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Dear NephCure Rare Kidney Disease Community,
As you may know, the U.S. Food and Drug Administration (FDA) has been reviewing an application for FILSPARI (sparsentan) for the treatment of focal segmental glomerulosclerosis (FSGS). The initial date for the FDA to make a decision on this drug was January 13, 2026. On that date, the FDA issued what is called a major amendment, which means the review process will take more time.
The information below is intended to clarify what this change to the FDA’s review timeline means, and just as importantly, what it does not mean.
What is a Major Amendment?
A major amendment is neither an approval nor a denial from the FDA. It means that the FDA now has more time to complete its review of the study data.
It means:
- The FDA is continuing its review of the drug and its study data.
- The FDA will be in contact with the study sponsor (Travere Therapeutics) and may ask for additional information or have further questions.
- The FDA issues a major amendment only when additional review time could potentially support an approval. It gives the FDA more time to fully evaluate the study data and review questions they have identified up to this point.
A major amendment extends the Prescription Drug User Fee Act (PDUFA) decision date by three months. The new PDUFA date for sparsentan in FSGS, or target date for the FDA to make their decision, is April 13, 2026.
The FDA may make a decision earlier than that date if they determine they have enough information to complete their review.
You may be aware that sparsentan has already been approved by the FDA to treat IgA nephropathy (IgAN) in adults, which is another rare and progressive kidney disease that can be characterized by proteinuria. Although this means that the FDA is already familiar with sparsentan and its safety and efficacy in IgAN, it’s important to note that the approval of any drug for a distinct disease must be studied and reviewed separately. In other words, approval for IgAN does not automatically mean approval for FSGS.
What Does This Mean for You?
For individuals affected by FSGS, every step forward matters. This extension allows additional time for careful review of data and discussion around this condition – its high costs to individuals’ quality of life and overall health, future risks, and the current lack of treatments. NephCure remains optimistic about the path forward for sparsentan, and respects the FDA’s rigorous and careful review process, particularly for complex diseases like FSGS.
At the same time, we understand that the added waiting period for this regulatory review can be difficult. Many in the FSGS community are living with uncertainty every day, and delays can feel deeply personal. We know that a great deal of disease progression can occur in a few short months for individuals living with FSGS. NephCure is committed to keeping the rare kidney disease community informed with clear updates, and we will continue to elevate the patient voice and keep the experiences, needs, and preferences of those living with FSGS at the forefront for decision-makers at the FDA.
Join the FSGS Community Town Hall
To help provide more details and answer your questions related to this update, NephCure will host a virtual FSGS Community Town Hall on Wednesday, January 21st at 7pm ET.
The town hall will be led by NephCure Specialists Drs. Kirk Campbell and Howard Trachtman.
It will focus on:
- Sharing more information on the drug development and FDA review process
- Explaining how this may impact you and your family
- Listening to our FSGS community and answering your questions
- Providing ways that you can make your voice heard by decision-makers
Anyone impacted by FSGS should join this important conversation. To register and submit your questions for the FSGS Community Town Hall, click here.
Additional resources and updates will be shared in the coming weeks to ensure the RKD community stays informed.
Sincerely,
Josh Tarnoff and the NephCure Team
