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Abstract: PO1530

Proteinuria End Points and Associations with Renal Survival in FSGS: Analysis of the UK National RaDaR Idiopathic Nephrotic Syndrome Cohort

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Saleem, Moin, University of Bristol, Bristol, Bristol, United Kingdom
  • Barratt, Jonathan, University of Leicester, Leicester, Leicestershire, United Kingdom
  • Braddon, Fiona E. M., UK Renal Registry, Bristol, Bristol, United Kingdom
  • Carroll, Kevin, KLC Statistics Ltd, Cheshire, England, United Kingdom
  • Diva, Ulysses A., Travere Therapeutics Inc, San Diego, California, United States
  • Hendry, Bruce M., Travere Therapeutics Inc, San Diego, California, United States
  • Mercer, Alex, JAMCO Pharma Consulting, Stockholm, Sweden
  • Pitcher, David, UK Renal Registry, Bristol, Bristol, United Kingdom
  • Steenkamp, Retha D., UK Renal Registry, Bristol, Bristol, United Kingdom
  • Turner, A. Neil, University of Edinburgh, Edinburgh, United Kingdom
  • Gale, Daniel P., Royal Free Hospital, London, London, United Kingdom
Background

In patients with FSGS, severity of proteinuria (PU) at onset and during follow up is associated with renal failure. In this study, we tested for associations between defined PU endpoints and renal survival in patients with FSGS from the UK National Registry of Rare Kidney Diseases Idiopathic Nephrotic Syndrome (RaDaR-INS) Cohort.

Methods

A total of 225 biopsy-proven or monogenic FSGS pts met study eligibility criteria, including a nephrotic PU value (≥3.5 g/g), a follow-up PU within 6-12 mo. and no ESKD (eGFR <15 mL/min/1.73m2 or on renal replacement therapy) or death prior to first PU follow-up. Baseline pertains to first nephrotic PU value (T0 for survival analyses). Applied PU responder/non-responder definitions are described (Table 1). Time to ESKD/death was analysed using accelerated failure time modelling of the Weibull distribution.

Results

Within 6-12 mo. from baseline, 63% of patients achieved complete or partial remission (CR/PR), while 37% were non-responders (NR). Applying the FSGS partial remission of PU endpoint (FPRE) and including CR patients, 49% met this definition (CR/FPRE-R), while 51% were FPRE-NR. A higher probability for survival was observed among patients achieving remission definitions (Figure 1), extending median time to ESKD/death by ≈8 years for CR/PR vs NR, and ≈17 years for CR/ FPRE-R vs NR (Table 1) independent of initial PU level. Further analyses are ongoing.

Conclusion

Achieving partial or complete remission of PU is associated with clinically meaningful increases in time FSGS patients are alive and free from ESKD.

Funding

  • Commercial Support