Clinical trial NCT03331289
Conditions: Diabetes Mellitus, Type 2
Sponsor: The University of Texas Health Science Center at San Antonio
Start date: 2018-02-28; Completion date: 2022-11-04
Enrollment: 107 participants; Allocation: RANDOMIZED; Intervention model: SINGLE_GROUP

Brief summary:
Research Design/Plan: After screening, each subject will receive 1 measurements of Endogenous Glucose Production \[EGP\] with prime-continuous Infusion of 3-3H-glucose. After completing the EGP measurement each subject will receive a Double Tracer Oral Glucose Tolerance Test \[OGTT\].

Methods: Visit 1: Screening. Medical history will be obtained, physical exam performed, and pregnancy test performed.

Visit 2: Endogenous Glucose Production Measurement: The rate of EGP will be measured with 3-3H-glucose.

Visit 3: Double Tracer OGTT

Detailed description:
Eligible subjects will receive a measurement of endogenous glucose production (EGP) with a prime-continuous infusion of 3-3H-glucose. The EGP measurement will be performed in the morning after a 10-12 hour overnight fast and will last 8 hours (from 6 AM to 2 PM). After a 3-hour tracer equilibration period, subjects (20 per group) will receive one of the following medications: (i) placebo; (ii) exenatide 5 ug subcutaneously; (iii) dapagliflozin (10 mg); and (iv) dapagliflozin 10 mg plus exenatide 5 ug. Following the test medication at 9 AM, blood samples will be drawn every 15 minutes for an additional 5 hours and plasma glucose, insulin, C-peptide, glucagon, cortisol, growth hormone, and catecholamine concentrations and glucose specific activity will be measured.

Visit 1: Screening. Medical history \& physical exam will be performed. Blood will be drawn for fasting plasma glucose \[FPG\], routine blood chemistries, complete blood count \[CBC\], lipid profile, HbA1c, and thyroid function \[TSH\], Urinalysis, electrocardiogram \[EKG\], albumin/creatinine ratio and pregnancy test will be performed.

Visit 2: EGP Measurement: The rate of endogenous glucose production will be measured with 3-3H-glucose infusion. \[3-3H\]-glucose infusion will be started at 6 in the morning \[AM\] and continued until 2:30 afternoon \[PM\](5 hours after drug administration). At 6 AM a catheter will be placed into an anticubital vein and a prime (40 uCi x FPG/100)- continuous (0.4 uCi) infusion of \[3-3H\]- glucose will be started and continued until 2:30 PM. (5 hours after drug administration). Participant's hand will be placed in a box heated to 50-60°C (122-140°F). Baseline blood samples will be obtained at-210, -60, -50, -45, -40, -35, -30, -20, -10, and 0 . After 3.5 hours of tracer equilibration blood samples will be obtained every 10-20 minutes from 9 AM to 2 PM. Plasma glucose, insulin, C-peptide, glucagon, cortisol, growth hormone, and catecholamine concentrations, and \[3-3H\]-glucose specific activity will be measured. Urine will be collected from 6 to 9 AM and from 9 AM to 2 PM. Urinary volume and glucose concentration will be measured and urinary glucose excretion rate calculated. The study will end at 2:30 PM.

Visit 3: Double Tracer Oral Glucose Tolerance Test \[OGTT\]: Within the week after the measurement of EGP, all subjects will have a 5-hour OGTT with measurement of plasma glucose, insulin (I), C-peptide (CP), and glucagon concentrations at -180, -6-, -5-, -45, -40, -35, -30, -20, -10, 0 and every 15-30 minutes thereafter to obtain a measure of overall glucose tolerance, insulin secretion (CP0-120/G0-120), insulin sensitivity (\[Matsuda Index=MI\]), beta cell function, (CP0-120/G0-120 x MI), and suppression of plasma glucagon concentration (64). At 7 AM a catheter will be placed into an antecubital vein and a prime (25 uCi x FPG/100)- continuous (0.25 uCi) infusion of \[3-3H\]- glucose will be started and continued until 3 PM. Urinary volume and glucose concentration will be measured and urinary glucose excretion rate calculated.

HbA1c will be measured 2x, 1 on the day of the OGTT \& 1 on the day of the EGP measurement.

