Optimizing Stage 2 T1DM Management: Assessing the Impact of GLP-1Ra on Metabolic Outcomes in Patients Receiving Teplizumab
Phase: EARLY_PHASE1
Conditions: Type 1 Diabetes
Sponsor: Vanderbilt University Medical Center

 
 
 
Study Title:  
Optimizing Stage 2 T1DM Management: Assessing the Impact 
of GLP-1Ra on Metabolic Outcomes in Patients Receiving 
Teplizumab 
 
 
NCT Number:  
NCT06338553 
 
 
Protocol date:  
October 23, 2025 
 
 
 
 
 
 
 
 
 

 
 
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Optimizing Stage 2 T1DM Management: Assessing the Impact of 
GLP-1Ra on Metabolic Outcomes in Patients Receiving 
Teplizumab 
 
  
 
 
Daniel Moore, M.D., Ph.D. 
Associate Professor of Pediatrics 
Ian M. Burr Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics 
Vanderbilt University Medical Center 
 
 
 
1500 21st Avenue South, Suite 1514 
Nashville, TN  37212-3157 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
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Table of Contents: 
 
Study Schema 
1.0 
Background 
2.0 
Rationale and Specific Aims 
3.0 
Animal Studies and Previous Human Studies 
4.0 
Inclusion/Exclusion Criteria 
5.0 
Enrollment/Randomization 
6.0 
Study Procedures 
7.0 
Risks of Investigational Agents/Devices (side effects) 
8.0 
Reporting of Adverse Events or Unanticipated Problems involving Risk to 
Participants or Others 
9.0 
Study Withdrawal/Discontinuation 
10.0 
Statistical Considerations 
11.0 
Privacy/Confidentiality Issues 
12.0 
Follow-up and Record Retention 
 

 
 
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1.0 
Background 
 
Type 1 Diabetes Mellitus (T1DM) is a chronic autoimmune disorder affecting millions of 
individuals worldwide. It is characterized by the destruction of insulin-producing 
pancreatic beta cells, leading to absolute insulin deficiency. Despite its global impact, 
management of T1DM remains a complex task, with challenges arising from the intricate 
factors influencing glycemic control and disease progression. 
 
T1DM is often categorized into different stages to facilitate diagnosis and management. 
Stage 1 T1DM is defined by the presence of multiple diabetes-related autoantibodies 
with normal blood glucose levels, indicating an early phase of autoimmune beta cell 
destruction but no clinical symptoms yet. Stage 2 T1DM, also known as dysglycemia, is 
marked by the presence of autoantibodies and abnormal blood glucose levels. In this 
stage, patients start to show signs of impaired glucose metabolism but may not have 
overt diabetes symptoms. Stage 3 T1DM is the stage where clinical symptoms of 
diabetes, such as increased thirst and frequent urination, become apparent due to 
significant insulin deficiency. 
 
Aims 1-3: Stage 2 T1DM and teplizumab 
Our study primarily focuses on individuals with stage 2 T1DM, who show signs of 
impaired glucose metabolism but are not yet fully symptomatic. In this group, the 
autoimmune process has started, and the beta cells are under attack, but the body still 
produces enough insulin to prevent overt symptoms of diabetes. 
 
A significant breakthrough in the field is the use of teplizumab (TZIELD®), an 
immunotherapeutic monoclonal antibody. Recent investigations have shown this drug 
delays the progression from stage 2 to stage 3 T1DM in high-risk individuals by 
modulating the immune response against pancreatic beta cells. However, even with 
TZIELD® treatment, these individuals eventually progress to insulin dependency, 
highlighting the ongoing challenges in managing T1DM. 
 
Alongside, these patients often face cardiometabolic challenges such as postprandial 
hyperglycemia, impaired glucose disposal, and endothelial dysfunction. These factors 
contribute to long-term complications of diabetes, presenting an urgent need for 
additional therapeutic interventions. 
 
In this context, we propose to investigate the potential benefits of GLP-1 receptor 
agonists (GLP-1Ra) in individuals with stage 2 T1DM undergoing TZIELD® treatment. 
GLP-1Ra have demonstrated metabolic advantages in Type 2 Diabetes Mellitus (T2DM), 
including improvements in postprandial glycemia, insulin sensitivity, and endothelial 
function. However, their role in T1DM, particularly in conjunction with TZIELD® therapy, 
remains unexplored. 
 
