Retrophin reports additional Phase 2 data on sparsentan in glomerulosclerosis
Retrophin announced additional results from the Phase 2 DUET study of sparsentan for the treatment of focal segmental glomerulosclerosis, a rare kidney disorder. The new findings are being presented at the American Society of Nephrology Kidney Week. As announced in September, top-line data from DUET showed the sparsentan treatment group achieved statistical significance in the study's primary efficacy endpoint, reduction of proteinuria. An analysis of the secondary endpoint presented Saturday showed that a "significantly greater" proportion of patients receiving sparsentan achieved modified partial remission of proteinuria versus irbesartan patients. In addition, four patients receiving sparsentan achieved complete remission as compared to zero irbesartan patients. Also presented Saturday was a post-hoc, intention-to-treat analysis showing that the sparsentan treatment group again demonstrated a greater than two-fold reduction of proteinuria versus irbesartan. Further analysis of the safety database from the initial eight-week, double-blind treatment period also showed sparsentan was generally safe and well-tolerated. Detailed results of the above-mentioned findings include: "An analysis of the secondary endpoint, which showed that after the eight-week, double-blind treatment period, 28.1% of patients receiving sparsentan achieved modified partial remission of proteinuria, compared to 9.4% of irbesartan-treated patients. The proportion of patients achieving modified partial remission increased during the open label period. After 48 weeks of treatment with sparsentan, 57.7% of patients achieved modified partial remission. In addition, 50% of patients that transferred from irbesartan to sparsentan at the beginning of the open label period achieved modified partial remission after 40 weeks of treatment. Complete remission, defined as proteinuria less than 0.3 g/g, was achieved by four patients receiving sparsentan during the eight-week, double-blind treatment period, compared to zero irbesartan-treated patients. A post-hoc ITT analysis showed a statistically significant difference in the mean reduction of proteinuria from baseline for the sparsentan treatment group compared to the irbesartan group after the study's eight-week, double-blind treatment period. The sparsentan group achieved a 42.7% mean reduction of proteinuria compared to 15.7% for the irbesartan group. The ITT analysis also showed that after eight weeks of treatment with 400 mg and 800 mg of sparsentan, the mean reduction of proteinuria from baseline was 44.8%, compared to 15.9% for the irbesartan-treated patients in these two cohorts. During the eight-week, double-blind period, the incidence of treatment-emergent adverse events for the sparsentan group was similar to the irbesartan group, except for edema. The severity of edema did not significantly worsen from baseline and no patients withdrew from the study as a result of edema during the eight-week, double-blind treatment period... The incidence of serious adverse events was similar across both groups. Eighty-four percent of patients who completed the eight-week, double-blind treatment period continue to receive sparsentan in the open-label extension."