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A study testing how inebilizumab works and how safe it is in children and teenagers aged 2 to 17 years with generalized myasthenia gravis

Verified siteRegistered drugNo placebo
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What is this trial about?

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

This study involves children and teenagers with generalized Myasthenia Gravis, a condition where the immune system attacks the connections between nerves and muscles, causing muscle weakness that can affect various parts of the body including the eyes, face, throat, and limbs. The treatment being tested is inebilizumab, also known by its code name AMG 335, which is given as an infusion into a vein. This medication is designed to work by targeting certain immune cells called B-cells that may play a role in causing the disease.

The purpose of the study is to understand how the body of children and teenagers processes inebilizumab, how the medication affects certain immune cells in the blood, and whether it is safe and well-tolerated in this age group. The study will measure how much of the medication is present in the blood over time, how it affects the number of specific immune cells known as CD20-positive B-cells, and whether any side effects occur during treatment. Participants may continue taking their current medications for myasthenia gravis, which could include steroids, other immune-suppressing medicines such as azathioprine, mycophenolate mofetil, or mycophenolic acid, and medications that help with muscle strength like pyridostigmine.

During the study, doctors will regularly check participants through blood tests and measurements of muscle strength and daily activities to see how the disease is responding to treatment. The study will also look at whether the body develops any immune response against the medication itself. All participants will receive the active treatment as this is an open-label study, meaning everyone will know they are receiving inebilizumab rather than a placebo.

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

    Upon joining the study, you will receive inebilizumab, which is the medication being tested. This is a type of treatment given directly into your vein, known as an intravenous infusion.

    The medication will be administered as Uplizna 100 mg concentrate for solution for infusion.

    During this period, you will continue taking any medications you were already using before the study, such as corticosteroids or other treatments for myasthenia gravis, at the same doses you were taking before enrollment.

    If you are taking acetylcholinesterase inhibitors (such as pyridostigmine, which helps improve muscle strength), you will continue taking them at the same stable dose you were using for at least 2 weeks before joining the study.

  2. Step 2

    Regular monitoring visits

    Throughout the study, you will attend regular visits where various assessments will be performed.

    Blood samples will be taken to measure the amount of medication in your bloodstream and to check how it affects your body.

    Specific blood tests will measure CD20+ B-cell counts, which are a type of immune cell that the medication targets.

    Standard laboratory tests will be performed to monitor your overall health and safety.

    Your vital signs will be checked, including blood pressure, heart rate, and temperature.

  3. Step 3

    Disease assessment evaluations

    Your myasthenia gravis symptoms will be evaluated using specific scoring systems.

    The Quantitative Myasthenia Gravis score will be measured to assess changes in your muscle strength and function.

    The Myasthenia Gravis Activities of Daily Living score will be used to evaluate how the condition affects your daily activities.

    These assessments will be repeated at scheduled intervals throughout the study to track any changes in your condition.

  4. Step 4

    Safety monitoring

    Throughout the entire study period, you will be monitored for any side effects or health changes.

    Any new symptoms or health problems that occur after starting the treatment will be recorded and evaluated.

    Blood tests will be performed regularly to check for the presence of anti-drug antibodies, which are proteins your body might produce in response to the medication.

    All safety information will be collected continuously during your participation in the study.

  5. Step 5

    Continuation of treatment

    The study will continue for an extended period, with the estimated completion date in 2030.

    You will continue to receive inebilizumab infusions according to the study schedule.

    All monitoring activities, including blood tests, symptom assessments, and safety evaluations, will continue throughout your participation.

    Your existing medications for myasthenia gravis will be maintained at stable doses as determined at the beginning of the study.

Who can join the trial?

9 criteria

  • You must be at least 2 years old but younger than 18 years old on the day you join the study.
  • You must have a diagnosis of generalized Myasthenia Gravis, which is a condition where muscles become weak and tire easily. This diagnosis must be confirmed by a positive blood test showing specific antibodies (proteins in your blood that fight against your own body) called anti-AChR or anti-MuSK.
  • You must also have at least one of the following: previous test results showing abnormal signals between nerves and muscles, previous positive response to a test using a medicine called edrophonium chloride, improvement in your muscle weakness symptoms when taking medicines called cholinesterase inhibitors, or symptoms that clearly match generalized Myasthenia Gravis and are not caused by another condition.
  • Your condition must be classified as Class II, III, or IV according to the Myasthenia Gravis Foundation of America system, which measures how severe your symptoms are.
  • Your Quantitative Myasthenia Gravis score must be 11 or higher at the time of screening. This score measures the severity of your muscle weakness.
  • You may be taking corticosteroids (medicines that reduce inflammation) alone, as long as your dose has not been increased in the 4 weeks before screening.
  • You may be taking one specific non-steroidal immunosuppressive therapy (medicines that calm down your immune system), such as azathioprine, mycophenolate mofetil, or mycophenolic acid, as long as you have been taking it continuously for at least 6 months and your dose has not been increased in the 4 months before screening.
  • You may be taking a combination of corticosteroids and one of the allowed non-steroidal immunosuppressive therapies, following the time requirements mentioned above.
  • If you are taking acetylcholinesterase inhibitors such as pyridostigmine (medicines that help improve muscle strength), your dose must have been stable for at least 2 weeks before joining the study.

Who cannot join the trial?

3 criteria

  • The study has not provided specific exclusion criteria in the available documentation
  • For detailed information about who cannot participate in this study, you would need to consult the complete study protocol with the research team
  • Generally, clinical trials have exclusion criteria to ensure participant safety and study accuracy, but these specific details are not available in the current documentation
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Investigated drugs

Inebilizumab is a medication being tested in this study for children and teenagers with generalized Myasthenia Gravis. This medicine works by targeting specific cells in the immune system that may be contributing to the muscle weakness caused by the disease. The study will look at how the body processes this medication, how it affects the immune system, and whether it is safe for young patients to use.

What is already known about the treatment

Inebilizumab – Inebilizumab is a medication given through an intravenous infusion (directly into a vein) that is being studied for the treatment of generalized Myasthenia Gravis in children and adolescents aged 2 to less than 18 years. This medication works by targeting and reducing specific immune cells called B-cells that produce antibodies, which in Myasthenia Gravis mistakenly attack the connections between nerves and muscles, leading to muscle weakness. Inebilizumab belongs to a class of drugs called monoclonal antibodies, which are laboratory-made proteins designed to target specific parts of the immune system. The medication is currently being evaluated in clinical trials to understand how it is processed by the body, how it affects the disease, and whether it is safe and well-tolerated in pediatric patients with this condition.

Investigated diseases

Generalized Myasthenia Gravis – Generalized Myasthenia Gravis is an autoimmune disorder that affects the communication between nerves and muscles throughout the body. The immune system produces antibodies that block or destroy muscle receptor cells, preventing muscle contraction. This condition causes weakness in various muscle groups, including those controlling eye and eyelid movement, facial expression, chewing, swallowing, and speaking. As the disease progresses, weakness can spread to affect the arms, legs, and muscles involved in breathing. Symptoms typically worsen with activity and improve with rest. The severity of muscle weakness can vary from day to day and may fluctuate over time.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase IITrial ID2025-520993-20-00Protocol code20240236Estimated enrolment12 patientsSponsorAmgen Inc.

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