GLASGOW, Scotland – June 6, 2026
AstraZeneca’s rare disease division, Alexion, has reported positive interim Phase III results for Ultomiris® (ravulizumab) in adults with immunoglobulin A nephropathy (IgAN), demonstrating a statistically significant and clinically meaningful reduction in proteinuria compared with placebo. Presented at the 63rd European Renal Association (ERA) Congress, the findings from the global I CAN Phase III trial highlight the potential of Ultomiris to become a disease-modifying therapy for patients living with this progressive and often devastating kidney disease. The study showed rapid and sustained reductions in proteinuria, a key marker of kidney damage and disease progression, while maintaining a safety profile consistent with previous clinical experience. The results strengthen growing evidence supporting terminal complement inhibition as a promising therapeutic strategy in IgAN and position Ultomiris as a potential new treatment option for patients at risk of chronic kidney disease progression and eventual kidney failure.
Phase III Trial Delivers Significant Reduction in Proteinuria
The prespecified interim analysis demonstrated that Ultomiris achieved a 46.6% reduction in 24-hour urine protein creatinine ratio (UPCR) from baseline at week 34, compared with a 5.6% reduction in the placebo group, resulting in a highly significant placebo-adjusted treatment effect of 43.4%. Investigators reported that reductions in proteinuria were evident as early as week 10, when patients receiving Ultomiris achieved a 36.7% reduction compared with 8.5% among placebo recipients. Importantly, the treatment effect remained durable through week 34 and was consistently observed across multiple patient subgroups regardless of demographic characteristics, disease severity, or baseline clinical status.
Proteinuria reduction is widely recognized as an important surrogate marker for slowing kidney disease progression in IgAN, making these results particularly meaningful for patients facing long-term risks of declining kidney function. The data suggest that targeting terminal complement activation may directly address one of the central biological mechanisms driving inflammation and kidney injury in the disease.
Complement Inhibition Shows Promise as Disease-Modifying Approach
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IgAN is a rare inflammatory kidney disorder characterized by the deposition of abnormal immunoglobulin A immune complexes within the kidneys, triggering complement-mediated inflammation and progressive tissue damage. Over time, many patients experience worsening kidney function that can ultimately lead to end-stage kidney disease (ESKD) requiring dialysis or transplantation. Researchers believe terminal complement activation plays a crucial role in disease progression, making it an attractive therapeutic target. Ultomiris, the longest-acting C5 complement inhibitor currently available, is designed to provide immediate, complete, and sustained inhibition of terminal complement activity.
According to trial investigators, the rapid and consistent reduction in proteinuria observed with Ultomiris supports the hypothesis that complement inhibition may alter the underlying disease process rather than simply managing symptoms. These findings could represent an important advancement in the treatment landscape for IgAN, where effective disease-modifying options remain limited despite significant unmet medical need.
Regulatory Momentum Builds for Rare Kidney Disease Treatment
The safety profile observed in the I CAN study was consistent with the established profile of Ultomiris across its approved indications, with no new safety concerns identified. The most frequently reported adverse events included upper respiratory tract infections, nasopharyngitis, and infusion-related reactions, with overall tolerability considered favorable. The ongoing Phase III study will continue through 106 weeks, with the final primary endpoint evaluating changes in estimated glomerular filtration rate (eGFR), a critical measure of kidney function. Positive interim findings have strengthened expectations for future regulatory submissions in major global markets.
Company leaders emphasized that the data reinforce the therapeutic potential of complement pathway inhibition and support ongoing efforts to expand Ultomiris into additional rare disease indications. As approximately half of patients with elevated proteinuria remain at risk of progressing to kidney failure within a decade of diagnosis, the latest results represent a significant milestone in the pursuit of innovative therapies capable of preserving kidney function and improving long-term outcomes for people living with IgAN.
Source: AstraZeneca press release
