UK IgA Nephropathy Launch Readiness

Budesonide (Tarpeyo, Calliditas/AstraZeneca) is MHRA-approved in the UK on US-style UPCR surrogate data, but its NICE technology appraisal remains unresolved pending confirmatory eGFR data from the NefIgArd Part B extension, illustrating the core UK evidentiary gap. Sparsentan (Filspari, Travere) is under MHRA review with stronger PROTECT 2-year eGFR data (slope −2.0 vs −4.7 mL/min/year on placebo), but as a smaller company its NICE submission timeline is less certain. Neither drug has reached a positive NICE decision, which means no positive UK IgAN precedent yet exists — the first drug to clear NICE will set the evidence bar every subsequent submission is measured against.

NICE's published scoping position is unambiguous: eGFR slope over at least two years is the required primary endpoint, and UPCR reduction alone, sufficient for FDA accelerated approval, will not support a positive UK technology appraisal. Compounding this, NICE's 2023 CKD guideline (NG203) now mandates optimised SGLT2i background therapy (dapagliflozin) for any patient with UPCR above roughly 0.5g/g before a novel IgAN agent is even considered, meaning the entire UK treatment cascade (ACEi/ARB, then SGLT2i, then novel agent) is pre-defined ahead of any submission. The UK Renal Registry sizes the addressable population precisely: roughly 12,000-15,000 biopsy-confirmed IgAN patients nationally, of whom 3,000-5,000 have UPCR above threshold despite optimised background therapy and are eligible for a novel agent; fewer than 500 currently access any novel therapy pre-NICE.

The pre-launch imperative is a protocol decision, not a commercial one: design Phase 3 with eGFR slope as primary (or co-primary) endpoint and mandatory SGLT2i background in every arm, or the UK submission is not viable regardless of proteinuria results. The economics support a workable NICE case once that evidence exists — delaying ESRD by 5-8 years saves the NHS an estimated £160,000-320,000 per patient in dialysis and transplant costs, which brings a WAC of £20,000-25,000/year within NICE's standard £20-30K/QALY threshold without an aggressive PAS. Engage the Renal Association's IgAN guideline committee 18-24 months ahead of submission; their clinical recommendations are a direct NICE reference point. Apply for MHRA's ILAP roughly 24 months pre-submission to pre-align MHRA and NICE evidence expectations before the trial design is locked.

This assessment synthesises three research angles into a single UK IgAN launch readiness view: competitive positioning against budesonide and sparsentan, novel-therapy-eligible population sizing anchored in the UK Renal Registry, and anticipated NICE/NHS payer posture derived from the NICE IgAN scoping consultation and the NG203 CKD guideline.

Sources: NICE GID-TA10820 IgAN scoping document; NICE NG203 CKD guidance 2023; UK Renal Registry annual report 2023; Renal Association IgAN clinical guideline; Barratt J et al. NEJM 2023 (NefIgArd); PROTECT 2-year eGFR data (Travere sparsentan).