The autoimmune rheumatological presentation of Common Variable Immunodeficiency Disorders with an overview of genetic testing

Primary immunodeficiency Disorders (PIDS) are rare, mostly monogenetic conditions which can present to a number of specialties. Although infections predominate in most PIDs, some individuals can manifest autoimmune or inflammatory sequelae as their initial clinical presentation. Identifying patients with PIDs can be challenging, as some can present later in life. This is often seen in patients with Common Variable Immunodeficiency Disorders (CVID), where symptoms can begin in the sixth or even seventh decades of life. Some patients with PIDs including CVID can initially present to rheumatologists with autoimmune musculoskeletal manifestations. It is imperative for these patients to be identified promptly as immunosuppression could lead to life-threatening opportunistic infections in these immunocompromised individuals. These risks could be mitigated by prior treatment with subcutaneous or intravenous (SCIG/IVIG) immunoglobulin replacement or prophylactic antibiotics. Importantly, many of these disorders have an underlying genetic defect. Individualized treatments may be available for the specific mutation, which may obviate or mitigate the need for hazardous broad-spectrum immunosuppression. Identification of the genetic defect has profound implications not only for the patient but also for affected family members, who may be at risk of symptomatic disease following an environmental trigger such as a viral infection. Finally, there may be clinical clues to the underlying PID, such as recurrent infections, the early presentation of severe or multiple autoimmune disorders, as well as a relevant family history. Early referral to a clinical immunologist will facilitate appropriate diagnostic evaluation and institution of treatment such as SCIG/IVIG immunoglobulin replacement. This review comprises three sections; an overview of PIDs, focusing on CVID, secondly genetic testing of PIDs and finally the clinical presentation of these disorders to rheumatologists.

CRISPR-Cas9 In Vivo Gene Editing of KLKB1 for Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a rare genetic disease that leads to severe and unpredictable swelling attacks. NTLA-2002 is an in vivo gene-editing therapy based on clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9. NTLA-2002 targets the gene encoding kallikrein B1 (KLKB1), with the goal of lifelong control of angioedema attacks after a single dose.

METHODS

In this phase 1 dose-escalation portion of a combined phase 1-2 trial of NTLA-2002 in adults with hereditary angioedema, we administered NTLA-2002 at a single dose of 25 mg, 50 mg, or 75 mg. The primary end points were the safety and side-effect profile of NTLA-2002 therapy. Secondary and exploratory end points included pharmacokinetics, pharmacodynamics, and clinical efficacy determined on the basis of investigator-confirmed angioedema attacks.

RESULTS

Three patients received 25 mg of NTLA-2002, four received 50 mg, and three received 75 mg. At all dose levels, the most common adverse events were infusion-related reactions and fatigue. No dose-limiting toxic effects, serious adverse events, grade 3 or higher adverse events, or clinically important laboratory findings were observed after the administration of NTLA-2002. Dose-dependent reductions in the total plasma kallikrein protein level were observed between baseline and the latest assessment, with a mean percentage change of -67% in the 25-mg group, -84% in the 50-mg group, and -95% in the 75-mg group. The mean percentage change in the number of angioedema attacks per month between baseline and weeks 1 through 16 (primary observation period) was -91% in the 25-mg group, -97% in the 50-mg group, and -80% in the 75-mg group. Among all the patients, the mean percentage change in the number of angioedema attacks per month from baseline through the latest assessment was -95%.

CONCLUSIONS

In this small study, a single dose of NTLA-2002 led to robust, dose-dependent, and durable reductions in total plasma kallikrein levels, and no severe adverse events were observed. In exploratory analyses, reductions in the number of angioedema attacks per month were observed at all dose levels. (Funded by Intellia Therapeutics; ClinicalTrials.gov number, NCT05120830.).

Uncovering the true burden of hereditary angioedema due to C1-inhibitor deficiency: A focus on the Asia-Pacific region

Hereditary angioedema (HAE) due to C1-inhibitor deficiency or dysfunction is a rare genetic disorder that causes recurrent episodes of swelling in various parts of the body. Treatment goals of HAE aim to "normalize" life for all patients; however, lack of diagnostic facilities and limited access to effective treatment options in developing nations cause delays in diagnosis and place a significant burden on patients. In this review, we aim to highlight the burden of disease caused by C1-inhibitor HAE across the Asia-Pacific region, considering its epidemiology, morbidity and mortality, and socioeconomic and psychological impact. We also review the availability of guideline-recommended diagnostic facilities and treatments, and how patients are currently managed. Data were collected from published literature and HAE experts in the region, who provided information regarding diagnosis and management in their countries. Current practice was reviewed against international guidelines, as well as local guidelines/consensus used in Australia, Japan, and China. Suggestions are provided for improving the time to diagnosis in the region, increasing access to guideline-recommended treatments, and providing support to reduce the burden on patients and caregivers. There is an urgent need to improve HAE services and provide access to life-saving treatment in developing countries, and efforts should be made to increase awareness of guideline recommendations in high-income economies that do not currently provide long-term prophylactic treatments.

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.

A Review of Randomized Controlled Trials of Hereditary Angioedema Long-Term Prophylaxis with C1 Inhibitor Replacement Therapy: Alleviation of Disease Symptoms Is Achievable

Through its fluctuating disease activity and unpredictable attacks, hereditary angioedema (HAE) imposes a substantial patient burden. To minimize HAE burden and improve quality of life, treatment should involve individualized management strategies that address on-demand therapy and short-term/long-term prophylaxis. Goals of long-term prophylaxis include reducing the number, severity, and burden of HAE attacks. The best characterized forms of HAE arise from deficiency or dysfunction of C1-inhibitor (C1-INH; types I/II), and C1-INH replacement therapy is a first-line intervention for on-demand (acute) treatment of HAE attacks, short-term prophylaxis before high-risk procedures, and long-term prophylaxis. Randomized, double-blind, placebo-controlled crossover trials have shown dose-dependent efficacy with plasma-derived C1-INH (pdC1-INH) 40-60 IU/kg subcutaneously, pdC1-INH 1000 U intravenously, and recombinant human C1-INH (rhC1-INH) 50 IU/kg (maximum 4200 IU) intravenously, all administered twice weekly, as long-term prophylaxis in patients with a history of 2 to ≥4 attacks/month. Overall, up to 83% (pdC1-INH 60 IU/kg) of patients experienced an HAE attack reduction threshold of ≥70%, and up to 58% (pdC1-INH 60 IU/kg) achieved an attack reduction threshold of ≥90%. Lower-dose intravenous pdC1-INH therapy (1000 U) was seemingly less effective, with 45% of 22 patients experiencing an HAE attack reduction threshold of ≥70%, and up to 23% achieving an attack reduction threshold of ≥90%. Higher-dose intravenous rhC1-INH 50 IU/kg (maximum, 4200 IU) twice weekly was of intermediate benefit. Despite a baseline mean attack frequency of 17.9 (during the 3 months prior to study treatment) and a mean attack frequency during a 4-week placebo period of 7.2, 52% of 23 patients experienced ≥70% reduction in attack frequency and 26% of 23 patients experienced ≥90% reduction in attack frequency. The increasing patient percentages treated with C1-INH replacement therapy as long-term prophylaxis meeting these high thresholds reinforces hopes and expectations that "attack freedom" is achievable, including for those with moderate or severe disease.

