A new IgA nephropathy medicine cut urine protein by nearly half

If you or someone you love lives with IgA nephropathy, here is good news. A medicine called ravulizumab cut the protein leaking into the urine by nearly half in a large trial.

That matters because protein in the urine is an early sign of how well the kidney’s filters are holding up. Less leak is the goal. And even if this is not your condition, it shows science finding a new way into a stubborn kidney disease.

How the study worked

In this phase 3 randomized trial, 485 adults with IgA nephropathy who still had protein in their urine despite standard treatment were assigned by chance to ravulizumab or a placebo, given by IV infusion every 8 weeks. The first planned look at the results covered 352 of them, 176 in each group, at week 34, and was published Oct. 23, 2026, in the New England Journal of Medicine. This is an interim look at 34 weeks, so the longer-term kidney results are still to come, and the trial was funded by Alexion, AstraZeneca Rare Disease Unit.

What they found

Doctors track protein in the urine with a simple lab ratio. In the ravulizumab group, that number fell by 46.6%, which is nearly half. In the placebo group it fell by 5.6%, about 6 percent.

Put side by side, urine protein ended up 43.4% lower with ravulizumab than with placebo. That is a clear, strong difference.

Side effects were reported a little less often with ravulizumab than with placebo. Serious ones were reported about half as often, 4.6% versus 9.0%.

Medicines that block this part of the immune system can raise the risk of a bacterial infection called meningococcal disease, so researchers watched for it closely. None occurred in the trial, and there were no deaths. Vaccination against meningococcus is required before starting this kind of medicine.

What is complement, and why block it?

Complement is part of your immune system, the body’s built-in defense team. In IgA nephropathy, it fuels inflammation in the kidney’s tiny filters. That leads to blood and protein in the urine and, over time, a gradual loss of kidney function.

Ravulizumab blocks the final steps of complement. That is a different part of the disease process than drugs that block APRIL or BAFF, so it could add another option for people whose disease keeps progressing.

What you can do today

If you have IgA nephropathy, find your most recent urine protein result and write down the number and the date. Bring it to your next kidney visit and ask what number your team is aiming for, and whether newer treatments or clinical trials fit your situation.