Houston, TX — November 6, 2025 — Leads & Copy — Travere Therapeutics, Inc., (Nasdaq: TVTX) has announced new data from the Phase 3 DUPLEX Study, which demonstrated that focal segmental glomerulosclerosis (FSGS) patients treated with FILSPARI® (sparsentan) were significantly more likely to reach proteinuria levels below 0.7 g/g compared to those receiving the maximum labeled dose of irbesartan.
The data, presented as a late-breaking poster at the American Society of Nephrology (ASN) Kidney Week 2025 in Houston, TX, November 6-9, also showed that achievement of this threshold correlated with reduced risk of kidney failure.
According to Jula Inrig, M.D., chief medical officer of Travere Therapeutics, the company is pleased to present new data from the pivotal DUPLEX Study, highlighting the correlation between proteinuria reduction and the potential of FILSPARI to reduce long-term kidney failure events.
The PARASOL Project previously identified a urine protein-to-creatinine ratio (UPCR) below 0.7 g/g as a clinically meaningful proteinuria target in FSGS. The late-breaking poster reported the proportion of FILSPARI-treated patients reaching this threshold compared to the maximum labeled dose of irbesartan in the DUPLEX Study, and the effect of reaching this target on progression to kidney failure. A DUPLEX-aligned cohort of patients with FSGS (n=386) from the UK National Registry of Rare Kidney Disease (RaDaR) was then utilized to model the impact of achieving UPCR below 0.7 g/g on five-year kidney failure risk, during a 24-month period.
Key findings from the late-breaking analyses include:
- Significantly more patients treated with FILSPARI achieved UPCR below 0.7 g/g earlier and more often than those treated with irbesartan at any time (37.5% vs. 21.4% relative risk [RR], 1.8 [95% CI, 1.3-2.4]) and at week 108 (19% vs. 11.2% (RR, 1.7 [95% CI, 1.03-2.8]).
- Irrespective of treatment with FILSPARI or irbesartan, patients who achieved UPCR below 0.7 g/g at any time were less likely to reach kidney failure than those who did not (3.6% vs. 11.2% (RR, 0.52 [95% CI, 0.2-1.8]).
- In the DUPLEX-aligned RaDaR cohort, achieving UPCR below 0.7 g/g at 24-months was associated with lower risk of kidney failure over an additional 60-months of follow up (hazard ratio [HR], 0.14 [95% CI, 0.05-0.38]). A similar lower risk was observed for those who achieved UPCR below 0.7 g/g at any time over 24-months (HR, 0.27 [95% CI, 0.16-0.45]).
In a separate oral presentation, the company shared an analysis predicting the reduction in risk of kidney failure events at five years for patients treated with FILSPARI based on the relative reduction in proteinuria from the DUPLEX Study. Treatment with FILSPARI resulted in a clinically meaningful and durable reduction in proteinuria, with FSGS patients achieving a 50% reduction from baseline UPCR, compared to a 32% reduction with the maximum labeled dose of irbesartan. This translates to a 26% relative reduction in UPCR for FILSPARI-treated patients compared to the maximum labeled dose of irbesartan at 24 months. The analysis uses a DUPLEX-aligned cohort of patients from RaDaR to examine the correlation between reduction in proteinuria and the long-term risk of kidney failure.
Key findings from the RaDaR analysis include:
- Within the RaDaR cohort, robust reductions in the risk of kidney failure were observed for patients achieving complete remission (UPCR below 0.3 g/g) and proteinuria below 0.7 g/g at 24 months.
- Any reduction in UPCR correlated to a reduction in risk of kidney failure events at 5 years (1-unit reduction of log-transformed UPCR HR, 0.41 [95% CI, 0.29-0.58]).
- When applied to the DUPLEX Study, the 26% relative reduction in UPCR for patients treated with FILSPARI compared to irbesartan, correlates to a significant and clinically meaningful reduction in 5-year risk of kidney failure of 24% (HR, 0.76 [95% CI, 0.69-0.85]).
People living with FSGS face a serious and progressive disease that often leads to kidney failure and dialysis. The PARASOL Project has determined that reducing proteinuria to the lowest possible levels is key to protecting kidney function in FSGS, and these analyses from the DUPLEX Study reinforce its findings. FILSPARI is not approved for use in FSGS. There are currently no FDA-approved pharmacologic therapies for FSGS.
At Travere Therapeutics, we are in rare for life. We are a biopharmaceutical company that comes together every day to help patients, families and caregivers of all backgrounds as they navigate life with a rare disease.
More information on Travere’s presence at ASN can be found here.
Contact: Jula Inrig, M.D., chief medical officer of Travere Therapeutics.
Source: Travere Therapeutics, Inc.
