Study of ALXN1920 in Adult Participants With Primary Membranous Nephropathy (PMN)

To join this study, you must be an adult between 18 and 75 years old and have been diagnosed with Primary Membranous Nephropathy (PMN). Your diagnosis needs to be confirmed by a specific blood test showing a certain level of a marker called anti-PLA2R antibody. You must also be considered at high risk for your kidney disease getting worse. This includes having high levels of protein in your urine on two separate occasions and having healthy kidney function (at least 60 mL/min/1.73 m2).

You also need to be taking certain blood pressure medicines (ACE inhibitors or ARBs) for at least 8 weeks at a stable dose, or be willing to start this treatment. If you are taking another medicine called Rituximab for your PMN, you must be willing to take antibiotics to prevent infections and have certain vaccinations.

There are also reasons why you might not be able to join. For example, if your kidney function is getting worse very quickly, or if you've had a kidney transplant, a planned transplant, or need dialysis. If you have any other serious health conditions that could interfere with the study, or if you've had a serious, life-threatening kidney issue called Nephrotic Syndrome within the last year, you would not be able to participate.

Taking part in this study would involve regular visits to the clinic for check-ups, blood tests, and urine tests to monitor your kidney function and general health. You would receive either the study medicine, ALXN1920, or a placebo, which looks like the real medicine but contains no active drug. You would also continue to receive your usual standard care for PMN. The study team will explain exactly what tests you'll have, how often your visits will be, and how long you'll be involved in the study. You will also need to take antibiotics if you are on Rituximab and ensure you are up to date on specific vaccinations.