Management of patients with hereditary angioedema in Germany: comparison with other countries in the Icatibant Outcome Survey

Background

The Icatibant Outcome Survey (IOS; NCT01034969) is a Shire‐sponsored, international, observational study monitoring the safety and effectiveness of icatibant, a bradykinin B2 receptor antagonist approved for the acute treatment of adults with hereditary angioedema with C1 inhibitor deficiency (HAE‐C1‐INH).

Objective

To report IOS data comparing demographic and icatibant treatment outcomes in patients with HAE‐C1‐INH from Germany to HAE‐C1‐INH patients from 11 other IOS countries.

Methods

A descriptive, retrospective, comparative analysis of data from 685 IOS patients with HAE‐C1‐INH from seven centres in Germany (n = 93) vs. centres from Austria, Brazil, Czech Republic, Denmark, France, Greece, Israel, Italy, Spain, Sweden and the United Kingdom (n = 592, July 2009–January 2017). Icatibant treatment outcomes were retrieved from patients with complete attack outcome data for time to treatment, time to resolution and attack duration (160 attacks in 42 German patients and 1442 attacks in 251 patients from other IOS countries).

Results

German patients reported significantly fewer severe/very severe attacks (38.7% vs. 57.5%, respectively; P < 0.001). The proportion of attacks treated with a single icatibant injection was significantly higher in German patients (97.1% vs. 91.6%, P = 0.0003). The median time to treatment (0.0 h vs. 1.5 h), time to resolution (3.0 h vs. 7.0 h) and attack duration (4.3 h vs. 10.5 h) in German patients vs. other IOS countries were all significantly shorter (all P < 0.0001). No meaningful differences were identified between patients from Germany and other countries with regard to sex, median age at enrolment, median age at symptom onset and median age at diagnosis.

Conclusion

German IOS patients share similar demographic characteristics to patients from other IOS countries yet treat their attacks with icatibant significantly earlier and have markedly fewer severe or very severe attacks. Factors including regional access to and availability of icatibant may drive these outcomes and warrant further investigation.

Evaluation of avoralstat, an oral kallikrein inhibitor, in a Phase 3 hereditary angioedema prophylaxis trial: The OPuS-2 study

Background

Effective inhibition of plasma kallikrein may have significant benefits for patients with hereditary angioedema due to deficiency of C1 inhibitor (C1‐INH‐HAE) by reducing the frequency of angioedema attacks. Avoralstat is a small molecule inhibitor of plasma kallikrein. This study (OPuS‐2) evaluated the efficacy and safety of prophylactic avoralstat 300 or 500 mg compared with placebo.

Methods

OPuS‐2 was a Phase 3, multicenter, randomized, double‐blind, placebo‐controlled, parallel‐group study. Subjects were administered avoralstat 300 mg, avoralstat 500 mg, or placebo orally 3 times per day for 12 weeks. The primary efficacy endpoint was the angioedema attack rate based on adjudicator‐confirmed attacks.

Results

A total of 110 subjects were randomized and dosed. The least squares (LS) mean attack rates per week were 0.589, 0.675, and 0.593 for subjects receiving avoralstat 500 mg, avoralstat 300 mg, and placebo, respectively. Overall, 1 subject in each of the avoralstat groups and no subjects in the placebo group were attack‐free during the 84‐day treatment period. The LS mean duration of all confirmed attacks was 25.4, 29.4, and 31.4 hours for the avoralstat 500 mg, avoralstat 300 mg, and placebo groups, respectively. Using the Angioedema Quality of Life Questionnaire (AE‐QoL), improved QoL was observed for the avoralstat 500 mg group compared with placebo. Avoralstat was generally safe and well tolerated.

Conclusions

Although this study did not demonstrate efficacy of avoralstat in preventing angioedema attacks in C1‐INH‐HAE, it provided evidence of shortened angioedema episodes and improved QoL in the avoralstat 500 mg treatment group compared with placebo.

