Limiting AAA With Metformin (LIMIT) Trial (LIMIT)

January 9, 2024 updated by: Ronald L. Dalman, MD, Stanford University

LIMItIng AAA With meTformin (LIMIT) Trial

In this research, the investigators are looking at the effects of a drug called metformin may have on the growth of abdominal aortic aneurysm (AAA)s. AAA is an abnormal enlargement of the aorta, which is the large artery in the abdomen (stomach area). The enlargement of the aorta carries a risk that it will rupture and cause life-threatening bleeding in the abdomen (belly). In this study the investigators hope to learn how metformin is associated with the enlargement or change in size of the AAA in study participants. Smaller studies have suggested that metformin may reduce the rate at which aortic aneurysms enlarge. This study will test this question: does metformin prevent AAAs from growing larger?

Study Overview

Status

Recruiting

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

480

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

    • California
      • Stanford, California, United States, 94305
        • Recruiting
        • Stanford Hospital and Clinics
        • Contact:
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

55 years to 90 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

7.2 Inclusion Criteria

  1. Provision of signed and dated informed consent;
  2. Stated willingness to comply with all study procedures and availability for the duration of the study
  3. Male or female, aged 50 to 95 years inclusive;
  4. Have a maximal orthogonal infrarenal aortic diameter between 35 and < 50 mm for males and between 30 and < 45 mm for females as measured by CTA;
  5. Eligible participants must have an estimated glomerular filtration rate (eGFR) of ≥ 30 ml/min/1.73 m2 at the initiation of trial participation, and must remain ≥ 30 ml/min/1.73 m2 throughout the term of the study to continue participation;
  6. HgbA1c must be ≤ 6.5% at initiation to receive study medication;
  7. Ability to take oral medication and be willing to adhere to the medication regimen throughout the course of the trial;
  8. Must be willing and able to undergo two computed tomographic aortograms (CTA, with timed intravenous iodinated contrast injections if possible) at initiation and termination of study participation;
  9. For females of reproductive potential: use of highly effective contraception for at least 1 month prior to screening, with an agreement to use such a method of contraception during study participation and for an additional 4 weeks after the end of study drug administration.

7.3 Exclusion Criteria 1. Diagnosis of, or taking medications for, diabetes mellitus, as defined as HgbA1c > 6.5% at baseline evaluation; 2. Known hypersensitivity to metformin hydrochloride. Individuals with known prior anaphylactic reaction to iodinated contrast will have the option of CT scan without contrast or will not be eligible to participate. Individuals with a prior allergic reaction not including anaphylaxis will be managed with the standard CT protocol for premedication for allergy to contrast - 3 doses of prednisone (50 mg p.o. per) beginning 13 hours prior to the procedure as well as 50 mg of Benadryl p.o. Premedication start times are as follows: 13 hours before contrast, 50 mg PO prednisone 7 hours before contrast, 50 mg PO prednisone