Treatment of hereditary angioedema—single or multiple pathways to the rescue

Hereditary angioedema (HAE) is a rare disease caused by mutations in the SERPING1 gene. This results in deficient or dysfunctional C1 esterase inhibitor (C1-INH) and affects multiple proteases involved in the complement, contact-system, coagulation, and fibrinolytic pathways. Current options for the treatment and prevention of HAE attacks include treating all affected pathways via direct C1-INH replacement therapy; or specifically targeting components of the contact activation system, in particular by blocking the bradykinin B₂ receptor (B2R) or inhibiting plasma kallikrein, to prevent bradykinin generation. Intravenously administered plasma-derived C1-INH (pdC1-INH) and recombinant human C1-INH have demonstrated efficacy and safety for treatment of HAE attacks, although time to onset of symptom relief varied among trials, specific agents, and dosing regimens. Data from retrospective and observational analyses support that short-term prophylaxis with intravenous C1-INH products can help prevent HAE attacks in patients undergoing medical or dental procedures. Long-term prophylaxis with intravenous or subcutaneous pdC1-INH significantly decreased the HAE attack rate vs. placebo, although breakthrough attacks were observed. Pathway-specific therapies for the management of HAE include the B2R antagonist icatibant and plasma kallikrein inhibitors ecallantide, lanadelumab, and berotralstat. Icatibant, administered for treatment of angioedema attacks, reduced B2R-mediated vascular permeability and, compared with placebo, reduced the time to initial symptom improvement. Plasma kallikrein inhibitors, such as ecallantide, block the binding site of kallikrein to prevent cleavage of high molecular weight kininogen and subsequent bradykinin generation. Ecallantide was shown to be efficacious for HAE attacks and is licensed for this indication in the United States, but the labeling recommends that only health care providers administer treatment because of the risk of anaphylaxis. In addition to C1-INH replacement therapy, the plasma kallikrein inhibitors lanadelumab and berotralstat are recommended as first-line options for long-term prophylaxis and have demonstrated marked reductions in HAE attack rates. Investigational therapies, including the activated factor XII inhibitor garadacimab and an antisense oligonucleotide targeting plasma prekallikrein messenger RNA (donidalorsen), have shown promise as long-term prophylaxis. Given the requirement of lifelong management for HAE, further research is needed to determine how best to individualize optimal treatments for each patient.

The Icatibant Outcome Survey: 10 years of experience with icatibant for patients with hereditary angioedema

In patients with hereditary angioedema (HAE), bradykinin causes swelling episodes by activating bradykinin B₂ receptors. Icatibant, a selective bradykinin B₂ receptor antagonist, is approved for on-demand treatment of HAE attacks. The Icatibant Outcome Survey (IOS; NCT01034969) is an ongoing observational registry initiated in 2009 to monitor effectiveness/safety of icatibant in routine clinical practice. As of March 2019, 549 patients with HAE type 1 or 2 from the IOS registry had been treated, for 5995 total attacks. This article reviews data published from IOS over time which have demonstrated that effectiveness of icatibant in a real-world setting is comparable to efficacy in clinical trials; one dose is effective for the majority of attacks; early treatment (facilitated by self-administration) leads to faster resolution and shorter attack duration; effectiveness/safety of icatibant has been shown across a broad range of patient subgroups, including children/adolescents and patients with HAE with normal C1 inhibitor levels; and tolerability has been demonstrated in patients aged ≥65 years. Additionally, this review highlights how IOS data have provided valuable insights into patients' diagnostic journeys and treatment behaviors across individual countries. Such findings have helped to inform clinical strategies and guidelines to optimize HAE management and limit disease burden. This research was sponsored by Takeda Development Center Americas, Inc. Takeda Development Center Americas, Inc., provided funding to Excel Medical Affairs for support in writing and editing this manuscript.

Variability of disease activity in patients with hereditary angioedema type 1/2: longitudinal data from the Icatibant Outcome Survey

BACKGROUND

Hereditary angioedema due to C1 inhibitor deficiency (HAE-1/2) is a chronic and debilitating disease. The unpredictable clinical course represents a significant patient burden.

OBJECTIVE

To analyse longitudinal registry data from the Icatibant Outcome Survey (IOS) in order to characterize temporal changes in disease activity in patients with HAE-1/2.

METHODS

Icatibant Outcome Survey (NCT01034969) is an international observational registry monitoring the clinical outcomes of patients eligible for icatibant treatment. The current analyses are based on data collected between July 2009 and July 2019. Retrospective data for attacks recorded in the 12 months prior to IOS enrolment and for each 12-month period up to 7 years were analysed.

RESULTS

Included patients reported angioedema attacks without long-term prophylaxis (LTP; n = 315) and with LTP (n = 292) use at the time of attack onset. Androgens were the most frequently used LTP option (80.8%). At the population level, regardless of LTP use, most patients (52-80%) reporting <5 attacks in Year 1 continued experiencing this rate; similarly, many patients (25-76%) who reported high attack frequency continued reporting ≥10 attacks/year. However, year on year, 31-51% of patients experienced notable changes (increase/decrease of ≥5 attacks) in annual attack frequency. Of patients who reported an absolute change of ≥10 attacks from Year 1 to 2, 17-50% continued to experience a change of this magnitude in subsequent years.

CONCLUSION

At the population level, attack frequency was generally consistent over 7 years. At the small group level, 28.8-34.5% of patients reported a change in attack frequency of ≥5 attacks from Year 1 to Year 2; up to half of these patients continued to experience this magnitude of variation in disease activity in later years, reflecting high intra-patient variability.

The Role of Herpes Viruses in Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a serious lung disease which can result from known genetic or environmental exposures but is more commonly idiopathic (IPF). In familial PF (FPF), the majority of identified causal genes play key roles in the maintenance of telomeres, the protective end structures of chromosomes. Recent evidence suggests that short telomeres may also be implicated causally in a significant proportion of idiopathic cases. The possible involvement of herpes viruses in PF disease incidence and progression has been examined for many years, with some studies showing strong, statistically significant associations and others reporting no involvement. Evidence is thus polarized and remains inconclusive. Here we review the reported involvement of herpes viruses in PF in both animals and humans and present a summary of the evidence to date. We also present several possible mechanisms of action of the different herpes viruses in PF pathogenesis, including potential contributions to telomere attrition and cellular senescence. Evidence for antiviral treatment in PF is very limited but suggests a potential benefit. Further work is required to definitely answer the question of whether herpes viruses impact PF disease onset and progression and to enable the possible use of targeted antiviral treatments to improve clinical outcomes.

Assessment and management of disease burden and quality of life in patients with hereditary angioedema: a consensus report

BACKGROUND

Hereditary angioedema (HAE) is a rare disease characterized by unpredictable, potentially life-threatening attacks, resulting in significant physical and emotional burdens for patients and families. To optimize care for patients with HAE, an individualized management plan should be considered in partnership with the physician, requiring comprehensive assessment of the patient's frequency and severity of attacks, disease burden, and therapeutic control. Although several guidelines and consensus papers have been published concerning the diagnosis and treatment of HAE, there has been limited specific clinical guidance on the assessment of disease burden and quality of life (QoL) in this patient population. Practical guidance is critical in supporting effective long-term clinical management of HAE and improving patient outcomes. The objective of this review is to provide evidence-based guidelines for an individualized assessment of disease burden and QoL in patients with HAE.

METHODS

A consensus meeting was held on February 29, 2020, consisting of 9 HAE experts from the United States and Europe with extensive clinical experience in the treatment of HAE. Consensus statements were developed based on a preliminary literature review and discussions from the consensus meeting.

