FDA Approves REMS Label Update for Sparsentan (Filspari) in IgA Nephropathy

Travere Therapeutics has announced the US Food and Drug Administration (FDA) approval of an updated Risk Evaluation and Mitigation Strategy (REMS) labeling for sparsentan (Filspari) for the treatment of IgA nephropathy (IgAN).1

According to an August 27, 2025, press release from the Company, the update reduces the frequency of liver function monitoring from monthly to every 3 months from the onset of treatment with sparsentan and removes the embryo-fetal toxicity (EFT) monitoring requirement from the REMS.1

“[Sparsentan] is becoming a foundational treatment for people living with IgA nephropathy, giving patients and their families hope for slowing the progression of their disease,” Jula Inrig, MD, chief medical officer of Travere Therapeutics, said in a statement.1 “Today’s approval of streamlined monitoring requirements reflects the strong safety profile of [sparsentan] established to date across clinical and real-world use, simplifying access for patients.”

As described in the release from Travere, the reduction of sparsentan liver monitoring REMS from monthly to every 3 months from the onset of treatment was supported by safety data from post-marketing surveillance as well as the phase 3 PROTECT Study in IgAN, the phase 3 DUPLEX Study, and the phase 2 DUET Study in focal segmental glomerulosclerosis (FSGS).1

The FDA determined that the REMS requirement for EFT for sparsentan was no longer necessary following an analysis of human pregnancy data compiled from the use of ERA medicines from the last 2 decades.1

The endothelin and angiotensin II receptor antagonist was granted accelerated approval for the treatment of IgAN in February 2023 based on clinically meaningful and statistically significant improvements in proteinuria compared to an active comparator in the phase 3 PROTECT study. It gained full approval in September 2024 based on 2-year confirmatory results from PROTECT, making sparsentan the second therapeutic to receive full approval for IgAN after Calliditas Therapeutics’ budesonide (Tarpeyo) delayed release capsules.2

A supplemental New Drug Application (sNDA) for sparsentan in FSGS is currently under review with the FDA, with a Prescription Drug User Fee Act target action date of January 13, 2026. The sNDA submission was supported by results from the phase 3 DUPLEX Study and the phase 2 DUET Study, 2 of the largest head-to-head interventional studies conducted to date in adult and pediatric patients with FSGS.1,3

While DUPLEX achieved its pre-specified interim FSGS partial remission of proteinuria endpoint with statistical significance at 36 weeks, it did not achieve the primary efficacy eGFR slope endpoint over 108 weeks of treatment. 2-year results from the study were published in the New England Journal of Medicine and showed that sparsentan delivered clinically meaningful benefit at 108 weeks with significant proteinuria reduction, higher rates of partial and complete remission, and a lower rate of end-stage kidney disease compared to the active control.3

DUET met the primary efficacy endpoint for the combined treatment group, demonstrating a greater than 2-fold reduction in proteinuria compared to irbesartan. Additionally, sparsentan was well-tolerated with a safety profile that was consistent across all clinical trials conducted to date and comparable to the maximally dosed active control, irbesartan, including no drug-induced liver injury and no fluid overload.3

If approved, sparsentan would be the first and only approved medicine indicated for FSGS.1,3

References

1. Travere Therapeutics. Travere Therapeutics Announces U.S. FDA Approves REMS Modification for FILSPARI® (sparsentan) in IgA Nephropathy. August 27, 2025. Accessed August 27, 2025. https://ir.travere.com/press-releases/news-details/2025/Travere-Therapeutics-Announces-U-S--FDA-Approves-REMS-Modification-for-FILSPARI-sparsentan-in-IgA-Nephropathy/default.aspx

2. Brooks A. FDA Approves Travere Therapeutics’ Sparsentan to Slow Kidney Function Decline in Adult Primary IgAN. HCPLive. September 5, 2024. Accessed August 27, 2025. https://www.hcplive.com/view/fda-approves-travere-therapuetics-sparsentan-for-proteinuria-reduction-in-adult-primary-igan

3. Brooks A. FDA Accepts Sparsentan (Filspari) sNDA for Focal Segmental Glomerulosclerosis. HCPLive. May 15, 2025. Accessed August 27, 2025. https://www.hcplive.com/view/fda-accepts-sparsentan-filspari-snda-for-focal-segmental-glomerulosclerosis