Rheumatology · Clinical trials
Hereditary Angioedema Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About hereditary angioedema — and why its trials are hard
Hereditary angioedema (HAE) is a rare, potentially life-threatening genetic disorder characterized by recurrent episodes of severe subcutaneous and submucosal swelling without urticaria. Most cases result from deficiency or dysfunction of C1 esterase inhibitor (C1-INH), leading to unregulated activation of the kallikrein-kinin pathway and excess bradykinin, the key mediator of swelling. Attacks commonly involve the extremities, face, gastrointestinal tract (causing severe abdominal pain), and, most dangerously, the larynx, where airway obstruction can be fatal. Because bradykinin rather than histamine drives attacks, HAE does not respond to antihistamines, corticosteroids, or epinephrine. Management divides into on-demand treatment of acute attacks and long-term prophylaxis to reduce attack frequency. A robust therapeutic armamentarium has emerged: plasma-derived C1-INH concentrates (Cinryze for prophylaxis, Berinert for acute attacks), the bradykinin B2-receptor antagonist icatibant, the kallikrein inhibitor ecallantide, the monoclonal kallikrein inhibitor lanadelumab, and the first oral prophylactic kallikrein inhibitor berotralstat. Individualized treatment plans and airway preparedness are central to care.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| C1 esterase inhibitor (human) (Cinryze) | 2008 | Routine prophylaxis to prevent attacks | Randomized, double-blind, placebo-controlled prophylaxis study (NEJM 2010) | Rate of angioedema attacks during treatment | Roughly halved attack frequency versus placebo (about 6.3 vs 12.7 attacks per 12-week period) |
| C1 esterase inhibitor (human) (Berinert) | 2009 | On-demand treatment of acute abdominal, facial, and laryngeal attacks | IMPACT1 (Phase 3, randomized, placebo-controlled) | Time to onset of symptom relief | Median time to relief 0.5 hours with 20 U/kg vs 1.5 hours with placebo (p=0.0025) |
| Icatibant (Firazyr) | 2011 | On-demand treatment of acute attacks (bradykinin B2-receptor antagonist) | FAST-3 (Phase 3, NEJM/randomized controlled) | Time to 50% reduction in symptom severity | Median time to 50% symptom reduction 2.0 hours vs 19.8 hours with placebo (p<0.001) |
| Ecallantide (Kalbitor) | 2009 | On-demand treatment of acute attacks (kallikrein inhibitor) | EDEMA3 and EDEMA4 (Phase 3) | Mean symptom complex severity score (TOS/MSCS) improvement at 4 hours | Significantly greater symptom improvement versus placebo at 4 hours (e.g., EDEMA4 MSCS change -0.8 vs -0.4, p=0.01) |
| Lanadelumab (Takhzyro) | 2018 | Subcutaneous prophylaxis (monoclonal kallikrein inhibitor) | HELP (Phase 3, JAMA 2018) | Number of HAE attacks over the treatment period | Approximately 87% reduction in monthly attack rate with 300 mg every 2 weeks versus placebo (p<0.001) |
| Berotralstat (Orladeyo) | 2020 | First oral, once-daily prophylaxis (kallikrein inhibitor) | APeX-2 (Phase 3) | Rate of HAE attacks over 24 weeks | 1.31 attacks/month with 150 mg vs 2.35 with placebo (p<0.001) |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in hereditary angioedema development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Avoralstat — OPuS-2 (Phase 3, oral kallikrein inhibitor, BioCryst) | Did not meet the primary endpoint of reduced attack frequency versus placebo | Insufficient and inconsistent drug exposure with the oral formulation was cited; development was discontinued in favor of berotralstat |
Choosing the right endpoint
Primary endpoints that matter in hereditary angioedema trials
- Attack rate (attacks per month/period) — Primary efficacy measure for prophylactic therapies such as lanadelumab and berotralstat
- Time to onset of symptom relief — Key on-demand endpoint capturing how quickly acute attacks begin to resolve after treatment
- Time to 50% symptom reduction — Standardized acute-treatment endpoint used in icatibant trials to quantify speed of response
- Symptom severity composite scores (MSCS/VAS) — Patient-reported and clinician-rated measures of attack severity used to judge treatment effect
How iNGENū runs hereditary angioedema trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
Request a fixed-milestone proposal and a tailored endpoint & feasibility summary for this indication.
Frequently asked questions
Hereditary Angioedema clinical trials — FAQs
Why don't antihistamines or epinephrine work for HAE?
What is the difference between on-demand and prophylactic HAE treatment?
Why was berotralstat an important addition?
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