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

Apellis Pharmaceuticals and Swedish Orphan Biovitrum (Sobi) have reported encouraging 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 68% reduction in proteinuria compared to placebo at 28 weeks in patients with C3 glomerulopathy (C3G) and primary immune complex membranoproliferative glomerulonephritis (IC-MPGN). Importantly, this benefit was sustained through one year of follow-up, according to data presented at the European Renal Association Congress.

The trial enrolled nearly 125 patients aged 12 and older diagnosed with these rare kidney diseases, which are characterized by inflammation linked to excessive deposits of the C3 complement protein. Both conditions can lead to kidney failure in half of patients within a decade of diagnosis.

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

Regulatory Outlook and Market Potential

Apellis, which partnered with Sobi in October 2020 for ex-U.S. markets, is now seeking to expand Empaveli's label. The FDA has accepted the company's application for C3G and IC-MPGN indications, granting Priority Review with a decision expected by July 28.

Analysts at William Blair view the new data as supporting Empaveli's "game-changing profile" in these rare kidney diseases. "Empaveli has best-in-class efficacy that should drive significant adoption in this underserved population over time," they noted in a recent report.

Competition in the Kidney Disease Space

While Apellis and Sobi make strides with Empaveli, other players are also advancing treatments for rare kidney diseases. Otsuka recently revealed promising 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 potentially "the strongest numerical result reported to date in IgAN Phase 3 trials."

Otsuka has yet to outline its regulatory strategy for sibeprenlimab but emphasized that proteinuria reduction is a recognized surrogate marker that has supported accelerated approvals in IgAN clinical trials.

As the landscape for rare kidney disease treatments evolves, the pharmaceutical industry awaits the FDA's verdict on Empaveli's expanded use, which could significantly impact patient care and market dynamics in this underserved therapeutic area.