FDA cleared Filspari for focal segmental glomerulosclerosis on Monday, handing Travere Therapeutics a fresh shot at what it values as a more than $3 billion U.S. peak sales opportunity.
The green light makes Filspari the first approved product for FSGS, a rare kidney disease affecting more than 30,000 patients in the addressable U.S. population. Combined with the IgA nephropathy indication it earned in 2023, the drug now covers a potential pool of over 100,000 patients. Travere’s full-year 2025 Filspari sales hit $322 million, up 144% from 2024.
Wall Street is bullish but conservative. Evercore ISI analysts forecast $1.4 billion in peak FSGS sales and $800 million for the IgAN indication, projecting the new indication ramps from $55 million in 2026 to $315 million in 2027 before reaching $640 million in 2028. Travere’s own more than $3 billion figure assumes a higher ceiling.
The FSGS label covers patients ages eight and older without nephrotic syndrome. Evercore noted the exclusion affects only about 15% of the real-world population, with the Duplex trial showing a 39% proteinuria reduction for non-nephrotic syndrome patients versus 22% across the full study cohort.
Travere’s commercial deployment didn’t wait. A 100-plus-person field team was ready at clearance, and the company’s 80% prescriber overlap between FSGS and IgAN providers means it doesn’t need to build a customer base from zero.
The road here wasn’t smooth: FDA delayed approval three months for additional clinical benefit data, and the Duplex trial missed its primary endpoint in 2023. Evercore projects FSGS sales won’t hit $640 million until 2028.
— Sarah Chen