Only 35 to 40 percent of the estimated 8,000 to 9,000 Americans with hereditary angioedema receive prophylaxis, and 2,500 to 4,000 who meet the eligibility criteria remain untreated.
Hereditary angioedema is an autosomal-dominant disorder of C1-esterase inhibitor, Type I deficiency in roughly 85 percent of patients and Type II dysfunction in the remaining 15 percent. The US HAE Association estimates a background prevalence near 1 in 50,000, implying an estimated 8,000 to 9,000 Americans carry the diagnosis. Six approved prophylaxis agents now compete for this population: lanadelumab holds roughly 45 percent of prophylaxis share, berotralstat the oral entrant close to 20 percent, and a further four agents split the remainder. Yet prophylaxis penetration across the whole diagnosed population sits at only 35 to 40 percent, well short of full coverage of the patients who could benefit.
Unlike a biomarker-gated therapy, HAE prophylaxis eligibility is not narrowed by a testing gap. It is defined by an attack-frequency threshold, three or more attacks per year, or a laryngeal-attack history, criteria already embedded in payer prior-authorization policy for every approved agent. Applying that threshold to the diagnosed population identifies 2,500 to 4,000 patients who qualify for prophylaxis and have never received it, the primary commercial target for any new entrant and the pool a launch team must reach before a competitor resets the efficacy bar. Every conversion step in this funnel, prevalence, Type I/II split, current prophylaxis share, and the untreated-eligible pool, carries its named source, live in the model.
US hereditary angioedema funnel — from estimated prevalence to the never-prophylaxed eligible pool
| Funnel Stage | Population | Source |
|---|---|---|
| Estimated total US HAE patients | 8,000–9,000 | US HAE Association, ~1:50,000 background prevalence |
| Type I C1-INH deficiency / Type II dysfunction split | 85% / 15% | Zuraw BL, N Engl J Med 2008 (PMID 18768946) |
| Currently on any prophylaxis | 35–40% of diagnosed patients | AXLRx HAE US Launch Readiness synthesis |
| Prophylaxis-eligible, never treated (≥3 attacks/yr or laryngeal history) | 2,500–4,000 | AXLRx HAE US Launch Readiness synthesis |
Sources: US HAE Association prevalence estimate; Zuraw BL, N Engl J Med 2008 (PMID 18768946); published US HAE prophylaxis share data (BioCryst investor day 2023; Takeda HAE market research); US payer prior-authorization policy documentation (UHC, Cigna, Express Scripts).
What this model answers
Every section answers a named commercial question your team is asking, scoped to your asset.
Delivers
- Background prevalence and the 8,000-9,000 patient estimate
- current prophylaxis penetration (35-40%)
- the 2,500-4,000 never-prophylaxed eligible pool and the attack-frequency/laryngeal-history criteria that define it
Delivers
- The attack-frequency and laryngeal-history threshold already embedded in payer PA policy
- the absence of a diagnostic-testing gap comparable to biomarker-selected therapies
- where the funnel actually narrows instead
Delivers
- 8-sheet structure (Strategic Context, Inputs, Model, Projections, Sensitivity, References, Market Context, QC)
- source citation per conversion step from HAEA, payer PA policy, and published prophylaxis-share data
Custom model delivered in 72 hours.
Commission This ModelWhat's inside
- Why the never-prophylaxed eligible pool, not switching stable patients, is the addressable opportunity
- Pressure-tested against payer PA criteria before the rest of the model is built out
- 8,000-9,000 estimated US HAE patients near 1:50,000 background prevalence (HAEA)
- Type I (85%) vs Type II (15%) split
- Diagnosed population and the diagnostic-delay dynamic
- Why the diagnosed pool anchors the funnel rather than a suspected-case estimate
- The ≥3 attacks/year or laryngeal-history criteria that defines eligibility
- Current prophylaxis penetration (35-40%) by agent
- 2,500-4,000 eligible, untreated patients
- Payer PA criteria already established by lanadelumab and berotralstat
- Which assumptions move the eligible pool most
- Scenario ranges across prevalence and eligibility-threshold assumptions
- Patient volume by horizon under conservative, base, and aggressive scenarios
- Revenue translation inputs
- The open questions your launch team must close before the model is finalised
- Structured for an internal forecast-review session
Included with every brief
How AXLRx builds this model
Prepared by MoatRx analysts.
Every AXLRx patient flow model is built on a five-layer funnel: population, disease burden (E1), diagnosis and specialist capture (E2), treatment eligibility (E3), market access (E4), then Year 1-3-5 projections across three scenarios. Delivered as a live Excel workbook, not a static table.
US hereditary angioedema sources: US HAE Association prevalence estimate, Zuraw BL N Engl J Med 2008 for pathophysiology and the Type I/II split, published prophylaxis-share and payer prior-authorization data for the eligibility and treatment layers.
- Background US HAE prevalence estimate (~1:50,000) attributed to the US HAE Association, a patient-advocacy figure, not a peer-reviewed count
- Type I (85%) / Type II (15%) split verified against Zuraw BL, NEJM 2008 (PMID 18768946)
- Prophylaxis penetration (35-40%) and the never-prophylaxed eligible pool (2,500-4,000) verified against published prophylaxis-share and payer PA-criteria data
- Attack-frequency and laryngeal-history eligibility criteria cross-checked against current US commercial payer coverage policy
Frequently asked questions
Commission this model
AXLRx delivers rare-disease patient flow models built for launch and forecasting teams sizing the US hereditary angioedema opportunity. Custom model in 72 hours.
Specify your indication, market, and cohort definition.
AXLRx analyst confirms funnel scope and comparator set before building.
Research-verified patient flow model in 72 hours with optional analyst readout.