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Kidney Week

Abstract: TH-PO622

Comparing Proteinuria and Kidney Survival in FSGS and IgA Nephropathy (IgAN): A NEPTUNE Analysis

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Mariani, Laura H., University of Michigan Michigan Medicine, Ann Arbor, Michigan, United States
  • Troost, Jonathan P., University of Michigan Michigan Medicine, Ann Arbor, Michigan, United States
  • Gong, Wu, Travere Therapeutics Inc, San Diego, California, United States
  • Bensink, Mark Eliot, Travere Therapeutics Inc, San Diego, California, United States
  • Athavale, Ambarish, University of California San Diego, La Jolla, California, United States
  • Canetta, Pietro A., Columbia University, New York, New York, United States
  • Derebail, Vimal K., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Drexler, Yelena, University of Miami School of Medicine, Miami, Florida, United States
  • Trachtman, Howard, University of Michigan Michigan Medicine, Ann Arbor, Michigan, United States
Background

Changes in disease activity markers are important outcomes for clinical trials in rare proteinuric kidney disease. While novel therapies may be effective in multiple etiologies, the relationship between proteinuria and kidney survival has not been directly compared across diseases.

Methods

We studied children and adults with FSGS or IgAN enrolled in Nephrotic Syndrome Study Network (NEPTUNE) at the time of clinically indicated biopsy and followed prospectively with proteinuria and eGFR at each study visit. We tested the association between lowest proteinuria within 12 months (mo) after biopsy and the time to composite of ESKD/40% eGFR decline using Kaplan-Meier method.

Results

211 FSGS and 58 IgAN patients were included. Compared to IgAN, FSGS patients had higher baseline eGFR, UPCR and obesity rates, but similar age and blood pressure. Relative change in proteinuria was -42% vs -39% by 12mo and -42% vs -63% by 24mo in FSGS and IgAN, respectively, but a significant proportion with either diagnosis did not achieve complete remission (Fig 1). Associations between higher protieinuria in 12mo and shorter kidney survival time were similar across diseases (Fig 2).

Conclusion

Lower proteinuria by 12mo after biopsy was associated with similar improvement in kidney survival in FSGS and IgAN. A substantial proportion of patients under usual care have high proteinuria at 24mo, highlighting unmet need for new treatments.

Proportion of patients reaching proteinuria thresholds over 24 months of follow-up, by pediatric & adult subgroups

K-M survival for composite of 40% eGFR decline or ESKD, comparing FSGS to IgA by lowest proteinuria achieved in 12 months follow-up post-biopsy

Funding

  • NIDDK Support – Travere Therapeutics