Aim 4: Early Stage 3 T1DM and GLP-1 Receptor Agonists 
Despite the promise of immunotherapy, there remains a critical need for additional 
interventions, particularly for patients who progress into early stage 3 T1DM. It's 
important to recognize that the distinction between stage 2 and stage 3 T1DM is 
somewhat arbitrary, as the progression from one stage to the next is continuous rather 
than discrete. Late stage 2 and early stage 3 patients often exhibit similar clinical 
characteristics, such as mildly elevated HbA1c levels, reflecting a gradual decline in β-
cell function. This continuum underscores that there's not a substantial difference 

 
 
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between patients at these stages, particularly those we're recruiting with mildly elevated 
HbA1c. 
 
In this context, our study will include patients with early stage 3 T1DM to assess the 
effectiveness of GLP-1Ra therapy. This class of medication is uniquely suited to this 
population, as it addresses not only insulin secretion deficits but also metabolic 
abnormalities like postprandial hyperglucagonemia—two factors that exacerbate 
postprandial hyperglycemia. 
 
A recent open-label, uncontrolled clinical study suggested that semaglutide provides 
benefits in improving glycemic outcomes in early stage 3 T1DM1. Building upon these 
findings, our study will rigorously investigate the cardiometabolic effects of semaglutide 
in early stage 3 T1DM. Furthermore, the insights gained will lay the groundwork for 
future combination trials that incorporate immunomodulation (teplizumab) alongside 
metabolic therapy (GLP-1Ra) in early stage 3 T1DM, potentially offering a 
comprehensive approach to preserving β-cell function. 
 
The transition from stage 2 to stage 3 represents a critical window where metabolic and 
immunological interventions might synergistically delay the complete β-cell destruction 
characteristic of established T1DM. Given the minimal differences between late stage 2 
and early stage 3 patients, studying early stage 3 T1DM allows us to evaluate whether 
oral GLP-1Ra alone can stabilize or improve β-cell function at this crucial phase. By 
acknowledging the continuum of disease progression, our approach provides an 
additional therapeutic tool for managing T1DM progression and may improve outcomes 
for patients at this pivotal stage. 
 
Unraveling the potential metabolic benefits of GLP-1Ra in these patient populations 
could significantly enhance our understanding of T1DM pathophysiology and open new 
avenues for therapeutic interventions. This could improve patient outcomes, enriching 
the quality of life and life expectancy for individuals with T1DM. 
 
2.0 
Rationale and Specific Aims 
 
The monoclonal antibody TZIELD® demonstrates potential for preserving β-cell function 
in early-stage type 1 diabetes mellitus (T1DM). As mass screening programs identify 
more patients in the early stages of T1DM, endocrinologists will confront Dual 
Derangements: diminishing insulin secretion and detrimental hyperglucagonemia. 
TZIELD® alone, however, does not provide long-term relief from these challenges, 
especially for patients with certain HLA haplotypes. Glucagon-like peptide-1 receptor 
agonists (GLP-1Ra) hold promise for enhancing immunotherapy by addressing these 
Dual Derangements due to their insulinotropic and glucagonostatic properties. Despite 
this potential, clinical and mechanistic data for GLP-1Ra as a disease-modifying therapy 
in early-stage T1DM remain limited.  
This pilot and feasibility study is designed to investigate the innovative combination of 
GLP-1Ra and immunotherapy in stage 2 T1DM patients, while also expanding to 
examine the effects of GLP-1Ra in early stage 3 T1DM. This approach aims to set the 
foundation for larger, definitive trials that could determine the impact of this novel 
therapeutic approach on dysmetabolism in early T1DM. 

 
 
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Our long-term goal is to determine whether repurposing GLP-1Ra for stage 2 T1DM in 
combination with immunotherapy can modify the disease course, reducing the need for 
exogenous insulin therapy and leading to improved cardiometabolic outcomes and 
quality of life. For early stage 3 T1DM, we aim to determine whether GLP-1Ra can offer 
similar protective effects in preserving β-cell function and stabilizing glycemic control. 
 
