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A Study of Tarperprumig Safety and Effectiveness in Adults with Blood Vessel Inflammation Caused by ANCA Antibodies

Fast replyInvestigationalNo placebo
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What is this trial about?

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

This study is looking at Anti-Neutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis, which is a condition where the body's immune system mistakenly attacks blood vessels, causing inflammation and damage to various organs. The study includes two specific types of this condition: GPA (granulomatosis with polyangiitis) and MPA (microscopic polyangiitis). The treatment being tested is Tarperprumig, also known by its code name ALXN1820, which is given as an injection under the skin. Some participants will receive Tarperprumig while others will receive placebo. The purpose of this study is to evaluate the safety and tolerability of Tarperprumig in people with newly diagnosed or relapsing ANCA-associated vasculitis.

The study will involve participants who are between 18 and 80 years old and have either newly diagnosed or relapsing ANCA-associated vasculitis for which treatment with certain medications is being considered. Participants must have a positive test for specific antibodies called PR3-ANCA or MPO-ANCA and must meet certain disease activity requirements based on a scoring system called BVAS (Birmingham Vasculitis Activity Score). The study will monitor various safety measures including any unwanted effects of the treatment, changes in vital signs, physical examinations, laboratory tests, and heart function tests measured by ECG (electrocardiogram).

During the study, researchers will also look at how well the treatment works by checking if participants achieve disease remission, which means the disease becomes inactive, at different time points including week 26 and week 52. They will measure changes in kidney function using eGFR (estimated glomerular filtration rate), which shows how well the kidneys are filtering waste from the blood. Other measurements will include checking for protein in the urine using tests called UPCR (urine protein-to-creatinine ratio) and UACR (urine albumin-to-creatinine ratio), as well as looking for blood in the urine. The study will also track any disease damage over time using the Vasculitis Damage Index and monitor whether the disease comes back after achieving remission. The study is expected to run for approximately 52 weeks for each participant.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment period with study medication

    After joining the study, you will receive either tarperprumig or a placebo. A placebo is an inactive substance that looks like the real medication but contains no active ingredient.

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

    You will receive this treatment alongside standard therapy, which may include rituximab or cyclophosphamide, medications commonly used to treat your condition.

    The study is designed so that neither you nor your doctor will know whether you are receiving the active medication or placebo during the treatment period.

  2. Step 2

    Regular monitoring and assessments

    Throughout the study, your health will be monitored through various assessments.

    Your doctor will check your vital signs, which include blood pressure, heart rate, and temperature.

    You will undergo physical examinations to assess your overall health.

    Regular blood tests and urine tests will be performed to monitor your kidney function and disease activity.

    An electrocardiogram (ECG) will be performed to check your heart's electrical activity.

    Your disease activity will be assessed using a scoring system called BVAS (Birmingham Vasculitis Activity Score), which measures the severity of your vasculitis symptoms.

  3. Step 3

    Week 26 evaluation

    At week 26 (approximately 6 months after starting), your doctor will evaluate whether your disease is in remission. Remission means that your disease symptoms have significantly improved or disappeared.

    Your kidney function will be assessed by measuring your estimated glomerular filtration rate (eGFR), which indicates how well your kidneys are filtering waste from your blood.

    Tests will measure the amount of protein in your urine using ratios called UPCR and UACR, which help assess kidney damage.

    The presence of blood in your urine (hematuria) will be measured by counting red blood cells.

    Your doctor will assess any damage caused by the disease using the Vasculitis Damage Index (VDI).

  4. Step 4

    Continued treatment and monitoring through week 52

    Treatment and monitoring will continue until week 52 (approximately 1 year).

    Regular assessments will continue throughout this period to track your disease activity and response to treatment.

    Your doctor will monitor whether you maintain remission or experience a relapse, which means the disease becomes active again after improvement.

    If you achieve remission, your doctor will track how long you maintain this improvement, referred to as sustained remission.

    The same tests performed at week 26 will be repeated at week 52, including kidney function tests, urine protein measurements, and disease activity scores.

  5. Step 5

    Safety monitoring throughout the study

    Throughout the entire study period, any side effects or health problems you experience will be carefully recorded and monitored.

