Emerging Insights: Phase 3 Results of Telitacicept for IgA Nephropathy

The telitacicept Phase 3 trial presented at ASN Kidney Week 2025 showed substantial reductions in proteinuria and preservation of kidney function.

The trial reported a 55% reduction in 24-hour urine protein-to-creatinine ratio with telitacicept versus an 8.8% reduction with placebo at week 39—a magnitude that could materially shift risk trajectories for patients with IgA nephropathy.

In a multicenter, double-blind Phase 3 study, adults were randomized 1:1 to telitacicept 240 mg weekly or placebo on top of background supportive care. The primary endpoint was change in 24‑hour urine protein-to-creatinine ratio at week 39: telitacicept produced a 55% reduction versus 8.8% with placebo, and investigators observed early eGFR stabilization.

Mean eGFR was essentially unchanged in the telitacicept arm at week 39 (−0.010 mL/min/1.73 m²) versus a modest decline in the placebo group (−0.77 mL/min/1.73 m²), supporting early stabilization of kidney function. No unexpected adverse events or new safety signals were reported through the reported timepoint; investigators described a favorable tolerability profile with no unexpected increases in serious adverse events through 39 weeks.

Telitacicept’s dual APRIL/BAFF inhibition targets upstream B‑cell pathways implicated in IgA nephropathy and plausibly explains the observed proteinuria reductions and eGFR stabilization. Compared with current supportive measures—RAAS blockade and SGLT2 inhibition—telitacicept provides a targeted immunologic approach for adults with persistent proteinuria despite optimized therapy. Regulatory timing and longer-term follow-up will determine access and monitoring requirements.

Key Takeaways:

• Telitacicept produced a clinically meaningful 55% reduction in proteinuria at week 39 versus 8.8% with placebo, coupled with early eGFR stabilization—signaling a potential disease‑modifying effect.
• Adults with IgA nephropathy and persistent proteinuria despite optimized supportive care (RAAS blockade ± SGLT2 inhibitor) are the primary population likely to benefit when telitacicept becomes available.
• Begin formulary and operational planning, anticipate monitoring for immunologic effects and renal response, and prepare focused patient counseling on expected benefits and safety during early follow‑up.