Study to Understand the Genetics of the Acute Response to Metformin and Glipizide in Humans

Phase 1Active Not RecruitingNCT01762046

Massachusetts General Hospital1,033 enrolled

Overview

The SUGAR-MGH investigators are studying the influence of inherited gene variants on the response to two commonly prescribed type 2 diabetes medications, metformin and glipizide. They hypothesize that variants in genes that are associated with type 2 diabetes or related traits may impact the effect of anti-diabetic medications. In addition, physiological responses to an insulin secretagogue or an insulin sensitizer may shed light on the mechanism of action of reported genetic associations.

Several common genetic variants have been reliably associated with type 2 diabetes and related glycemic traits. Study investigators hypothesize that variants in genes that are reproducibly associated with type 2 diabetes or related glycemic traits may impact the effect of anti-diabetic medications. In particular, sulfonylureas may have differential effects on individuals depending on the allelic variant they carry at KCNJ11 E23K; conversely, because TCF7L2 is postulated to influence insulin secretion by regulating the action of glucagon-like peptide 1 (GLP-1), and sulfonylureas act at a different step in the insulin secretion pathway, the effect of sulfonylureas on insulin secretion could be independent of genetic variation at TCF7L2. In addition, physiological responses to an insulin secretagogue or an insulin sensitizer may shed light on the mechanism of action of reported genetic associations. Despite the convincing associations of several genetic variants with type 2 diabetes and their involvement in physiological pathways involved in drug response, their impact on pharmacological interventions has not been systematically examined. The completion of the Human Genome Project and the high-density characterization of common human variation in four different ethnic groups highlight the promise of genomic medicine. The elucidation of the genetic architecture of complex phenotypes may help clinicians understand disease heterogeneity, uncover new pathophysiological mechanisms, open the opportunity for novel therapeutic interventions, provide predictive diagnostic and prognostic information, and allow for individually tailored therapy that takes into account both the probability of response and the incidence of drug-induced complications.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Conditions

Diabetes Mellitus, Type 2

Interventions

GlipizideDRUG

MetforminDRUG

Oral Glucose Tolerance TestOTHER

Eligibility

Sex: ALLMin age: 18 YearsMax age: 85 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Male or non-pregnant female \> 18 years of age * Investigators will target preferentially people at risk of diabetes or requiring diabetes meds * The first tier of risk will be illustrated by one of the following variables (e.g. established type 2 diabetes on diet therapy alone, elevated random glucose in electronic medical record, PCOS, metabolic syndrome, obesity, history of gestational diabetes, etc.) * The second tier of risk will be illustrated by other features that correlate with diabetes risk, such as a history of hypertension or dyslipidemia * Otherwise healthy subjects may also be candidates for the study. * Able and willing to give consent relevant to genetic investigation Exclusion Criteria: * Pregnant, nursing or at risk of becoming pregnant * Currently taking any medications for the treatment of diabetes * Currently on metformin for any other indication (e.g. PCOS) * Onset of diabetes in a family member before age 25, with autosomal transmission of diabetes across three generations * History of liver or kidney disease * Known severe allergic reactions to sulfonamides * History of porphyria * Documented estimated glomerular filtration rate (GFR) \< 60 ml/min/1.73 m2, based on the most recent serum creatinine measurement available in the electronic medical record, and calculated by the Modification of Diet in Renal Disease equation (49) available at http://www.nephron.com/cgi-bin/MDRD\_GFR.cgi * Currently taking medications known to affect glycemic parameters, such as glucocorticoids, growth hormone or fluoroquinolones * Planned radiologic or angiographic study requiring contrast within one week of completion of this study * Established coronary artery disease (CAD), defined as: * History of myocardial infarction. * History of revascularization (coronary artery bypass grafting, percutaneous coronary intervention (e.g. stenting or balloon angioplasty). * Evidence of ischemia on cardiac stress test. * Enrolled in any other interventional study at time of screening through completion of study protocol * History of bariatric surgery * History of seizures * History of stroke/CVA

Locations (3)

Massachusetts General Hospital

Boston, Massachusetts, United States

Brigham and Women's Hospital

Boston, Massachusetts, United States

Joslin Diabetes Center

Boston, Massachusetts, United States

Outcomes

Primary Outcomes

Glipizide Response as Measured by Area Over the Glucose Curve Between Time 0 and 240 Minutes According to Genotype

Investigators will measure glucose levels at 0,30,60,90,120,180 and 240 minutes post 5mg Glipizide administration on Visit 1(Day1), and compare them by genotype at selected loci.

Time frame: 0, 30, 60, 90, 120, 180 and 240 minutes post 5mg oral glipizide dose, Day 1 (visit 1)

Glipizide Response as Measured by Area Under the Insulin Curve Between Time 0 and 240 Minutes According to Genotype

Investigators will measure insulin levels at 0,30,60,90,120,180 and 240 minutes post 5mg Glipizide administration on Visit 1(Day1), and compare them by genotype at selected loci.

Time frame: 0,30,60,90,120,180 and 240 minutes on Day 1 (Visit 1)

Metformin Response - Change in Fasting Glucose From Visit 1 to Visit 2

Time frame: Day 1 (Visit 1) and Day 8 (Visit 2)

Metformin Response - Change in HOMA-IR From Visit 1 to Visit 2

Investigators will measure the change in glycemic measures between Visit 1 (Day 1) and Visit 2 (Day 8) as an index of Metformin response, and compare them by genotype at selected loci. HOMA-IR is calculated from fasting glucose and fasting insulin values at both visit 1 (day 1) and visit 2 (day 8). HOMA-IR was calculated using (fasting glucose\*fasting insulin)/405) formula. A bigger difference/drop between visit 1 and visit 2 will show that metformin had an effect on insulin resistance index for these participants. The higher the HOMA-IR, the more insulin resistant you are.

Time frame: Day 1 (Visit 1) and Day 8 (Visit 2)

Secondary Outcomes

Data from ClinicalTrials.gov

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Incretin Levels

Investigators will measure GLP-1 and GIP during the OGTT from 0 to 120 minutes of Visit 2, and compare them by genotype at selected loci.

Time frame: 0, 5, 10, 15, 30, 60 and 120 minutes, Day 8 (Visit 2)

Proinsulin (Fasting) at Visit 1 and Visit 2 by Genotype for rs7903146

Investigators will measure proinsulin levels at regular intervals during Visits 1 and 2, and compare them by genotype at selected loci.

Time frame: Day 1 (Visit 1) and Day 8 (Visit 2)

Metabolomics

Investigators will perform metabolomic profiling of plasma samples at regular intervals during Visits 1 and 2, by using initially a targeted approach on an existing platform that measures \~400 metabolites (both polar and non-polar); they will compare their relative concentrations by genotype at selected loci before and after the study interventions.

Time frame: Day 1 (Visit 1) and Day 8 (Visit 2)

Vitamin D

Investigators will measure 25-hydroxy vitamin D levels at baseline, and examine its effects on glycemic measures during Visits 1 and 2.

Time frame: Baseline

Fasting Glucagon at Visit 1 and Visit 2 by Genotype for rs7903146

Investigators will measure glucagon levels at regular intervals during Visits 1 and 2, and compare them by genotype at selected loci.

Time frame: Day 1 (Visit 1) and Day 8 (Visit 2)