Travere Therapeutics FILSPARI Shows Positive Long-Term Results in FSGS Treatment
Travere Therapeutics announced long-term results from the ongoing Phase 3 DUPLEX Study open-label extension of FILSPARI in the treatment of focal segmental glomerulosclerosis. Patients who initiated FILSPARI in the double-blind period and remained on therapy in the OLE maintained durable reductions in proteinuria, resulting in further achievement of clinically meaningful low proteinuria thresholds over time. Patients who transitioned from active control maximum labeled dose irbesartan to FILSPARI at the start of the OLE subsequently demonstrated rapid and sustained reductions in proteinuria similar to those who initiated FILSPARI at the beginning of the double-blind period. The results were presented at the European Renal Association 2026 Congress in Glasgow, Scotland June 3-6. The Phase 3 DUPLEX Study is a global, randomized, multicenter, double-blind, parallel-arm, active-controlled clinical trial that assessed the efficacy and safety of FILSPARI in patients with biopsy-proven or genetic FSGS compared to maximum labeled dose irbesartan for up to 108 weeks. At the end of the double-blind period, all patients were eligible to enroll in the open-label extension portion of the trial following a 4-week washout period and receive FILSPARI for up to three additional years. During the DUPLEX double-blind period, patients treated with FILSPARI achieved higher rates of complete and partial remission compared to maximum labeled dose irbesartan. Complete remission (urine protein-to-creatinine ratio, UPCR less than0.3 g/g) was achieved by 18.5% of FILSPARI-treated patients compared to 7.5% of those who received irbesartan, while partial remission (UPCR less than1.5 g/g) was achieved by 69.0% and 50.8% of patients, respectively. Following transition to the OLE, patients who remained on FILSPARI maintained durable reductions in proteinuria, resulting in further achievement of clinically meaningful low proteinuria thresholds over time. Among these patients, 37.5% achieved complete remission at any time across the double-blind or OLE period, and 87.5% achieved partial remission. Patients who transitioned from irbesartan to FILSPARI in the OLE after washout experienced rapid and sustained reductions in proteinuria, consistent with the reductions observed among patients who began FILSPARI during the double-blind period. Among these patients, 28.9% achieved complete remission at any time across the double-blind or OLE period, and 74.6% achieved partial remission. FILSPARI was generally well tolerated during the long-term OLE follow-up in the study with a safety profile consistent with previous findings.
