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Study of Mezagitamab in Adults with Primary IgA Nephropathy (Berger's Disease) to Reduce Protein in Urine

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on Primary IgA Nephropathy (also known as Berger's disease), which is a kidney condition where proteins called immunoglobulins build up in the kidneys and cause damage. The study will test a medication called mezagitamab (also known as TAK-079) given by subcutaneous injection under the skin, along with regular kidney disease treatments.

The purpose of this research is to determine if mezagitamab can reduce the amount of protein in the urine of people with Primary IgA Nephropathy. During the study, participants will receive either mezagitamab or placebo injections for up to 104 weeks (2 years). The medication or placebo will be given alongside their usual kidney disease treatments.

The study will monitor changes in kidney function and the amount of protein in participants' urine throughout the treatment period. Researchers will also check for signs of improvement in other symptoms related to kidney disease, including the presence of blood in the urine. The study will track how well participants' bodies respond to the treatment and measure the amount of medication in their blood.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial evaluation

    Your participation begins with confirming that you have IgA Nephropathy (also known as Berger's disease), documented by a kidney biopsy performed within the last 10 years

    Your kidney function will be checked through tests to confirm that your estimated glomerular filtration rate (eGFR) is above 30 mL/min/1.73m2

    Your urine protein levels must show either protein-to-creatinine ratio (UPCR) of 0.8 g/g or higher, or daily protein excretion of 1 g or more

    Your blood pressure readings must be 150/100 mmHg or lower

  2. Step 2

    Treatment phase - first 36 weeks

    You will receive either mezagitamab or a placebo through subcutaneous injection (under the skin)

    The main goal is to measure changes in your protein levels in urine after 36 weeks of treatment

    Regular urine samples will be collected over 24 hours to measure protein levels

    Your kidney function will be monitored through blood tests

  3. Step 3

    Continued monitoring - up to 52 weeks

    Your kidney function will continue to be monitored through regular blood tests

    Changes in your kidney function will be tracked to detect any significant decline

    The presence of blood in your urine will be monitored

  4. Step 4

    Extended follow-up - up to 104 weeks

    Long-term monitoring of your kidney function will continue

    Regular testing will track protein levels in your urine

    Blood samples will be taken to measure medication levels and check for antibodies

    Your urine will be checked for the presence of blood

Who can join the trial?

8 criteria

  • Must have elevated protein levels in urine, shown by either:
    • A urine protein-to-creatinine ratio of 0.8 grams or higher, or
    • Daily protein excretion of 1 gram or more in a 24-hour urine collection
    • Must have adequate kidney function with an eGFR (estimated glomerular filtration rate - a measure of kidney function) greater than 30 mL/min/1.73m²
    • Must have been diagnosed with primary IgA Nephropathy (Berger's disease) confirmed by a kidney biopsy performed within the last 10 years
    • Must have controlled blood pressure with:
      • Systolic (upper number) pressure of 150 mmHg or less
      • Diastolic (lower number) pressure of 100 mmHg or less
      • Must be an adult (18 years or older)
      • Can be either male or female

Who cannot join the trial?

15 criteria

  • Age under 18 years or over 75 years
  • Pregnant or breastfeeding women
  • History of kidney transplant
  • Active infection requiring treatment
  • History of cancer in the past 5 years (except successfully treated skin cancer)
  • Current treatment with other investigational drugs
  • Severe liver disease (problems with liver function)
  • Uncontrolled diabetes (high blood sugar levels)
  • Severe heart disease or heart failure
  • History of severe allergic reactions to medications
  • Active autoimmune disease (when body's immune system attacks healthy cells) other than IgA Nephropathy
  • Major surgery within 3 months before starting the study
  • Alcohol or drug abuse within the past year
  • Mental conditions that could interfere with study participation
  • Unable to provide informed consent
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Investigated drugs

Mezagitamab (TAK-079) is an investigational medication being studied for treating IgA nephropathy, a kidney disease where abnormal antibodies build up in the kidneys. The medication is designed to work with other background therapies to help reduce the amount of protein in the urine (proteinuria), which is a key indicator of kidney damage in people with IgA nephropathy. This medication targets specific components of the immune system that are believed to be involved in the disease process.

What is already known about the treatment

Mezagitamab (TAK-079) - An investigational monoclonal antibody medication that is currently being studied in Phase 3 clinical trials for the treatment of Primary IgA Nephropathy (also known as Berger's disease). The drug is administered through intravenous infusion and works by targeting specific immune system components involved in the disease process. As a biological therapy, it belongs to the class of targeted immunomodulators that aim to reduce protein excretion in urine (proteinuria) in patients with IgA nephropathy who are receiving standard background therapy. The medication is still under clinical investigation and is not yet approved for general medical use.

Investigated diseases

Primary Immunoglobulin A Nephropathy (IgAN) - A kidney disease also known as Berger's disease, where abnormal immunoglobulin A (IgA) proteins build up in the kidneys. The disease causes inflammation in the tiny filtering units of the kidneys called glomeruli. This condition leads to the release of protein and blood into the urine. Over time, IgAN affects the kidneys' ability to filter waste products from the blood. The disease typically progresses slowly, and symptoms may include changes in urination patterns and visible blood in the urine.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-520825-19-00Protocol codeTAK-079-3001Estimated enrolment347 patientsSponsorTakeda Development Center Americas Inc.

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