US Pompe sizing separates two populations by design: 5,000-10,000 total prevalence, and a much narrower 375-600 inadequate-responder cohort within the roughly 2,000 patients already on ERT.
US Pompe disease prevalence is estimated at 5,000 to 10,000 patients, with late-onset disease (LOPD) accounting for an estimated 70 to 80 percent of that total. That prevalence figure describes everyone living with the disease, diagnosed or not, and is not the number a commercial model should size against directly. The treated population is far smaller and better characterized: an estimated 2,000 US LOPD patients are currently on enzyme replacement therapy, split across three approved agents. Sizing a new entrant's opportunity against the full 5,000-10,000 prevalence figure would overstate the near-term reachable population by ignoring how much of that pool remains undiagnosed or untreated.
Within the roughly 2,000 treated LOPD patients, an estimated 25 to 30 percent, 375 to 600 patients, are inadequate responders: they show FVC decline of 5 percent or more per year, or a 6-minute-walk decline of 10 percent or more over 12 months, despite 12 or more months of ERT. This is driven largely by high-titre neutralising anti-drug antibodies, which develop in 30 to 40 percent of Pompe ERT patients overall and measurably reduce enzyme efficacy. This inadequate-responder cohort, not the broader prevalence pool or even the full treated population, is the addressable market for a new agent: a therapy without an ADA-differentiated claim has no clean opening in a field already served by two next-generation ERTs.
US Pompe sizing — prevalence, treated cohort, and inadequate-responder segment compared
| Sizing Layer | Population Estimate | Source |
|---|---|---|
| Total prevalence (diagnosed + undiagnosed) | 5,000-10,000 patients | AMDA / NORD Pompe epidemiology |
| Late-onset share of prevalence | 70-80% of total | AMDA / NORD Pompe epidemiology |
| Treated cohort (on ERT) | ~2,000 LOPD patients | US Pompe registry / IQVIA Pompe Rx data 2024 |
| Inadequate responders within treated cohort | 375-600 patients (25-30%) | COMET & PROPEL ADA sub-analyses |
Sources: AMDA / NORD Pompe disease epidemiology; US Pompe registry and IQVIA Pompe Rx data 2024; COMET and PROPEL anti-drug-antibody sub-analyses; Kishnani PS et al. Genet Med 2006 (PMID 16702877).
What this model answers
Every section answers a named commercial question your team is asking, scoped to your asset.
Delivers
- The prevalence-versus-treated-cohort distinction
- the ~2,000-patient treated-LOPD base
- why sizing against raw prevalence overstates near-term opportunity
Delivers
- The 375-600 inadequate-responder estimate (25-30% of the treated cohort)
- the anti-drug-antibody mechanism driving inadequate response
- why this cohort, not the broader pool, is the addressable market
Delivers
- Sensitivity ranking of every sizing input
- why the ADA-positive rate (30-40% of all ERT patients) moves the addressable total more than prevalence itself
Custom model delivered in 72 hours.
Commission This ModelWhat's inside
- Why the treated-cohort inadequate-responder count, not total prevalence, is the sizing figure that determines addressable opportunity
- Pressure-tested against the prevalence-vs-treated-cohort gap before the rest of the model is built out
- Total US Pompe prevalence (5,000-10,000) and the late-onset (LOPD) share (70-80%)
- Why this figure describes the diagnosed-plus-undiagnosed population, not the addressable market
- The ~2,000-patient treated-LOPD base across all three approved ERTs
- Cross-check against the prevalence-based estimate
- The 375-600 inadequate-responder estimate (25-30% of the treated cohort)
- The anti-drug-antibody mechanism (30-40% of ERT patients) driving inadequate response
- ADA-positive rate ranked above prevalence rate as the binding assumption
- Scenario ranges tied to ADA-testing adoption and diagnosis rate
- The full triangulated model, re-runnable with your own assumptions
- The open sizing questions your team must close before the number is used in planning
Included with every brief
How AXLRx builds this model
Prepared by MoatRx analysts.
Every AXLRx market sizing model triangulates at least two independent methods, prevalence-based and treated-cohort/claims-based, before accepting a patient count. This is explicitly a sizing model (static patient count), distinct from a Patient Flow or forecasting model (dynamic revenue/uptake).
Pompe US sizing sources: AMDA/NORD Pompe epidemiology, US Pompe registry and IQVIA Pompe Rx data 2024, COMET and PROPEL anti-drug-antibody sub-analyses, and Kishnani PS et al. Genet Med 2006 (PMID 16702877).
- Total US prevalence and LOPD share verified against AMDA/NORD Pompe epidemiology references
- Treated-cohort count verified against US Pompe registry and IQVIA Pompe Rx data 2024
- Inadequate-responder rate and ADA mechanism verified against COMET and PROPEL ADA sub-analyses
Frequently asked questions
Commission this model
AXLRx delivers Pompe disease market sizing models built for forecasting and strategy teams sizing the US LOPD opportunity. Custom model in 72 hours.
Specify your indication, market, and cohort definition.
AXLRx analyst confirms triangulation methods and comparator set before building.
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