Travere Therapeutics Receives Full FDA Approval for FILSPARI in FSGS

Published: 2026-04-14 15:22:45 ET TVTX

Published on 04/14/2026 at 03:22 pm EDT

Travere Therapeutics, Inc. has received approval from the U.S. Food and Drug Administration (FDA) for FILSPARI (sparsentan) to reduce proteinuria in adult and pediatric patients aged 8 years and older with focal segmental glomerulosclerosis (FSGS) without nephrotic syndrome. FILSPARI is the first and only medicine approved by the FDA for the treatment of FSGS, marking its expansion beyond IgA nephropathy (IgAN) into a second rare kidney disease. FILSPARI is currently the most commonly prescribed FDA-approved medicine for IgAN and Ligand is entitled to a 9% royalty on worldwide net sales.

People with FSGS who do not have nephrotic syndrome span across types of FSGS and represent a population aligned with the KDIGO guidelines for treating glomerular diseases. Nephrotic syndrome is commonly defined as the presence of three concurrent criteria: proteinuria greater than 3.5 g/24h, edema, and albumin less than 3.0 g/dL. Travere estimates that the addressable population in the U.S. is more than 30,000 individuals with FSGS who do not have nephrotic syndrome.

In Travere?s Phase 3 DUPLEX Study, the largest head-to-head interventional study in FSGS to date, patients treated with FILSPARI in the overall study population experienced a statistically significant 46% reduction in proteinuria from baseline to Week 108 compared to 30% for those treated with maximum labeled dose irbesartan (nominal p-value, 0.0299). In patients without nephrotic syndrome, FILSPARI demonstrated even greater improvements compared to maximum labeled dose irbesartan across proteinuria and eGFR. Those without nephrotic syndrome who were treated with FILSPARI experienced a 48% reduction in proteinuria from baseline to Week 108 compared to 27% for those treated with irbesartan, which was statistically significant (nominal p-value, 0.0075).

FILSPARI-treated patients without nephrotic syndrome also demonstrated a benefit in eGFR with a treatment difference of 1.1 mL/min/1.73 m2 based on mean change from baseline to Week 108 (-11.3 mL/min/1.73 m2 for FILSPARI compared to -12.4 mL/min/1.73 m2 for maximum labeled dose irbesartan). Across both adult and pediatric patients, FILSPARI was generally well tolerated, with a safety profile comparable to irbesartan and consistent across clinical programs. In patients without nephrotic syndrome, FSGS is largely driven by stress on the kidney?s glomeruli and the activation of the pathways that cause inflammation and scarring. FILSPARI?s dual mechanism of action addresses these processes by targeting endothelin A and angiotensin II receptors, which are believed to help protect the kidney and reduce damage.

Focal segmental glomerulosclerosis (FSGS) is a rare proteinuric kidney disorder in both children and adults defined by progressive scarring of the kidney and often leads to kidney failure. FSGS is characterized by proteinuria, where protein leaks into the urine due to a breakdown of the normal filtration mechanism in the kidney. Once in the urine, protein is considered to be toxic to other parts of the kidney, especially the tubules, and is believed to contribute to further disease progression.

FSGS without nephrotic syndrome spans all categories of the disorder. The Phase 3 DUPLEX Study is the largest interventional study to date in FSGS. It was a global, randomized, multicenter, double-blind, parallel-arm, active-controlled Phase 3 clinical trial that assessed the efficacy and safety of FILSPARI in 371 patients ages 8 to 75 years with biopsy-proven or genetic FSGS.

After a two-week washout period, patients were randomized 1:1 to receive either FILSPARI or irbesartan, the active control, and subsequently dose titrated to the maximum dose of 800 mg of sparsentan or 300 mg of irbesartan, as tolerated. In the study, nephrotic syndrome was defined as (a) documentation of nephrotic syndrome in the medical history, or (b) the concurrent presence of proteinuria >3.5 g/24 hours (adults) or UPCR >2.0 g/g (pediatric patients).