EMPAVELI Shows Promising Long-Term Results for Rare Kidney Diseases, Setting Stage for Market Battle
Apellis Pharmaceuticals and Swedish partner Sobi revealed compelling one-year data showing their complement inhibitor EMPAVELI® maintained robust efficacy in patients with C3 glomerulopathy and primary immune complex membranoproliferative glomerulonephritis .
The findings, presented today at a late-breaking session of the European Renal Association Congress, demonstrate EMPAVELI's potential to address an urgent unmet need for the approximately 13,000 patients in the United States and Europe suffering from these progressive kidney diseases.
"A Ray of Hope in the Prime of Life"
For patients diagnosed with C3G or primary IC-MPGN, the prognosis has historically been grim. Nearly half progress to kidney failure within 5-10 years of diagnosis, often requiring dialysis or transplantation. Even more concerning, about 90% of patients who receive kidney transplants experience disease recurrence.
"The one-year Phase 3 results are very compelling, confirming EMPAVELI's sustained benefits across key markers of disease," said Fadi Fakhouri, investigator for the VALIANT study. "Given the high risk of kidney failure, treatment efficacy is incredibly important to C3G and primary IC-MPGN patients, many of whom are in the prime of their lives."
The VALIANT study showed that EMPAVELI produced a statistically significant 68% reduction in proteinuria (protein in urine, a key marker of kidney damage) compared to placebo at 26 weeks, with this substantial benefit maintained through one year of treatment. Importantly, the drug also stabilized kidney function as measured by estimated glomerular filtration rate .
David vs. Goliath in the Rare Disease Arena
What makes these results particularly notable is how they position EMPAVELI against its chief competitor, Novartis's oral factor B inhibitor iptacopan , which received FDA approval for C3G in March 2025.
While iptacopan offers the convenience of oral administration, its Phase 3 results showed approximately 35% reduction in proteinuria at six months – less than half the reduction demonstrated by EMPAVELI. This stark difference in efficacy could prove decisive for physicians and patients, despite EMPAVELI requiring subcutaneous injections twice weekly.
"This is really a fascinating moment in rare disease drug development," said Eleanor, a nephrologist at not involved in the study. "We're seeing a subcutaneous therapy with potentially superior efficacy competing against an oral option. For patients facing kidney failure, that efficacy differential could outweigh convenience factors."
A Lifeline for Transplant Recipients
The VALIANT study included both native kidney patients and those who had received transplants – a critical distinction since C3G/IC-MPGN frequently recurs in transplanted kidneys. Patients who switched from placebo to EMPAVELI at the start of the open-label period demonstrated similar improvements in proteinuria reduction and kidney function stabilization.
"These data reinforce the strength of the EMPAVELI efficacy and safety profile across a broad population of patients with C3G and primary IC-MPGN, including adults and adolescents with native and post-transplant kidney disease," noted Peter Hillmen, chief medical advisor for rare disease at Apellis.
Market Implications: High Stakes in a Niche Space
With FDA and EMA decisions pending (expected summer 2025 and Q4 2025, respectively), the commercial implications are significant despite the relatively small patient population. Industry analysts estimate the complement 3 glomerulopathy market was valued at approximately $9.3 billion in 2024, with projections reaching $12.3 billion by 2035.
For Apellis, EMPAVELI's potential approval in C3G/IC-MPGN represents a significant expansion opportunity beyond its current indications. The company reported $166.8 million in total revenue for Q1 2025, with EMPAVELI contributing $19.7 million from its paroxysmal nocturnal hemoglobinuria indication.
Financial analysts project that if approved, EMPAVELI could generate between $300-400 million annually from C3G/IC-MPGN in the U.S. alone when at peak market penetration, assuming orphan drug pricing consistent with other rare disease treatments.
The Path to Patient Access
Despite promising clinical results, several hurdles remain before patients can access EMPAVELI for these rare kidney diseases. Insurance coverage for ultra-orphan drugs often requires extensive negotiation, and the high anticipated annual cost—potentially $450,000-$550,000 per patient—will likely face scrutiny from payers.
"Even with strong data, gaining access for patients often depends on health economic arguments demonstrating long-term cost offsets from delaying dialysis or transplantation," explained healthcare economist Jason. "Companies need to prove value beyond clinical efficacy."
Additionally, diagnosis rates for C3G and IC-MPGN remain suboptimal, with misdiagnosis rates as high as 40-50%. Increased physician education and awareness will be essential for identifying appropriate patients.
Broader Implications
If approved, EMPAVELI would join a growing arsenal of complement inhibitors revolutionizing treatment for rare diseases. Beyond C3G and IC-MPGN, researchers are exploring applications in atypical hemolytic uremic syndrome, IgA nephropathy, and transplant rejection.
For investors watching this space, the regulatory decisions in mid-2025 represent a pivotal moment. Success could propel Apellis shares significantly higher, while expanding Sobi's presence in the rare disease market.
"The VALIANT data exemplify how targeted therapies can address previously untreatable conditions," said Dr. Fakhouri. "For patients living with these devastating kidney diseases, every month of preserved kidney function represents a meaningful victory."
As the regulatory review progresses, patients and clinicians alike await what could be the first FDA-approved therapy specifically targeting the underlying complement dysregulation in C3G and primary IC-MPGN—diseases that have historically lacked effective treatment options.
Disclaimer: This article is for informational purposes only and does not constitute investment advice. Past performance of mentioned companies does not guarantee future results. Readers should consult financial advisors for personalized guidance regarding investment decisions.