Arms: arm 1: we will examine whether the coadministration of exenatide plus dapagliflozin will prevent the increase in EGP and result in an additive or even synergistic decrease in plasma glucose conc compared to each agent alone. arm 2: we will examine whether the coadministration of exenatide plus dapagliflozin will prevent the increase in EGP and result in an additive or even synergistic decrease in plasma glucose conc compared to each agent alone. arm 3: we will examine whether the coadministration of exenatide plus dapagliflozin will prevent the increase in EGP and result in an additive or even synergistic decrease in plasma glucose conc compared to each agent alone. arm 4: we will examine whether the coadministration of exenatide plus dapagliflozin will prevent the increase in EGP and result in an additive or even synergistic decrease in plasma glucose conc compared to each agent alone.
Interventions: intervention 1: Placebo intervention 2: Exenatide intervention 3: Dapagliflozin intervention 4: Exenatide and Dapagliflozin
Intervention descriptions: intervention 1: Placebo will be administered to 20 subjects after a 3 hour tracer equilibration period intervention 2: Exenatide will be administered to 20 subjects after a 3 hour tracer equilibration period intervention 3: Dapagliflozin will be administered to 20 subjects after a 3 hour tracer equilibration period intervention 4: Exenatide and Dapagliflozin will be administered to 20 subjects after a 3 hour tracer equilibration period

Protocol documents:
Prot_SAP_000.pdf: 
17-582H, DeFronzo, Form BC, 03-21-19, AMD.docx 
vSept3-2014 
1 
COVER PAGE FOR PROTOCOL AND STATISTICAL ANALYSIS PLAN 
 
 
 
 
 
Official Study Title:  
Can Exenatide Prevent the Increase in EGP in Response to Dapagliflozin-induced 
Increase in Glucosuria 
 
 
NCT number: NCT03331289 
 
IRB Approval Date: 03/21/2019 
 
Unique Protocol ID: HSC20170582H 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


17-582H, DeFronzo, Form BC, 03-21-19, AMD.docx 
vSept3-2014 
2 
 
Protocol Template Form 
 
Item 1 UTHSCSA 
Tracking Number 
HSC20170582H 
 
Item 2 Abstract / Project Summary 
Provide a succinct and accurate description of the proposed 
research. State the purpose/aims. Describe concisely the research 
design and methods for achieving the stated goals. This section 
should be understandable to all members of the IRB, scientific and 
non-scientific.   
DO NOT EXCEED THE SPACE PROVIDED. 
Purpose/Objectives: To examine whether coadministration of the GLP-1 receptor agonist exenatide (a potent inhibitor 
of glucagon and stimulator of insulin secretion) with an SGLT2 inhibitor dapagliflozin can prevent/ameliorate the 
compensatory rise in Endogenous Glucose Production (EGP) and produce an additive, even synergistic decrease in the 
plasma glucose concentration 
 
Research Design/Plan:After screening, each subject will receive 1 measurements of EGP with prime-continuous 
Infusion of 3-3H-glucose. After completing the EGP measurement each subject will receive a Double Tracer OGTT. 
 
Methods: Visit 1: Screening. Medical history will be obtained, physical exam performed, and pregnancy test performed. 
Visit 2: Endogenous Glucose Production Measurement: The rate of EGP will be measured with 3-3H-glucose.  
Visit 3: Double Tracer OGTT 
 
Clinical Relevance: The primary end point is the change in EGP. The difference in rate of EGP during the last hour of the 
study (from 240-300 minutes) between drug-treatment and placebo treatment studies represents the effect of drug 
treatment on EGP, which will be compared among the 3 drug. treatments (exenatide; dapagliflozin; exenatide plus 
dapagliflozin) with ANOVA 
 
 
 
Item 3 
Background 
 
Describe past experimental 
and/or clinical findings 
leading to the formulation 
of your study.   
For research involving 
unapproved drugs, 
describe animal and 
human studies.   
For research that involves 
approved drugs or devices, 
describe the FDA approved 
uses of this drug/device in 
relation to your protocol. 
Insert background: Glucosuria produced by inhibition of the renal sodium-glucose 
transporter-2 (SGLT2) lowers the fasting plasma glucose (FPG) concentration but causes a 
“paradoxical” 
increase in endogenous glucose production (EGP). Although the increase in EGP can be viewed as a 
compensatory mechanism that opposes urinary glucose loss and prevents the development of 
hypoglycemia in NGT individuals, in T2DM individuals it occurs while the plasma glucose concentration 
is still in the hyperglycemic range. Moreover, it offsets by ~50% the urinary glucose loss produced by 
SGLT2 inhibitors and attenuates their glucose lowering ability. The increase in EGP following SGLT2 
inhibition is associated with an increase in plasma glucagon concentration and decrease in plasma 
insulin concentration. Because renal glucose production is stated to be unresponsive to an increase in 
the plasma glucagon concentration, it is likely that the liver contributes, at least in part, to the 
increase in EGP [which is triggered by glucosuria]. However, an increase in glucose production by the 
kidney cannot be excluded. We hypothesize that there is a previously unrecognized, [completely 
novel] “reno-hepatic” interaction that participates in the regulation of plasma glucose concentration. 
This “reno-hepatic axis” is [activated by glucosuria] and stimulates hepatic, as well as renal, glucose 
production. The aim of the present study is to: (i) determine the source of increase in EGP, liver versus 
kidney [or both]; and (ii) examine the signal activated by glucosuria that is responsible for the increase 
in EGP. 


