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Study on the Safety and Effectiveness of Bezuclastinib for Patients with Advanced Systemic Mastocytosis

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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 Advanced Systemic Mastocytosis, which is a rare disorder where certain cells in the body, called mast cells, grow uncontrollably and accumulate in various organs. The study is investigating a treatment called Bezuclastinib, also known by its code name CGT9486. Bezuclastinib is a type of medication that is taken orally in the form of a tablet and works by inhibiting specific mutations in a protein called KIT kinase, which is often involved in the growth of mast cells in this disease.

The purpose of the study is to evaluate the safety and effectiveness of Bezuclastinib in patients with Advanced Systemic Mastocytosis. The study is divided into different parts. Initially, it aims to find a safe and effective dose of Bezuclastinib. Once the optimal dose is identified, the study will further assess how well this dose works in treating the disease. Participants will take the medication and undergo regular assessments to monitor their response to the treatment and any side effects they may experience.

Throughout the study, various health parameters will be monitored, including changes in the levels of certain markers in the blood and bone marrow, such as the KIT D816V mutation and serum tryptase levels. The study will also track the overall response to the treatment, the duration of response, and any changes in symptoms or quality of life. The trial is expected to continue until 2027, providing valuable information on the potential benefits and risks of Bezuclastinib for patients with this challenging condition.

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

    Joining the study

    Upon joining the study, the patient is diagnosed with one of the following conditions: aggressive systemic mastocytosis, systemic mastocytosis with an associated hematologic neoplasm, or mast cell leukemia.

    The patient must have measurable disease and an ECOG status between 0 and 3, indicating their level of functioning in daily activities.

    Laboratory screening results must be clinically acceptable within certain limits.

  2. Step 2

    Part 1: dose optimization

    The patient receives the medication CGT9486 in the form of a tablet, taken orally.

    The main objective is to identify a clinically active and tolerable dose range of the medication.

    Safety assessments and dose modifications are conducted, along with pharmacokinetic (how the drug moves through the body) and pharmacodynamic (the effects of the drug on the body) assessments.

    The overall response rate to the medication is evaluated.

  3. Step 3

    Part 2 stage 1: dose confirmation

    The patient continues to receive CGT9486 at the optimal dose identified in Part 1.

    The focus is on confirming the optimal dose's safety and effectiveness.

    Similar assessments as in Part 1 are conducted, including safety and dose modifications, pharmacokinetic and pharmacodynamic assessments, and overall response rate.

  4. Step 4

    Part 2 stage 2: expansion

    The patient continues treatment with the confirmed optimal dose of CGT9486.

    The primary goal is to determine the medication's efficacy at this dose.

    The overall response rate is the main focus of this stage.

  5. Step 5

    Secondary assessments

    Throughout the trial, secondary assessments include monitoring the incidence of adverse events, changes in laboratory results, and the duration and time to response.

    Other assessments involve progression-free survival, overall survival, and changes in specific blood and bone marrow markers.

    The patient's quality of life and symptom changes are also evaluated.

Who can join the trial?

9 criteria

  • The patient must have been diagnosed with one of the following types of **advanced mastocytosis**:
    • **Aggressive Systemic Mastocytosis (ASM)**: A severe form of mastocytosis affecting multiple organs.
    • **Systemic Mastocytosis with an Associated Hematologic Neoplasm (SM-AHN)**: Mastocytosis that occurs with another blood-related disease.
    • **Mast Cell Leukemia (MCL)**: A rare and aggressive form of leukemia involving mast cells.
    • The patient must have a **measurable disease** according to specific criteria used by doctors to assess the condition.
    • The patient must have an **ECOG Status** between 0 to 3. This is a scale used to assess how a disease affects a patient's daily living abilities, where 0 means fully active and 3 means limited self-care.
    • The patient must have **clinically acceptable laboratory screening results**. This means their blood tests and other lab results must be within certain safe limits.
    • Other specific criteria defined in the study protocol may also apply.
    • The study is open to both **male and female** patients.
    • The study includes patients from a **vulnerable population**, which means it may involve individuals who need special protection or consideration.

Who cannot join the trial?

5 criteria

  • Patients who do not have Advanced Systemic Mastocytosis cannot participate. This is a condition where certain cells in the body grow uncontrollably.
  • 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 part of the specified clinical trial groups cannot participate. This means the study is looking for specific types of participants.
  • Both male and female patients are eligible, but if a patient does not meet other gender-specific criteria, they cannot participate.
  • Patients who are considered part of a vulnerable population may not be eligible. This refers to groups who might need special protection or care.
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Investigated drugs

Bezuclastinib is a medication being studied for its safety and effectiveness in treating patients with advanced systemic mastocytosis, a condition where there is an abnormal accumulation of mast cells in the body. The trial aims to find a dose that is both effective and well-tolerated by patients. Bezuclastinib is being tested to see how it works in the body and how it affects the symptoms of the disease.

What is already known about the treatment

Bezuclastinib – This medication is administered orally and is currently being studied in clinical trials for its safety and effectiveness in treating advanced systemic mastocytosis. It is not yet widely used in medical practice, as it is still under investigation. The main therapeutic indication for bezuclastinib is advanced systemic mastocytosis, a condition characterized by the accumulation of mast cells in various organs. At the molecular level, bezuclastinib works by inhibiting specific enzymes that are involved in the growth and survival of these mast cells. It is classified pharmacologically as a tyrosine kinase inhibitor, which targets and blocks the action of certain proteins that promote cancer cell growth.

Investigated diseases

Advanced Systemic Mastocytosis – This is a rare condition characterized by the accumulation of mast cells in various tissues, including the skin, bone marrow, liver, and spleen. These mast cells release substances that can cause symptoms such as skin rashes, abdominal pain, and anaphylaxis. Over time, the disease can lead to organ dysfunction due to the infiltration of mast cells. The progression of the disease varies, with some individuals experiencing a slow progression while others may have a more rapid course. Symptoms can fluctuate, with periods of stability followed by exacerbations. The condition is often associated with genetic mutations, particularly in the KIT gene.
Trial detailsLast updated 4 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-511407-42-00Protocol codeCGT9486-20-201Estimated enrolment140 patientsSponsorCogent Biosciences Inc.

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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).