The UK SMA population carries two defensible numbers, a ~1,000-patient confirmed cohort and a 1,800-2,000-patient total prevalence estimate, and this funnel uses both correctly.
The UK SMA population carries two defensible numbers, and a patient flow model has to use both correctly. The SMA UK patient organisation census 2023 puts the actively-tracked, newborn-screening-era cohort at roughly 1,000 patients: about 200 Type 1, 400 Type 2 (the largest living group), 350 Type 3, and 50 adult-onset Type 4. A separate reconciliation used across this corpus, including AXLRx's UK SMA Launch Readiness assessment, sizes total UK SMA prevalence at 1,800-2,000 patients once the pre-newborn-screening-era legacy adult population, diagnosed before the census methodology and often outside specialist follow-up, is added back in. This funnel treats ~1,000 as the confirmed, type-segmented cohort and 1,800-2,000 as the outer-bound total prevalence estimate, the same confirmed-cohort-versus-total-prevalence framing used for this indication's Market Sizing Model.
The UK became the first country in Europe to add SMA to national newborn screening, in 2021, identifying roughly 20-25 pre-symptomatic infants a year and routing them to one of 6 NHS-designated gene therapy centres. NICE's HST24 Managed Access Agreement (2023) now covers an estimated 50-60 annual UK Zolgensma cases, the observed on-therapy volume this model uses as its bottom-up validation anchor against the top-down 1,000-patient confirmed cohort.
UK spinal muscular atrophy funnel — from total prevalence to the Zolgensma on-therapy anchor
| Funnel Stage | Population | Source |
|---|---|---|
| Total UK SMA prevalence (incl. legacy pre-NBS adults) | 1,800-2,000 | AXLRx UK SMA Launch Readiness reconciliation |
| Confirmed, type-segmented UK cohort (Types 1-4) | ~1,000 (Type 1 ~200 / Type 2 ~400 / Type 3 ~350 / Type 4 ~50) | SMA UK patient organisation census 2023 |
| Newborn-screening-identified pre-symptomatic infants | ~20-25/yr | NHS NBS Programme SMA expansion 2021 (first in Europe) |
| On-therapy anchor: annual Zolgensma cases under NICE HST24 MAA | 50-60/yr | NICE HST24 (2023); 6 NHS gene therapy centres |
Sources: SMA UK patient organisation census 2023; NHS NBS Programme SMA expansion 2021; NICE HST15 (2021) and HST24 (2023) Managed Access Agreement documentation; NICE TA755 (risdiplam) and TA588 (nusinersen) evidence submissions.
What this model answers
Every section answers a named commercial question your team is asking, scoped to your asset.
Delivers
- The SMA UK patient organisation census methodology
- the pre-newborn-screening-era legacy adult population excluded from active tracking
- how this reconciles with the total UK prevalence estimate used in this indication's Market Sizing Model
Delivers
- Type 1 ~200/Type 2 ~400/Type 3 ~350/Type 4 ~50 split
- the 6 NHS gene therapy centre network
- NICE HST15/HST24, TA755, and TA588 eligibility by type
Delivers
- ~20-25/yr NBS-identified infants, the first such programme in Europe
- the 50-60/yr HST24 Managed Access Agreement volume as a bottom-up validation check
- NHS gene therapy centre capacity constraints
Custom model delivered in 72 hours.
Commission This ModelWhat's inside
- Why the confirmed ~1,000-patient cohort, not the 1,800-2,000 total-prevalence outer bound, sets the type-segmented addressable population
- Reconciling the two figures before the funnel is built out
- ~1,000 actively-tracked patients (SMA UK patient organisation census 2023)
- 1,800-2,000 total prevalence including legacy pre-newborn-screening-era adults
- Type 1 ~200 / Type 2 ~400 / Type 3 ~350 / Type 4 ~50
- Four NHS regional SMA networks
- ~20-25/yr since 2021, Europe's first national SMA screening programme
- Routing to 6 NHS-designated gene therapy centres
- Three NICE-recommended therapies across the Type 1-4 spectrum
- HST24 Managed Access Agreement: 50-60/yr Zolgensma volume
- Which assumptions move the eligible pool most
- Scenario ranges across the confirmed-cohort and total-prevalence estimates
- Patient volume by horizon under conservative, base, and aggressive scenarios
- Revenue translation inputs
- The open questions your forecasting 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 and disease burden (E1), diagnosis and specialist capture (E2), subtype and severity eligibility (E3), market access (E4), then Year 1-3-5 projections across three scenarios. For UK SMA, the model reconciles two cohort estimates rather than picking one: the SMA UK patient organisation census's ~1,000-patient actively-tracked cohort by type, and the 1,800-2,000-patient total prevalence estimate used elsewhere in this corpus once the pre-newborn-screening-era legacy adult population is included.
UK SMA sources: SMA UK patient organisation census 2023 for the confirmed, type-segmented cohort; NHS NBS Programme SMA expansion 2021 for newborn-screening volume; and NICE HST15 (2021), HST24 (2023), TA755, and TA588 evidence submissions for eligibility criteria and the Managed Access Agreement's observed Zolgensma volume, used as this model's on-therapy validation anchor.
- Confirmed UK SMA cohort sizing by type verified against SMA UK patient organisation census 2023
- Total UK SMA prevalence estimate (1,800-2,000, including legacy pre-NBS adults) verified against the reconciliation used in AXLRx's UK SMA Launch Readiness assessment
- Newborn-screening pathway and annual volume verified against NHS NBS Programme SMA expansion 2021
- NICE HST24 Managed Access Agreement annual Zolgensma volume (50-60/yr across 6 centres) verified against NICE HST24 (2023) documentation
Frequently asked questions
Commission this model
AXLRx delivers rare disease patient flow models built for forecasting and launch teams sizing the UK spinal muscular atrophy opportunity. Custom model in 72 hours.
Specify your indication, market, and cohort definition.
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Research-verified patient flow model in 72 hours with optional analyst readout.