Retrophin reports positive long-term data from extension of Phase 2 DUET Study
Retrophin announced new positive data from the ongoing open-label extension of the Phase 2 DUET Study of sparsentan for the treatment of focal segmental glomerulosclerosis, a rare kidney disorder that often leads to end-stage renal disease. As previously reported, the overall sparsentan treatment group demonstrated a greater than two-fold reduction in proteinuria compared to the irbesartan treatment group, after an eight-week, double-blind treatment period in the Phase 2 DUET Study. Additional results showing that patients with FSGS who remained on sparsentan for 40 weeks during the open-label extension period of DUET achieved progressive reduction in proteinuria and stable estimated glomerular filtration rate, were reported at ASN Kidney Week 2017. New findings from the open-label extension of the Phase 2 DUET Study presented at ASN Kidney Week 2018 include: Patients with FSGS who remained on sparsentan for 76 weeks during the open-label period achieved additional progressive reduction of proteinuria. In patients who received sparsentan as part of the original eight-week, double-blind treatment period, median urine protein-to-creatinine ratio was reduced from 2.8 g/g at baseline to 0.9 g/g at week 84. Patients who crossed over to sparsentan from the original irbesartan control group experienced additional and sustained reduction in proteinuria during the treatment period, with median UP/C decreasing from 2.3 g/g at crossover to 1.1 g/g at week 84. An increasing proportion of patients achieved the FSGS partial remission of proteinuria endpoint, defined as UP/C: less than or equal to1.5 g/g and greater than 40% reduction of proteinuria from baseline, with ongoing sparsentan treatment in the open-label extension. In patients who received sparsentan as part of the original eight-week, double-blind treatment period, the proportion of patients who achieved FPRE increased from 28% at week eight to 60% at week 84. The proportion of patients who crossed over to sparsentan from the original irbesartan control group and achieved FPRE increased from 9% at week eight to 50% at week 84. Treatment with sparsentan in the open-label extension was associated with a stabilization of eGFR out to week 84. The observed beneficial effects of sparsentan on proteinuria were associated with a sustained reduction in mean systolic and diastolic blood pressure. Sparsentan continued to be generally well-tolerated during the open-label extension period. Sixty-two patients continue to receive treatment with sparsentan in the ongoing open-label extension of DUET.