The immediate objective is to investigate the impact of GLP-1Ra's insulinotropic and 
glucagonostatic effects on dysmetabolism in stage 2 and early stage 3 T1DM. We 
hypothesize that these effects will each delay the need for exogenous insulin by 
improving three key aspects of dysmetabolism: 1) postprandial glycemia, 2) disposition 
index (i.e., the ability of the islet cells to compensate for a given insulin sensitivity), and 
3) endothelial function.  
Aims 1-3: Stage 2 T1DM and TZIELD® with GLP-1Ra 
The rationale for this hypothesis is based on two observations: first, GLP-1Ra combined 
with immunomodulatory therapy sustains endogenous secretion in response to an 
MMTT during the first year of stage 3; and second, GLP-1Ras mitigate postprandial 
hyperglucagonemia in longer-duration T1DM. To test our hypothesis, we will conduct 
studies in individuals with stage 2 T1DM treated with TZIELD® using a crossover design 
(figure 1) structured around the following specific aims: 
Aim 1: Investigate the impact of GLP-1Ra on postprandial glycemia in a pilot study. We 
will measure postprandial glycemia during an MMTT before TZIELD® treatment. After 
TZIELD® we will compare the effects of placebo versus semaglutide (Rybelsus®),a 
GLP-1Ra.  
Aim 2: Study the impact of GLP-1Ra on the disposition index (DI) in a pilot study. We will 
use the oral glucose minimal model to measure DI during an MMTT before and after 
TZIELD® treatment, comparing the effects of placebo versus Rybelsus®. As an 
exploratory outcome, we will quantify β-cell endoplasmic reticulum dysfunction by 
measuring the proinsulin-to-C-peptide ratio during the MMTT. 
Aim 3: Determine the impact of GLP-1Ra on endothelial function in a pilot study. We will 
use B-mode ultrasound to measure flow mediated vasodilation (FMD), a bioassay of 
endothelial function, during each MMTT. Because endothelial cells are often among the 
first affected by hyperglycemia and insulin resistance, we aim to illuminate how GLP-
1Ra may mitigate early vascular disease progression. 
 
 

 
 
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Aim 4: Determine how much GLP-1Ra monotherapy therapy changes the disposition 
index (DI) in a pilot study of early stage 3 T1DM.  
Despite the promise of TZIELD®, the medication is not currently approved for patients 
with stage 3 T1DM. Thus, individuals who progress into stage 3 T1DM continue to face 
significant challenges, including loss of β-cell function and the need for exogenous 
insulin. As patients move into stage 3, there is an opportunity for metabolic interventions 
that may preserve residual insulin production and mitigate the long-term impact of 
hyperglycemia. Accordingly, we will conduct a randomized, double-blind, placebo-
controlled crossover study involving patients with early stage 3 T1DM. Each participant 
will undergo four mixed meal tolerance tests (MMTTs): two at baseline shortly after 
diagnosis and two after a six-month interval. During each MMTT, participants will receive 
either a single dose of GLP-1Ra (oral semaglutide) or placebo in a randomized order. 
This design allows us to assess the independent effects of GLP-1Ra on the disposition 
index (DI) by comparing the results between the GLP-1Ra and placebo conditions at 
both time points. By evaluating changes in DI and other metabolic parameters over time, 
we aim to determine how GLP-1Ra monotherapy influences β-cell function and insulin 
sensitivity in early stage 3 T1DM. 
To enhance our understanding of GLP-1Ra’s mechanistic effects in both stage 2 and 
early stage 3 T1DM, we will perform bivariate analyses examining the relationship 
between GLP-1Ra’s insulinotropic and glucagonostatic effects and each aim’s primary 
outcome. These analyses will inform the design of a fully powered multivariate linear 
regression analysis in a subsequent larger study.  
 