17-582H, DeFronzo, Form BC, 03-21-19, AMD.docx 
vSept3-2014 
3 
Item 4 
Purpose and rationale 
Insert purpose, objectives 
and research 
questions/hypotheses 
here. 
 If you cut and paste from 
another document, make 
sure the excerpted 
material answers the 
question 
Insert purpose: Understanding the factors that regulate EGP is key to understanding normal glucose 
homeostasis and development of hyperglycemia in T2DM. We and others have shown that glucosuria 
produced by SGLT2 inhibition (SGLT2i) stimulates EGP, indicating the presence of an interaction 
between the kidney and liver, i.e. “a renohepatic axis” that coordinates the regulation of EGP and 
plasma glucose conc . The present study will provide evidence for the existence of this previously 
unrecognized reno-hepatic axis and define the mechanisms responsible for the interaction between 
the kidney and liver. In addition to providing novel insights about the regulation of glucose 
homeostasis, the present study has important clinical implications. Although SGLT2i are effective in 
producing glucosuria, they cause only a modest decrease in HbA1c (0.6-0.8%). On one hand, the 
presence of a “reno-hepatic axis” that leads to a compensatory increase in EGP in response to 
glucosuria maintains the FPG in NGT individuals and prevents hypoglycemia. On the other hand, the 
increase in EGP in T2DM individuals is “paradoxical” in that it occurs while plasma glucose conc is in 
the hyperglycemic range and offsets by ~50% urinary glucose loss (10) (see results below) produced by 
SGLT2 inhibitors and attenuates their glucose lowering effect. Thus, determining the mechanisms that 
mediate the rise in EGP in response to glucosuria will allow the development of strategies that prevent 
the rise in EGP and increase the efficacy of SGLT2. 
 
 
Item 5 
Study Population(s) Being 
Recruited 
 
In your recruitment plan, how 
many different populations of 
prospective subjects do you plan to 
target? Provide number: 1  
 
 
 
Identify the criteria for inclusion: 
 
 
Identify the criteria for exclusion: 
e.g., a population can be individuals 
with type 2 diabetes controlled with 
diet and/or a population of healthy 
controls.  Or a population can be 
individuals attending an education 
program, etc. 
 
List each different population on a 
separate row and provide a short 
descriptive label:   
(e.g., normal-healthy, diabetics, 
parents, children, etc.) 
 
To add rows use copy & paste 
T2DM according to ADA criteria 
subjects must be in good general health as 
determined by physical exam, medical 
history, blood chemistries, CBC, TSH, EKG 
and urinalysis 
18-70 years old 
21-45 kg/m 
Male and Female 
≥7.0% and≤ up to 10.5% 
Drug naïve and/or on a stable dose (more 
than 3 months) of metformin and/or 
sulfonylurea 
Subjects who are Type 1 Diabetes, have 
proliferative diabetic retinopathy, plasma 
creatinine >1.4 females or >1.5 males will 
be excluded. 
Subjects taking drugs known to affect 
glucose metabolism (other than metformin 
and sulfonylurea) 
 
 
 
 
 
 


17-582H, DeFronzo, Form BC, 03-21-19, AMD.docx 
vSept3-2014 
4 
 
 
 
 
Item 6 
Research Plan / Description of the Research Methods a.  Provide a comprehensive narrative describing the research methods.   
Provide the plan for data analysis (include as applicable the sample size calculation). 
 
Step-by-Step Methods:  
After screening, eligible subjects will receive a measurement of endogenous glucose production (EGP) with a prime-
continuous infusion of 3-3H-glucose. The EGP measurement will be performed in the morning after a 10-12 hour 
overnight fast and will last 8.5 hours (from 6 AM to 2:30 PM). After a 3.5-hour tracer equilibration period, subjects (20 
per group) will receive one of the following medications: (i) placebo; (ii) exenatide 5 ug subcutaneously; (iii) 
dapagliflozin (10 mg); and (iv) dapagliflozin 10 mg plus exenatide 5 ug (see flowsheet for EGP). Following the test 
medication at 9:30 AM, blood samples will be drawn every 15 minutes for an additional 5 hours and plasma glucose, 
insulin, C-peptide, glucagon,  and glucose specific activity will be measured. 
 