RESULTS

Final statements reflect the consensus of the expert panel and include the assessment of attack severity, evaluation of disease burden, and long-term clinical management of HAE caused by C1-esterase inhibitor deficiency. Patient-reported outcome measures for assessing HAE attack severity and frequency are available and valuable tools; however, attack frequency and severity are insufficient markers of disease severity unless they are evaluated in the broader context of the effect on an individual patient's QoL. QoL assessments should be individualized for each patient and minimally, they should address the interference of HAE with work, school, social, family, and physical activity, along with access to and burden of HAE treatment. Advances in HAE therapies offer the opportunity for comprehensive, individualized treatment plans, allowing patients to achieve minimal attack burden with reduced disease and treatment burden.

CONCLUSION

This consensus report builds on existing guidelines by expanding the assessment of disease burden and QoL measures for patients with HAE.

Impact of lanadelumab on health-related quality of life in patients with hereditary angioedema in the HELP study

Background

An objective of the phase 3 HELP Study was to investigate the effect of lanadelumab on health‐related quality of life (HRQoL) in patients with hereditary angioedema (HAE).

Methods

Patients with HAE‐1/2 received either lanadelumab 150 mg every 4 weeks (q4wks; n = 28), 300 mg q4wks (n = 29), 300 mg every 2 weeks (q2wks; n = 27), or placebo (n = 41) for 26 weeks (days 0–182). The Angioedema Quality of Life Questionnaire (AE‐QoL) was administered monthly, consisting of four domain (functioning, fatigue/mood, fears/shame, nutrition) and total scores. The generic EQ‐5D‐5L questionnaire was administered on days 0, 98, and 182. Comparisons were made between placebo and (a) all lanadelumab‐treated patients and (b) individual lanadelumab groups for changes in scores (day 0–182) and proportions achieving the minimal clinically important difference (MCID, −6) in AE‐QoL total score.

Results

Compared with the placebo group, the lanadelumab total group demonstrated significantly greater improvements in AE‐QoL total and domain scores (mean change, −13.0 to −29.3; p < 0.05 for all); the largest improvement was in functioning. A significantly greater proportion of the lanadelumab total group achieved the MCID (70% vs 37%; p = 0.001). The lanadelumab 300 mg q2wks group had the highest proportion (81%; p = 0.001) and was 7.2 times more likely to achieve the MCID than the placebo group. Mean EQ‐5D‐5L scores at day 0 were high in all groups, indicating low impairment, with no significant changes at day 182.

Conclusion

Patients with HAE‐1/2 experienced significant and clinically meaningful improvements in HRQoL measured by AE‐QoL following lanadelumab treatment in the HELP Study.

Lanadelumab demonstrates rapid and sustained prevention of hereditary angioedema attacks

Background

Lanadelumab demonstrated efficacy in preventing hereditary angioedema (HAE) attacks in the phase 3 HELP Study.

Objective

To assess time to onset of effect and long‐term efficacy of lanadelumab, based on exploratory findings from the HELP Study.

Methods

Eligible patients with HAE type I/II received lanadelumab 150 mg every 4 weeks (q4wks), 300 mg q4wks, 300 mg q2wks, or placebo. Ad hoc analyses evaluated day 0‐69 findings using a Poisson regression model accounting for overdispersion. Least‐squares mean monthly HAE attack rate for lanadelumab was compared with placebo. Intrapatient comparisons for days 0‐69 versus steady state (days 70‐182) used a paired t test for continuous endpoints or Kappa statistics for categorical endpoints.

Results

One hundred twenty‐five patients were randomized and treated. During days 0‐69, mean monthly attack rate was significantly lower with lanadelumab (0.41‐0.76) vs placebo (2.04), including attacks requiring acute treatment (0.33‐0.61 vs 1.66) and moderate/severe attacks (0.31‐0.48 vs 1.33, all P ≤ .001). More patients receiving lanadelumab vs placebo were attack free (37.9%‐48.1% vs 7.3%) and responders (85.7%‐100% vs 26.8%). During steady state, the efficacy of lanadelumab vs placebo was similar or improved vs days 0‐69. Intrapatient differences were significant with lanadelumab 300 mg q4wks for select outcomes. Lanadelumab efficacy was durable—HAE attack rate was consistently lower vs placebo, from the first 2 weeks of treatment through study end. Treatment emergent adverse events were comparable during days 0‐69 and 70‐182.

Conclusion

Protection with lanadelumab started from the first dose and continued throughout the entire study period.

Subcutaneous C1 inhibitor for prevention of attacks of hereditary angioedema: additional outcomes and subgroup analysis of a placebo-controlled randomized study

Background

Hereditary angioedema (HAE) is a debilitating disorder resulting from C1-esterase inhibitor (C1-INH) deficiency. In the COMPACT phase 3 study the prophylactic use of a subcutaneous C1 inhibitor (C1-INH [SC], HAEGARDA^®, CSL Behring) twice weekly significantly reduced the frequency of acute edema attacks. Analysis of treatment effects by subgroups, onset of effect, and other exploratory analysis have not been reported.

Methods

This is a post hoc exploratory analysis on data from the randomized, placebo-controlled COMPACT study. 90 patients with C1-INH-HAE were randomized to 1 of 4 treatment sequences: C1-INH (SC) 40 or 60 IU/kg of body weight twice weekly for 16 weeks, preceded or followed by a placebo period. The pre-specified primary efficacy endpoint was the time-normalized number of HAE attacks, and pre-specified secondary efficacy endpoints were the percentage of patients with a certain treatment response (≥ 50% reduction on C1-INH (SC) versus placebo in the time-normalized number of attacks) and the time-normalized number of use of rescue medication. Pre-specified exploratory endpoints included severity of attacks, alone and combined with rescue medication use. Post hoc analyses included exploration of onset of effect and clinical assessment of patients with < 50% of response.

Results

Subgroup findings by various patient characteristics showed a consistent preventive effect of C1-INH (SC). In a post hoc analysis of attacks, the onset of the preventive effect within the first 2 weeks after treatment initiation in COMPACT showed that 10/43 patients (23%) experienced attacks of any severity with 60 IU/kg versus 34/42 patients (81%) with placebo. The need for rescue medication was tenfold lower with 60 IU/kg (35 treated attacks) versus placebo (358 treated attacks). A qualitative analysis of the 4 patients treated with 60 IU/kg and with < 50% reduction of attacks demonstrated a reduction in severity of attacks, rescue medication use, and symptom days which was considered a clinically meaningful treatment effect.

Conclusions

C1-INH (SC) prophylaxis demonstrated a preventive treatment effect with evidence of benefit within 2 weeks. A consistent treatment effect at recommended C1-INH (SC) dosing was evident in all subgroups of patients with type I/II HAE and by various measures of disease and treatment burden.

Trial registration EU Clinical Trials Register, 2013-000916-10, Registered 10 December 2013, https://www.clinicaltrialsregister.eu/ctr-search/trial/2013-000916-10; ClinicalTrials.gov Register, NCT01912456, Registered 31 July 2013, https://clinicaltrials.gov/ct2/show/NCT01912456.

Elderly versus younger patients with hereditary angioedema type I/II: patient characteristics and safety analysis from the Icatibant Outcome Survey

Background

Hereditary angioedema with C1 inhibitor deficiency (C1-INH-HAE) is characterized by recurrent swelling in subcutaneous or submucosal tissues. Symptoms often begin by age 5-11 years and worsen during puberty, but attacks can occur at any age and recur throughout life. Disease course in elderly patients is rarely reported.

