A Study to Learn More About How Well the Study Treatment Finerenone Works, How Safe it is, How it Moves Into, Through, and Out of the Body, and the Effects it Has on the Body When Taken With an ACE Inhibitor or Angiotensin Receptor Blocker in Children With Chronic Kidney Disease and Proteinuria

This study is looking for children aged between 6 months and 17 years old who have been diagnosed with long-term kidney disease (CKD) and currently have too much protein in their urine (proteinuria). Their kidney function should be stable at the beginning of the study, and they must already be taking an ACE inhibitor or ARB medicine for their kidney condition, with the dose of this medicine having been stable for at least 30 days.

There are also some specific health conditions and treatments that would mean a child cannot join the study. For example, children who are planning to have kidney surgery, have recently had a specific type of kidney condition called hemolytic uremic syndrome, or are about to receive a kidney transplant generally won't be able to participate. Also, if a child has a kidney transplant already, or has certain serious conditions affecting the kidney's blood supply, they would not be eligible.

Children who have recently needed dialysis for sudden kidney problems or who are receiving certain treatments for a condition called nephrotic syndrome (where the kidneys leak a lot of protein) might also not be able to take part. These rules are in place to make sure the study is as safe as possible for all participants and that the results are clear.

If your child takes part, the study will involve different stages. First, there will be up to two screening visits over about 104 days to see if your child is suitable for the main part of the study. If they qualify, they will then enter the treatment phase, which lasts for around 180 days (about 6 months).

During these 6 months, your child will take either the study medicine (finerenone) or a dummy medicine (placebo) every day, in addition to their usual ACE inhibitor or ARB medication. They will need to visit the study clinic at least 7 times. At these visits, doctors and nurses will measure your child's blood pressure, heart rate, temperature, height, and weight. They will also take blood and urine samples to check kidney function, protein levels, and how the study medicine is affecting the body. Your child will have physical examinations, and their heart will be checked using an ECG (to measure electrical activity) and an echocardiogram (a special ultrasound scan of the heart).

You and your child will also be asked questions about any other medicines they are taking, how they are feeling, and if they have experienced any side effects. Doctors will carefully record any medical problems that happen during the study. After the last dose of study medicine, there will be a final check-up about 30 days later to make sure your child is doing well.