Skip to content
Clinical Trials – home

Indolent systemic mastocytosis Trials in Disease

2 / 3 trials open to patients17 countries

In short

Currently, there are 3 clinical trials investigating new treatment options for indolent systemic mastocytosis across multiple European countries. These trials are testing medications that target specific mechanisms of the disease, aiming to improve symptom control and quality of life for patients whose symptoms are not adequately managed by standard therapies.

Clinical trial locations

Study of Elenestinib for Patients with Indolent Systemic Mastocytosis

This trial is investigating Elenestinib, also known as BLU-263, a medication taken as a film-coated tablet. The study aims to determine the right dose of this medication for treating patients whose symptoms are not adequately controlled by standard treatments.

Who can participate: The study is open to patients at least 16 years old in most countries, or 18 years old in France, Sweden, Germany, and Spain. Participants must have a confirmed diagnosis of indolent systemic mastocytosis or smoldering systemic mastocytosis through bone marrow biopsy. They must have a specific genetic marker called KIT D816V in their blood or bone marrow, or have CD25+ mast cells in their bone marrow. Eligible patients need to have symptoms affecting at least two body systems, such as skin flushing, rapid heartbeat, fainting, low blood pressure, diarrhea, nausea, vomiting, or stomach cramps, along with specific blood test results. Patients must have tried at least two different types of treatments without achieving adequate symptom control, and their current symptom management must be stable for at least 14 days before screening.

Who cannot participate: The trial excludes patients with other serious health conditions that might interfere with the study, those who are pregnant or breastfeeding, and those unable to follow study procedures. Patients with uncontrolled infections, recent major surgery, unstable heart conditions, or severe liver or kidney problems are also excluded.

Main goals: The study will assess symptom changes, monitor the burden of mast cells in the body, and evaluate quality of life improvements. Safety will be closely monitored through regular assessments including vital signs, electrocardiograms, and laboratory tests. The medication works by inhibiting specific enzymes involved in the growth and survival of mast cells.

Study of TL-895 for Patients with Relapsed or Refractory Myelofibrosis or Indolent Systemic Mastocytosis

This clinical trial is testing TL-895, an oral medication taken as a film-coated tablet, in patients with either myelofibrosis or indolent systemic mastocytosis. The study is expected to conclude by the end of 2025.

Who can participate: For patients with indolent systemic mastocytosis, you must be 18 years or older with a confirmed diagnosis based on bone marrow biopsy review following World Health Organization criteria. You need to have moderate-to-severe symptoms and adequate blood, liver, and kidney function. Your Eastern Cooperative Oncology Group performance status should be 2 or less, which measures how your disease affects daily living abilities.

Who cannot participate: Patients with other serious health conditions that might interfere with the study, those who are pregnant or breastfeeding, or those who have participated in another recent clinical trial are excluded. Patients taking medications that might interfere with the study drug or those unable to follow study procedures cannot participate.

Main goals: The study aims to determine the recommended phase 2 dose and schedule of TL-895. It will monitor symptoms regularly using a Total Symptom Score at specific intervals, such as at week 24. The medication is classified as a kinase inhibitor, targeting pathways that are often overactive in certain blood disorders. Throughout the study, participants will be assessed to ensure their safety and to evaluate the effectiveness of the treatment.

Study of Avapritinib for Patients with Indolent Systemic Mastocytosis Not Adequately Managed by Standard Therapy

This trial is studying Avapritinib, a tyrosine kinase inhibitor designed to target specific mutations in the KIT gene that are commonly found in patients with this condition. The medication is taken orally as a film-coated tablet.

Who can participate: Patients must be 18 years or older with a confirmed diagnosis of systemic mastocytosis based on bone marrow biopsy review. Eligible participants need to have moderate-to-severe symptoms with a minimum symptom score of 28 over a 14-day period. You must have tried at least two different treatments such as antihistamines, stomach acid reducers, leukotriene inhibitors, cromolyn sodium, corticosteroids, or omalizumab, without achieving adequate symptom control. Current treatments must be stable for at least 14 days, and if taking corticosteroids, the dose must be 20 mg/day or less of prednisone or equivalent. Patients must have an ECOG Performance Status of 0 to 2 and be able to provide written informed consent.

Who cannot participate: The study excludes patients outside the specified age range, those unwilling or unable to follow study procedures, patients with other medical conditions that might interfere with the study, those taking medications that could affect study results, and pregnant or breastfeeding women. Patients who have participated in another recent clinical trial are also excluded.

Main goals: The study is divided into three parts: determining the appropriate dose, comparing symptom changes between those taking the medication and placebo, and assessing long-term safety and effectiveness. The trial will monitor changes in symptoms, mast cell burden, and quality of life. Regular health assessments including vital signs, electrocardiograms, and laboratory tests will ensure patient safety throughout the study.

Summary

All three clinical trials for indolent systemic mastocytosis are available across multiple European countries, with Belgium, France, Germany, Italy, and Spain offering access to all three studies. Each trial focuses on a different investigational medication targeting specific mechanisms of the disease: Elenestinib (BLU-263), TL-895, and Avapritinib. All three medications are tyrosine kinase inhibitors taken orally as tablets, designed to address symptoms not adequately controlled by standard therapies.

The trials share similar inclusion criteria, generally requiring confirmed diagnosis through bone marrow biopsy, moderate-to-severe symptoms, and previous unsuccessful attempts with standard treatments. Age requirements vary slightly, with one study accepting patients from 16 years old in most countries, while the others require participants to be at least 18 years old.

These studies represent important research efforts to find more effective treatment options for patients living with this rare condition, focusing not only on symptom relief but also on quality of life improvements and long-term safety monitoring.

This guide is here to help you understand the condition. It does not replace a conversation with your doctor, who knows your situation best.

Clinical trials for Indolent systemic mastocytosis

Recruiting trials first

See all 3 trials →
Quick filters

3 clinical trials in this condition

Countries:AustriaAustria
  • Participants:18–64 years · 65+ years
  • Substances:Elenestinib Phosphate
  • Sponsor:Blueprint Medicines Corp.
Countries:BelgiumBelgium
  • Participants:18–64 years · 65+ years
  • Substances:1-4-{[6-Amino-5-(4-Phenoxy-Phenyl)-Pyrimidin-4-Ylamino]-Methyl}-4-Fluoro-Piperidin-1-Yl)-Propenone
  • Sponsor:Telios Pharma Inc.
Countries:BelgiumBelgium
  • Participants:18–64 years · 65+ years
  • Substances:Avapritinib
  • Sponsor:Blueprint Medicines Corp.
See all 3 trials →filters applied: condition = Indolent systemic mastocytosis

Related conditions in the same therapeutic area

Back to all diseases
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

Legal notice · Published by CTIN POLAND sp. z o.o., ul. rtm. Witolda Pileckiego 67/109, 02-781 Warsaw, Poland · KRS 0001111334 · REGON 528919042 · NIP 9512598637

© 2026 Clinical Trials EU – European Clinical Trials Information Network

GDPR compliance, ISO 9001 and ISO 27001 certified (LL-C Certification)

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).