UK Sickle Cell Disease HTA Strategy Model

NICE's two completed sickle cell disease appraisals failed and succeeded in ways that both deny a new entrant a clean precedent. Crizanlizumab, an intravenous anti-P-selectin antibody for preventing vaso-occlusive crises, was recommended under technology appraisal TA743 in October 2021 within a managed access agreement for people aged 16 and over, even though the committee found the company base case modelled well above NICE's standard cost-per-QALY threshold. The recommendation was never a cost-effectiveness endorsement; it was a decision to collect long-term evidence while patients had access. That access ended in 2023 when the STAND confirmatory trial did not confirm a clinical benefit, the MHRA withdrew the marketing authorisation, and NICE withdrew TA743. The lesson for a new agent is that a managed access route can be won on uncertainty but can also be lost on a single confirmatory read-out, so the durability evidence plan matters as much as the launch price.

Casgevy shows the same constraint at gene-therapy scale. Exagamglogene autotemcel was recommended under TA1044 with managed access for severe sickle cell disease in people 12 and over who are eligible for a stem cell transplant but have no matched related donor, at a list price of £1,651,000 for the one-time treatment. NHS England modelled a potential £330-495M annual budget impact for 200 to 300 eligible patients a year, a figure no NHS budget line absorbs as lump-sum payments, so the economics are framed as a roughly £165,000-a-year outcome-based annuity against the £80,000 to £120,000 a year the NHS already spends managing a severe patient. For a new non-gene entrant the combined signal is specific: NICE will accept a managed access construct, but only when the sponsor brings a credible durability case and a payment mechanism that fits an NHS budget, not a headline price alone. Our gap register scores both failure modes, the crizanlizumab durability collapse and the Casgevy affordability structure, as separate defences a new dossier must build before it is finalised.

Every AXLRx HTA strategy model is built from primary HTA-body sources: NICE technology appraisals and final guidance documents, not secondary summaries. Every appraisal outcome and comparator claim is pressure-tested through the 3-test defence framework before it is accepted.

UK sickle cell disease HTA sources: NICE TA743 (crizanlizumab, recommended via managed access 2021, guidance later withdrawn), NICE TA1044 (exagamglogene autotemcel / Casgevy, recommended with managed access), the MHRA and EMA/CHMP crizanlizumab licence-withdrawal record (2023), and the Pfizer worldwide voxelotor withdrawal notice (September 2024).