The individual sparsentan cohorts, however, failed to show statistically valid superiority to irbesartan although clear signals of relative improvement were observed. The trial hit its primary endpoint of reducing proteinurea, or protein in the urine, and yielded only one adverse event in a case of anemia.
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Retrophin CEO Stephen Aselage said: “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”. There were no withdrawals due to fluid retention during the eight-week blinded treatment period. In addition, every patient who completed the trial entered the ongoing open-label extension study, and the bulk of these patients are still receiving therapy today.
About The DUET Study The DUET study is an global, randomized, double-blind, Phase 2 clinical trial assessing the safety and efficacy of sparsentan in 109 patients with focal segmental glomerulosclerosis (FSGS), of which 96 qualified for the evaluable database. If regulatory approval is achieved, it could mean a huge win for the company financially, as now there are drugs approved in the market for treating FSGS.
Retrophin plans to present detailed results from the study at an upcoming medical meeting or in a peer-reviewed publication. That makes this a must-watch drug for investors in both Retrophin and Ligand.
The reduction for the two highest doses of sparsentan was a bit better at 47.4% than the overall mean.
FSGS affects up to 40,000 people in the United States, and analysts expect Retrophin can charge between US$100,000 and US$150,000 per patient per year if sparsentan is approved. It is a progressive form of kidney disease and accounts for 2.3% of patients with end-stage renal disease (ESRD).
While FSGS has no specific treatment, sparsentan is created to treat proteinuria, or excess serum protein in the urine, a key driver of FSGS. Sparsentan’s dual mechanism of action combines angiotensin receptor blockade with endothelin receptor type A blockade. The drug already had orphan drug designation in this indication in both the US and the EU.
Sparsentan was tested on 109 patients with FSGS, which is a rare kidney disorder that leads to end-stage renal disease.
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Kim, like other analysts, said he remained optimistic that sparsentan could secure an accelerated approval, “although there’s nothing set in stone”.