Methods

The Icatibant Outcome Survey (IOS) is an observational study evaluating the safety, tolerability, and efficacy of icatibant. We conducted descriptive analyses in younger (age < 65 years) versus elderly patients (age ≥ 65 years). Here, we report patient characteristics and safety-related findings.

Results

As of February 2018, 872 patients with C1-INH-HAE type I/II were enrolled, of whom 100 (11.5%) were ≥ 65 years old. Significant differences between elderly versus younger patients, respectively, were noted for median age at symptom onset (17.0 vs 12.0 years), age at diagnosis (41.0 vs 19.4 years), and delay between symptom onset and diagnosis (23.9 vs 4.8 years) (P ≤ 0.0001 for all). Median age at diagnosis was significantly higher in elderly patients regardless of family history (P < 0.0001). Throughout the study, icatibant was used to treat 6798 attacks in 574 patients, with 63 elderly patients reporting 715 (10.5%) of the icatibant-treated attacks. No serious adverse events (SAEs) in elderly patients were judged to be possibly related to icatibant, whereas two younger patients reported three possibly related SAEs. Excluding off-label use and pregnancy (evaluated for regulatory purposes), the percentage of patients with at least one possibly/probably related AE was similar for elderly (2.0%) versus younger patients (2.7%). No deaths linked to icatibant treatment were identified. All related events in elderly patients were attributed to general disorders/administration site conditions, whereas related events in younger patients occurred across various system organ class designations.

Conclusions

Elderly patients with C1-INH-HAE were significantly older at diagnosis and had greater delay in diagnosis than younger patients. Elderly patients contributed to approximately 10% of the icatibant-treated attacks. Our analysis found similar AE rates (overall and possibly/probably related) in icatibant-treated elderly versus younger patients, despite the fact that elderly patients had significantly more comorbidities and were receiving a greater number of concomitant medications. Our analysis did not identify any new or unexpected safety concerns.

Hereditary angioedema: an update on causes, manifestations and treatment

Hereditary angioedema is a rare genetic disorder caused by deficiency of C1 esterase inhibitor (C1-INH) and characterized by recurrent episodes of severe swelling that affect the limbs, face, intestinal tract and airway. Since laryngeal oedema can be life-threatening as a result of asphyxiation, correct diagnosis and management of hereditary angioedema is vital. Hereditary angioedema attacks are mediated by bradykinin, the production of which is regulated by C1-INH. Hereditary angioedema therapy relies on treatment of acute attacks, and short- and long-term prophylaxis. Acute treatment options include C1-INH concentrate, icatibant and ecallantide. Self-administration of treatment is recommended and is associated with increased quality of life of patients with hereditary angioedema. Advances in diagnosis and management have improved the outcomes and quality of life of patients with hereditary angioedema.

The United Kingdom Primary Immune Deficiency (UKPID) registry 2012 to 2017

This is the second report of the United Kingdom Primary Immunodeficiency (UKPID) registry. The registry will be a decade old in 2018 and, as of August 2017, had recruited 4758 patients encompassing 97% of immunology centres within the United Kingdom. This represents a doubling of recruitment into the registry since we reported on 2229 patients included in our first report of 2013. Minimum PID prevalence in the United Kingdom is currently 5·90/100 000 and an average incidence of PID between 1980 and 2000 of 7·6 cases per 100 000 UK live births. Data are presented on the frequency of diseases recorded, disease prevalence, diagnostic delay and treatment modality, including haematopoietic stem cell transplantation (HSCT) and gene therapy. The registry provides valuable information to clinicians, researchers, service commissioners and industry alike on PID within the United Kingdom, which may not otherwise be available without the existence of a well-established registry.

Lanadelumab for the Prophylactic Treatment of Hereditary Angioedema with C1 Inhibitor Deficiency: A Review of Preclinical and Phase I Studies

Hereditary angioedema (HAE) with C1 esterase inhibitor (C1-INH) deficiency (C1-INH-HAE) is a rare disease characterized by diminished levels or dysfunctional activity of C1-INH, leading to dysregulated plasma kallikrein activity within the kallikrein-kinin pathway. Symptoms manifest as painful, potentially life-threatening swelling of subcutaneous tissues throughout the body and/or submucosal edema in the upper airway or gastrointestinal tract. Attacks recur with unpredictable frequency, intensity, and duration, placing a heavy burden on patients' daily lives. Despite improved availability of medications for on-demand treatment during attacks and prophylaxis of future attacks, unmet needs remain. Lanadelumab, a fully human monoclonal antibody, may help address some of the limitations of existing prophylactic options (e.g., the need for intravenous administration or frequent dosing). Preclinical studies demonstrate that it is highly potent and specifically inhibits plasma kallikrein, and findings from phase Ia and Ib studies suggest this agent is well tolerated and provides sustained inhibition of plasma kallikrein, allowing for less frequent dosing. The phase III HELP Study (NCT02586805) evaluating the efficacy and safety of lanadelumab in preventing HAE attacks has been completed, and its open-label extension (NCT02741596) is ongoing. Lanadelumab is now approved in the USA and Canada for prophylaxis to prevent attacks of HAE in patients aged ≥ 12 years. This review provides an overview of the discovery and clinical development of lanadelumab, from preclinical through phase Ib studies, characterizing its safety/tolerability, efficacy, and pharmacokinetic and pharmacodynamic profiles. It also highlights how this agent may positively impact clinical care of patients with C1-INH-HAE.

Effect of Lanadelumab Compared With Placebo on Prevention of Hereditary Angioedema Attacks: A Randomized Clinical Trial

IMPORTANCE

Current treatments for long-term prophylaxis in hereditary angioedema have limitations.

OBJECTIVE

To assess the efficacy of lanadelumab, a fully human monoclonal antibody that selectively inhibits active plasma kallikrein, in preventing hereditary angioedema attacks.

DESIGN, SETTING, AND PARTICIPANTS

Phase 3, randomized, double-blind, parallel-group, placebo-controlled trial conducted at 41 sites in Canada, Europe, Jordan, and the United States. Patients were randomized between March 3, 2016, and September 9, 2016; last day of follow-up was April 13, 2017. Randomization was 2:1 lanadelumab to placebo; patients assigned to lanadelumab were further randomized 1:1:1 to 1 of the 3 dose regimens. Patients 12 years or older with hereditary angioedema type I or II underwent a 4-week run-in period and those with 1 or more hereditary angioedema attacks during run-in were randomized.

INTERVENTIONS

Twenty-six-week treatment with subcutaneous lanadelumab 150 mg every 4 weeks (n = 28), 300 mg every 4 weeks (n = 29), 300 mg every 2 weeks (n = 27), or placebo (n = 41). All patients received injections every 2 weeks, with those in the every-4-week group receiving placebo in between active treatments.

MAIN OUTCOME AND MEASURES

Primary efficacy end point was the number of investigator-confirmed attacks of hereditary angioedema over the treatment period.

