Apellis and Sobi's Empaveli Shows Promise in Rare Kidney Diseases

Apellis Pharmaceuticals and Swedish Orphan Biovitrum (Sobi) have reported promising long-term data for their complement regulator Empaveli (pegcetacoplan) in rare kidney diseases, potentially strengthening the drug's position ahead of an upcoming FDA decision.

Sustained Efficacy in C3G and IC-MPGN

In the Phase III VALIANT trial, Empaveli demonstrated a significant and sustained reduction in proteinuria for patients with C3 glomerulopathy (C3G) and primary immune complex membranoproliferative glomerulonephritis (IC-MPGN). The trial, which enrolled nearly 125 patients aged 12 and older, showed that Empaveli reduced proteinuria by 68% compared to placebo at 28 weeks, with the effect maintained through one year of follow-up.

Analysts at William Blair described Empaveli's profile as "game-changing" in these rare kidney diseases, citing its "best-in-class efficacy" as a driver for potential significant adoption in this underserved population.

Mechanism of Action and Regulatory Status

Empaveli, designed for subcutaneous injection, works by inhibiting the complement cascade, a part of the body's immune system. This mechanism of action previously earned the drug FDA approval in May 2021 for paroxysmal nocturnal hemoglobinuria, followed by European approval under the brand name Aspaveli.

Apellis and Sobi are now seeking to expand Empaveli's label. The FDA has accepted their application for use in C3G and IC-MPGN, granting Priority Review with a decision expected by July 28, 2025.

Competitive Landscape in Kidney Disease Treatment

While Empaveli shows promise, it's not the only player in the rare kidney disease space. Otsuka recently revealed encouraging data for its antibody therapy sibeprenlimab in immunoglobulin A nephropathy (IgAN). Late-stage results showed sibeprenlimab reduced proteinuria by 51.2% versus placebo, a result Guggenheim Partners called "impressive" and "the strongest numerical result reported to date in IgAN Phase 3 trials."

As the pharmaceutical industry continues to advance treatments for rare kidney diseases, these developments highlight the potential for new therapies to address significant unmet needs in nephrology.