Research shows patients with persistent proteinuria above one gram per day are at high risk of kidney failure. Reducing proteinuria in patients with immunoglobulin A (IgA) can prevent further kidney function decline. In the recent PROTECT clinical trial, researchers investigated the effects of sparsentan (brand name Filspari) in patients with IgA nephropathy. Learn more about what they did, what they found, and what it means.* 

What they did

Researchers recruited 404 participants with IgA nephropathy who had an estimated glomerular filtration rate (or percentage of remaining kidney function) of at least 30, and proteinuria of 1 gram per day or higher. Participants were assigned to receive either:

• Sparsentan, at 400 mg daily, or
• Irbesartan, at 300 mg daily.

After 36 weeks of taking the assigned medication, researchers compared and analyzed the blood pressure and proteinuria changes in the participants. 

What they found

Added benefits in participants taking sparsentan were discovered during researchers’ analysis. Their findings included: 

• A minimal difference in blood pressure changes between the sparsentan and irbesartan groups
• A more significant decline in urine protein to creatinine ratio in participants taking sparsentan than irbesartan (49.8% v. 15.1%)
• Higher rates of remission in proteinuria in the sparsentan group compared to the irbesartan group

What it means

The reduction in proteinuria, and acceptable safety profile, makes sparsentan a valuable treatment option for IgA nephropathy patients. 

“The substantial and sustained reduction in proteinuria observed with sparsentan in this context,” the study authors concluded, “is clinically important and supports a favorable effect on long-term kidney function.”

*Persaud, N. (2023). Proteinuria Reduction in IgA Nephropathy Greater With Sparsentan. Renal and Urology News. https://www.renalandurologynews.com/home/conference-highlights/national-kidney-foundation-annual-meeting/nkf-2023-spring-meeting/proteinuria-reduction-in-iga-nephropathy-greater-with-sparsentan/