Visit 1: Screening. Medical history will be obtained and physical exam will be performed. Blood will be drawn for FPG, 
routine blood chemistries, CBC, lipid profile, HbA1c, and thyroid function. Urinalysis, EKG, albumin/creatinine ratio and 
pregnancy test will be performed. 
 
Visit 2:  Endogenous Glucose Production Measurement: The rate of endogenous glucose production will be measured 
with 3-3H-glucose infusion.    [3-3H]-glucose infusion will be started at 6 AM and continued until 2:30 PM (5 hours 
after drug administration). At 6 AM a catheter will be placed into an anticubital vein and a prime (40 uCi x FPG/100)- 
continuous (0.4 uCi) infusion of  [3-3H]- glucose will be started and continued until 2:30 PM.  (5 hours after drug 
administration). Participant’s hand will be placed in a box heated to 50-60°C (122-140°F). Baseline blood samples will be 
obtained at-210, -60, -50, -45, -40, -35, -30, -20, -10, and 0. After 3.5 hours of tracer equilibration blood samples will be 
obtained every 10-20 minutes from 9:30 AM to 2:30 PM. Plasma glucose, insulin, C-peptide, glucagon, and [3-3H]-
glucose specific activity will be measured. Urine will be collected from 6 to 9:30 AM and from 9:30 AM to 2:30 PM. 
Urinary volume and glucose concentration will be measured and urinary glucose excretion rate calculated. The study 
will end at 2:30 PM. The total amount of blood taken during this time is 164 ml or 12 tablespoons.  
 
Visit 3:  Double Tracer Oral Glucose Tolerance Test (DT-OGTT):  Within one to two  weeks after  the measurement of 
EGP, all subjects will have a 5-hour DT-OGTT with measurement of plasma glucose, insulin (I), C-peptide (CP), and 
glucagon concentrations at -180, -6, -5, -45, -40, -35, -30, -20, -10, 0 and every 15-30 minutes thereafter to obtain a 
measure of overall glucose tolerance, insulin secretion (CP0-120/G0-120), insulin sensitivity (Matsuda index [MI]), 
beta cell function, (CP0-120/G0-120 x MI), and suppression of plasma glucagon concentration (64). At 7 AM a 
catheter will be placed into an anticubital vein and a prime (25 uCi x FPG/100)- continuous (0.25 uCi) infusion of  [3-3H]- 
glucose will be started and continued until 3 PM. Urinary volume and glucose concentration will be measured and 
urinary glucose excretion rate calculated. The total amount of blood taken during the OGTT is 226 ml about 15 
tablespoons. HbA1c will be measured twice, once on the day of the DT-OGTT and once on the day of the EGP 
measurement. 
 
Note: The repeated double tracer listed in the grant application will not be performed as part of this protocol. The 
grant will be amended to remove at continuing review of the grant application.  
 
 
Data Analysis Plan: The primary end point is the change in EGP. The difference in rate of EGP during the last hour of the 
study (from 240-300 minutes) between drug-treatment and placebo treatment studies represents the effect of drug 
treatment on EGP, which will be compared among the 3 drug treatments (exenatide; dapagliflozin; exenatide plus 
dapagliflozin) with ANOVA. Post hoc testing will be performed with Bonferroni correction for multiple comparisons. The 
following primary comparison will be performed: (i) change in EGP above baseline following dapagliflozin alone versus 
dapagliflozin/exenatide.  
 
 


17-582H, DeFronzo, Form BC, 03-21-19, AMD.docx                                    vSept3-2014                                                                                                                                                                                                                                        5 
 
 
Item 7 Risks Section: 
Complete the following table to describe the risks of all research procedures listed in Step 2, Institutional Form (items 28-34).  Do not list risks of Routine care 
procedures here.  
 ☒ N/A, Risks are described in the informed consent document – do not complete this table. 
Research procedures 
 
example: 
• 
History and physical 
• 
Questionnaire 
• 
Laboratory tests 
 
Add or delete rows as needed 
Risks 
 
List the reasonably expected risks 
under the following categories as appropriate: 
Chart Review 
Serious and likely; 
o Insert risk here or enter "none" 
Serious and less likely; 
o Insert risk here or enter "none" 
Serious and rare; 
o Insert risk here or enter "none" 
Not serious and likely; 
o Insert risk here or enter "none" 
Not serious and less likely 
o Breach of confidentiality