The international WAO/EAACI guideline for the management of hereditary angioedema-The 2017 revision and update

Hereditary Angioedema (HAE) is a rare and disabling disease. Early diagnosis and appropriate therapy are essential. This update and revision of the global guideline for HAE provides up-to-date consensus recommendations for the management of HAE. In the development of this update and revision of the guideline, an international expert panel reviewed the existing evidence and developed 20 recommendations that were discussed, finalized and consented during the guideline consensus conference in June 2016 in Vienna. The final version of this update and revision of the guideline incorporates the contributions of a board of expert reviewers and the endorsing societies. The goal of this guideline update and revision is to provide clinicians and their patients with guidance that will assist them in making rational decisions in the management of HAE with deficient C1-inhibitor (type 1) and HAE with dysfunctional C1-inhibitor (type 2). The key clinical questions covered by these recommendations are: (1) How should HAE-1/2 be defined and classified?, (2) How should HAE-1/2 be diagnosed?, (3) Should HAE-1/2 patients receive prophylactic and/or on-demand treatment and what treatment options should be used?, (4) Should HAE-1/2 management be different for special HAE-1/2 patient groups such as pregnant/lactating women or children?, and (5) Should HAE-1/2 management incorporate self-administration of therapies and patient support measures?

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.

Challenges of C1-Inhibitor Concentrate Self-Administration

Self-administration of therapy can help hereditary angioedema (HAE) patients regain control of their disease or reduce its impact and improve the quality of their lives. However, data from a self-administration survey, and subsequent discussion at an international HAE expert meeting, identified several barriers to self-administration therapy. These barriers include difficulty in administration technique, availability of nursing resources and the mental capacity of the patient. Encouragingly, international HAE experts identified that once a patient has acquired self-administration skills, they generally retain them in the long-term. As patient uptake increases, it was recommended that follow-up management plans should be established to address any issues from the patient's perspective.

Mutational spectrum of the C1INH (SERPING1) gene in patients with hereditary angioedema

Hereditary angioedema (HAE) is an autosomal dominant disease that manifests as intermittent acute swellings of the skin and mucosal surfaces, which, in the gastrointestinal tract and larynx, may even be fatal. HAE results from functional deficiency of the C1 inhibitor (C1INH) protein, which plays a key role in the classical pathway of complement activation. C1INH is the sole inhibitor of the activated proteases C1r and C1s, and is the major regulator of activated coagulation Factor XII and plasma kallikrein, which limits the generation of the vasoactive peptide bradykinin. In this paper, we report on the genetic analysis of 173 families (including 326 members) with a clinical diagnosis of HAE. Direct sequencing, Southern blotting and quantitative PCR by the MLPA method were used to screen for mutations in C1INH (SERPING1). In 142 families (82.1%), a causative C1INH gene mutation could be identified. A total of 80 novel point mutations of C1INH not published previously were detected in 96 pedigrees (including 172 members). Our results corroborate C1INH (SERPING1) deficiency as a disease of extreme allelic heterogeneity with almost each individual family carrying their own mutation. Routine molecular genetic analysis is an effective way of confirming the clinical diagnosis and identifying mutation carriers early on before any clinical manifestation becomes apparent. It is, therefore, a valuable tool in prevention and adequate treatment of acute and life-threatening oedema.

Retrochorionic hematoma in congenital afibrinogenemia: resolution with fibrinogen concentrate infusions

Without treatment, pregnancies in patients with congenital afibrinogenemia terminate in miscarriage at 5-6 weeks of gestation. Animal model studies have suggested that implantation site bleeding contributes to miscarriage in afibrinogenemia; however, retrochorionic hematoma in human congenital afibrinogenemia has not been previously observed. A patient with congenital afibrinogenemia receiving fibrinogen prophylaxis developed a retrochorionic hematoma in the first trimester. With continuous intensified fibrinogen concentrate replacement the hematoma resolved over 6 weeks, and the patient delivered a healthy infant. Median fibrinogen levels in the first trimester were 48 mg/dL and in second and third trimester 44 mg/dL. Median fibrinogen levels under 60 mg/dL may be adequate to maintain pregnancy in patients with congenital afibrinogenemia, although it is possible that higher levels might reduce the risk of hemorrhagic events.

