Travere Therapeutics Seeks FDA Approval for FILSPARI® to Treat FSGS

Travere Therapeutics, Inc., a biopharmaceutical company focused on rare diseases, has formally submitted a supplemental New Drug Application (sNDA) to the U.S. Food and Drug Administration (FDA) for FILSPARI® (sparsentan), targeting the treatment of focal segmental glomerulosclerosis (FSGS). This submission seeks priority review for the drug, which, if approved, could become the first FDA-sanctioned treatment for FSGS, a rare kidney disorder known for causing kidney failure. FSGS affects an estimated 40,000 individuals in the U.S., with a similar prevalence in Europe.

The sNDA submission is underpinned by data from the Phase 3 DUPLEX Study and the Phase 2 DUET Study. These represent comprehensive interventional studies focused on both adult and pediatric patients suffering from FSGS. The studies demonstrated that FILSPARI significantly reduced proteinuria—a condition characterized by excess protein in urine that contributes to kidney damage. The drug was well-tolerated, with its safety profile aligning with previous clinical trials.

FILSPARI is an innovative oral medication that differs from immunosuppressive treatments, as it specifically targets podocyte injury by blocking the endothelin A receptor (ETAR) and the angiotensin II subtype 1 receptor (AT1R). It holds current approval for slowing kidney function decline in adults with IgA nephropathy, another leading cause of kidney failure.

Eric Dube, Ph.D., CEO of Travere Therapeutics, highlighted the urgent need for treatments that address FSGS by reducing proteinuria and preserving kidney function. He noted the positive impact of FILSPARI in treating IgA nephropathy and expressed optimism about its potential role in treating FSGS.

In tandem with the sNDA submission, the FDA informed Travere Therapeutics that REMS monitoring for embryo-fetal toxicity related to FILSPARI is no longer necessary, allowing the company to pursue amendments to alter the existing REMS sNDA concerning liver monitoring. This change is expected to streamline healthcare delivery without affecting the review timeline, with a target action date for a REMS modification set for August 28, 2025.

FSGS presents a complex challenge due to its nature, marked by progressive kidney scarring. Besides proteinuria, patients often suffer from symptoms like edema, low blood albumin levels, abnormal lipid profiles, and hypertension. Currently, there are no approved pharmacological treatments for FSGS, making the approval of FILSPARI potentially groundbreaking.

The DUPLEX Study, the largest of its kind comparing FILSPARI with a maximally dosed active comparator, achieved significant proteinuria reduction at 36 weeks but did not meet its primary efficacy endpoint over 108 weeks. Nevertheless, the study underscored clinically meaningful benefits, including higher remission rates and reduced progression to end-stage kidney disease. Similarly, the DUET Study confirmed FILSPARI's efficacy, with a two-fold reduction in proteinuria compared to irbesartan.

Travere Therapeutics is committed to developing therapies for rare diseases. The company collaborates globally to understand patient needs and deliver life-altering treatments, as evident in its pursuit of approval for FILSPARI in treating FSGS. The outcome of the ongoing FDA review process holds the potential to offer new hope to individuals affected by this challenging kidney disorder.