3.0 
Animal Studies and Previous Human Studies 
 
Doctors face Dual Derangements in treating early-stage T1DM: diminishing insulin 
secretion and detrimental hyperglucagonemia. 
T1DM is a chronic autoimmune disorder characterized by the destruction of insulin-
producing β-cells in the pancreas, leading to lifelong dependence on exogenous 

 
 
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insulin2. Interventions during the critical period of early-stage T1DM, particularly stage 
2, could potentially slow β-cell decline and delay the need for exogenous insulin 
therapy, improving long-term outcomes. TZIELD®, a monoclonal antibody, shows 
potential to extend β-cell function in stage 23-6 and early stage 3 T1DM7, spurring 
interest in additional therapeutic strategies to target the Dual Derangements of 
diminishing insulin secretion2, 8 and detrimental hyperglucagonemia9-11 which 
are hallmarks of early-stage T1DM.  
Patients treated with TZIELD® during early-stage T1DM may particularly benefit from 
the insulinotropic and glucagonostatic properties of GLP-1Ra in confronting the Dual 
Dilemmas.  
GLP-1Ra, a class of medications used in T2DM, lower blood glucose by enhancing 
glucose-dependent insulin secretion, suppressing glucagon release, and slowing 
gastric emptying 12-14. Studies in T2DM15, 16 and longstanding T1DM17 suggest GLP-
1Ra improve endothelial function, reduce inflammation, and potentially preserve β-cell 
function. In longer-duration T1DM, exenatide, a GLP-1Ra, mitigates postprandial 
hyperglucagonemia and improves glycemic control18-20. Combining GLP-1Ra with 
immunomodulatory therapy (liraglutide and anti-interleukin-21 antibody) sustained 
endogenous insulin secretion in response to a mixed meal tolerance test (MMTT) 
during the first year of stage 3 T1DM21. This evidence suggests GLP-1Ra, particularly 
when combined with TZIELD®, may hold promise for stage 2 T1DM patients. 
 
In summary, while TZIELD® offers a promising avenue for preserving β-cell function 
in early-stage T1DM, its potential may be further enhanced when combined with GLP-
1Ra. Previous studies indicate that GLP-1Ra addresses the Dual Derangements 
characteristic of early-stage T1DM and has been beneficial in T2DM and longer-
duration T1DM. Given this background, our study aims to explore the complementary 
effects of combining TZIELD® with GLP-1Ra in stage 2 T1DM patients, potentially 
ushering in a novel therapeutic strategy. 
 
 
4.0 
Inclusion/Exclusion Criteria 
 
Aims 1-3: Stage 2 T1DM with TZIELD® and GLP-1Ra 
 
Inclusion Criteria 
- 
Age: 12-50 years 
- 
BMI: 18-31 kg/m2 (adults) or 5-95th %ile (pediatric) 
- 
Stage 2 T1DM (i.e., ≥ 2 islet auto-antibodies and: 
- 
fasting glucose ≥ 100 mg/dL and < 126 mg/dL OR  
- 
2-hr OGTT /MMTT ≥ 140 mg/dL and < 200 mg/dL OR 
- 
During an OGTT having a glucose of > 199 mg/dL at 30, 60, or 90 
minutes)  
 
Exclusion Criteria 
- 
Comorbidities: 
- 
SBP > 140 mmHg and DBP > 100 mmHg 
- 
eGFR by MDRD equation of < 60 mL/min/1.73m2 
- 
AST or ALT > 2.5 times ULN 
- 
Family history of medullary thyroid carcinoma 

 
 
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- 
Diagnosis of pancreatitis or gastroparesis within the past 3 years 
- 
Medications: Any diabetes medication, any antioxidant vitamin supplement (<2 
weeks before a study), any systemic glucocorticoid, antipsychotic, atenolol, 
metoprolol, propranolol, niacin, any thiazide diuretic, any OCP with > 35 mcg 
ethinyl estradiol, growth hormone, any immunosuppressant, antihypertensive, 
any antihyperlipidemic 
- 
Other: pregnancy, peri- or post-menopausal women, active smoker 
 
Aim 4: Early Stage 3 T1DM with GLP-1Ra Monotherapy 
 
Inclusion Criteria 
- 
Age: 12-50 years 
- 
BMI: 18-31 kg/m2 (adults) or 5-95th %ile (pediatric) 
- 
Early stage 3 T1DM with either 
- 
HbA1c 6.5% to 8.0% at diagnosis OR 
- 
HbA1c 5.7% to 6.4% with oral glucose test meeting ADA criteria for stage 
3 T1DM within the past three months prior to or during screening visit 
- 
Time of stage 3 diagnosis: within eight weeks of first study visit 
 