RESULTS

Among 125 patients randomized (mean age, 40.7 years [SD, 14.7 years]; 88 females [70.4%]; 113 white [90.4%]), 113 (90.4%) completed the study. During the run-in period, the mean number of hereditary angioedema attacks per month in the placebo group was 4.0; for the lanadelumab groups, 3.2 for the every-4-week 150-mg group; 3.7 for the every-4-week 300-mg group; and 3.5 for the every-2-week 300-mg group. During the treatment period, the mean number of attacks per month for the placebo group was 1.97; for the lanadelumab groups, 0.48 for the every-4-week 150-mg group; 0.53 for the every-4-week 300-mg group; and 0.26 for the every-2-week 300-mg group. Compared with placebo, the mean differences in the attack rate per month were -1.49 (95% CI, -1.90 to -1.08; P < .001); -1.44 (95% CI, -1.84 to -1.04; P < .001); and -1.71 (95% CI, -2.09 to -1.33; P < .001). The most commonly occurring adverse events with greater frequency in the lanadelumab treatment groups were injection site reactions (34.1% placebo, 52.4% lanadelumab) and dizziness (0% placebo, 6.0% lanadelumab).

CONCLUSIONS AND RELEVANCE

Among patients with hereditary angioedema type I or II, treatment with subcutaneous lanadelumab for 26 weeks significantly reduced the attack rate compared with placebo. These findings support the use of lanadelumab as a prophylactic therapy for hereditary angioedema. Further research is needed to determine long-term safety and efficacy.

TRIAL REGISTRATION

EudraCT Identifier: 2015-003943-20; ClinicalTrials.gov Identifier: NCT02586805.

Improvement in diagnostic delays over time in patients with hereditary angioedema: findings from the Icatibant Outcome Survey

The objective of this analysis was to evaluate the change over time in age at first symptoms, age at diagnosis, and delay in diagnosis using data from the Icatibant Outcome Survey (IOS). Patients with a diagnosis of C1-INH-HAE who were born before the year 1990 and who were diagnosed before they reached 25 years of age were included in the analysis. Both age at diagnosis and delay in diagnosis of C1-INH-HAE appear to decline with later decade of birth, despite wide variation across the countries assessed, suggesting that improved disease awareness causes increased rates of earlier diagnosis over time. Our findings demonstrate that some patients are still experiencing long delays to diagnosis, indicating an ongoing need for improved disease awareness.

Loss-of-function nuclear factor κB subunit 1 (NFKB1) variants are the most common monogenic cause of common variable immunodeficiency in Europeans

BACKGROUND

The genetic cause of primary immunodeficiency disease (PID) carries prognostic information.

OBJECTIVE

We conducted a whole-genome sequencing study assessing a large proportion of the NIHR BioResource-Rare Diseases cohort.

METHODS

In the predominantly European study population of principally sporadic unrelated PID cases (n = 846), a novel Bayesian method identified nuclear factor κB subunit 1 (NFKB1) as one of the genes most strongly associated with PID, and the association was explained by 16 novel heterozygous truncating, missense, and gene deletion variants. This accounted for 4% of common variable immunodeficiency (CVID) cases (n = 390) in the cohort. Amino acid substitutions predicted to be pathogenic were assessed by means of analysis of structural protein data. Immunophenotyping, immunoblotting, and ex vivo stimulation of lymphocytes determined the functional effects of these variants. Detailed clinical and pedigree information was collected for genotype-phenotype cosegregation analyses.

RESULTS

Both sporadic and familial cases demonstrated evidence of the noninfective complications of CVID, including massive lymphadenopathy (24%), unexplained splenomegaly (48%), and autoimmune disease (48%), features prior studies correlated with worse clinical prognosis. Although partial penetrance of clinical symptoms was noted in certain pedigrees, all carriers have a deficiency in B-lymphocyte differentiation. Detailed assessment of B-lymphocyte numbers, phenotype, and function identifies the presence of an increased CD21low B-cell population. Combined with identification of the disease-causing variant, this distinguishes between healthy subjects, asymptomatic carriers, and clinically affected cases.

CONCLUSION

We show that heterozygous loss-of-function variants in NFKB1 are the most common known monogenic cause of CVID, which results in a temporally progressive defect in the formation of immunoglobulin-producing B cells.

Real-world outcomes in hereditary angioedema: first experience from the Icatibant Outcome Survey in the United Kingdom

Background

Hereditary angioedema (HAE) is a potentially life-threatening, bradykinin-mediated disease, often misdiagnosed and under-treated, with long diagnostic delays. There are limited real-world data on best-practice management of HAE in the UK.

Objectives

To characterize the clinical profile, management and outcomes of patients with HAE type I and II from three specialist centres in the UK using data from the Icatibant Outcome Survey (IOS; Shire, Zug, Switzerland), an international observational study monitoring safety and effectiveness of icatibant, a selective bradykinin B2 receptor antagonist.

Methods

We performed retrospective analyses of IOS data for patients with HAE type I and II from three centres in the UK and compared UK data with pooled IOS data from 10 countries (48 centres).

Results

Analyses included 73 UK and 579 non-UK patients with HAE type I or II. Median diagnostic delay was 6.2 and 5.9 years, respectively. Analysis of data collected from February 2008 to July 2016 included 286 icatibant-treated attacks in 58 UK patients and 2553 icatibant-treated attacks in 436 non-UK patients (median of 3.0 attacks per patient in both groups). More attacks were treated by icatibant self-administration in UK patients (95.8%) than in non-UK patients (86.8%, p < 0.001). Time to icatibant treatment, time to resolution and attack duration were not significantly different in the UK versus non-UK patients.

Conclusion

UK patients from the specialist centres studied report similar diagnostic delay and similar icatibant treatment outcomes to their non-UK counterparts. However, improvements in the timely diagnosis of HAE are still required.

Trial registration ClinicalTrials.gov NCT01034969

Oral Plasma Kallikrein Inhibitor for Prophylaxis in Hereditary Angioedema

BACKGROUND

Hereditary angioedema is a life-threatening illness caused by mutations in the gene encoding C1 inhibitor (also called C1 esterase inhibitor) that lead to overactivation of the kallikrein-bradykinin cascade. BCX7353 is a potent oral small-molecule inhibitor of plasma kallikrein with a pharmacokinetic and pharmacodynamic profile that may help prevent angioedema attacks.

METHODS

In this international, three-part, dose-ranging, placebo-controlled trial, we evaluated four doses of BCX7353 (62.5 mg, 125 mg, 250 mg, and 350 mg once daily) for the prevention of angioedema attacks over a 28-day period. Patients with type I or II hereditary angioedema with a history of at least two angioedema attacks per month were randomly assigned to BCX7353 or placebo. The primary efficacy end point was the number of confirmed angioedema attacks. Key secondary end points included angioedema attacks according to anatomical location and quality of life.

RESULTS

A total of 77 patients underwent randomization, 75 received BCX7353 or placebo, and 72 completed the trial. The rate of confirmed angioedema attacks was significantly lower among patients who received BCX7353 at daily doses of 125 mg or more than among those who received placebo, with a 73.8% difference at 125 mg (P<0.001). Significant benefits with respect to quality-of-life scores were observed in the 125-mg and 250-mg dose groups (P<0.05). Gastrointestinal adverse events, predominantly of grade 1, were the most commonly reported adverse events, particularly in the two highest BCX7353 dose groups.

CONCLUSIONS

Once-daily oral administration of BCX7353 at a dose of 125 mg or more resulted in a significantly lower rate of attacks of hereditary angioedema than placebo. Mild gastrointestinal symptoms were the principal side effect. (Funded by BioCryst Pharmaceuticals; APeX-1 ClinicalTrials.gov number, NCT02870972 .).

