CH50) were determined at the time of diagnosis. We found a significant correlation between severity scores and baseline C1-INH(f) levels, as determined by ELISA assay (p=0.0003). On the other hand, there was no correlation between severity scores and other complement parameters (C1-INH(a), C4, and CH50). We consider the correlation between severity scores and baseline C1-INH(f) levels an important pathophysiological observation. Our findings underlie the potential significance of monitoring functional C1-INH levels in relation to clinical disease course.

Efficacy of human C1 esterase inhibitor concentrate compared with placebo in acute hereditary angioedema attacks.

BACKGROUND: Hereditary angioedema caused by C1 esterase inhibitor deficiency is a rare disorder. OBJECTIVE: To compare the efficacy of pasteurized C1 esterase inhibitor concentrate (Berinert, CSL Behring) at intravenous doses of 10 or 20 U/kg body weight with placebo in the treatment of single, acute abdominal or facial attacks in patients with hereditary angioedema. METHODS: This was a randomized, double-blind, placebo-controlled study in 125 patients with type I or II hereditary angioedema. The primary outcome was time from start of treatment to onset of symptom relief. Secondary outcomes were time to complete resolution, proportion of patients with worsened intensity of angioedema symptoms between 2 and 4hours after treatment, and number of vomiting episodes within 4 hours. RESULTS: Median time to onset of relief was significantly shorter with C1 esterase inhibitor concentrate at a dose of 20 U/kg than with placebo (0.5 vs 1.5 hours; P = .0025), whereas with 10 U/kg, the time to onset of relief was only slightly shorter than with placebo (1.2 vs 1.5 hours; P = .2731). Compared with placebo, the reduction in time to onset of relief was greatest for severe attacks (0.5 vs 13.5 hours). The secondary outcomes consistently supported the efficacy of the 20 U/kg dose. C1 esterase inhibitor concentrate was safe and well tolerated. No seroconversions were observed for HIV, hepatitis virus, or human B19 virus. CONCLUSION: C1 esterase inhibitor concentrate given intravenously at a dose of 20 U/kg is an effective and safe treatment for acute abdominal and facial attacks in patients with hereditary angioedema, with a rapid onset of relief.

Fixed-Dose Subcutaneous C1-Inhibitor Liquid for Prophylactic Treatment of C1-INH-HAE: SAHARA Randomized Study.

BACKGROUND: Hereditary angioedema (HAE) with C1 inhibitor deficiency (C1-INH) is characterized by swelling of subcutaneous and/or submucosal tissues. OBJECTIVE: To evaluate efficacy/safety of fixed-dose subcutaneous plasma-derived C1-INH (pdC1-INH) liquid for HAE attack prevention (NCT02584959). METHODS: Eligible patients were ≥12 years with ≥2 monthly attacks prescreening or pre-long-term prophylaxis. In a partial crossover design, 80% of patients were randomized to placebo or pdC1-INH liquid for 14 weeks and crossed over from active to placebo or vice versa for another 14 weeks. The remainder were randomized to pdC1-INH liquid for 28 weeks. The primary efficacy endpoint was normalized number of attacks (NNA) versus placebo. Key additional endpoints were the proportion of patients achieving NNA reduction ≥50%, attack severity, number of attack-free days, and safety. RESULTS: Seventy-five patients were randomized and 58 (77%) completed the study. Mean age 41 years; 88% HAE type I. Least-squares means of NNA were reduced from 3.9 with placebo to 1.6 with pdC1-INH (from day 1; P < .0001). Most patients had ≥50% NNA reduction with pdC1-INH (from day 1, 78%). A total of 8.8% of placebo-treated patients were attack-free and 5.3%, 22.8%, and 63.2% had mild, moderate, and severe attacks, respectively; 37.5% of pdC1-INH-treated patients were attack-free and 8.9%, 26.8%, and 26.8% had mild, moderate, and severe attacks, respectively. Treatment-emergent adverse event rates were similar between groups (52% vs 56% for pdC1-INH crossover vs placebo, respectively). CONCLUSIONS: Fixed-dose subcutaneous pdC1-INH liquid was superior to placebo in preventing HAE attacks and demonstrated a favorable safety profile.

Consequences of Misdiagnosed and Mismanaged Hereditary Angioedema Laryngeal Attacks: An Overview of Cases from the Romanian Registry.

Emergency department (ED) physicians frequently encounter patients presenting with angioedema. Most of these involve histamine-mediated angioedema; however, less common forms of angioedema (bradykinin-mediated) also occur. It is vital physicians correctly recognize and treat this; particularly since bradykinin-mediated angioedema does not respond to antihistamines, corticosteroids or epinephrine and hereditary angioedema (HAE) laryngeal attacks can be fatal. Here we present four case reports illustrating how failures in recognizing, managing, and treating laryngeal edema due to HAE led to asphyxiation and death of the patient. Recognition of the specific type of angioedema is critical for rapid and effective treatment of HAE attacks. Bradykinin-mediated angioedema should be efficiently differentiated from the most common histamine-mediated form. Improved awareness of HAE and the associated risk of life-threatening laryngeal edema among emergency physicians, patients, and relatives and clear ED treatment protocols are warranted. Moreover, appropriate treatments should be readily available to reduce fatalities associated with laryngeal edema.

