Treatment of severe indolent systemic mastocytosis with masitinib

Phase 3 Study to Compare Oral Masitinib to Placebo in Treatment of Patients With Smouldering or Indolent Severe Systemic Mastocytosis, Unresponsive to Optimal Symptomatic Treatment

PHASE3 · AB Science · NCT04333108

This study is testing if a new medication called masitinib can help people with severe symptoms of systemic mastocytosis who haven't found relief from other treatments.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment140 (estimated)
Ages18 Years to 75 Years
SexAll
SponsorAB Science (industry)
Drugs / interventionsmasitinib
Locations17 sites (Amiens and 16 other locations)
Trial IDNCT04333108 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates the efficacy and safety of oral masitinib compared to a placebo in patients with severe symptoms of indolent or smoldering systemic mastocytosis who have not responded to optimal symptomatic treatments. The study is a multicenter, randomized, double-blind, placebo-controlled trial that involves a 24-week treatment period. Participants will receive escalating doses of masitinib, a selective tyrosine kinase inhibitor, aimed at modulating mast cell activity. The trial focuses on patients experiencing significant symptoms related to mast cell mediator release.

Who should consider this trial

Good fit: Ideal candidates are patients with documented smoldering or indolent systemic mastocytosis and severe symptoms unresponsive to previous treatments.

Not a fit: Patients with cutaneous mastocytosis or those who have not experienced treatment failure with prior therapies may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly alleviate severe symptoms for patients suffering from systemic mastocytosis.

How similar studies have performed: Other studies have shown promise with similar approaches targeting mast cell activity, but this specific application of masitinib is novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Patient with one of the following documented mastocytosis subtypes (variants): Smouldering Systemic Mastocytosis, Indolent Systemic Mastocytosis
2. An excess of mast cells or a presence of abnormal mast cells in at least two organs (among skin, bone-marrow and GI Tract).
3. Patient with documented systemic mastocytosis and evaluable disease based upon histological criteria
4. Patient with documented treatment failure of his/her symptom(s) (within the past 2 years) with at least two of the symptomatic treatments used at optimized dose: Anti H1, Anti H2, Proton pump inhibitor, Antidepressants, Cromoglycate Sodium, Antileukotriene.
5. Patient with severe symptoms of mastocytosis over the 14-day run-in period including at least one among pruritus, flushes, and depression: pruritus score ≥ 9, number of flushes per week ≥ 8, Hamilton rating scale for depression (HAMD-17) score ≥ 19.

Exclusion Criteria:

1. Patient with one of the following mastocytosis: Cutaneous Mastocytosis, Systemic Mastocytosis with an Associated clonal Hematologic Non Mast cell lineage Disease (SM-AHNMD), Mast cell leukemia (MCL), Aggressive systemic mastocytosis (ASM)
2. Previous treatment with any Tyrosine Kinase Inhibitor
3. Treatment with any investigational agent within 8 weeks prior to screening.

Where this trial is running

Amiens and 16 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Indolent Systemic Mastocytosis, Mastocytosis with handicap, Mastocytosis, Mast cell, Mast cell infiltration, Skin, Bone marrow, Pruritus

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.