MIrabegron and Physiological Function in Cold Environments

NCT05990387 | Completed Phase 1 Results FDA Drug

• 1 other identifier: 2011690870; Aim 2
• Study Type: interventional
• Target: 17
• Locations: 1 country
• Sites: 1

Brief Summary

Many Navy diving operations are performed in cold water. Despite technical advances to improve thermal protection for cold water diving, these applications are cumbersome and do not provide complete thermal protection as thermal discomfort is subjectively reported by many Navy divers. Brown adipose tissue is highly thermogenic in humans. Therefore, activation of brown adipose tissue might improve cold water tolerance and lower thermal discomfort during cold water diving operations. Mirabegron is a beta-3-adrenergic receptor agonist that is used to treat overactive bladder. Beta-3-adrenergic receptors are located on the urinary bladder, gallbladder and brown adipose tissue. Recent evidence has demonstrated that acute mirabegron administration increases thermogenesis for \~3 hours in humans. However, it is currently not known which dose of mirabegron can increase thermogenesis for longer durations. It is also not known if mirabegron administration can improve cold water tolerance and thermal discomfort during cold water immersion. Finally, it is not known if mirabegron can increase thermogenesis during sympathetic stimulation. This project will fill these knowledge gaps by determining if acute mirabegron administration will delay the fall in core temperature and the onset of shivering during a progressive cold-water immersion challenge. This study is part of a collection of studies that will show if mirabegron is a potential ergogenic aid that can be used to improve cold water tolerance in Navy divers which will ultimately improve the likelihood of successful missions.

Conditions

Resting Energy Expenditure; Thermogenesis; Brown Adipose Tissue

Outcome Measures

Primary Outcomes (1)

• Cold Temperature Deflection Point

  Core temperature will be continuously measured using rectal thermistors. The point at which core temperature begins to fall (i.e., deflection point) will be identified using Prism 8 software by plotting core temperature vs. water temperature.

  Through session completion, up to 4 hours

Secondary Outcomes (3)

• Thermogenesis - Oxygen Consumption

  Through session completion, up to 4 hours

• Shivering Inflection Point - Surface Mechanomyography

  Through session completion, up to 4 hours

• Shivering Inflection Point - Bedside Shivering Scale

  Through session completion, up to 4 hours

Study Arms (2)

Placebo

PLACEBO COMPARATOR

Given once, followed by observation for up to 4 hours in a progressively cold water challenge

Drug: Placebo

100 mg Mirabegron

EXPERIMENTAL

Given once, followed by observation for up to 4 hours in a progressively cold water challenge

Drug: Mirabegron

Interventions

Mirabegron DRUG

Dose-response effect on thermogenesis

Also known as: Myrbetriq

100 mg Mirabegron

Placebo DRUG

Placebo control condition

Placebo

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Men and women
• years old
• Participate in 150 minutes or more of at least moderate intensity exercise per week during the previous 2 years

You may not qualify if:

• diagnosed autonomic disease
• diagnosed cardiovascular disease
• diagnosed metabolic disease
• diagnosed neurologic disease
• diagnosed endocrine disease
• diagnosed respiratory disease
• diagnosed liver dysfunction
• diagnosed kidney dysfunction
• Women who are pregnant or breastfeeding
• Individuals currently taking a medication (with the exception of birth control, including hormonal contraception) that cannot be safely discontinued for 5 biological half-lifes prior to each study visit based on consultation with the study physician.
• Current tobacco or electronic cigarette use or consistent use within the last 1 year

Sponsors & Collaborators

• Indiana University: lead
• Office of Naval Research (ONR): collaborator

Study Sites (1)

Indiana University

Bloomington, Indiana, 47405, United States

Location

MeSH Terms

Interventions

mirabegron

Results Point of Contact

• Title: Dr. Blair Johnson
• Organization: Indiana University

bj33@iu.edu

8128558699

Study Officials

• Blair D Johnson, PhD

  Indiana University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor School of Public Health

Study Record Dates

• First Submitted: August 4, 2023
• First Posted: August 14, 2023
• Study Start: July 19, 2023
• Primary Completion: April 23, 2024
• Study Completion: April 23, 2024
• Last Updated: July 3, 2025
• Results First Posted: July 3, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)