Chugai files Japanese NDA for sparsentan in IgA nephropathy
- Chugai submitted an application to Japan's Ministry of Health, Labour and Welfare for sparsentan to treat IgA nephropathy.
- Global Phase III (PROTECT) showed UPCR change at Week 36: −49.8% for sparsentan vs −15.1% for irbesartan (p<0.0001).
- Japanese Phase III (RE-021-001) showed a −58.5% UPCR reduction at Week 36, consistent with global results.
- Key adverse events included hypotension, hyperkalemia, dizziness and peripheral edema; eGFR slope results suggested potential long-term renal benefit.
Regulatory filing
Chugai filed a regulatory application with Japan's Ministry of Health, Labour and Welfare for sparsentan for the treatment of patients with IgA nephropathy. The company notes sparsentan’s once-daily dosing and its dual inhibition of the endothelin receptor and angiotensin II receptor as relevant to long-term disease management.
Key efficacy results
The submission is based on two Phase III studies: the global PROTECT study and the Japanese RE-021-001 study, both in patients with persistent proteinuria. In PROTECT, sparsentan produced a −49.8% change from baseline in urine protein/creatinine ratio (UPCR) at Week 36 versus −15.1% for active control irbesartan (p<0.0001). In RE-021-001, sparsentan achieved a −58.5% UPCR reduction at Week 36, consistent with the global findings.
Renal function and safety
PROTECT’s key secondary endpoint—the total slope of estimated glomerular filtration rate (eGFR) over time—suggested a potential benefit in preserving kidney function. Sparsentan was generally well tolerated with a safety profile consistent with prior studies; treatment-emergent adverse events during the double-blind period included hypotension, hyperkalemia, dizziness and peripheral edema, and no new safety signals were identified in Japanese patients.
Source: Chugai Pharmaceutical
