Travere Therapeutics drug, approved for one rare and deadly kidney disease, fails in study of another

SAN DIEGO  — Travere Therapeutics, a biotech focused on treating rare diseases, on Monday announced that a Phase 3 trial of an experimental treatment for focal segmental glomerulosclerosis, a rare and deadly kidney disease, failed to improve kidney function.

In the 371-person study, half of patients were randomly assigned to receive the drug, known as sparsentan, while the other half received irbesartan, a blood pressure treatment used as a control. Both groups were monitored for two years, and while the study’s main measurement — average kidney function — was higher among patients on sparsentan compared to the placebo group, the finding was not statistically significant.

Other secondary measures, such as urine protein levels, were lower among those on the drug, pointing in the right direction, and the company told investors and analysts in a conference call on Monday that the therapy was generally safe.


The company’s leaders told investors and analysts on the call that it plans to meet with U.S. and European regulators to determine if there’s a path forward for the treatment, and that meetings could happen this summer. Until then, they said that it’s too soon to know if the company will run another trial.

The findings are nonetheless a clear setback for Travere, which had hoped to use positive data from the trial to apply for approval to use the drug to treat focal segmental glomerulosclerosis in the U.S. and Europe. And the announcement comes just a few months after the Food and Drug Administration approved sparsentan for IgA nephropathy, a rare and deadly autoimmune disease that attacks the kidneys.


“We are disappointed that we did not achieve the primary efficacy endpoint in this study, but we did see results that trended favorably for sparsentan that we are further exploring to determine a potential path forward in FSGS,” said CEO Eric Dube in a press release. “We are grateful for the patients, their caregivers, the investigators, clinical staff, the patient advocacy groups and our entire team at Travere who came together to support the DUPLEX Study.”

Focal segmental glomerulosclerosis, also known as FSGS, results from a gradual buildup of scar tissue in the parts of the kidneys that filter blood. Over time, the disease can lead to swelling from a buildup of fluid throughout the body, high blood pressure, and kidney failure within 10 to 15 years.

Roughly 40,000 people live with FSGS in the U.S., and on the company’s conference call chief medical officer Jula Inrig noted that 40% of patients will have a disease relapse even after receiving a kidney transplant. Current treatments are meant to control blood pressure and the buildup of protein in the urine, but there’s no approved therapy for FSGS.

Travere had been hoping sparsentan would be the first. The drug is a small molecule that blocks receptors for the peptides angiotensin II and endothelin 1. The biotech originally licensed the rights to it from Ligand Pharmaceuticals in 2012.

At that time, Travere was called Retrophin and run by founder Martin Shkreli, the former hedge fund manager and “pharma bro” who came under fire for raising the price tags of drugs his companies acquired by as much as 2000% to 5000%. He was later imprisoned for defrauding investors and fired by Retrophin’s board in 2014, triggering a legal feud that wasn’t settled until 2019. In 2020, Retrophin rebranded as Travere.

The company’s leaders stressed that they don’t believe results from the FSGS study are bad news for sparsentan’s prospects as a treatment for IgA nephropathy, or IgAN. The drug was granted accelerated approval for IgA nephropathy in February by the FDA based on interim results from a different Phase 3 trial, PROTECT, which found a statistically significant reduction in urine protein levels among those on the therapy.

By the end of this year, the company will have two years’ worth of data from PROTECT, which will shed light on whether the reductions in protein levels that IgA nephropathy patients experienced translate into improved kidney function, the most important outcome in these studies.

Travere shares traded at $22.61 at the market’s close on Monday but dipped to around $17 during after-hours trading.

Source: STAT