The U.S. Food and Drug Administration (FDA) has granted full approval to Filspari® (sparsentan) for the treatment of adults with primary IgA nephropathy (IgAN), a chronic kidney disease that leads to progressive kidney function decline. This decision follows previous accelerated approval based on early clinical trial data and is now reinforced by the final analysis of the phase 3 PROTECT trial, which compared Filspari to irbesartan in slowing disease progression.

Key Findings from the PROTECT Trial

The phase 3 PROTECT trial aimed to assess the safety and efficacy of sparsentan in adults with IgAN who remained at high risk of disease progression despite being on standard treatments such as ACE inhibitors or angiotensin receptor blockers (ARBs).

• Study Design. A total of 404 patients with persistent proteinuria were randomly assigned to receive either sparsentan or irbesartan. The participants were followed for just over two years, with researchers measuring each person’s estimated glomerular filtration rate (eGFR) to track their kidney function.
• Results. The final analysis revealed that sparsentan significantly reduced the rate of kidney function decline compared to irbesartan. In addition to improving kidney function, sparsentan led to sustained reductions in proteinuria, a key indicator of IgAN progression. 

Impact on Treatment for IgA Nephropathy

Filspari provides a new therapeutic option for IgAN patients that goes beyond the current standard of care, offering significant advantages in slowing the progression of kidney damage.

With full FDA approval, Filspari is now expected to be more widely prescribed as a non-immunosuppressive, once-daily oral treatment. The drug is now available in 200mg and 400mg tablets, enabling flexibility in dosing based on individual patient needs.

*Ernst, D. (2024, September 9). Filspari Approved to Slow Kidney Function Decline in IgA Nephropathy. Renal and Urology News. https://www.renalandurologynews.com/news/filspari-approved-to-slow-kidney-function-decline-in-iga-nephropathy/ 

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