Shares of Retrophin Inc. (NASDAQ: RTRX) climbed early on Wednesday following positive top-line news from its mid-stage trial for the treatment of focal segmental glomerulosclerosis (FSGS). Overall, the study achieved statistical significance in the primary efficacy endpoint for the overall sparsentan treatment group, demonstrating a greater than two-fold reduction of proteinuria compared to irbesartan after the eight-week, double-blind treatment period.
Keep in mind that although the comparison of individual sparsentan dose cohorts to irbesartan showed clear signals of relative improvement, they did not reach statistical significance.
FSGS is a rare kidney disorder without an approved pharmacologic treatment. It is estimated to affect up to 40,000 patients in the United States, with similar prevalence in Europe. The disorder is defined by progressive scarring of the kidney and often leads to end-stage renal disease. In simple terms, the kidney does not filter proteins in it correctly.
Top-line results suggested that sparsentan was generally safe and well-tolerated in the DUET study. One serious adverse event, anemia, classified as potentially related to treatment, occurred in the sparsentan group but did not result in study discontinuation during the eight-week blinded treatment period. There were no withdrawals due to fluid retention during the eight-week blinded treatment period. All patients who completed the eight-week treatment period entered the ongoing open label extension study, and the vast majority of these patients continue to receive therapy.
Stephen Aselage, CEO of Retrophin, commented:
We are very pleased with the robust top-line results from DUET, which suggest sparsentan could be a significant advancement in the treatment of FSGS. FSGS patients today face poor outcomes with limited medical options; we look forward to working with the FDA to find the most expeditious path forward that would deliver the first approved pharmacologic treatment to the FSGS community.
Alvin Shih, M.D., executive vice president and head of research and development for Retrophin, commented:
The results from DUET serve as proof of concept for sparsentan’s novel approach of combining endothelin receptor type A blockade with angiotensin II inhibition for the treatment of FSGS. Significant reductions in proteinuria, along with a well-tolerated preliminary safety profile have us excited about being one step closer to providing a new treatment option for patients with FSGS.
Shares of Retrophin closed Tuesday up 1.4% at $16.32, with a consensus analyst price target of $25.67 and a 52-week trading range of $11.60 to $29.64. Following the release of the results, the stock was up nearly 25% at $20.49 in early trading indications Wednesday.