Exclusion Criteria 
- 
DKA history: history of diabetic ketoacidosis requiring hospital admission 
- 
Comorbidities: 
- 
Family history of medullary thyroid carcinoma 
- 
Diagnosis of pancreatitis or gastroparesis within the past 3 years 
- 
Medications: Any diabetes medication, any antioxidant vitamin supplement (<2 
weeks before a study), any systemic glucocorticoid, antipsychotic, atenolol, 
metoprolol, propranolol, niacin, any thiazide diuretic, any OCP with > 35 mcg 
ethinyl estradiol, growth hormone, any immunosuppressant, antihypertensive, 
any antihyperlipidemic 
- 
Other: pregnancy, peri- or post-menopausal women, active smoker 
 
 
5.0 
Enrollment/Randomization 
 
Aims 1-3: Stage 2 T1DM with TZIELD® and GLP-1Ra 
 
We have chosen a randomized, double-blind, placebo-controlled, crossover study 
design. Volunteers will participate in three MMTT studies as depicted in Figure 2. We will 
recruit many participants from Vanderbilt’s T1DM Immunotherapy Clinic, but in some 
cases will recruit participants receiving TZIELD® from other institutions. 
 
 
 

 
 
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Randomization: The first study visit will occur before participants receive TZIELD®. We 
will schedule the first of two post-TZIELD® studies between two to seven months after 
completing TZIELD® treatment. The study team will randomize the sequence of the two 
studies into one of two treatment orders using random permuted blocks of four.  
 
Enrollment: Enrollment will occur at the beginning of the first MMTT study.  
 
Enrollment will take place in the Vanderbilt Clinical Research Center (CRC). The 
Vanderbilt CRC is located on the 2rd floor of Medical Center North on the Vanderbilt 
University Medical Center (VUMC) campus (1211 Medical Center Dr, Nashville, TN 
37232; telephone number: 615-322-2312).  
 
Aim 4: Early Stage 3 T1DM with GLP-1Ra Monotherapy 
 
We will employ a randomized, double-blind, placebo-controlled crossover design. 
Participants with early stage 3 T1DM will undergo four Mixed Meal Tolerance Test 
(MMTT) studies: two at baseline shortly after diagnosis and two after a six-month interval 
(figure 3). During each pair of studies, participants will receive a single dose of GLP-1Ra 
(oral semaglutide, Rybelsus®) in one study and placebo in the other, with the order 
randomized to minimize potential sequencing effects. This approach allows us to assess 
the effects of GLP-1Ra on metabolic parameters and β-cell function at two critical time 
points in disease progression. 
 

 
 
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Randomization: The study team will randomize participants to receive either GLP-1Ra 
(oral semaglutide, Rybelsus®) or placebo at the first visit.   
 
Enrollment: enrollment will occur at the initial at the first visit. Eligibility will be confirmed 
based on clinical HbA1c or OGTT results obtained prior to the first visit, as well as a brief 
medical history and physical examination conducted at the start of the visit. 
 
Enrollment will take place in the Vanderbilt Clinical Research Center (CRC). The 
Vanderbilt CRC is located on the 2rd floor of Medical Center North on the Vanderbilt 
University Medical Center (VUMC) campus (1211 Medical Center Dr, Nashville, TN 
37232; telephone number: 615-322-2312). 
 
6.0 
Study Procedures 
 
 
Aims 1-3: Stage 2 T1DM with TZIELD® and GLP-1Ra 
 
6.1 
Overview 
In this randomized, double-blind, placebo-controlled, crossover study, we 
aim to evaluate the metabolic benefits of GLP-1Ra for individuals with 
stage 2 T1DM receiving TZIELD® treatment. Participants undergo three 
Mixed Meal Tolerance Test (MMTT) studies to quantify postprandial 
hyperglycemia, disposition index (DI), and nitric oxide mediated 
endothelial function.  
 
