Povetacicept (ALPN-303) - (RAINIER)

June 1, 2026: Vertex Pharmaceuticals Incorporated (NASDAQ: VRTX) announced the FDA accepted its Biologics License Application (BLA) for povetacicept, an investigational dual BAFF/APRIL inhibitor, for treatment of adults with immunoglobulin A nephropathy (IgAN). The FDA assigned a PDUFA target action date of November 30, 2026.

The BLA is supported by a pre-specified Week 36 interim analysis from the ongoing Phase 3 RAINIER trial (NCT06564142), a global randomized, double-blind, placebo-controlled study of povetacicept 80 mg subcutaneous dosing every four weeks vs placebo on top of standard of care in 605 adults with IgAN. RAINIER met its primary interim objective: a 52.0% reduction from baseline in urine protein-to-creatinine ratio (UPCR) at Week 36 and a 49.8% reduction vs placebo (P<0.0001). Secondary endpoints were also met, including a 79.3% reduction vs placebo in serum galactose-deficient IgA1 (P<0.0001) and hematuria resolution in 85.1% vs 23.4% (61.7% vs placebo; P<0.0001). Povetacicept was generally safe and well tolerated with no related serious adverse events.

Vertex noted povetacicept has FDA Breakthrough Therapy Designation for IgAN and described ongoing development in primary membranous nephropathy (Phase 2/3 OLYMPUS) and generalized myasthenia gravis (recently initiated Phase 2 ETNA). Final RAINIER analysis is planned at two years, with primary endpoint of total eGFR slope through Week 104.