Pharmacogenetics of Response to Sitagliptin (PRS) (PRS)

February 17, 2026 updated by: Amber Beitelshees, University of Maryland, Baltimore

Sitagliptin's Effects on Glucose-stimulated Insulin Secretion and Oral Glucose

This is a research study to find out how different people respond to a medication called sitagliptin. Sitagliptin is an FDA approved medication that is used to treat diabetes. We are asking for healthy, non-diabetic volunteers to participate in this 7-week study. If you agree to participate, you will take part in 2 clinic visits that are 4-6 weeks apart. At the clinic visits you will have an oral glucose tolerance test (OGTT) and other blood tests to see how your body processes glucose (sugar). An OGTT is a test in which your drink glucose and then blood samples are taken afterward at specific time points to measure glucose and insulin in your blood. Each clinic visit will last about 5 hours.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
400

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

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

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Pennsylvania
      • Lancaster, Pennsylvania, United States, 17602
        • University of Maryland Amish Research Clinic

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • • Age: >18 years old

    • Members of Old Order Amish community in Lancaster, PA

Exclusion Criteria:

  • • Pregnancy (reproductive age women will undergo pregnancy tests immediately before receiving the drug)

    • Diabetes: HbA1c > 6.5% or fasting plasma glucose >126 mg/dL
    • Estimated glomerular filtration rates (eGFR) <60 mL/min/1.73 m2
    • Anemia: hematocrit < 35%
    • Thyroid status: TSH<0.4 or TSH>5.5
    • ALT or AST in excess of 2X upper limit of normal
    • Drugs that in the physician's judgment would alter response to sitagliptin
    • Significant health issues that in the physician's judgment could increase the risk for participants.

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: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Sitagliptin
Sitagliptin 100 mg given 2 hours prior to the oral glucose tolerance test
Procedure: Oral Glucose Tolerance Test
Three hour glucose tolerance test
Placebo Comparator: Placebo
Placebo given 2 hours prior to the oral glucose tolerance test
Procedure: Oral Glucose Tolerance Test
Three hour glucose tolerance test

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Sitagliptin-induced enhancement of early insulin secretion
Time Frame: 6 weeks
This represents the incretinomimetic effect of sitagliptin, which contributes importantly to the mechanism whereby DPP4is decrease HbA1c in T2D patients. Because histograms for sitagliptin-induced increase in our index of early insulin secretion (T30:T60) demonstrated a skewed distribution, we will apply a logarithmic transformation of data which yields a normal distribution. Thus, the drug effect is defined as: log(T30:T60 ins)sita - log(T30:T60 ins)control.
6 weeks
Sitagliptin-induced change in glucose tolerance
Time Frame: 6 weeks
Sitagliptin-induced change in glucose tolerance. This is a consequence of enhanced insulin secretion, which reflects most closely the desired effect of the drug to decrease plasma glucose and decrease HbA1c. Because histograms for sitagliptin-induced increase in our index of glucose tolerance (T30:T60) demonstrated a skewed distribution, we will apply a logarithmic transformation of data which yields a normal distribution. Thus, the drug effect is defined as: log(T30:T60 gluc)sita - log(T30:T60 gluc)control.
6 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Area under the curve for insulin concentration
Time Frame: 6 weeks
Area under the curve of insulin concentration measured from oral glucose tolerance test using trapezoidal rule
6 weeks
Area under the curve for glucose concentration
Time Frame: 6 weeks
Area under the curve for glucose concentration measured from the oral glucose tolerance test using the trapezoidal rule
6 weeks
Area under the curve for intact GIP
Time Frame: 6 weeks
Area under the curve for levels of intact GIP during the first hour of the OGTT as calculated by the trapezoidal rule
6 weeks
Area under the curve for intact GLP1
Time Frame: 6 weeks
Area under the curve for levels of intact GLP1 during the first hour of the OGTT as calculated by the trapezoidal rule
6 weeks
Area under the curve for C-peptide levels
Time Frame: 6 weeks
Area under the curve for C-peptide levels as a direct index of insulin secretion
6 weeks

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Parameters of a mathematical model (insulin secretion and glucose sensitivity of the β-cell
Time Frame: 6 weeks
We will apply mathematical modeling to the oral glucose tolerance test data it assess measures of insulin secretion and glucose sensitivity of the β-cell
6 weeks

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Maryland, Baltimore

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Amber L Beitelshees, PharmD, MPH, University of Maryland, Baltimore
  • Principal Investigator: Simeon I Taylor, MD, PhD, University of Maryland, Baltimore

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 (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2031

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2032

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 3, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 3, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 6, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 18, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HP-00111892

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Given that the Amish are a unique founder population, they are more easily identified and at-risk for stigmatization. Therefore, we must consult with the community in order to address this plan to share individual level data.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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