6.2 
Timeline 
The first study visit will occur before participants receive TZIELD® (pre-
TZIELD® MMTT in figure 2). We will schedule the first of two post-
TZIELD® studies (post-TZIELD® placebo MMTT and post-TZIELD® 
GLP-1Ra MMTT in figure 2) between two to seven months after 
completing TZIELD® treatment. The study team will randomize the 
sequence of the two post-TZIELD® studies into one of two treatment 
orders (e.g., GLP-1Ra then placebo or placebo then GLP-1Ra). 

 
 
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Participants will complete these two studies over a maximum span of 
seven months, with a minimum washout period of one week between 
studies to minimize carryover effects.  
 
 
In certain circumstances, a potential participant may have already 
undergone TZIELD® treatment prior to joining the study. This could be 
because they received TZIELD® at a different institution or due to 
scheduling constraints that prevent them from participating in the pre-
TZIELD® MMTT before receiving TZIELD®. In such cases, where the 
participant is otherwise eligible for the study, the PI may elect to skip the 
pre-TZIELD® MMTT and proceed directly to the two post-TZIELD® 
MMTTs.   
 
6.3 
Study preparation 
To promote consistency across participants and limit potential external 
influences, we have established several guidelines. To limit potential 
confounding factors that could impact metabolic responses to GLP-1Ra, 
we will ask subjects to refrain from vigorous exercise prior to each study.. 
Our team will instruct participants to consume a diet consisting of at least 
150 grams of carbohydrates during the day before each experiment. 
Participants will begin fasting at 10 PM the night before the study. For 
female participants, we will aim to align study visits with the follicular 
phase of their menstrual cycle (days 2-10) to minimize potential 
confounding factors related to insulin sensitivity22. 
 
To ensure an accurate measurement of key study outcomes with minimal 
confounding, participants will take the following precautions before each 
STUDY visit: 
- 
Hold vitamin supplementation for 72 hours 
- 
Avoid NSAIDs and aspirin for 24 and 72 hours, respectively, if feasible 
- 
Refrain from smoking and avoid secondhand smoke exposure for 12 
hours 
- 
Consume no caffeine for 12 hours 
- 
Abstain from exercise for 12 hours  
 
6.4 
Protocol overview 
Figure 3 illustrates the experimental protocol for each study. 
 

 
 
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6.5 
Consent, parental consent, and adolescent assent 
The PI or designated KSP will obtain consent from all participants in the 
the clinic or before the first visit. In the case of participants ages 12-17 the 
PI or KSP will obtain adolescent and consent from both parents, 
consistent with guidance from 45 CFR 46 Subpart D § 46.406406Consent 
will be obtained in a private room in the CRC, in the Eskind Diabetes 
Center, in the pediatric endocrinology clinic in the Doctors’ Office Tower, 
or in some cases in a telephone call prior to beginning study procedures. 
The consent and assent form will be provided to the subject and family (if 
applicable) for review prior to the visit. The PI or designated Key Study 
Personnel will review the consent forms with the participant in detail and 
provide time for discussing any questions. The study team will provide a 
copy of the consent form to the participant. The participant and parents 
will sign the consent or assent either using an e-Consent document 
securely stored in Redcap or a paper copy, which the study team will 
store in a study folder kept in a locked drawer. 
 
6.6 
History and Physical Exam 
The PI or designee will review each subject’s clinical history, perform a 
physical exam, measure vital signs, and make anthropometric 
measurements. 
 
6.7 
Urine pregnancy test 

 
 
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Before each MMTT, female participants will provide a urine sample to 
exclude pregnancy to ensure safety and prevent potential harm to an 
unborn child. 
 
6.8 
Intravenous (IV) angiocatheter placement 
Upon arrival, CRC staff will establish IV catheter access. This will 
facilitate serial blood sampling. 
 
6.9 
Basal measurements 
A study team member will draw three baseline blood samples (at -60, -
52.5, and -45 minutes in figure 3) as listed in Table 1. 
 