Targeted next-generation sequencing for the molecular diagnosis of hereditary angioedema due to C1-inhibitor deficiency.

SERPING1 genotyping of subjects suspicious for hereditary angioedema due to C1-INH deficiency (C1-INH-HAE) is important for clinical practice as well as for research reasons. Conventional approaches towards the detection of C1-INH-HAE-associated SERPING1 variants are cumbersome and time-demanding with many pitfalls. To take advantage of the benefits of next-generation sequencing (NGS) technology, we developed and validated a custom NGS platform that, by targeting the entire SERPING1 gene, facilitates genetic testing of C1-INH-HAE patients in clinical practice. In total, 135 different C1-INH-HAE-associated SERPING1 variants, out of the approximately 450 reported, along with 115 negative controls and 95 randomly selected DNA samples from affected family members of C1-INH-HAE index patients, were included in the forward and reverse validation processes of this platform. Our platform's performance, i.e. analytical sensitivity of 98.96%, a false negative rate of 1.05%, analytical specificity 100%, a false positive rate equal to zero, accuracy of 99.35%, and repeatability of 100% recommends its implementation as a first line approach for the genetic testing of C1-INH-HAE patients or as a confirmatory method. A noteworthy advantage of our platform is the concomitant detection of single nucleotide variants and copy number variations throughout the whole length of the SERPING1 gene, moreover providing information about the size and the localization of the latter. During our study, 15 novel C1-INH-HAE-related SERPING1 variants were detected.

Recombinant Human C1-Esterase Inhibitor to Treat Acute Hereditary Angioedema Attacks in Adolescents.

BACKGROUND: Recombinant human C1-esterase inhibitor (rhC1-INH) is efficacious and well tolerated for managing hereditary angioedema (HAE) attacks in adults. However, there are insufficient data on its efficacy and safety in adolescents. OBJECTIVE: To evaluate the efficacy and safety profiles of rhC1-INH for acute HAE attacks in adolescents. METHODS: Adolescents (aged 12-18 y) with HAE enrolled in 2 randomized controlled trials and 2 open-label extension trials were included and received intravenous rhC1-INH for acute attacks. Times to the beginning of sustained symptom relief (visual analog scale change from baseline ≥20 mm) and minimal symptoms (visual analog scale score of <20 mm across locations) were assessed. Safety parameters included hypersensitivity reactions, anti-rhC1-INH antibodies, and host-related impurities. RESULTS: Sixteen adolescents (50 attacks, aged 14-18 y) received rhC1-INH. Attacks were managed with single-dose rhC1-INH 50 U/kg (46.0%) and single-dose rhC1-INH 2100 U (16%), and 32.0% were treated with additional doses after receiving an initial rhC1-INH 2100 U dose (total dose, 4200-6300 U). Most attacks (88.0%) occurred at a single location; 59.1% (26 of 44) were abdominal. Across the first 5 attacks, median times to the beginning of symptom relief ranged from 19.0 to 78.5 minutes; median times to minimal symptoms ranged from 120 to 190 minutes. Pharmacokinetics showed that rhC1-INH restored functional plasma C1-esterase inhibitor levels to the normal (>70%) range for almost all evaluable patients. No severe or drug-related adverse events or hypersensitivity reactions occurred. No treatment-emergent antibodies to rhC1-INH or host-related impurities were observed. CONCLUSIONS: rhC1-INH is efficacious and well tolerated among adolescents with HAE.

Psychometric Field Study of Hereditary Angioedema Quality of Life Questionnaire for Adults: HAE-QoL.

BACKGROUND: Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) may affect health-related quality of life (HRQoL). A specific HRQoL questionnaire for adult patients with C1-INH-HAE, the HAE-QoL, has recently been developed in Spain. OBJECTIVE: The objective of this study was to perform a cross-cultural validation and psychometric study of the HAE-QoL in an international setting. METHODS: Cross-cultural adaptation of the Spanish HAE-QoL draft version and an international rating phase with experts were performed. The resultant version of the HAE-QoL, a clinical questionnaire, and Short Form 36-item Health Survey Version 2.0 (SF-36v2) were pilot tested internationally. Item reduction was based on both descriptive and exploratory factor analysis. Psychometric properties were assessed. RESULTS: Cross-cultural adaptation of the HAE-QoL was performed in 18 countries. The draft version of the HAE-QoL was pilot tested in 332 patients, and accurate data were obtained from 290 patients from 11 countries. The reduction process resulted in a new version with 25 items and 7 dimensions (treatment difficulties, physical functioning and health, disease-related stigma, emotional role and social functioning, concern about offspring, perceived control over illness, and mental health). Strong psychometric properties were observed (Cronbach's α 0.92; test-retest reliability 0.87). Convergent validity showed mild to moderate correlations with SF-36v2 physical and mental component summaries (0.45 and 0.64, respectively) and with SF-36v2 dimensions (P < .004). HAE-QoL scores discriminated significantly among severity groups (median: asymptomatic 133.5 vs severe 84.0; P < .001); between patients with and without long-term prophylaxis (median: 101 vs 90; P = .001); and between patients with and without psychiatric and/or psychological care (median: 74 vs 103; P ≤ .001). CONCLUSIONS: The HAE-QoL, currently available in 18 languages, showed good reliability and validity evidence.