Travere Therapeutics’ Filspari (sparsentan) gained full FDA approval for focal segmental glomerulosclerosis (FSGS), expanding its rare kidney disease label after earlier approvals in IgA nephropathy. The regulatory package validates proteinuria as a surrogate endpoint, giving the company access to a second revenue opportunity. Industry commentary around the approval suggests analysts view the expanded indication as meaningful, particularly given Filspari’s positioning as a proteinuria-reduction therapy. The approval also strengthens Travere’s clinical narrative following a winding regulatory history that included earlier setbacks and a need to demonstrate a credible pathway to label-level endpoints. From a treatment landscape perspective, the FSGS approval adds a new fully approved option for children and adults meeting specific criteria, with analysts projecting significant commercial potential for a drug in a still-narrow segment. For biotech teams, the decision is a reminder that surrogate endpoint strategy—when validated by regulators—can be as decisive as novel endpoints in advancing rare-disease labels.