UK Fabry Disease Payer & HTA

Agalsidase beta has never been formally appraised by NICE; migalastat's HST4 recommendation (2016) was the first oral mutation-specific rare disease therapy NICE approved. Together they underpin an estimated £144M NHS Fabry programme, with a £70-130K/patient/year switch incentive still unrealised at scale.

Agalsidase beta (Fabrazyme) has never been through a formal NICE technology appraisal; it has been commissioned by NHS England as a highly specialised service via clinical commissioning policy since the early 2000s, predating today's NICE Highly Specialised Technology (HST) pathway, for symptomatic Fabry disease with renal, cardiac, or neurological involvement. NHS net cost is estimated at £150,000-£250,000 per patient per year post-PAS across roughly 600 UK ERT patients, with continuation assessed via eGFR trajectory and GL-3 clearance every 24 months. Migalastat (Galafold) followed as the first positive NICE recommendation for an oral, mutation-specific rare disease therapy, recommended under NICE's Highly Specialised Technology appraisal HST4, based on an indirect comparison against ERT rather than a head-to-head trial, recommended for adults with an amenable GLA mutation at an estimated post-PAS cost of £80,000-£120,000 per year for around 200 UK patients. Combined, the NHS Fabry programme costs an estimated £144M per year across roughly 800 patients, one of the largest NHS lysosomal storage disorder budgets.

The economic incentive to switch amenable-mutation patients from ERT to migalastat is substantial and, by NICE's own analysis, still under-realised: each switch saves the NHS an estimated £70,000-£130,000 per patient per year. If migalastat uptake under NICE HST4 reaches 30% of eligible amenable-mutation patients, total NHS savings could reach £20-40M per year versus an ERT-only scenario, and the UK already has the highest reported migalastat uptake globally, with NHS Genomic Medicine Service GLA mutation panel testing expanding the pool of confirmed switch-eligible patients. A third agent, pegunigalsidase alfa (Elfabrio), was recommended by NICE under TA915 (published 4 October 2023) for patients with a suboptimal response to agalsidase beta, anti-drug-antibody-positive patients with inadequate GL-3 clearance, where the BALANCE trial showed non-inferiority on the primary eGFR endpoint and a secondary GL-3 benefit in the high-ADA-titre subgroup; Chiesi's NICE cost-effectiveness case rested on demonstrating that subgroup-specific clinical superiority justified a premium over agalsidase beta at PAS pricing.