What happened
Shares of Travere Therapeutics (TVTX -2.41%) were down more than 40% as of noon on Thursday after the company released mixed phase 3 trial results regarding Filspari, its prospective IgA nephropathy (IgAN) therapy.
So what
Travere is a pharmaceutical company that focuses on rare diseases. The company said on Thursday that Filspari showed promising results in preserving kidney function and clinically meaningful results in estimated glomerular filtration rate (eGFR, which shows how well kidneys function), compared to irbesartan. Unfortunately, the company also said the drug narrowly missed statistical significance in eGFR total slope, which can be a better metric to show changes in kidney function than just eGFR. IgA nephropathy (IgAN), also called Berger's disease, is a rare kidney disease where there's a buildup of immunoglobulin A (IgA), a protein that helps the body fight infections, in the kidneys. IgAN is a leading cause of kidney failure due to glomerular disease and, according to Travere, affects up to an estimated 150,000 people in the U.S. and is one of the most common glomerular diseases in Europe and Japan.
Now what
The company is looking to broaden indications for Filspari, which received accelerated approval in February from the Food and Drug Administration (FDA) to reduce proteinuria in adults with primary immunoglobulin A nephropathy. At present, the drug is sold with a boxed warning because of toxicity concerns and is available only through a Risk Evaluation and Mitigation Strategy (REMS) approved by the FDA. The mixed results could hurt the drug's chances of traditional approval.
The drop does seem a big dramatic, until you realize how much Travere is counting on Filspari's full approval. The company recently sold all of its rights and assets connected to Cholbam, used to treat bile acid synthesis disorders, and gallstones therapy Chenodal to Mirum Pharmaceuticals for $445 million. Travere has one other marketed product, Thiola, used to prevent cystine kidney stone formation.