 
6.10 
Study drug administration 
Forty-five minutes before receiving a liquid mixed meal, participants will 
receive either Rybelsus® or placebo as depicted in figure 3. For the pre-
TZIELD® MMTT, participants will receive placebo. In the two post-
TZIELD® studies participants will receive Rybelsus® or placebo in a 
random, double-blinded fashion. We chose this timing to align with the 
pharmacokinetics of Rybelsus®, maximizing its potential effect during the 
postprandial period.  
 
The Vanderbilt Investigational Drug Service will store the study drugs and 
manage the blinding procedure. 
 
Rationale for drug dose and timing: We pragmatically selected a drug 
dose and timing based on existing literature and approved uses in T2DM. 
Semaglutide is a long-acting GLP-1Ra with a half-life that allows for once-
weekly dosing, when injected subcutaneously. However, in this study, we 
will use the oral form of semaglutide (Rybelsus®). This oral version 
requires daily administration and reaches peak plasma concentrations in 
approximately 1 hour23. Therefore, administration 45 minutes before the 
MMTT should maximize its postprandial effect. As our participants will be 
naïve to this drug class, we aim to minimize adverse drug effects, 
especially nausea.  
 
6.11 
Mixed meal tolerance test (MMTT) 
At time zero (figure 3) participants will consume a BOOST® High Protein 
shake (at 6 mL/kg up to 360 mL, consistent with other T1DM studies19, 24-
30). We will label this shake with 500 mg of liquid acetaminophen. The 

 
 
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addition of acetaminophen serves as a marker for gastric emptying, 
allowing us to measure its levels later to assess the rate at which the 
stomach empties. We will collect plasma samples at -30, -15, 0, 10, 20, 
30, 60, 90, 120, 150, 180, and 240 min for measurement of compounds 
listed in table 1. 
 
6.12 
Flow mediated dilation (FMD) 
At 210 minutes, we will determine FMD. Originally developed in 1992, the 
FMD technique has become the most commonly utilized non-invasive 
method for assessing vascular endothelial dysfunction.31 The study team 
will use the Phillips EPIQ 7C ultrasound machine with an L12-3 transducer. 
Ms. JoAnn Gottlieb, an ultrasonographer with extensive experience using 
this technique, will assist in these studies.  
 
Baseline Measurements: The baseline radial artery diameter and velocity 
will be measured. The brachial artery will be scanned beginning at the 
insertion of the biceps and proceeding proximally. Color flow imaging will 
verify the brachial artery and to locate collateral vessels to serve as 
landmarks in sequent studies. Once a suitable position is found, brachial 
artery diameter will be measured over at least 10 cardiac cycles. Velocity 
will be averaged over at least a 10-20 second period. 
 
Vascular occlusion: A pillow will support each participant’s arm with the 
palm facing forward. We will position an appropriately sized blood pressure 
cuff 5 cm distal to the elbow. A rapid cuff inflator will occlude radial artery 
blood flow. The cuff will be inflated to at least 25-50 mm Hg above systolic 
blood pressure for five minutes to elicit a reactive hyperemic stimulus for 
endothelium mediated vasodilation. 
 
Reactive Hyperemia (Post-cuff release) Measurements: Post-cuff 
measurements of arterial diameters and blood velocities will be initiated ten 
seconds prior to cuff release and continued for three minutes following cuff 
release.  
 
FMD Analysis: The primary outcome of the FMD study is %FMD, defined 
as: 
%𝐹𝐹𝐹𝐹𝐹𝐹= 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦−𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏
 
 
Endothelium independent vasodilation: After the participant rests for 
another 10 min, we will measure nitroglycerin-induced vasodilation as an 
index of endothelium-independent vasodilation. We will administer a 400 
μg sublingual dose of nitroglycerin and assess the brachial artery 
response by imaging the artery continuously for 3 min. We will quantify 

 
 
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endothelium-independent vasodilation as the percent increase in brachial 
artery diameter 3 min after the nitroglycerin dose. 
 
6.13 
Study completion 
Upon completion of the study, we will allow the study subject to eat, then 
the CRC staff will discharge the patient to home.  
 
6.14 
Rescheduling studies after a technical issue 
It is possible once a clamp visit has begun a technical issue will prevent 
the successful completion of the study. For example, IV access may be 
lost during the study. In the event such a technical issue occurs, the PI 
may elect to reschedule a new, repeat study visit provided he deems the 
technical issue poses no serious danger to the participant were it to occur 
again and the participant wishes to repeat the study. 
 
