Rare Disease Stocks Plunge 15% Following FDA Decision Delay

Travere Therapeutics Inc. (NASDAQ: TVTX) shares plunged 14.63%, closing at $29.14 on the Nasdaq on January 13, after briefly tumbling nearly 20% intraday on heavy trading volume. The company’s market capitalization shrank by about $333 million (roughly ₩480 billion) in a single session. Since investors had pinned high hopes on FDA approval for its rare kidney disease therapy, the sudden sell-off delivered a serious blow to sentiment.

The immediate catalyst was news that the FDA had postponed the Prescription Drug User Fee Act (PDUFA) action date for Filspari, Travere’s focal segmental glomerulosclerosis (FSGS) candidate. On January 13, Travere disclosed that the agency extended its review by three months to evaluate additional efficacy data, moving the “approve-or-reject” deadline from January 13 to April 13. Although no extra safety or manufacturing information was requested, pushing back this key milestone deflated near-term expectations. Just one day earlier, the company had highlighted in an 8-K filing and press release that it expects about $410 million in U.S. product sales in 2025 and holds approximately $323 million in cash—an upbeat growth story that was overshadowed by the regulatory delay.

Travere Therapeutics is a U.S. biotech firm specializing in rare kidney, liver and metabolic disease treatments. Its flagship medicine, Filspari, is already approved and marketed in the U.S. for IgA nephropathy (IgAN). As of the second quarter of 2025, U.S. sales of Filspari surged 165% year-over-year, establishing it as the company’s primary growth driver. Beyond the FSGS label expansion, Travere is advancing additional pipeline programs such as pegtibatinase for classical homocystinuria (HCU) to underpin its medium- to long-term growth outlook.

For investors, the FDA’s review extension doesn’t cast doubt on Filspari’s commercial potential so much as obscure the timing of revenue realization. Late last year, bullish analyst reports and M&A speculation around an FSGS approval had driven the stock up over 10%, fueling optimism. Looking ahead, market participants will closely monitor the nature of the supplementary data the FDA has requested and whether Travere can maintain its lead over Novartis’ competing FSGS program before the rescheduled April decision.