Travere will present new FILSPARI (sparsentan) data from SPARTAN, DUPLEX and PROTECT in IgA nephropathy and FSGS at ASN Kidney Week 2026.
Written By: Mayuri Vaja, PharmD
Reviewed By: Pharmacally Editorial Team
Travere Therapeutics will present nine new data sets, including five oral presentations, on FILSPARI® (sparsentan) in IgA nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS) at the American Society of Nephrology (ASN) Kidney Week 2026 in Denver, Colorado, from October 21–25. The data include final findings from the Phase 2 SPARTAN study, a post hoc analysis of the Phase 3 DUPLEX study, and urinary biomarker findings from the Phase 3 PROTECT study.
SPARTAN Study Reports Proteinuria Remission with First-Line FILSPARI
The final analysis of the Phase 2 SPARTAN study evaluated once-daily oral FILSPARI as first-line therapy in newly diagnosed, renin-angiotensin system (RAS) blockade-naïve adults with biopsy-proven IgAN. The open-label, single-group study enrolled 12 participants who received a target dose of 400 mg and were followed for up to 110 weeks.
Clinical finding | Result |
Complete proteinuria remission | 75% of participants |
Definition of complete remission | Urine protein excretion <0.3 g/day |
LS mean eGFR change at Week 110 | −1.75 mL/min/1.73 m² |
Chronic eGFR slope, Week 6–110 | −1.11 mL/min/1.73 m²/year |
Overall eGFR slope, baseline–Week 110 | −1.54 mL/min/1.73 m²/year |
The findings provide longer-term data on proteinuria and kidney function following first-line sparsentan treatment. However, the small sample size and open-label, single-arm design mean that the SPARTAN findings should be interpreted as supportive rather than comparative efficacy evidence.
DUPLEX Analysis Shows Lower Proteinuria in FSGS Without Nephrotic Syndrome
A post hoc analysis of the Phase 3 DUPLEX study evaluated 254 patients with FSGS without nephrotic syndrome, the population included in FILSPARI’s U.S. FSGS indication.
Clinical finding at Week 108 | FILSPARI | Irbesartan |
Mean UPCR reduction | 48% | 27% |
Complete proteinuria remission | 20% | 6% |
UPCR <1.5 g/g | 79% | 50% |
Chronic eGFR slope | −3.7 mL/min/1.73 m²/year | −6.2 mL/min/1.73 m²/year |
Kidney failure | 2% | 8% |
Treatment-emergent adverse events | 92% | 94% |
UPCR below 1.5 g/g was a threshold associated with partial proteinuria remission. Because this was a post hoc subgroup analysis, the findings should be interpreted in the context of the analysis design rather than as results from a trial prospectively designed solely to compare treatments in patients without nephrotic syndrome.
Biomarker Findings Explore Renal Effects of Sparsentan
Travere will also present urinary biomarker data from the Phase 3 PROTECT study. The analysis evaluated biomarkers associated with macrophage and B-cell activation, inflammation, and complement activation.
At Week 110, reductions across all four biomarker groups were significantly greater with FILSPARI than with the maximum labeled dose of irbesartan. Additional ASN presentations will examine proteomic and transcriptomic findings related to pathways involved in glomerular disease.
Together, these analyses are intended to provide additional biological context for the clinical findings reported with sparsentan in IgAN.
FILSPARI Expands Its Role Across Rare Kidney Diseases
FILSPARI is a dual endothelin and angiotensin II receptor antagonist. In the U.S., it is approved to slow kidney function decline in adults with primary IgAN who are at risk of disease progression and to reduce proteinuria in adults and children aged 8 years and older with FSGS without nephrotic syndrome.
In April 2026, the FDA granted full approval for the FSGS indication based on evidence from the Phase 3 DUPLEX study. The approval covers patients aged 8 years and older with FSGS without nephrotic syndrome and represents an expansion of FILSPARI’s U.S. indication beyond IgAN.
The new data will be presented at ASN Kidney Week 2026 in Denver from October 21–25. Travere’s program includes nine presentations covering clinical outcomes, biomarkers, real-world treatment experience, safety, and mechanistic analyses of sparsentan.
FILSPARI Important Safety Information
FILSPARI carries boxed warnings for hepatotoxicity and embryo-fetal toxicity and is available only through the FILSPARI REMS program. Aminotransferase elevations of at least three times the upper limit of normal have been observed in up to 3.5% of FILSPARI-treated patients. Liver tests should be obtained before treatment and monitored every three months during treatment.
FILSPARI is contraindicated during pregnancy because of the risk of fetal harm. It should not be coadministered with ARBs, other endothelin receptor antagonists, or aliskiren because of the potential for hypotension, hyperkalemia and changes in renal function.
Important warnings and precautions include hypotension, acute kidney injury, hyperkalemia and fluid retention. Kidney function and serum potassium should be monitored periodically, particularly in patients at increased risk of acute kidney injury or hyperkalemia.
The most common adverse reactions reported in patients with IgAN include hyperkalemia, hypotension, peripheral edema, dizziness, anemia and acute kidney injury. In patients with FSGS, common adverse reactions include peripheral edema, hypotension, hyperkalemia, dizziness and anemia.
Reference
Travere to Present New Data Supporting FILSPARI® (sparsentan) as Foundational Treatment in IgA Nephropathy and FSGS at ASN Kidney Week 2026, Travere Therapeutics, October 2, 2026
A Study of the Safety and Activity of Sparsentan for the Treatment of Patients With Immunoglobulin A Nephropathy (SPARTAN), ClinicalTrials.gov ID NCT04663204
About the Writer
Mayuri Vaja (Linkedin) is a Pharm.D professional with a strong interest in clinical research, pharmacovigilance, and medical writing, supported by certifications in pharmacovigilance and academic projects exploring AI in healthcare and drug safety.
With a growing focus on evidence-based healthcare and scientific communication, she is developing expertise in clinical research and translating healthcare evidence into clear, meaningful content.
As a Pharmacally healthcare writer, Mayuri is committed to creating accurate, research-driven, and clinically relevant healthcare content while continuously strengthening her professional skills.