1 hour before contrast, 50 mg PO prednisone + 50 mg PO diphenhydramine These individuals will also be given the option of CT scan without contrast if unwilling to follow the premedication as indicated above; 3. Presence of metabolic acidosis, defined as total CO2 below the lower limit of normal on chemistry panel obtained during determination of study eligibility; 4. Expected survival less than two years; 5. Prior surgical AAA repair, or anticipated repair within two years; 6. Known thoracic aortic aneurysm disease, as defined as a prior dissection or thoracic aortic diameter > 5 cm); 7. The presence of known syndromic aortic conditions, including but not limited to Ehlers Danlos or Marfan Syndromes, or the at-risk allele in the ACTA2 gene mutation or similar conditions; 8. Severe liver disease, jaundice, or active hepatitis; 9. Severe anemia, defined as a Hgb < 10g/dl; 10. Concurrent participation in other investigational drug trials; 11. For female participants of childbearing potential: pregnancy, intent to become pregnant, lactation, or unwilling or unable to use an effective method of contraception; 12. Alcoholism or chronic excessive alcohol intake; 13. Common iliac artery aneurysms > 3.5 cm; 14. Uncontrolled hypertension defined as Systolic BP≥200, or considered to have hypertensive emergency or urgency.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Metformin group
Participants will either be assigned to take metformin 500 mg tablet(s) daily or identical tablet(s) that contain no active drug, also taken every day. Over the first four weeks of the study, you will increase your dosage every week by one pill, so at the end of the first month you will be taking up to four pills per day. If you develop any symptoms or side effects from pill ingestion during this process, your dose will be decreased to the last number of pills you were able to take without developing side effects.
Smaller studies have suggested that metformin may reduce the rate at which aortic aneurysms enlarge. This study will test this question: does metformin prevent AAAs from growing larger?
Other Names:
  • AAA
Placebo Comparator: Placebo Group
Participants will either be assigned to take metformin 500 mg tablet(s) daily or identical tablet(s) that contain no active drug, also taken every day. Over the first four weeks of the study, you will increase your dosage every week by one pill, so at the end of the first month you will be taking up to four pills per day. If you develop any symptoms or side effects from pill ingestion during this process, your dose will be decreased to the last number of pills you were able to take without developing side effects.
One group will be randomized to receive the study drug Metformin and the other group will receive a placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
The primary outcome measure will be the change in maximal orthogonal diameter of the infrarenal aorta, as measured by computed tomographic (CT) aortography, in centimeters.
Time Frame: Baseline to 2 years
The change in maximal orthogonal diameter of the infrarenal aorta, as measured by computed tomographic (CT) aortography, over the course of the study in participants taking metformin XR (extended release) vs. placebo. It is calculated as the difference in CTA-determined diameter (in mm) from baseline to the follow-up CT study at the end of study participation, divided by time elapsed between two measurements (e.g., annual rate of change in CT-diameter). The justification for this endpoint is that maximal orthogonal transverse diameter by CTA is the primary standard to measure AAA disease progression, determine need for surgical intervention, and correlate with clinical outcomes.
Baseline to 2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Profile of Adverse cardiovascular events
Time Frame: Baseline to 2 years
Incidence of adverse cardiovascular events including: unanticipated adverse events (AEs) and serious AEs (SAEs), AEs leading to premature discontinuation from the study intervention and serious treatment-emergent AEs, clinically significant AE events, such as cardiovascular AEs and surgical AAA repairs.
Baseline to 2 years
Study drug compliance
Time Frame: Baseline to 2 years
Pill counts will be used to measure study drug compliance.
Baseline to 2 years
All-cause mortality
Time Frame: Baseline to 2 years
All-cause mortality will be summarized using Kaplan-Meier survival curves for each arm. Participants alive at last follow-up will be censored at last time known alive.
Baseline to 2 years
Change in existing medication regimen as a measure of metformin treatment
Time Frame: Baseline to 2 years
Concurrent medication regimen will be tabulated and listed according to the drug classifications
Baseline to 2 years
Change in serological markers of the liver as a measure of impact of metformin treatment
Time Frame: Baseline to 2 years
Albumin and total protein, total bilirubin, ALT, and AST will be assessed for these serological markers.
Baseline to 2 years
Change in serological markers of the kidney as a measure of impact of metformin treatment
Time Frame: Baseline to 2 years
Urea nitrogen (BUN) and creatinine will be assessed for these serological markers.
Baseline to 2 years
Change in serological markers of the hematopoietic function as a measure of impact of metformin treatment
Time Frame: Baseline to 2 years
Complete Blood Count (CBC) will be assessed for this serological marker.
Baseline to 2 years
Change from baseline in Living with Abdominal Aortic Aneurysm (AAA) Survey
Time Frame: Baseline to 2 years
62 question instrument for evaluating AAA specific Quality of Life
Baseline to 2 years
Change from baseline in Short Form (SF-36) health survey
Time Frame: Baseline to 2 years
36 question instrument for evaluating Health-Related Quality of Life
Baseline to 2 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Ronald Dalman, MD, Stanford University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 28, 2022

Primary Completion (Estimated)

March 31, 2027

Study Completion (Estimated)

March 31, 2027

Study Registration Dates

First Submitted

June 6, 2020

First Submitted That Met QC Criteria

August 3, 2020

First Posted (Actual)

August 5, 2020

Study Record Updates

Last Update Posted (Actual)

January 10, 2024

Last Update Submitted That Met QC Criteria

January 9, 2024

Last Verified

January 1, 2024

More Information

Terms related to this study

Other Study ID Numbers

  • IRB-56500
  • 1R61HL146835-01A1 (U.S. NIH Grant/Contract)
  • 4R33HL146835-02 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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