P0228THE NEFIGARD TRIAL: THE EFFECT OF NEFECON® (BUDESONIDE) IN PATIENTS WITH PRIMARY IGA NEPHROPATHY AT RISK OF DEVELOPING END-STAGE RENAL DISEASE
Authors: Barratt Jonathan , Stone Andrew , Kristensen Jens 
Published: June 2020

Abstract

Background and Aims
Since the first description of IgA nephropathy (IgAN) over 50 years ago, it has been recognised that the mucosal immune system plays a crucial role in the pathogenesis of this common global cause of kidney failure. Recently, particular attention has focussed on the importance of the gut-associated lymphoid tissue (GALT) as the potential source of the poorly O-galactosylated IgA1 that triggers the formation of nephritogenic immune complexes in IgAN. Pathway analysis based on a large meta-analysis of genome wide association studies identified the intestinal immune network for IgA production as the most enriched KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway in IgAN. Furthermore, separate studies have shown that the IgA in glomerular IgA deposits is indistinguishable from mucosal IgA. The therapeutic potential of selectively targeting GALT was demonstrated in the NEFIGAN trial (NCT01738035), which assessed the safety and efficacy of a novel targeted-release formulation of budesonide (NEFECON®), designed to deliver budesonide to the GALT-rich distal ileum in patients with IgAN. After 9 months’ treatment, urine protein–creatinine ratio (UPCR) was reduced by 29.3% in the NEFECON® 16 mg group compared with the placebo group. Estimated glomerular filtration rate (eGFR) dropped 4.7 ml/min/1.73 m2 in the placebo group with no deterioration seen in the NEFECON® 16 mg group. Incidence of patients reporting adverse events was similar in all groups. These data led to the design of the NefIgArd study which aims to assess the efficacy, safety, and tolerability of NEFECON® 16 mg in patients with IgAN at risk of end-stage renal disease.

Method
The NefIgArd study is a randomised, double-blind, placebo-controlled Phase 3 trial, with two parts –

PART A
a 15–35-day screening period, 9-month treatment and 3-month follow-up period; and

PART B
a 12-month no-treatment follow-up period (Figure). The study is recruiting across 146 nephrology clinics in 19 countries. Patients must be at least 18 years old with biopsy-confirmed primary IgAN and persistent proteinuria &gt;1 g/24 h and eGFR between 35 and 90 ml/min per 1.73 m2 (CKD-EPI) despite optimised renin–angiotensin system blockade. Patients are randomised on a 1:1 ratio to NEFECON® 16 mg/day or placebo. Consistent with the Kidney Health Initiative White Paper “Proteinuria Reduction as a Surrogate End Point in Trials of IgA Nephropathy” published in early 2019, the primary outcome of Part A is to assess the effect of NEFECON® 16 mg on 24 h UPCR at 9 months compared with placebo. The Part B primary outcome is based on data presented at the NKF/FDA/EMA workshop in March 2018 that supported eGFR slope as an endpoint for full approval and will assess the effect of NEFECON® 16 mg on a 2-year eGFR-based endpoint compared with placebo. In comparison with other studies that are recruiting, we believe that the relatively short period required to provide validation of the surrogacy of proteinuria reduction will significantly reduce the risks of non-protocol treatments and loss of patients from the study that could dilute the true treatment effect of NEFECON®.

Results
As of 1 January 2020, 207 patients have been randomised, and Part A is expected to complete in Q4 2020, with Part B completing in 2022. To ensure the NefIgArd study results are fully translatable to the global IgAN population, NefIgArd will also open in China in 2020.

Conclusion
The NefIgArd study builds on the experience of the NEFIGAN trial, the largest commercially sponsored study ever completed in IgAN. The design of the NefIgArd study has used state-of-the-art data to evaluate kidney outcomes, using proteinuria as a reasonably likely surrogate of the effect of NEFECON® on long-term kidney outcomes and confirming long-term renoprotection using an NKF/FDA/EMA-suggested eGFR-based endpoint as a basis for full approval.