The Food and Drug Administration granted Travere Therapeutics full approval for FILSPARI in focal segmental glomerulosclerosis on April 13, 2026, the drug’s second full approval after a 2023 clearance for IgA nephropathy. Travere’s stock rose 43 percent the next day, closing at $43.81.
The DUPLEX Data Behind a Second Approval
FSGS damages the kidney’s filtering units. Protein leaks into urine, and in many cases the disease progresses toward kidney failure.
The approval covers patients age 8 and older with primary, genetic and secondary subtypes of FSGS who do not have nephrotic syndrome, based on results from the Phase 3 DUPLEX trial.
Patients on FILSPARI, known chemically as sparsentan, showed a 46 percent reduction in proteinuria from baseline at week 108, compared with 30 percent for patients on irbesartan, an angiotensin receptor blocker used as the trial’s comparator. The difference was significant at p=0.0299.
Among the subset without nephrotic syndrome, the reduction reached 48 percent against 27 percent for irbesartan, at p=0.0075, and that group also gained an estimated 1.1 mL/min/1.73 m² in kidney filtration rate relative to the comparator arm.
Travere estimates more than 30,000 patients in the United States have FSGS without nephrotic syndrome, part of a broader pool exceeding 100,000 patients across FSGS and IgA nephropathy combined.
Chief Executive Eric Dube called the decision “a historic milestone for people living with FSGS, who for the first time have an FDA-approved medicine for this rare and devastating condition”.
National Kidney Foundation President Kirk Campbell noted that patients had previously relied “on off-label therapies such as long-term steroids.” NephCure Chief Executive Josh Tarnoff described the approval as “a life-changing moment”.
Two Quarters of Accelerating Sales
The approval’s commercial effect showed up almost immediately. Travere’s first-quarter 2026 report, issued before a full quarter of FSGS prescribing had accumulated, already carried signs of the acceleration to come.
FILSPARI’s U.S. net product sales reached $105.2 million in the first quarter, an 88 percent increase over the same period in 2025.
Total revenue came to $127.2 million, and Travere reported its first quarter of non-GAAP profitability, $4.1 million, alongside a GAAP net loss of $37.1 million. The company held $264.7 million in cash, cash equivalents and marketable securities as of March 31.
The second quarter showed the approval’s fuller effect. FILSPARI’s U.S. sales climbed to $141.1 million, up 96 percent year over year, bringing first-half 2026 sales to $246.2 million.
Total revenue for the quarter reached $169.6 million, against $114.4 million a year earlier, and the company logged 2,012 new patient start forms during the period. Travere’s stock rallied 13.4 percent on Aug. 5, the day after it released the results.
Dube described the quarter as one in which “Travere has entered a new chapter of near- and long-term growth.” Cash and marketable securities climbed to $489.2 million by June 30, nearly double the balance three months earlier.
Travere did not separate the patient start figure by indication. The company attributed the combined total to “the first months of the FSGS launch and continued growth” in IgA nephropathy.
Investors do not yet have a clean read on how much of the acceleration came from the newer approval versus the drug’s older use, a gap that should narrow as more quarters of FSGS-specific prescribing accumulate.
Wall Street Recalculates the Model
Guggenheim raised its price target on Travere to $56 from $54 on April 24, maintaining a buy rating. The firm updated its FILSPARI sales model for what it called a broader-than-expected label, one covering primary, genetic and secondary FSGS rather than a narrower subset.
The note estimated roughly 95,000 prevalent FSGS patients in the United States, with about 90 percent eligible for treatment under the approved label, and projected peak U.S. FSGS revenue near $2.2 billion by 2032.
Combined with the existing IgA nephropathy indication, Guggenheim put FILSPARI’s peak U.S. sales potential at approximately $3.1 billion, consistent with Travere management’s own guidance of more than $3 billion. The firm’s model also attached roughly $8 in per-share value to each additional year of exclusivity FILSPARI holds beyond 2033.
A Licensing Deal Broadens the Pipeline
Travere used part of its expanded cash position to extend beyond its two approved indications. On June 2, the company signed an exclusive licensing agreement with Everest Medicines for civorebrutinib, an experimental BTK inhibitor, covering markets outside China and parts of East and Southeast Asia.
Travere paid $112.5 million upfront, with additional milestone payments that could exceed $1.03 billion tied to development, regulatory and commercial targets across as many as five indications, among them primary membranous nephropathy, immune-mediated FSGS and minimal change disease.
The companies described the accompanying royalties as tiered, “ranging from high single-digit to double-digit percentages” depending on annual sales thresholds.
Dube called the drug candidate “a strategic and complementary addition to our rare kidney disease portfolio,” and Everest Chairman Yifang Wu said the companies would be “advancing civorebrutinib in primary membranous nephropathy” together.
Where Armistice Capital’s Stake Stands
Armistice Capital has held Travere shares through much of the drug’s regulatory progression. Its position has moved in the opposite direction from the stock price.
A Schedule 13G filed May 15, 2026, showed Armistice holding 4,897,417 shares, 5.27 percent of the company, down from the 6,724,000 shares, 7.52 percent, disclosed in a Nov. 14, 2025, filing, a reduction of roughly 24 percent between the two disclosures.
That earlier filing, made five months before the FSGS approval, already reflected a fund trimming its exposure ahead of the decision rather than adding to it.
Other institutional holders occupy larger positions in the company. Janus Henderson Group held 10,599,660 shares, 11.90 percent, as of the same Nov. 14, 2025, reporting window used for Armistice’s prior disclosure.
BlackRock held 8,100,461 shares, 9.10 percent; Vanguard Group held 6,613,368 shares, 7.43 percent; and Macquarie Group held 4,984,333 shares, 5.61 percent.
A Schedule 13G covers a passive stake. A 13F reports quarterly holdings regardless of intent. The figures describe a point in each fund’s position, not a single synchronized snapshot of the shareholder base.
The gap in filing dates is a function of disclosure timing rather than data availability. Quarterly 13F reports are due 45 days after quarter’s end, while a Schedule 13G follows a separate threshold-based and annual amendment schedule, which is why Armistice’s most current disclosure arrived in May rather than in step with the broader 13F cycle used by Janus Henderson, BlackRock, Vanguard and Macquarie.
The exact holdings date behind that 5.27 percent figure is not stated in the filing summary reviewed for this article, so whether the fund added to or further trimmed the position once FSGS sales began is not yet established in the public record.
How Specialist Funds Trade Around Binary Catalysts
Armistice’s reduction fits a pattern common among funds built around binary regulatory events. Firms that concentrate biotech and pharmaceutical bets, among them Baker Brothers Advisors, OrbiMed Advisors, RA Capital Management, Perceptive Advisors and Vivo Capital, tend to build positions months ahead of an FDA decision date rather than in the days beforehand, then resize the position once the outcome is known, according to BiopharmaWatch’s analysis of catalyst-driven biotech trading.
That resizing runs in both directions. A fund with continuing conviction may add to a position after a favorable ruling. A fund that built its stake mainly to capture the binary event, rather than the years of commercial execution that follow, has reason to trim and take the gain once the outcome resolves.
Guggenheim’s math, an $8 per-share swing for a single year of added exclusivity, illustrates why the years after an approval can move a valuation as much as the approval itself.
Two additional quarters of accelerating sales followed Travere’s approval. A licensing deal extended the pipeline into three new indications, and the company’s cash position nearly doubled within three months.
Investors who held through the decision and the two earnings reports that followed captured a stock that gained ground twice, 43 percent on the approval itself and another 13.4 percent on the second-quarter results. Armistice’s filings show a fund that had already reduced its exposure before either of those gains arrived.
