Recently, Travere Therapeutics provided a major update about its supplemental new drug application (sNDA) for its drug FALSPARI (sparsentan) for the treatment of patients with focal segmental glomerulosclerosis (FSGS). The news in question is that the FDA provided communication to it that an advisory committee panel to review the drug is no longer needed. With that being said, the Prescription Drug User Fee Act (PDUFA) target action date was kept the same as before, which was January 13, 2026. This is the date on or before which the FDA has to decide whether or not FILSPARI should be approved to treat these rare kidney disease patients.
FSGS is a rare kidney disorder characterized by excessive scarring. This is a major issue because it first and foremost leads to reduced kidney function and ultimately proteinuria (protein in the urine). The proteinuria that occurs is toxic enough as it is, but that is not all that this disorder causes. Other problems that it can cause are swelling of parts of the body (edema) and high blood pressure as well. It remains to be seen if the FDA decides to approve FALSPARI for these patients, but the fact that an advisory committee panel is not being considered anymore is encouraging. On the flip side, this doesn’t guarantee with certainty that the drug will be approved for U.S. marketing.
U.S. marketing approval for FALSPARI being given to treat these patients with FSGS would definitely boost the company’s stock price and provide a boost in revenue for it. However, there is another possible win that can be claimed from this, which is that it could achieve the ability to have the first approved medication for these patients. That’s because, at the moment, there are no regulatory-approved drugs for them. This drug provides an excellent mode of action because it incorporates the targeting of two specific receptors that drive inflammation and fibrotic damage, and they are the endothelin A receptor (ETAR) and the angiotensin II type 1 receptor (AT1R). In FSGS these cause a breakdown in the filtration system that leads to the proteinuria that is found in these FSGS patients.
The point is to ultimately maintain the filtration barrier and reduce proteinuria levels as much as possible. The sNDA of FALSPARI was possible thanks to the positive results that were released from the phase 2 DUET and phase 3 DUPLEX studies. Both of these studies provided evidence of achieving a reduction in proteinuria over an extended period of time. Consider that the patients who achieved either a partial response (PR) or complete response (CR) in the DUPLEX study had reduced their risk progressing to kidney failure by 67% to 77%. The reason why the move to receive approval of FSGS is considered under an sNDA is because FALSPARI is already approved by the FDA to treat patients with immunoglobulin A nephropathy (IgAN).
The mechanism of action (MOA) of FALSPARI to treat patients with IgAN is by blocking the receptors noted beforehand, which are ETAR and AT1R. The reason for blocking these is to reduce the inflammation and fibrosis that they cause that leads to progressive disease. The thing is that FALSPARI is already doing well in the indication it is already approved for. As a matter of fact, net product revenues for this drug in the U.S. in the second quarter of 2025 were said to reach $71.9 million. The significance of this is that this is a massive percentage year-over-year growth rate of 165%. If this drug is also approved for FSGS, this would only serve to boost the amount of revenue that could be generated from it.