Measurement of Typhi Vi antibodies can be used to assess adaptive immunity in patients with immunodeficiency

Vaccine‐specific antibody responses are essential in the diagnosis of antibody deficiencies. Responses to Pneumovax II are used to assess the response to polysaccharide antigens, but interpretation may be complicated. Typhim Vi^®, a polysaccharide vaccine for Salmonella typhoid fever, may be an additional option for assessing humoral responses in patients suspected of having an immunodeficiency. Here we report a UK multi‐centre study describing the analytical and clinical performance of a Typhi Vi immunoglobulin (Ig)G enzyme‐linked immunosorbent assay (ELISA) calibrated to an affinity‐purified Typhi Vi IgG preparation. Intra‐ and interassay imprecision was low and the assay was linear, between 7·4 and 574 U/ml (slope = 0·99–1·00; R² > 0·99); 71% of blood donors had undetectable Typhi Vi IgG antibody concentrations. Of those with antibody concentrations  > 7·4 U/ml, the concentration range was 7·7–167 U/ml. In antibody‐deficient patients receiving antibody replacement therapy the median Typhi Vi IgG antibody concentrations were  < 25 U/ml. In vaccinated normal healthy volunteers, the median concentration post‐vaccination was 107 U/ml (range 31–542 U/ml). Eight of eight patients (100%) had post‐vaccination concentration increases of at least threefold and six of eight (75%) of at least 10‐fold. In an antibody‐deficient population (n = 23), only 30% had post‐vaccination concentration increases of at least threefold and 10% of at least 10‐fold. The antibody responses to Pneumovax II and Typhim Vi^® correlated. We conclude that IgG responses to Typhim Vi^® vaccination can be measured using the VaccZyme Salmonella typhi Vi IgG ELISA, and that measurement of these antibodies maybe a useful additional test to accompany Pneumovax II responses for the assessment of antibody deficiencies.

Effectiveness of icatibant for treatment of hereditary angioedema attacks is not affected by body weight: findings from the Icatibant Outcome Survey, a cohort observational study

Background

Icatibant is a bradykinin B2-receptor antagonist used for the treatment of hereditary angioedema attacks resulting from C1-inhibitor deficiency. Treatment is not adjusted by body weight however the impact of body mass index (BMI) on the effectiveness of icatibant is not documented in the literature. We examined disease characteristics and icatibant treatment effectiveness in patients stratified by BMI in the Icatibant Outcome Survey, an ongoing, international, observational study monitoring the real-world safety and effectiveness of icatibant.

Methods

Attack and treatment characteristics as well as outcomes following treatment with icatibant were compared among patients with underweight, normal, overweight, and obese BMI.

Results

Data from 2697 icatibant-treated attacks in 342 patients (3.5, 44.7, 34.8, and 17.0% patients of underweight, normal, overweight, and obese BMI, respectively) were analyzed. There was no significant difference in the frequency and severity of attacks across BMI groups, although obese patients tended to have more attacks of high severity. There was no impact of BMI on the frequency of laryngeal attacks, but patients with normal BMI had fewer cutaneous attacks and more abdominal attacks. Most attacks (71.9–83.8%) were treated with a single icatibant injection without the need for rescue with plasma-derived C1-inhibitor (pdC1-INH), regardless of BMI. Patients with obese BMI used pdC1-INH as rescue treatment more often (P < 0.0001; P = 0.0232 excluding 2 outliers) and treated attacks earlier than patients with normal BMI (P = 0.007). Furthermore, time to resolution and duration of attack were shorter for patients with high BMI (P < 0.001 for overweight and P < 0.05 for obese versus normal).

Conclusion

Overall, icatibant was comparatively effective in treating attacks in patients across all BMI groups.

Trial registration NCT01034969.

Electronic supplementary material

The online version of this article (10.1186/s13601-018-0195-x) contains supplementary material, which is available to authorized users.

Cladribine treatment of multiple sclerosis is associated with depletion of memory B cells

Background

The mechanism of action of oral cladribine, recently licensed for relapsing multiple sclerosis, is unknown.

Objective

To determine whether cladribine depletes memory B cells consistent with our recent hypothesis that effective, disease-modifying treatments act by physical/functional depletion of memory B cells.

Methods

A cross-sectional study examined 40 people with multiple sclerosis at the end of the first cycle of alemtuzumab or injectable cladribine. The relative proportions and absolute numbers of peripheral blood B lymphocyte subsets were measured using flow cytometry. Cell-subtype expression of genes involved in cladribine metabolism was examined from data in public repositories.

Results

Cladribine markedly depleted class-switched and unswitched memory B cells to levels comparable with alemtuzumab, but without the associated initial lymphopenia. CD3⁺ T cell depletion was modest. The mRNA expression of metabolism genes varied between lymphocyte subsets. A high ratio of deoxycytidine kinase to group I cytosolic 5′ nucleotidase expression was present in B cells and was particularly high in mature, memory and notably germinal centre B cells, but not plasma cells.

Conclusions

Selective B cell cytotoxicity coupled with slow repopulation kinetics results in long-term, memory B cell depletion by cladribine. These may offer a new target, possibly with potential biomarker activity, for future drug development.

Electronic supplementary material

The online version of this article (10.1007/s00415-018-8830-y) contains supplementary material, which is available to authorized users.

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.

Misdiagnosis trends in patients with hereditary angioedema from the real-world clinical setting

BACKGROUND

Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) causes swelling in the skin and upper airways and pain in the abdomen because of mucosal swelling. C1-INH-HAE is frequently misdiagnosed, leading to delays in diagnosis, inadequate treatment, and unnecessary procedures.

OBJECTIVE

To evaluate the history of misdiagnosis in patients participating in the Icatibant Outcome Survey (IOS).

METHODS

The IOS is an observational study in which safety and effectiveness of icatibant have been evaluated since 2009. As part of the IOS, patients record any misdiagnoses received before being diagnosed as having C1-INH-HAE.

RESULTS

In January 2016, a total of 418 of 633 IOS patients with C1-INH-HAE type I or II had provided misdiagnosis data. Of these, 185 of 418 (44.3%) received 1 or more prior misdiagnoses. The most common misdiagnoses were allergic angioedema (103 of 185) and appendicitis (50 of 185). A variety of other misdiagnoses were reported, including a substantial number of gastrointestinal disorders (excluding appendicitis). Misdiagnosis rates were similar between males (41.1%) and females (46.5%) and between C1-INH-HAE type I (43.7%) and type II (51.6%). Patients with family members diagnosed as having C1-INH-HAE were significantly less likely to be misdiagnosed than patients without a family history (140 of 366 [41.7%] vs 38 of 58 [65.5%], respectively; P = .001). Patients with a prior misdiagnosis had longer median delay to C1-INH-HAE diagnosis (13.3 years) than patients without (1.7 years; P < .001).

CONCLUSION

From this large database, approximately 50% of patients with C1-INH-HAE type I or II have previously had their conditions misdiagnosed, most commonly as allergic angioedema or appendicitis. Misdiagnosis results in marked delays in receiving the correct diagnosis, during which time patients cannot access effective, lifesaving treatment.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01034969.

Breakthrough attacks in patients with hereditary angioedema receiving long-term prophylaxis are responsive to icatibant: findings from the Icatibant Outcome Survey

Background

Patients with hereditary angioedema (HAE) due to C1-inhibitor deficiency (C1-INH-HAE) experience recurrent attacks of cutaneous or submucosal edema that may be frequent and severe; prophylactic treatments can be prescribed to prevent attacks. However, despite the use of long-term prophylaxis (LTP), breakthrough attacks are known to occur. We used data from the Icatibant Outcome Survey (IOS) to evaluate the characteristics of breakthrough attacks and the effectiveness of icatibant as a treatment option.

