A Study to Evaluate Laser Speckle Contrast Imaging to Assess Changes in Chemical Agent-Induced Skin Blood Flow in Healthy Participants (MK-0000-420)

A Pilot Study to Evaluate the Use of Laser Speckle Contrast Imaging on Changes in Dermal Blood Flow Induced by Intradermal Capsaicin and Topical AITC in Healthy Participants

Pain is a significant issue and there is a need for better treatments for pain management. Local changes in skin blood flow can be used as an indicator of pain in the body. Capsaicin and allyl isothiocyanate (AITC) increase blood flow and cause pain. The purpose of this study is to evaluate the use of laser speckle contrast imaging (LSCI) as a tool to assess changes in skin blood flow. Researchers want to learn about the effect size and reproducibility of using LSCI to measure the blood flow response to capsaicin and AITC.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Drug: Allyl Isothiocyanate (AITC); Drug: Capsaicin; Other: Vehicle for AITC; Other: Vehicle for Capsaicin

• Study Type: Interventional
• Enrollment (Actual): 12
• Phase: Phase 1

Contacts and Locations

Study Locations

• Belgium
  • Vlaams-Brabant
    • Leuven, Vlaams-Brabant, Belgium, 3000
      • Center for Clinical Pharmacology (CCP) (Site 0001)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Is in good health based on medical history, physical examination, vital sign measurements, and electrocardiograms performed before randomization
• Has a skin surface without significant skin allergies, pigmentary disorders or active dermatological conditions that may interfere with the conduct of the laser speckle contrast imaging (LSCI) assessment

Exclusion Criteria:

• Has a history of clinically significant endocrine, gastrointestinal, hematological, hepatic, immunological, renal, respiratory, or genitourinary abnormalities or diseases
• Has a history of stroke, chronic seizures, epilepsy, peripheral neuropathy or other clinically significant neurological disease or cognitive impairment that are severe enough to interfere with assessment of pain (sensory) systems

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Laser Speckle Contrast Imaging; Participants receive topical Allyl Isothiocyanate (AITC) application and intradermal capsaicin application sequentially along with a placebo comparator (vehicle for AITC and vehicle for capsaicin) once every 2 weeks per protocol to perform laser speckle contrast imaging.	Drug: Allyl Isothiocyanate (AITC); Topical administration; Drug: Capsaicin; Intradermal administration; Other: Vehicle for AITC; Topical administration; Other: Vehicle for Capsaicin; Intradermal administration

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Dermal Blood Flow (DBF) in the Region of Interest (ROI)	DBF is defined as the local changes in the skin blood flow after application of study intervention. DBF will be measured via a Laser Speckle Contrast Imager. The mean DBF in the ROI will be reported.	Up to approximately 60 minutes
Area Under the Curve from Time 0 to 20 Minutes (AUC0-20) of Mean DBF in the ROI	AUC0-20 is defined as the area under the curve from time 0-20 minutes. DBF is defined as the local changes in the skin blood flow after application of study intervention. DBF will be measured via a Laser Speckle Contrast Imager. AUC0-20 of mean DBF in ROI will be reported.	Up to approximately 20 minutes
Area Under the Curve from Time 0 to 60 Minutes (AUC0-60) of Mean DBF in the ROI	AUC0-60 is defined as the area under the curve from time 0-60 minutes. DBF is defined as the local changes in the skin blood flow after application of study intervention. DBF will be measured via a Laser Speckle Contrast Imager. AUC0-60 of mean DBF in ROI will be reported.	Up to approximately 60 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from Baseline in the Mean Intensity of DBF (Flare-1 Mean)	Flare-1 mean is defined as the mean perfusion of measurement points exceeding baseline mean DBF + 1 standard deviation. The change from baseline in the mean intensity of DBF (Flare-1 Mean) will be reported.	Baseline, Up to 60 minutes
Change from Baseline in the Area of DBF (Flare-1 Area)	Flare-1 area is defined as the total area of points with perfusion values exceeding baseline mean DBF + 1 standard deviation. The change from baseline in the area of DBF (Flare-1 Area) will be reported.	Baseline, Up to 60 minutes
Change from Baseline in the Mean Intensity of DBF (Flare-2 Mean)	Flare-2 mean is defined as the mean perfusion of points with perfusion values exceeding baseline mean DBF + 2 standard deviations. The change from baseline in the mean intensity of DBF (Flare-2 Mean) will be reported.	Baseline, Up to 60 minutes
Change from Baseline in the Area of DBF (Flare-2 Area)	Flare-2 area is defined as total area of points with perfusion values exceeding baseline mean DBF + 2 standard deviations. The change from baseline in the area of DBF (Flare-2 Area) will be reported.	Baseline, Up to 60 minutes
Mean Change From Baseline in Pain Intensity Measured Using a Pain Numeric Rating Scale (NRS)	The participant's pain intensity will be assessed on each arm utilizing a pain numeric rating scale (NRS). NRS will characterize pain on a scale of 0 to 10, with 0 being 'no pain' and 10 being the 'worst pain' imaginable. The higher score indicates worse pain intensity. The mean change from baseline in pain intensity will be reported.	Baseline, Up to 60 minutes

Collaborators and Investigators

• Sponsor: Merck Sharp & Dohme LLC
• Investigators: Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

Helpful Links

• Merck Clinical Trials Information

Study record dates

Study Major Dates

• Study Start (Actual): September 25, 2023
• Primary Completion (Actual): December 15, 2023
• Study Completion (Actual): December 15, 2023

Study Registration Dates

• First Submitted: January 30, 2025
• First Submitted That Met QC Criteria: January 30, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 30, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Antineoplastic Agents; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Peripheral Nervous System Agents; Enzyme Inhibitors; Dermatologic Agents; Sensory System Agents; Protective Agents; Antipruritics; Anticarcinogenic Agents; Capsaicin; Phenethyl isothiocyanate
• Other Study ID Numbers: 0000-420; MK-0000-420 (Other Identifier: MSD)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: http://engagezone.msd.com/doc/ProcedureAccessClinicalTrialData.pdf

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No