15,000-17,000 diagnosed UK patients narrow to a 4,000-6,000-patient conventional-therapy gap, plus a separate 200-300-per-year gene-therapy-eligible pool constrained by NHS hub capacity.
The UK's sickle cell disease population, 15,000 to 17,000 patients, is the largest in Europe and, unlike most rare diseases, essentially fully diagnosed: NHS newborn screening has covered SCD since 1999, so virtually every patient is identified at birth, with roughly 350-500 new diagnoses added each year. That diagnosed certainty is what makes the funnel below it meaningful, the gaps that remain are treatment gaps, not diagnostic ones.
Hydroxycarbamide is the NHS standard of care for moderate-to-severe disease, but a 2022 NHS audit found only about half of eligible patients actually receiving it. That leaves an estimated 4,000-6,000 UK patients inadequately controlled, three or more crises a year despite therapy, with no approved novel agent to turn to: crizanlizumab was reviewed by NICE in 2021 and not recommended on cost-effectiveness grounds, then had its marketing authorisation withdrawn in 2023 following the EMA's decision. Gene therapy sits in a separate, much smaller pool. Casgevy, MHRA-approved in November 2023 and NICE-recommended under managed access since February 2025, is eligible to an estimated 200-300 severe patients a year who cannot access a matched-donor transplant, but NHS commissioning is still concentrated in a handful of specialist hubs and full-scale rollout remains two to three years away.
UK sickle cell disease funnel — from diagnosed population to the inadequately controlled and gene-therapy-eligible pools
| Funnel Stage | Population | Source |
|---|---|---|
| Diagnosed UK SCD population | 15,000-17,000 | NHS SCD Programme 2023 |
| New SCD births per year | 350-500 | NHS SCD Programme 2023 |
| Patients on hydroxycarbamide (of those eligible) | ~50% | NHS SCD audit 2022 |
| Inadequately controlled patients (≥3 crises/yr despite therapy) | 4,000-6,000 | NHS SCD audit 2022; NICE TA743 withdrawal context |
| Gene-therapy-eligible patients per year (Casgevy, NICE TA1044) | 200-300 | NICE TA1044; NHS England SCD gene therapy planning 2024 |
Sources: NHS SCD Programme 2023; NHS SCD audit 2022; NICE clinical guideline CG143 and quality standard QS58; NICE TA1044 (Casgevy, February 2025); NICE TA743 crizanlizumab decision and withdrawal notice; NHS England SCD gene therapy planning 2024.
What this model answers
Every section answers a named commercial question your team is asking, scoped to your asset.
Delivers
- The 4,000-6,000 inadequately controlled pool
- why crizanlizumab's 2021 non-recommendation and 2023 withdrawal left this gap open
- the NICE cost-effectiveness precedent any new agent must clear
Delivers
- 200-300 Casgevy-eligible patients per year under NICE TA1044 managed access
- the specialist-hub capacity constraint
- the NHS budget-exposure modelling behind it
Delivers
- 8-sheet structure (Strategic Context, Inputs, Model, Projections, Sensitivity, References, Market Context, QC)
- 108 formulas, zero hardcoded cells
- NHS/NICE source citation per conversion step
Custom model delivered in 72 hours.
Commission This ModelWhat's inside
- Why the inadequately controlled pool, not diagnosis, sets the true UK addressable market
- Pressure-tested against NHS hydroxycarbamide audit data before the rest of the model is built out
- 15,000-17,000 diagnosed UK SCD patients, the largest in Europe (NHS SCD Programme 2023)
- Universal newborn screening since 1999 and 350-500 new births per year
- ~50% of eligible patients on hydroxycarbamide (NHS SCD audit 2022)
- British Society for Haematology criteria for moderate-to-severe disease
- 4,000-6,000 patients with 3+ crises a year despite therapy
- The crizanlizumab precedent: NICE non-recommendation, then 2023 withdrawal
- 200-300 patients per year eligible for Casgevy under NICE TA1044 managed access
- Specialist-hub capacity as the binding constraint on rollout
- Which assumptions move the addressable pool most
- Scenario ranges across the conventional-therapy and gene-therapy pathways
- Patient volume by horizon under conservative, base, and aggressive scenarios
- Revenue translation inputs for the 4,000-6,000-patient conventional-therapy gap
- 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, disease burden (E1), treatment capture (E2), treatment gap and eligibility (E3), market access (E4), then Year 1-3-5 projections across three scenarios. Delivered as a live Excel workbook, not a static table: 108 formulas across 8 sheets, zero hardcoded cells.
UK Sickle Cell Disease sources: NHS SCD Programme annual reporting, the 2022 NHS SCD audit, NICE clinical guideline CG143 and quality standard QS58, NICE technology appraisal TA1044, and NHS England gene therapy planning documentation.
- Diagnosed UK SCD population and annual new-birth estimate verified against NHS SCD Programme 2023 reporting
- Hydroxycarbamide utilisation and the inadequately controlled patient estimate cross-checked against the NHS SCD audit 2022
- Crizanlizumab's NICE non-recommendation and subsequent 2023 withdrawal verified against the NICE TA743 decision and withdrawal notice
- Gene-therapy eligibility and NHS budget-exposure modelling verified against NICE TA1044 and NHS England SCD gene therapy planning 2024
Frequently asked questions
Commission this model
AXLRx delivers rare disease patient flow models built for forecasting and launch teams sizing the UK sickle cell disease treatment gap and gene-therapy-eligible pool. 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.