(PROSPECTOR) Screening Study Evaluating the Prevalence of the KIT D816V Mutation in Patients With Systemic Mast Cell Activation

Study Evaluating the Prevalence of the KIT D816V Mutation in Peripheral Blood of Patients With Evidence of Systemic Mast Cell Activation (MCA)

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT04811365

Enrollment

379

Registered

2021-03-23

Start date

2021-06-29

Completion date

2023-03-31

Last updated

2023-04-06

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

KIT D816V Mutation, Systemic Mast Cell Activation

Brief summary

This is a multi-center screening study with the primary objective to determine the prevalence of KIT D816V mutation in peripheral blood in patients with evidence of systemic mast cell activation (MCA).

Interventions

OTHERScreening

After providing informed consent, relevant medical history data, and blood and buccal swab samples will be collected at a single visit from patients presenting with systemic mast cell activation symptoms

Study design

Observational model

OTHER

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

* Presenting with at least one of the three criteria below as evidence of systemic mast cell activation: 1. Involvement of 2 or more organ systems, characterized by skin (pruritus, urticaria, flushing and angioedema), cardiovascular (tachycardia, syncope, and hypotension), gastrointestinal (diarrhea, nausea, vomiting, and gastrointestinal cramping) or respiratory/naso-ocular (wheezing, conjunctival injection, and nasal stuffiness) AND serum basal tryptase levels ≥8 ng/ml. One of the organ systems must be the cardiovascular system. 2. Severe anaphylaxis (Ring and Messmer grading ≥II) due to Hymenoptera sting, regardless of serum basal tryptase levels. 3. Severe anaphylaxis (Ring and Messmer grading ≥II), with cardiovascular involvement and documented event-related tryptase elevation fitting the formula 20% of baseline plus 2 ng/ml evaluated in at least 1 event.

Exclusion criteria

* Patient previously diagnosed with any of the following WHO systemic mastocytosis (SM) sub-classifications: mastocytosis in the skin, indolent SM, smoldering SM, SM with associated hematological neoplasm, aggressive SM, mast cell leukemia, mast cell sarcoma

Design outcomes

Primary

Measure	Time frame
Proportion of patients with KIT D816V mutation in peripheral blood	Day 1

Secondary

Measure	Time frame
Mean KIT D816V mutated allele fraction in peripheral blood	Day 1
Proportion of patients with increased tryptase Alpha/ Beta 1 (TPSAB1) alpha-tryptase gene copy number (GCN) in buccal mucosa	Day 1

Countries

Belgium, France, Germany, Italy, Spain, Switzerland, United Kingdom, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026