A Study of ALXN1920 Compared to Placebo in Adults with Primary Membranous Nephropathy at High Risk for Disease Progression

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What is this study about?

This study is looking at Primary Membranous Nephropathy, which is a kidney disease that causes damage to the filtering units of the kidneys, leading to protein leaking into the urine. The study will test a medicine called ALXN1920, which is also known by the code name TPP-3621. Some people in the study will receive ALXN1920 while others will receive placebo. The medicine will be given as an injection under the skin. The purpose of the study is to see how well ALXN1920 works compared to placebo in reducing the amount of protein in the urine of people with this kidney disease who are at high risk for the disease getting worse.

People taking part in this study will be adults between 18 and 75 years old who have been diagnosed with Primary Membranous Nephropathy through a positive blood test for a specific antibody called anti-PLA2R antibody. They will need to have high levels of protein in their urine despite being treated with standard blood pressure medicines for at least eight weeks. During the study, participants will continue taking their usual kidney disease treatments along with the study medicine or placebo. The study will last up to 26 weeks, and doctors will regularly check the amount of protein in the urine, blood test results, and overall health of the participants.

Throughout the study, doctors will measure changes in protein levels in the urine, blood albumin levels, which is a protein that can be low in people with this kidney disease, and levels of the anti-PLA2R antibody in the blood. They will also count certain immune cells called CD20+ B cells in the blood and check various markers in the urine and blood. The study team will monitor for any side effects and measure how much of the study medicine is in the body over time. Additionally, they will check if the body develops any immune response to the study medicine.

1 Initial treatment preparation

Upon joining the study, your blood pressure medication (ACE inhibitors or ARB) will be continued. These medications help control blood pressure and reduce protein loss in urine.

Your doctor will ensure that the dose of this medication has been adjusted to the highest level you can tolerate.

You will receive prophylactic antibiotics to reduce the risk of infections during the study. These are preventive antibiotics taken to protect you while receiving other study treatments.

You will be vaccinated against Neisseria meningitidis, a type of bacteria that can cause serious infections.

2 Study medication administration

You will be assigned to receive either ALXN1920 or placebo. A placebo is an inactive substance that looks like the study medication but contains no active treatment.

The study medication will be administered as an injection under the skin (subcutaneous injection).

The assignment to ALXN1920 or placebo will be done randomly, similar to flipping a coin, and neither you nor your doctor will know which treatment you are receiving during the study.

3 Regular monitoring visits

Throughout the study, you will attend scheduled visits at the study site.

During these visits, urine samples will be collected to measure the amount of protein in your urine. This may include both 24-hour urine collections and single urine samples.

Blood samples will be taken to measure various substances, including albumin levels (a protein in blood), anti-PLA2R antibody levels (antibodies related to your kidney condition), and CD20+ B cell counts (a type of immune cell).

Your blood pressure will be measured regularly.

Electrocardiograms (ECGs) will be performed. This is a test that records the electrical activity of your heart.

Your doctor will check for any side effects or health changes you may experience.

4 Safety assessments

Throughout the study, you will be monitored for any adverse events, which are any unwanted medical occurrences or side effects.

Additional blood and urine tests will be performed to check for specific markers related to kidney function and the study medication’s effects on your body.

Tests will be conducted to measure the concentration of ALXN1920 in your blood and urine to understand how your body processes the medication.

Your immune response to the study medication will be assessed by checking for anti-drug antibodies, which are antibodies your body might produce in response to the medication.

5 Completion of treatment period

The study treatment period will continue according to the protocol schedule.

You will continue to attend all scheduled visits and complete all required assessments.

The study is expected to continue until March 2027, though your individual participation duration will be specified by your study doctor.

Who Can Join the Study?

