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Study on Masitinib for Patients with Severe Mast Cell Activation Syndrome Unresponsive to Treatment

Verified siteInvestigationalNo placebo
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What is this trial about?

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

This clinical trial is focused on studying a condition known as Mast Cell Activation Syndrome (MCAS). This is a disorder where certain cells in the body, called mast cells, release too many chemicals, leading to symptoms like skin rashes, flushing, and abdominal pain. The trial will test a medication called masitinib, which is a type of drug known as a tyrosine kinase inhibitor. This medication is taken orally in the form of a coated tablet.

The purpose of the study is to evaluate how effective and safe masitinib is compared to a placebo in treating patients with severe MCAS who have not responded well to other treatments. The study will last for 24 weeks, during which participants will be randomly assigned to receive either masitinib or a placebo. The trial is designed to be double-blind, meaning neither the participants nor the researchers will know who is receiving the actual medication or the placebo until the study is completed.

Throughout the study, participants will have regular check-ups to monitor their response to the treatment and any side effects. The main goal is to see if there is a significant improvement in symptoms such as itching, flushing, depression, and fatigue by the end of the 24 weeks. This trial aims to provide valuable information on whether masitinib can be a beneficial treatment option for those suffering from severe MCAS.

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

    Randomization and initial treatment

    Upon joining the study, you will be randomly assigned to receive either masitinib or a placebo. This process is double-blind, meaning neither you nor the researchers will know which treatment you are receiving.

    The treatment involves taking masitinib in the form of a coated tablet orally. The dosage will be determined as part of the study's dose-range finding approach.

  2. Step 2

    Treatment duration

    The study will last for a total of 24 weeks. During this period, you will continue to take the assigned treatment as directed.

    Regular monitoring will occur to assess the efficacy and safety of the treatment.

  3. Step 3

    Monitoring and assessments

    Throughout the study, you will attend regular visits every four weeks. These visits are designed to monitor your response to the treatment.

    The primary focus will be on evaluating improvements in symptoms such as pruritus (itching), flushes, depression, and fatigue.

  4. Step 4

    Final evaluation

    At the end of the 24-week period, a final assessment will be conducted to determine the overall response to the treatment.

    The primary endpoint is a confirmed response of at least 50% improvement in the specified symptoms.

Who can join the trial?

11 criteria

  • Patient with severe **Mast cell activation syndrome (MCAS)**. This means having episodes of symptoms like skin rashes, swelling, flushing, itching, nausea, voice changes, vomiting, diarrhea, stomach cramps, fainting, fast heartbeat, wheezing, red eyes, stuffy nose, and headaches affecting two or more body systems.
  • Patient must show an increase in a blood marker called **serum total tryptase** during or shortly after symptoms, or have above-normal levels of certain substances related to MCAS in blood or urine tests.
  • Patient must have severe symptoms over a 14-day period, such as high scores for itching, frequent flushing, depression, or fatigue.
  • Patient must have tried and not responded to at least two different treatments for their condition in the past two years, with each treatment lasting at least 8 weeks.
  • Patient must be on a stable dose of **Anti-H1** medication for at least 4 weeks before starting the study and continue this dose during the study. Other treatments like **Corticosteroids**, **Anti-H2**, or others must also be stable if used.
  • Patient must be between 18 to 75 years old.
  • Patient must weigh more than 45 kg and have a **Body Mass Index (BMI)** between 18 and 35.
  • Female patients who can have children must have a negative pregnancy test and agree to use effective birth control methods during the study and for 8 months after the last treatment. Male patients with partners who can have children must also agree to use effective birth control methods during the study and for 5 months after the last treatment.
  • Patient must be able and willing to attend study visits and follow study procedures.
  • Patient must be able to understand, sign, and date a consent form before starting any study-related procedures.
  • Patient must be able to understand and follow instructions in case of severe side effects like low white blood cell count or severe skin reactions.

Who cannot join the trial?

8 criteria

  • Patients who have a different condition than mast cell activation syndrome cannot participate. This is a condition where certain cells in the body release too many chemicals, causing symptoms like itching, swelling, and low blood pressure.
  • Patients who are not experiencing severe symptoms that do not improve with the best available treatments cannot participate.
  • Patients who are not within the specified age range for the study cannot participate. The study is open to certain age groups only.
  • Patients who are not willing or able to follow the study procedures cannot participate.
  • Patients who are pregnant or breastfeeding cannot participate.
  • Patients who have other medical conditions that might interfere with the study cannot participate.
  • Patients who are taking medications that might interfere with the study cannot participate.
  • Patients who have participated in another clinical trial recently cannot participate.
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Investigated drugs

Masitinib is an oral medication being studied for its potential to help patients with severe mast cell activation syndrome (MCAS). This condition involves an overreaction of certain cells in the body, leading to various symptoms. The trial aims to see if masitinib can improve symptoms in patients who have not responded well to other treatments.

What is already known about the treatment

Masitinib – Masitinib is administered orally and is currently being studied in clinical trials for its effectiveness in treating severe mast cell activation syndrome (MCAS) that does not respond to standard treatments. It is in the phase II stage of clinical trials, where its safety and efficacy are being compared to a placebo. The main therapeutic indication for Masitinib is MCAS, a condition characterized by excessive activation of mast cells, leading to various symptoms. At the molecular level, Masitinib works by inhibiting certain enzymes called tyrosine kinases, which play a role in the activation and proliferation of mast cells. It is classified pharmacologically as a tyrosine kinase inhibitor.

Investigated diseases

Mast Cell Activation Syndrome – This condition involves the inappropriate and excessive activation of mast cells, which are a type of white blood cell involved in allergic responses and inflammation. Individuals with this syndrome may experience a range of symptoms, including skin reactions like itching and flushing, as well as systemic issues such as fatigue and depression. The symptoms can vary widely in severity and may be triggered by various factors, including stress, certain foods, or environmental changes. Over time, the condition can lead to significant discomfort and impact daily life, as the symptoms can be persistent and challenging to manage. The progression of the syndrome is often unpredictable, with periods of symptom flare-ups and remissions.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-515193-27-00Protocol codeAB20006Estimated enrolment5 patientsSponsorAb Science

sourced from the EU Clinical Trials Register and site verification

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).