UK PNH Patient Flow Model

Two source families describe the UK PNH population differently, and neither is wrong. The Leeds National PNH Registry, the UK's single national PNH service, reports approximately 600 patients on complement-inhibitor therapy plus 100 to 150 additional patients carrying small PNH clones who are monitored without treatment, a disease-landscape figure of roughly 600 to 750 clinically active patients. NICE and NHS England payer sources describe a broader population, citing approximately 1,000 patients on complement-inhibitor therapy against a total UK PNH prevalence near 1,500. The reconciliation: the Leeds figure counts patients actively followed through the national registry at a point in time, while the payer-facing total includes patients captured through broader NHS Highly Specialised Services claims and estimated undiagnosed prevalence. This model uses the wider 1,500-patient total as the addressable ceiling and the 600-to-750-patient Leeds figure as the confirmed, registry-verified treated core.

Inside that treated population sits the segment that actually determines commercial opportunity: extravascular haemolysis (EVH), persistent anaemia despite adequate anti-C5 blockade. Leeds's 30-year natural-history dataset puts the EVH-dominant, transfusion-burdened cohort at roughly 200 to 250 patients, rising toward 400 to 500 under a broader residual-anaemia definition. Annual new UK diagnoses run 50 to 70, with a median time-to-diagnosis of just 6 to 12 months, the fastest internationally, reflecting the concentration of diagnostic and referral capacity at Leeds and the other NHS HSS-designated centres. Both ravulizumab and iptacopan have cleared NICE's standard Technology Appraisal route rather than the softer Highly Specialised Technology pathway despite PNH's ultra-rare status, meaning the EVH segment, not appraisal risk, is where a differentiated asset has room to move.

Every AXLRx patient flow model is built on a five-layer funnel: population, disease burden (E1), diagnosis and specialist capture (E2), treatment and biomarker eligibility (E3), market access (E4), then Year 1-3-5 projections across three scenarios. Delivered as a live Excel workbook, not a static table: 104 formulas across 8 sheets, zero hardcoded cells.

UK PNH sources: Leeds National PNH Registry natural-history and treated-population data, NICE Technology Appraisals TA698 (ravulizumab) and TA1000 (iptacopan), and NHS England Highly Specialised Services commissioning documentation.