    These are called treatment-emergent adverse events (TEAEs), which are any medical problems that occur after starting the study medication.

    Serious health problems, called treatment-emergent serious adverse events (TESAEs), will be closely monitored and reported.

    All changes in your health status compared to your condition at the beginning of the study will be documented.

Who can join the trial?

15 criteria

  • You must be between 18 and 80 years old at the time you agree to join the study
  • You must have newly diagnosed or returning ANCA-associated vasculitis, which is a condition where your immune system attacks your blood vessels. This includes specific types called GPA or MPA
  • Your doctor must consider that treatment with medications called rituximab or cyclophosphamide is appropriate for you
  • You must have a positive test for specific antibodies called PR3-ANCA or MPO-ANCA, either during the screening process or in the past. These are proteins in your blood that help diagnose your condition
  • You must have at least one major sign of active disease, or at least 3 minor signs, or at least 2 kidney-related signs according to a disease activity measurement called BVAS
  • Your kidney function must show an estimated glomerular filtration rate of at least 15, which is a measure of how well your kidneys are filtering waste from your blood
  • There is no weight requirement for this study
  • If you are a man, you must agree to use a condom during sexual activity and not donate sperm during the study and for a specified time after the last dose of the study medication
  • If you are a man, your partner who can become pregnant should also use highly effective birth control
  • If you are a woman who can become pregnant, you must use a highly effective birth control method with less than 1% failure rate during the study and for a specified time after the last dose
  • If you are a woman who can become pregnant, you must have a negative pregnancy test within 24 hours before receiving the first dose of study medication
  • If you are a woman, you must not be pregnant or breastfeeding
  • If you are a woman who can become pregnant, you must agree not to donate eggs during the study and for a specified time after the last dose
  • You must be willing and able to provide written consent to participate in the study
  • You must be able to follow all the requirements of the study

Who cannot join the trial?

4 criteria

  • The study information provided does not list specific reasons why patients cannot participate in this clinical trial
  • If you are interested in participating, the research team will review your complete medical history to determine if you meet all requirements for the study
  • General factors that often prevent participation in clinical trials may include having other serious medical conditions, taking certain medications, being pregnant or breastfeeding, or having allergies to study medications
  • The final decision about your eligibility will be made by the study doctors after a thorough medical evaluation
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Investigated drugs

  • Tarperprumig

    is an investigational medication being tested in this clinical trial for people with a condition that causes inflammation of blood vessels. This medication is being studied to see if it is safe and effective in treating adults with this type of vasculitis.

  • Placebo

    is an inactive substance that looks like the real medication but contains no active treatment. It is used in this study to compare the effects of tarperprumig against no active treatment, helping researchers understand if the medication truly works.

What is already known about the treatment

Tarperprumig – Tarperprumig is an investigational medication currently being studied in clinical trials for the treatment of ANCA-associated vasculitis, a condition where the immune system mistakenly attacks blood vessels causing inflammation and damage. The drug is being tested in a Phase 2 trial to evaluate its safety and effectiveness in adult patients who are newly diagnosed or experiencing a relapse of this autoimmune disease. While the specific form of administration and exact mechanism of action are not detailed in the available trial information, the medication is designed to help control the abnormal immune response that causes blood vessel inflammation in these patients. As an experimental treatment, tarperprumig is not yet approved for general medical use and is only available through participation in controlled clinical research studies.

Investigated diseases

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis – This is a group of rare autoimmune diseases where the body's immune system mistakenly attacks small and medium-sized blood vessels throughout the body. The condition occurs when abnormal antibodies called ANCA cause inflammation and damage to the walls of blood vessels. This inflammation can affect various organs including the kidneys, lungs, skin, joints, and nervous system. The disease can appear suddenly as a new diagnosis or can return after a period of improvement, which is called relapsing. As the condition progresses, it may cause reduced kidney function, protein in the urine, blood in the urine, and damage to affected organs. The severity of symptoms varies depending on which blood vessels and organs are involved in the inflammatory process.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-521706-17-00Protocol codeALXN1820-ANCA-201Estimated enrolment75 patientsSponsorAlexion Pharmaceuticals Inc.

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