Kidney function may remain stable with approved C3G therapy, data suggest
76-week analysis also found sustained reductions in urine protein
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A healthcare professional uses a kidney model to illustrate its internal structures. New clinical trial data suggest an approved therapy may help preserve kidney function in people with C3G. (Image by iStock)
Kidney function remained largely stable over 76 weeks (about 1.5 years) of treatment with Empaveli (pegcetacoplan) in people with C3 glomerulopathy (C3G) or a related kidney disease, according to a new analysis of clinical trial data.
Biogen, which markets Empaveli in the U.S., presented the findings earlier this month at the American Society of Nephrology Kidney Week in Denver, Colorado.
“Long-term disease management remains a significant challenge for many people living with C3G, making durable treatment outcomes especially meaningful,” Daniel Jones, PhD, vice president and head of global medical affairs for Empaveli at Biogen, said in an emailed statement to C3G News. “The 76-week data further support EMPAVELI’s efficacy and safety profile while providing encouraging evidence of sustained clinical benefit for patients over time.”
Long-term data offer hope for people with C3G
C3G is a rare disorder in which the complement system, part of the immune system, becomes overactive and damages the kidneys. Despite standard treatment, up to 50% of patients develop kidney failure within 10 years.
Empaveli is given by an infusion under the skin and works by blocking C3, a protein involved in the complement system. It is approved in the U.S. to reduce the loss of kidney function and lower proteinuria (high levels of protein in the urine) in people with C3G ages 12 and older. It is also approved for another rare kidney disorder called primary immune-complex membranoproliferative glomerulonephritis (IC-MPGN).
Empaveli’s approval for C3G and IC-MPGN was based mainly on VALIANT (NCT05067127), a global Phase 3 clinical trial involving more than 100 patients with either disease, ages 12 and older. For the first six months, participants received either Empaveli or a placebo. All participants then received Empaveli for another six months.
After completing VALIANT, participants could join VALE (NCT05809531), an ongoing extension study in which all participants receive Empaveli. Researchers are following them to assess longer-term outcomes.
The new analysis included data from 120 patients with C3G or IC-MPGN across both studies to assess outcomes through 76 weeks (about 1.5 years) of Empaveli treatment.
Researchers measured kidney function using estimated glomerular filtration rate (eGFR), which estimates how well the kidneys filter waste from the blood. It is expressed in milliliters per minute per 1.73 square meters (mL/min/1.73 m²).
To make the results comparable, researchers measured changes from when each patient started Empaveli, whether they received it from the beginning of VALIANT or switched to it after six months on placebo.
Kidney function remains largely stable after 76 weeks of treatment
In people with C3G, kidney function tends to decline as the disease progresses. But in the analysis of patients with C3G or IC-MPGN, kidney function remained largely stable over 76 weeks of Empaveli treatment. eGFR decreased by an average of 1.4 mL/min/1.73 m².
Results differed depending on how much kidney scarring patients had before treatment. Those with less scarring had a small estimated average increase in eGFR of 1.7 mL/min/1.73 m² after 76 weeks. In those with more scarring, eGFR decreased by an estimated average of 11 mL/min/1.73 m².
Empaveli was also associated with lasting reductions in proteinuria. After 76 weeks, the estimated average reduction in the urine protein-to-creatinine ratio, a measure of proteinuria, was 64.1%. Reductions were generally greater among patients who had less kidney scarring before treatment.
A separate analysis of adolescents ages 12–17 with C3G or IC-MPGN also reported changes in kidney function and proteinuria after 76 weeks of Empaveli treatment. Their estimated average eGFR increased by 8.4 mL/min/1.73 m², while proteinuria decreased by an estimated average of 67.5%.
Safety data from these long-term analyses were consistent with Empaveli’s known profile.
Overall, the findings “further reinforce EMPAVELI’s long-term efficacy and safety profile,” Daniel Quirk, MD, Biogen’s chief medical officer, said in a company press release.
Empaveli can be given through an infusion pump or a disposable on-body injector. Researchers also presented a separate study examining how patients with C3G or IC-MPGN and caregivers of adolescent patients experienced using the injector.
Patients and caregivers report high satisfaction with on-body injector
All seven respondents in a survey of adult patients or caregivers of adolescent patients reported high satisfaction with the injector. On a scale of 1 to 7, five gave it the highest score of 7, while the other two gave it a 6.
Respondents also gave high ratings for ease of use and confidence in using the injector. Interviews with six participants revealed similar positive experiences.
“I feel like I could teach a child how to [use the injector]. It’s just that simple,” one participant said. Interviewees also described how the injector fit into their daily routines. “You can literally stick it on your stomach under your clothes without worrying about it pulling. You can still do the dishes, put on a coat, get in the car, or sit in a meeting, and no one would even know it’s there,” another participant said.
Although the study included only a small number of patients or caregivers, the researchers, including scientists at Biogen subsidiary Apellis, said the early findings suggest the Empaveli injector is convenient and easy to use.