Methods

Data on LTP use, attacks, and treatments were recorded. Attack characteristics, treatment characteristics, and outcomes (time to treatment, time to resolution, and duration of attack) were compared for attacks that occurred with versus without LTP.

Results

Data on 3228 icatibant-treated attacks from 448 patients with C1-INH-HAE were analyzed; 30.1% of attacks occurred while patients were using LTP. Attack rate, attack severity, and the distribution of attack sites were similar across all types of LTP used, and were comparable to the results found in patients who did not receive LTP. Attacks were successfully treated with icatibant; 82.5% of all breakthrough attacks were treated with a single icatibant injection without C1-INH rescue medication. Treatment outcomes were comparable for breakthrough attacks across all LTP types, and for attacks without LTP.

Conclusions

Patients who use LTP should be aware that breakthrough attacks can occur, and such attacks can be severe. Thus, patients with C1-INH-HAE using LTP should have emergency treatment readily available. Data from IOS show that icatibant is effective for the treatment of breakthrough attacks.

Trial Registration NCT01034969

The Icatibant Outcome Survey: experience of hereditary angioedema management from six European countries

BACKGROUND

Hereditary angioedema (HAE) due to C1-inhibitor deficiency (C1-INH-HAE) is a rare, potentially fatal, bradykinin-mediated disease. Icatibant is a bradykinin B2 receptor antagonist originally approved in 2008 in the European Union and 2011 in the United States as an acute therapy option for HAE attacks in adults.

OBJECTIVE

To compare demographics, disease characteristics and treatment outcomes of icatibant-treated HAE attacks in patients with C1-INH-HAE enrolled in the Icatibant Outcome Survey across six European countries: Austria, France, Germany, Italy, Spain and the UK.

METHODS

The Icatibant Outcome Survey [IOS; Shire, Zug, Switzerland (NCT01034969)] is an international observational study monitoring the safety and effectiveness of icatibant. Descriptive, retrospective analyses compared IOS country data derived during July 2009-April 2015.

RESULTS

Overall, 481 patients with C1-INH-HAE provided demographic data. A significant difference across countries in age at onset (P = 0.003) and baseline attack frequency (P < 0.001) was found although no significant differences were found with respect to gender (majority female; P = 0.109), age at diagnosis (P = 0.182) or delay in diagnosis (P = 0.059). Icatibant was used to treat 1893 attacks in 325 patients with majority self-administration in all countries. Overall, significant differences (all P < 0.001) were found across countries in time to treatment [median 1.8 h; median range: 0.0 (Germany-Austria) to 4.4 (France) h], time to resolution [median 6.5 h; median range: 3 (Germany-Austria) to 12 (France) h] and attack duration [median 10.5 h; median range: 3.1 (Germany-Austria) to 18.5 (France) h].

CONCLUSION

These data form the first European cross-country comparison of disease characteristics and icatibant use in patients with C1-INH-HAE who are enrolled in IOS. International variation in icatibant practice and treatment outcomes across the six European countries assessed highlight the need to further investigate the range of country-specific parameters driving regional variations in icatibant use.

Comparing acquired angioedema with hereditary angioedema (types I/II): findings from the Icatibant Outcome Survey

Icatibant is used to treat acute hereditary angioedema with C1 inhibitor deficiency types I/II (C1-INH-HAE types I/II) and has shown promise in angioedema due to acquired C1 inhibitor deficiency (C1-INH-AAE). Data from the Icatibant Outcome Survey (IOS) were analysed to evaluate the effectiveness of icatibant in the treatment of patients with C1-INH-AAE and compare disease characteristics with those with C1-INH-HAE types I/II. Key medical history (including prior occurrence of attacks) was recorded upon IOS enrolment. Thereafter, data were recorded retrospectively at approximately 6-month intervals during patient follow-up visits. In the icatibant-treated population, 16 patients with C1-INH-AAE had 287 attacks and 415 patients with C1-INH-HAE types I/II had 2245 attacks. Patients with C1-INH-AAE versus C1-INH-HAE types I/II were more often male (69 versus 42%; P = 0·035) and had a significantly later mean (95% confidence interval) age of symptom onset [57·9 (51·33-64·53) versus 14·0 (12·70-15·26) years]. Time from symptom onset to diagnosis was significantly shorter in patients with C1-INH-AAE versus C1-INH-HAE types I/II (mean 12·3 months versus 118·1 months; P = 0·006). Patients with C1-INH-AAE showed a trend for higher occurrence of attacks involving the face (35 versus 21% of attacks; P = 0·064). Overall, angioedema attacks were more severe in patients with C1-INH-HAE types I/II versus C1-INH-AAE (61 versus 40% of attacks were classified as severe to very severe; P < 0·001). Median total attack duration was 5·0 h and 9·0 h for patients with C1-INH-AAE versus C1-INH-HAE types I/II, respectively.

Clinical spectrum and features of activated phosphoinositide 3-kinase δ syndrome: A large patient cohort study

BACKGROUND

Activated phosphoinositide 3-kinase δ syndrome (APDS) is a recently described combined immunodeficiency resulting from gain-of-function mutations in PIK3CD, the gene encoding the catalytic subunit of phosphoinositide 3-kinase δ (PI3Kδ).

OBJECTIVE

We sought to review the clinical, immunologic, histopathologic, and radiologic features of APDS in a large genetically defined international cohort.

METHODS

We applied a clinical questionnaire and performed review of medical notes, radiology, histopathology, and laboratory investigations of 53 patients with APDS.

RESULTS

Recurrent sinopulmonary infections (98%) and nonneoplastic lymphoproliferation (75%) were common, often from childhood. Other significant complications included herpesvirus infections (49%), autoinflammatory disease (34%), and lymphoma (13%). Unexpectedly, neurodevelopmental delay occurred in 19% of the cohort, suggesting a role for PI3Kδ in the central nervous system; consistent with this, PI3Kδ is broadly expressed in the developing murine central nervous system. Thoracic imaging revealed high rates of mosaic attenuation (90%) and bronchiectasis (60%). Increased IgM levels (78%), IgG deficiency (43%), and CD4 lymphopenia (84%) were significant immunologic features. No immunologic marker reliably predicted clinical severity, which ranged from asymptomatic to death in early childhood. The majority of patients received immunoglobulin replacement and antibiotic prophylaxis, and 5 patients underwent hematopoietic stem cell transplantation. Five patients died from complications of APDS.

CONCLUSION

APDS is a combined immunodeficiency with multiple clinical manifestations, many with incomplete penetrance and others with variable expressivity. The severity of complications in some patients supports consideration of hematopoietic stem cell transplantation for severe childhood disease. Clinical trials of selective PI3Kδ inhibitors offer new prospects for APDS treatment.

Osteomyelitis complicating pyomyositis in HIV disease

Pyomyositis has previously been described in association with human immunodeficiency virus (HIV) and as a discrete entity in HIV seronegative patients from tropical climates (tropical pyomyositis). Pyomyositis and osteomyelitis are usually considered a late complication of advanced HIV disease. We describe a patient with well-controlled HIV and both types of musculoskeletal infection. The case highlights an unusual presentation, the utility of MRI in soft tissue infection and an excellent outcome from prolonged antimicrobial therapy following surgical debridement.

