Data from Lauren McCracken - Curated by EPG Health - Last updated 29 June 2018

For many the fear of the unknown is a daunting thought, but particularly so for patients with HAE. Left untreated, this disease causes unpredictable recurrent severe swelling, typically of the limbs, face, intestinal tract and airway.

There are three types of HAE (I, II, III) which can be determined by the levels of C1-esterase inhibitor (C1-INH), a protein that blocks the activity of inflammation promoting proteins (U.S. National Library of Medicine, 2018). Our understanding of the pathogenesis of HAE, and subsequently the treatment, is improving constantly. There was plenty of new, exciting data presented at the recent European Academy of Allergy and Immunology (EAACI) Congress. Meet Professor Maurer in the video below, where he introduces some of the new study results presented at the Congress.

Are you up to speed with HAE diagnosis?

The first challenge of HAE is getting diagnosis right. HAE diagnosis is often delayed or missed due to having symptoms in common with allergic or gastrointestinal conditions. Valerieva et al. presented a case study of a 72-year-old man who displayed symptoms of HAE at 8-years-old but wasn’t correctly diagnosed until age 70, when his grandson developed severe orofacial oedema. Despite having a positive family history of recurrent abdominal pain and angioedema, this patient suffered 3 emergency surgeries, 5 endoscopies and a 62-year delay in diagnosis. This case study highlights the importance of screening family members of all generations for unrecognised angioedema, abdominal pain and measurement of C1-INH (Valerieva et al., 2018).

Misdiagnosis frequently occurs in emergency departments, perhaps not surprising as to date there is no published tool for the screening and management of patients with undiagnosed HAE. Betschel et al. hoped to change this with their poster presented at this year’s Congress, demonstrating a rapid triage tool for the diagnosis and management of HAE. A panel of 9 experts agreed upon 4 HAE-specific predictive variables: recurrent angioedema, absence of hives, recurrent abdominal pain/swelling, and lack of response to allergic therapy. These variables were then assessed in a group of 107 patients presenting with angioedema, testing for association between variables and HAE outcome and significance. Regression analysis found recurrent angioedema, no response to allergy treatments and recurrent abdominal pain to have a significant association with HAE. The authors developed a prototype of the hereditary angioedema rapid triage (HAE-RT) tool, which will now be tested in an emergency clinical setting (figure 1).

HAE-RT prototype

Figure 1: HAE-RT prototype (Betschel et al., 2018).

EAACI excitement centring around HAE treatment

Without treatment, patients with HAE can suffer from unpredictable attacks every few weeks lasting days at a time (U.S. National Library of Medicine, 2018). Data from two pivotal phase III studies presented at the EAACI Congress, supported the promising strategy of addressing the C1-INH deficiency which causes HAE.

A lot of positive noise came from discussions of the Clinical Study for Optimal Management of Preventing Angioedema with Low-Volume Subcutaneous C1-Inhibitor Replacement Therapy (COMPACT) study; a phase III randomised, multicentre, double-blind, placebo-controlled, crossover study investigating the preventative use of subcutaneous (SC) C1-INH in patients with HAE. Routine treatment with C1-INH (SC) 60 IU/kg was approved by the FDA in June 2017 with indications of preventing HAE attacks in adults and adolescents, following the results of the COMPACT study (FDA, 2018).

The importance of the COMPACT study was apparent from the 5 posters being presented at the Congress. It was revealed that treatment with self-injected twice weekly doses of 60 IU/kg C1-INH dramatically reduced the monthly rate of HAE attacks, severity of attacks, and number of days with symptoms (figure 2). In addition, use of rescue mediation was also reduced, and similar results were seen when the study population was split into gender groups (Riedl et al., 2018).

Result for the COMPACT study

Figure 2: Result for the COMPACT study (Cicardi et al., 2018; Craig et al., 2018; Levy et al., 2018).

The second study grabbing the attention of the Congress delegates was the Hereditary Angioedema Long-term Prophylaxis (HELP) study, with two posters being presented by Professor Marcus Maurer. The HELP study was also a randomised, double-blind, placebo-controlled, parallel-group phase III trial, investigating lanadelumab (a specific, potent and long-acting fully human monoclonal antibody inhibitor of plasma kallikrein) in HAE type I/II. Treatment in this investigation involved 1 of 3 lanadelumab regimens (150 mg every 4 weeks, and 300 mg every 2 or 4 weeks) or a placebo.

All three lanadelumab regimens were successful but the 300 mg dose given every 2 weeks appeared to have the most beneficial results; 66.7% of patients achieved a ≥90% reduction in attack rate, compared to 4.9% of patients receiving placebo. The majority of this group of patients also experienced <1 attack per 4-week period during the 26-week and steady state treatment periods (88.9% and 96.2% respectively) (Maurer et al., 2018).

The COMPACT and HELP study data suggests a promising future in the treatment of HAE. The combination of quicker diagnosis and potential new therapies could have a real impact on the quality of life for patients with HAE.


Betschel S, Avilla E, Kanani A, Keith P, Binkley K, Lacuesta G, et al. Hereditary Angioedema Rapid Triage (HAE-RT) Tool: Translating Research into Clinical Practice. Poster presented at EAACI May 2018.

Cicardi M, Zuraw B, Craig T, Longhurst H, Feuersenger H, Jacobs I, et al. Onset of effect of prophylactic treatment with subcutaneous C1-esterase inhibitor (C1-INH [SC]) for prevention of hereditary angioedema (HAE) attacks: Findings from the phase III COMPACT study. Poster presented at EAACI May 2018.

Craig T, Zuraw B, Cicardi M, Longhurst H, Chiao J, Feuersenger H, et al. Prevention of hereditary angioedema (HAE) attacks by anatomical location with subcutaneous C1-esterase inhibitor (C1-INH [SC]) treatment: Results from the phase III COMPACT study. Poster presented at EAACI May 2018.

FDA, 2018. Available from:
(accessed June 2018).

Levy D, Craig T, Zuraw B, Cicardi M, Longhurst H, Feuersenger H, et al. Prophylaxis with subcutaneous C1-esterase inhibitor (C1-INH [SC]) reduces symptom days and severity of symptoms in patients with hereditary angioedema (HAE): Results from the COMPACT study. Poster presented at EAACI May 2018.

Maurer M, Davis-Lorton M, Schranz J, Hao J, Busse P. High Responder Rates in Lanadelumab-Treated Patients in the Phase 3 HELP Study. Poster presented at EAACI May 2018.

Riedl M, Jacobs J, Li H, Levy D, Chiao J, Feuersenger H, et al. Efficacy of prophylaxis with subcutaneous C1-esterase inhibitor (C1-INH [SC]) in female patients with hereditary angioedema: Subgroup analysis from the COMPACT study. Poster presented at EAACI May 2018.

U.S. National Library of Medicine, 2018. Available from: (accessed June 2018).

Valerieva A, Staevska M, Cicardi M. The physician and hereditary angioedema friend or foe: 62-year diagnostic delay and iatrogenic procedures. Poster presented at EAACI May 2018.


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