Travere Reports FILSPARI Biomarker Data in IgA Nephropathy

SAN DIEGO, Calif. — October 23, 2026

FILSPARI Demonstrates Reductions Across Four Biomarkers

FILSPARI is a dual endothelin and angiotensin II receptor antagonist developed for the treatment of IgAN. The therapy is designed to target pathways involved in kidney injury and disease progression. The PROTECT Study evaluated its efficacy and safety against irbesartan, an angiotensin receptor blocker, in adults with biopsy-confirmed IgAN. In the new biomarker analysis, investigators assessed four urinary markers associated with different aspects of the disease process. sCD163, a marker associated with macrophage activation, decreased by 60.1% from baseline with FILSPARI at Week 110, compared with 26.0% with irbesartan. BAFF, which is associated with B-cell activation and survival, declined by 64.4% with FILSPARI versus 45.2% with irbesartan. C5b-9, a marker of complement pathway activation, decreased by 50.2% with FILSPARI compared with 7.3% with irbesartan. IL-6, a pro-inflammatory cytokine, declined by 45.4% in the FILSPARI group, while the irbesartan group experienced an 8.7% increase. All changes were least-squares mean percentage changes from baseline normalized to urine creatinine. The company reported nominal p-values of less than 0.001 for sCD163, 0.02 for BAFF, 0.032 for C5b-9 and less than 0.001 for IL-6. These results indicate differences between treatment groups across several biological markers rather than a change limited to one inflammatory pathway. Jula Inrig, M.D., chief medical officer of Travere Therapeutics, said the findings provide additional insight into how FILSPARI’s dual mechanism may affect the underlying biology of IgAN. Chee Kay Cheung, M.B.Ch.B., Ph.D., consultant nephrologist at University Hospitals of Leicester NHS Trust, noted that the findings extend an exploratory signal observed in the earlier SPARTAN study and provide evidence from a larger randomized trial. The analysis remains biomarker-focused, and further research is needed to determine how changes in individual markers relate to long-term patient outcomes.

PROTECT Trial Connects Biomarker Findings With Clinical Outcomes

The Phase 3 PROTECT Study was a global, randomized, multicenter, double-blind, active-controlled clinical trial involving 404 adults with IgAN. Participants had biopsy-confirmed disease, urine protein excretion of at least 1.0 gram per day and an estimated glomerular filtration rate (eGFR) of at least 30 mL/min/1.73 m² despite optimized renin-angiotensin system inhibitor therapy. Participants were randomized in a 1:1 ratio to receive FILSPARI at 400 mg per day or irbesartan at 300 mg per day for up to 110 weeks. The primary efficacy endpoint was the change in proteinuria from baseline at Week 36, while the key secondary endpoint was the rate of change in eGFR through Week 110. Of the overall study population, 295 participants were included in the biomarker analysis. FILSPARI was associated with rapid and sustained reductions in all four urinary biomarkers across measured time points through Week 110. These findings complement previously reported clinical results in which FILSPARI demonstrated greater proteinuria reduction and a slower rate of kidney function decline than maximum labeled-dose irbesartan. Together, the clinical and biomarker data support further investigation of the therapy’s effects on kidney disease activity. However, biomarker changes should not be interpreted as definitive proof that the treatment modifies every underlying mechanism of IgAN or prevents long-term kidney failure. The reported p-values were nominal, and the findings need to be interpreted in the context of the analysis design and the wider clinical evidence. Travere is positioning FILSPARI as a potential foundational, non-immunosuppressive treatment for IgAN, a chronic kidney disease characterized by IgA deposits in the kidneys and progressive risk of kidney damage. The company’s interpretation is that dual endothelin and angiotensin receptor antagonism may provide effects beyond conventional renin-angiotensin system inhibition. The clinical significance of the biomarker differences will depend on how consistently they align with sustained kidney function and other patient outcomes.

Travere Advances Its Kidney Disease Treatment Strategy

The ASN Kidney Week presentation adds to Travere Therapeutics’ evidence base for FILSPARI in IgAN. The company is focused on developing treatments for rare diseases and works with patients, families, caregivers and the broader rare-disease community to address unmet medical needs. The latest PROTECT biomarker findings provide additional information about the potential biological effects of sparsentan and complement the study’s reported proteinuria and kidney function results. By demonstrating differences across markers associated with macrophage activation, B-cell activity, complement activation and inflammation, the analysis offers a broader view of the treatment’s effects than clinical measures alone. Nevertheless, the findings should be considered alongside established clinical endpoints, safety information and longer-term follow-up when assessing the treatment’s overall benefit. The results were presented at ASN Kidney Week 2026, a major scientific meeting focused on kidney research and clinical care. Travere continues to emphasize FILSPARI’s potential role as a non-immunosuppressive, kidney-targeted treatment option for people living with IgAN. The company’s clinical development strategy reflects the need for therapies that address disease progression while offering alternatives to treatments that suppress the immune system. Further assessment of the relationship between urinary biomarker changes, proteinuria reduction and preservation of kidney function may help clarify the clinical relevance of these findings. The newly presented data strengthen the scientific rationale for continued evaluation of FILSPARI, while additional evidence will be important to establish the extent to which its observed biological effects translate into long-term benefits for patients with IgA nephropathy.

Source:Travere Therapeutics ,Press release