San Diego-based Travere Therapeutics announced positive interim results from a Phase III trial investigating Filspari (sparsentan) in adults with IgA nephropathy (IgAN), a rare progressive kidney disease. Filspari is a selective dual-acting receptor antagonist indicated to reduce proteinuria in adults with IgAN.

The interim analysis showed that patients treated with 400mg of Filspari achieved a mean reduction of 49.8% in proteinuria compared to baseline. Participants in the active control arm received 300 mg of irbesartan and achieved a mean reduction of 15.1%% in proteinuria. The trial (NCT03762850) enrolled 404 patients.

Additionally, 20.8% of the treatment cohort achieved complete remission, urine protein excretion <0.3 g/day, compared to 7.9% participants in the control arm. Partial remission, urine protein excretion <1.0 g/day, was achieved in 70.3% of participants in Filspari arm compared to 44.1% of comparator cohort.

The trial’s secondary endpoints are measuring estimated glomerular filtration rate (eGFR) over a 52-, 104-, and 110-week periods.

Although Filspari received the FDA’s accelerated approval in February 2023, Travere is yet to establish if the drug is able to slow down kidney function decline. The topline data analysis from confirmatory endpoints is expected in Q4 2023, which are intended to support traditional FDA approval.

In H2 2023, Travere together with its collaborator CSL Vifor anticipate a review decision by the EMA on the potential approval for Filspari as a treatment of IgAN in Europe. If approved, the drug will receive conditional marketing authorisation (CMA) in all EU member states, as well as Iceland, Liechtenstein, and Norway.

According to GlobalData’s Clinical Trial Database, there are 89 planned or ongoing clinical trials investigating drugs in IgAN, also known as Berger’s disease. The majority of these trials are in late-stage development, with the biggest portion in Phase II.

IgAN is the most common type of glomerulonephritis worldwide, with an incidence of 2.5 per 100,000 population per year. The disease progression can lead to end stage kidney disease or decreasing eGFR.