Study of the prothrombin gene 20201 GA variant in FV:Q506 carriers in relationship to the presence or absence of juvenile venous thromboembolism

The G20210A transition of the prothrombin gene has been identified as a common but probably mild hereditary risk factor for venous thromboembolism (VTE). However, the prothrombin gene variant might contribute to the penetrance of thromboembolic disease in many patients with other prothrombotic defects, such as the FV:R506Q mutation. In this investigation, the A20210 allele was found in 9 of 450 healthy controls (2%). Among 89 asymptomatic FV:Q506 carriers, 3 subjects were doubly affected (3.4%). In contrast, of 263 unrelated carriers of the FV:Q506 mutant with a history of juvenile VTE, 30 also had the prothrombin gene G20210A variant (11.4%), including 25 of 220 patients who were heterozygous (11.4%) and 5 of 43 homozygous (11.6%) for FV:Q506. Thus, the A20210 allele of the prothrombin gene is significantly overrepresented in symptomatic FV:Q506 carriers compared with healthy controls (P<0.0001) and asymptomatic relatives carrying the FV mutant (P=0.02). Persons homozygous for the 20210A allele were not found. A statistically significant increase in the prevalence of more unusual sites of venous thrombosis at clinical onset was found in doubly affected patients (9 of 30; 30%) compared with patients without the prothrombin gene variant (26 of 233; 11. 1%) (P=0.004). First VTE occurred spontaneously in 53.3% of all doubly affected patients (16 of 30) and in 28.3% of all simply affected patients (66 of 233) (P=0.005). Among patients with VTE preceded by circumstantial risk factors, the A20210 allele was found in 7.7% (14 of 181). We conclude that the A20210 allele of the prothrombin gene is frequently coinherited in symptomatic FV:Q506 carriers and possibly influences age, site, and type of thrombotic onset manifestation in these patients.

A multicenter pharmacosurveillance study for the evaluation of the efficacy and safety of recombinant factor VIII in the treatment of patients with hemophilia A. German Kogenate Study Group

In this open multicenter study the safety and efficacy of recombinant factor VIII (rFVIII) was assessed in 39 previously treated patients with hemophilia A (factor VIII basal activity < or = 15%). Recombinant FVIII was administered for prophylaxis and treatment of bleeding episodes and for surgical procedures. A total of 3679 infusions of rFVIII were given. Efficacy of rFVIII as assessed by subjective evaluation of response to infusion and mean annual consumption of rFVIII was comparable to that of plasma derived FVIII concentrates. The incremental recovery of FVIII (2.4 +/- 0.83%/IU/kg, 2.12 +/- 0.61%/IU/kg, resp.) was within the expected range. No clinical significant FVIII inhibitor was detected in this trial. Five of 16 susceptible patients showed a seroconversion for parvovirus B19. However, the results are ambiguous in two cases and might be explained otherwise in one further case. Thus, in two patients a reliable seroconversion for parvovirus B19 was observed.

Experience with Haemate P in von Willebrand's disease in adults

The virally inactivated pasteurized FVIII concentrate Haemate P contains nearly intact vWF multimers. It is currently the treatment of choice to achieve satisfactory hemostasis for moderate to severe vWD and for patients with variants of vWD that cannot be adequately treated with DDAVP or for whom DDAVP is contraindicated. Therefore, we treated patients with type Ia, type IIa, type IIb and type III vWD with Haemate P. A correction of the hemostatic defect was seen in all patients. The type of bleeding events included 24 gastrointestinal, 18 other mucosal, 5 central nervous system, 15 orthopedic and 4 other. 28 dental surgical procedures, 9 operative deliveries, 5 tonsillectomies, 17 orthopedic and 11 miscellaneous surgeries were performed under the cover of Haemate P.