Mirabegron / Polycystic Ovary Syndrome / B Complex Plus Vitamin C Tablets · Phase 1 Trial

The Physiological Responses and Adaptation of Brown Adipose Tissue to Chronic Treatment With Beta3-Adrenergic Receptor Agonists

ClinicalTrials.gov · August 19, 2026

Preliminary Why this matters to you Expert discussion

Early or partial results. Treat as a signal, not a conclusion.

AI Summary

This is a Phase 1 trial registration (NCT03049462) examining physiological responses of brown adipose tissue to mirabegron, a beta-3 agonist, in people with polycystic ovary syndrome. The study is still recruiting; no outcome data are posted in this registry record.

What was studied

Phase 1, Interventional, Randomized, Parallel, Quadruple masking, Basic Science purpose. Polycystic Ovary Syndrome; age from 18 Years; to 40 Years. Intervention: Cohort 1. Compared with: Cohort 2A — Active Comparator; Cohort 3A — Active Comparator; Cohort 2B — Placebo Comparator; Cohort 3B — Placebo Comparator. n = 100. 1 site: United States.

Key findings

Safety

Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.

Who this may help

No clinical conclusions can be drawn from a registry record with no results posted. Clinicians should await publication of outcomes before interpreting any findings on BAT physiology or mirabegron efficacy in PCOS.

Plain-language summary

Phase 1 interventional study of a beta-3 agonist in polycystic ovary syndrome with planned physiological endpoints; no results posted in this registry record.

Study design

As stated by the source record.

MethodsPrimary outcome measures: Cohorts 1 and 2: Change in BAT metabolic activity (assessed at 4 weeks); Cohort 3: Change in insulin sensitivity (assessed at 4 weeks)

DesignPhase 1, Interventional, Randomized, Parallel, Quadruple masking, Basic Science purpose

PopulationPolycystic Ovary Syndrome; age from 18 Years; to 40 Years

Sample size100

InterventionCohort 1

ComparatorCohort 2A — Active Comparator; Cohort 3A — Active Comparator; Cohort 2B — Placebo Comparator; Cohort 3B — Placebo Comparator

Setting1 site: United States

Reported figures

Quoted from the source exactly as published.

Planned enrollment100

Study phasePhase 1

Primary outcome measure (Cohorts 1 & 2)Change in BAT metabolic activity at 4 weeks

Primary outcome measure (Cohort 3)Change in insulin sensitivity at 4 weeks

Intervention duration4 weeks

Clinical bottom line

Caveats

Results are not yet reported in this registry record; study is still recruiting.
No blinding specified for outcome assessors or participants in relation to BAT or metabolic endpoints.
Partial randomization design (men only randomized; all women receive mirabegron).
Phase 1 study; generalizability to broader populations and clinical relevance unknown until results are posted.

Evidence assessment

Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.

Study design

moderate

Phase 1, interventional, with some randomization (men only); small planned sample.

Directness

moderate

Measures BAT metabolic activity and insulin sensitivity directly via imaging and FSIVGIT.

Consistency

insufficient

No results reported; cannot assess consistency with other evidence.

Risk of bias

limited

Phase 1, partial randomization (men only), no blinding specified for BAT or metabolic assessments.

Sample adequacy

limited

Estimated 100 participants enrolled across three cohorts; Phase 1 exploratory design.

What is missing. This record has no key findings. That is a gap in the analysis, not a judgement about the study.

Source abstract

Registry record from ClinicalTrials.gov (NCT03049462). This is a study registration, not published results. Lead sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Recruitment status: RECRUITING. Phase: PHASE1. Study type: INTERVENTIONAL. Enrollment: 100 participants (ESTIMATED). Conditions: Polycystic Ovary Syndrome. Interventions: DRUG: Mirabegron; OTHER: B Complex Plus Vitamin C Tablets. Primary outcome measures: Cohorts 1 and 2: Change in BAT metabolic activity , 4 weeks; Cohort 3: Change in insulin sensitivity , 4 weeks. Brief summary: Background: Brown adipose tissue (BAT) is a type of fat in the body. It may prevent weight gain, improve insulin sensitivity, and reduce fatty liver. Researchers want to see if BAT helps the body burn energy. Objective: To learn more about how BAT works to burn energy. Eligibility: People ages 18-40 with a body mass index between 18 and 40 Design: Participants will be screened with: Medical history Physical exam Blood, urine, and heart tests Dietitian interview Participants will have an overnight baseline visit. This includes: Repeats of screening tests Exercise test Scans. For one scan, a radioactive substance is injected into the arm. FSIVGIT: An IV is inserted into veins in the right and left arms. Glucose and insulin are injected in one arm. Blood glucose and insulin levels are measured from the other. Metabolic suite: Participants stay 18-19 hours in a room that measures their metabolic rate. Monitors on the body measure heart rate, movement, and temperature. Optional fat biopsy: A small piece of tissue is removed with a needle. Participants will take 2-4 pills daily for 4 weeks. All women will take the drug mirabegron. Men will be randomly get either the drug or a placebo. All participants will have a visit after 2 weeks of the pills. They will repeat the screening tests. Participants will have an overnight visit 2 weeks later. They will repeat the baseline tests. Participants will keep food and medication diaries. Participants will have a follow-up visit 2 weeks after stopping the pills. This includes heart tests.

Follow from this

Taken from the source record, never inferred. Follow any of these and new work involving them reaches your briefing.

NCT03049462MirabegronPolycystic Ovary SyndromeB Complex Plus Vitamin C TabletsNational Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)