Human Platelets Utilize Cycloxygenase-1 to Generate Dioxolane A3, a Neutrophil-activating Eicosanoid

Eicosanoids are important mediators of fever, pain, and inflammation that modulate cell signaling during acute and chronic disease. We show by using lipidomics that thrombin-activated human platelets generate a new type of eicosanoid that both stimulates and primes human neutrophil integrin (Mac-1) expression, in response to formylmethionylleucylphenylalanine. Detailed characterization proposes a dioxolane structure, 8-hydroxy-9,11-dioxolane eicosatetraenoic acid (dioxolane A₃, DXA₃). The lipid is generated in nanogram amounts by platelets from endogenous arachidonate during physiological activation, with inhibition by aspirin in vitro or in vivo, implicating cyclooxygenase-1 (COX). Pharmacological and genetic studies on human/murine platelets revealed that DXA₃ formation requires protease-activated receptors 1 and 4, cytosolic phospholipase A₂ (cPLA₂), Src tyrosine kinases, p38 MAPK, phospholipase C, and intracellular calcium. From data generated by purified COX isoforms and chemical oxidation, we propose that DXA₃ is generated by release of an intermediate from the active site followed by oxygenation at C8. In summary, a new neutrophil-activating platelet-derived lipid generated by COX-1 is presented that can activate or prime human neutrophils, suggesting a role in innate immunity and acute inflammation.

Optimizing hereditary angioedema management through tailored treatment approaches

Hereditary angioedema (HAE) is a rare but serious and potentially life threatening autosomal dominant condition caused by low or dysfunctional C1 esterase inhibitor (C1-INH) or uncontrolled contact pathway activation. Symptoms are characterized by spontaneous, recurrent attacks of subcutaneous or submucosal swellings typically involving the face, tongue, larynx, extremities, genitalia or bowel. The prevalence of HAE is estimated to be 1:50,000 without known racial differences. It causes psychological stress as well as significant socioeconomic burden. Early treatment and prevention of attacks are associated with better patient outcome and lower socioeconomic burden. New treatments and a better evidence base for management are emerging which, together with a move from hospital-centered to patient-centered care, will enable individualized, tailored treatment approaches.

Immune deficiency: changing spectrum of pathogens

Current UK national standards recommend routine bacteriology surveillance in severe antibody-deficient patients, but less guidance exists on virology screening and viral infections in these patients. In this retrospective audit, we assessed the proportion of positive virology or bacteriology respiratory and stool samples from patients with severe, partial or no immune deficiency during a 2-year period. Medical notes were reviewed to identify symptomatic viral infections and to describe the course of persistent viral infections. During the 2-year period, 31 of 78 (39·7%) severe immune-deficient patients tested had a positive virology result and 89 of 160 (55.6%) had a positive bacteriology result. The most commonly detected pathogens were rhinovirus (12 patients), norovirus (6), Haemophilus influenzae (24), Pseudomonas spp. (22) and Staphylococcus aureus (21). Ninety-seven per cent of positive viral detection samples were from patients who were symptomatic. Low serum immunoglobulin IgA levels were more prevalent in patients with a positive virology sample compared to the total cohort (P = 0·0078). Three patients had persistent norovirus infection with sequential positive isolates for 9, 30 and 16 months. Virology screening of symptomatic antibody-deficient patients may be useful as a guide to anti-microbial treatment. A proportion of these patients may experience persistent viral infections with significant morbidity.

Analysis of characteristics associated with reinjection of icatibant: Results from the icatibant outcome survey

PURPOSE

Phase 3 icatibant trials showed that most hereditary angioedema (HAE) (C1 inhibitor deficiency) acute attacks were treated successfully with one injection of icatibant, a selective bradykinin B2 receptor antagonist. We conducted a post hoc analysis of icatibant reinjection for HAE type I and II attacks in a real-world setting by using data from the Icatibant Outcome Survey, an ongoing observational study that monitors the safety and effectiveness of icatibant treatment.

METHODS

Descriptive retrospective analyses of icatibant reinjection were performed on Icatibant Outcome Survey data (February 2008 to December 2012). New attacks were defined as the onset of new symptoms after full resolution of the previous attack. Potential associations between the patient and attack characteristics and reinjection were explored by using logistic regression analysis.

RESULTS

Icatibant was administered for 652 attacks in 170 patients with HAE type I or II. Most attacks (89.1%) were treated with a single icatibant injection. For attacks that required two or three injections, the second injection was given a median of 11.0 hours after the first injection, with 90.4% of second injections administered ≥6 hours after the first injection. Time to resolution and attack duration were significantly longer for two or three injections versus one icatibant injection (p < 0.0001 and p < 0.05, respectively). Multivariate logistic regression analysis identified sex, attack severity, and laryngeal attacks as significantly correlated with reinjection (all p ≤ 0.05). These factors did not remain predictors for reinjection when two outlier patients with distinct patterns of icatibant use were excluded.

CONCLUSIONS

In this real-world setting, most HAE attacks resolved with one icatibant injection. There was no distinct profile for patients or attacks that required reinjection when outliers with substantially different patterns of use were excluded. Because new attacks were not distinguished from the recurrence of symptoms, reinjection rates may be slightly higher than shown here. Clinical trial identifier: NCT01034969.

C1 inhibitor deficiency: 2014 United Kingdom consensus document

C1 inhibitor deficiency is a rare disorder manifesting with recurrent attacks of disabling and potentially life-threatening angioedema. Here we present an updated 2014 United Kingdom consensus document for the management of C1 inhibitor-deficient patients, representing a joint venture between the United Kingdom Primary Immunodeficiency Network and Hereditary Angioedema UK. To develop the consensus, we assembled a multi-disciplinary steering group of clinicians, nurses and a patient representative. This steering group first met in 2012, developing a total of 48 recommendations across 11 themes. The statements were distributed to relevant clinicians and a representative group of patients to be scored for agreement on a Likert scale. All 48 statements achieved a high degree of consensus, indicating strong alignment of opinion. The recommendations have evolved significantly since the 2005 document, with particularly notable developments including an improved evidence base to guide dosing and indications for acute treatment, greater emphasis on home therapy for acute attacks and a strong focus on service organization.

Pseudomonas infection in antibody deficient patients

Pseudomonas aeruginosa (PA) is commonly isolated from the respiratory secretions of antibody deficiency patients, but the significance of this has not been well studied. We have reviewed our adult antibody deficiency cohort of 179 patients and assessed the prevalence and characteristics of PA infection and the effects of early antibiotic eradication treatments. Of the 34 patients with PA, 55.9% (19) underwent successful eradication and were infection-free, 38.2% (13) had intermittent infection, and 5.9% (2) had chronic PA. PA infection was significantly associated with bronchiectasis (p < 0.0001), with 36.1% (22 out of 61) of patients with bronchiectasis developing a PA infection. Infection status was also significantly associated with chronic sinusitis (p < 0.0001). Most treated PA exacerbations were symptomatic and with colony counts of ≥1000 cfu/ml. Current eradication protocols used at our center involve early treatment at first positive isolate with ciprofloxacin for 3 weeks and nebulized colomycin for 3 months, and if eradication fails, intravenous ceftazidime and gentamycin or colomycin is administered for 2 weeks. Continued sputum surveillance and early eradication treatments upon positive PA culture may help to limit chronic PA infection in antibody deficiency patients.