You must be between 18 and 75 years old at the time you sign the consent form to join the study
You must have a confirmed diagnosis of Primary Membranous Nephropathy, which is a kidney disease where the filtering parts of your kidneys become damaged
Your diagnosis must be confirmed by a blood test showing anti-PLA2R antibody levels greater than 50 RU/mL. These are specific proteins in your blood that indicate this kidney condition
You must be at high risk for your kidney disease getting worse, which means you need to meet certain requirements about your blood pressure medication and protein levels in your urine
You must have been taking ACE inhibitors or ARB medications for at least 8 weeks before joining. These are blood pressure medications that also help protect your kidneys. The dose should be at the highest level you can tolerate
If you have not been on these blood pressure medications for 8 weeks yet, you may enter a preparation period of up to 8 weeks
Your blood pressure must be below 140 mmHg in at least 75% of readings taken over the past 8 weeks while on these medications
You must have two separate measurements showing high levels of protein in your urine, each showing more than 3.5 grams per day. The second measurement should not show more than a 50% decrease from the first
You can be male or female
You must agree to follow the birth control methods required by the study
You must sign the informed consent form, which means you understand and agree to follow the study rules and requirements
You must be willing to provide consent for optional genetic research samples if you choose to participate in that part
You must be willing to receive the standard background care treatments
You must be willing to take antibiotic medications to prevent infections while receiving the study treatment
You must be willing to receive a vaccine against Neisseria meningitidis, which is a type of bacteria that can cause serious infections

Who Cannot Join the Study?

The source data does not provide specific exclusion criteria, which are the reasons why a patient cannot participate in the study
Without detailed information about who cannot join this clinical trial, it is not possible to list the specific conditions or situations that would prevent participation
Generally, exclusion criteria in clinical trials may include things like other serious health problems, certain medications being taken, pregnancy, or laboratory test results that fall outside acceptable ranges, but the specific criteria for this study are not available in the provided information

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Oncopole Claudius Regaud	Toulouse	France

Other Sites

Site Name	City	Country
Hospital General Universitario Gregorio Maranon	Madrid	Spain
Istituto Di Ricerche Farmacologiche Mario Negri	Ranica	Italy
Fundacio Puigvert	Barcelona	Spain
Virgen del Rocío University Hospital	Sevilla	Spain
Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico	Milan	Italy
Universita’ Politecnica Delle Marche	Ancona	Italy
Centre Hospitalier Universitaire De Nice	Nice	France

Trial status

Country	Status	Recruitment Start
France	Recruiting	17.10.2025
Italy	Recruiting	17.10.2025
Spain	Recruiting	17.10.2025

Trial locations

Investigated drugs:

ALXN1920

ALXN1920 is an experimental medication being tested in this clinical trial for people with primary membranous nephropathy, a kidney disease. This medicine is being studied to see if it can help reduce the amount of protein in the urine, which is a sign of kidney damage. The medication is given to participants who have a high risk of their kidney disease getting worse.

Placebo is an inactive substance that looks like the real medication but contains no active medicine. It is used in this study to compare against ALXN1920 to help researchers understand if the real medication is working better than no treatment.

Investigated diseases:

Nephropathy

Primary Membranous Nephropathy – Primary Membranous Nephropathy is a kidney disease that affects the filters in the kidneys called glomeruli. The disease occurs when the immune system mistakenly attacks the kidney’s filtering membranes, causing them to become thick and damaged. This damage leads to protein leaking from the blood into the urine, a condition called proteinuria. As the disease progresses, the kidneys gradually lose their ability to filter waste properly. People with this condition may experience swelling in their legs and ankles due to fluid retention and low levels of protein in the blood. The disease can progress at different rates, with some individuals experiencing a more rapid decline in kidney function than others.

Trial ID:

2025-520780-40-00

Protocol code:

ALXN1920-PMN-201

Trial Phase:

Therapeutic exploratory (Phase II)

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A Study of ALXN1920 Compared to Placebo in Adults with Primary Membranous Nephropathy at High Risk for Disease Progression

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?