Aim 4: Early Stage 3 T1DM with GLP-1Ra Monotherapy 
 
6.15 
Overview 
In this section, we outline the study procedures for Aim 4, which focuses 
on evaluating the metabolic and beta-cell function effects of GLP-1 
receptor agonist (GLP-1Ra) therapy in participants with early stage 3 
Type 1 Diabetes Mellitus (T1DM). This study will utilize a randomized, 
double-blind, placebo-controlled crossover design, where participants will 
undergo four Mixed Meal Tolerance Test (MMTT) visits. Participants will 
receive oral semaglutide (GLP-1Ra) during two visits and placebo during 
the other two visits, with the order randomized and counterbalanced. 
 
All participants will continue their background insulin therapy as 
prescribed by their primary endocrinologist throughout the study. The trial 
is designed to assess the acute effects of GLP-1Ra on metabolic 
outcomes at two critical time points: shortly after diagnosis and after a six-
month interval. 
 
The primary goal of Aim 4 is to assess the potential for GLP-1Ra to 
improve the disposition index (DI), reflecting the preservation of beta-cell 
function and enhancement of insulin sensitivity in early stage 3 T1DM. By 
comparing the effects of GLP-1Ra and placebo within the same 
participants at two time points, we aim to determine how GLP-1Ra 
monotherapy influences metabolic outcomes independent of other 
therapies. 
 
6.16 
Timeline and Visits 
 
Participants will undergo four study visits for data collection: 
 
- 
Visit 1 and Visit 2 (Baseline Visits): Shortly after enrollment, 
participants will undergo two MMTT study visits, each separated by at 
least three days to allow for washout of the study drug. In one visit, 
participants will receive oral semaglutide (GLP-1Ra), and in the other, 
they will receive placebo. The order of GLP-1Ra and placebo 
administration will be randomized and double-blinded. 

 
 
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- 
Visit 3 and Visit 4 (Follow-up Visits): Approximately six months after 
the baseline visits, participants will undergo two additional MMTT 
study visits, again separated by at least one week. They will receive 
GLP-1Ra and placebo in randomized order. 
 
6.17 
Consent, parental consent, and adolescent assent 
The PI or designated KSP will obtain consent from all participants in the 
the clinic or at the beginning of the first study visit. In the case of 
participants ages 12-17 the PI or KSP will obtain adolescent and consent 
from both parents, consistent with guidance from 45 CFR 46 Subpart D § 
46.406406. Consent will be obtained in a private room in the CRC, in the 
Eskind Diabetes Center, in the pediatric endocrinology clinic in the 
Doctors’ Office Tower, or in some cases in a telephone call prior to 
beginning study procedures. The consent and assent form will be 
provided to the subject and family (if applicable) for review prior to the 
visit. The PI or designated Key Study Personnel will review the consent 
forms with the participant in detail and provide time for discussing any 
questions. The study team will provide a copy of the consent form to the 
participant. The participant and parents will sign the consent or assent 
either using an e-Consent document securely stored in Redcap or a 
paper copy, which the study team will store in a study folder kept in a 
locked drawer. 
 
6.18 
Study Preparation 
 
6.18.1 Standardization to minimize confounding of key outcomes 
 
To promote consistency across participants and limit potential external 
influences, we have established several guidelines. We ask subjects to 
refrain from vigorous exercise and adhere to a standardized diet prior to 
each study visit to limit potential confounding factors that could impact 
metabolic responses to GLP-1Ra. Participants will be instructed to 
consume a consistent diet, maintaining their usual caloric intake and 
macronutrient composition for three days prior to each study. Our team 
will provide dietary guidelines to ensure consistency. Participants will 
begin fasting at 10 PM the night before the study. For female participants, 
we will aim to align study visits with the follicular phase of their menstrual 
cycle (days 2-10) to minimize potential confounding factors related to 
insulin sensitivity22. 
 
To ensure an accurate measurement of key study outcomes with minimal 
confounding, participants will take the following precautions before each 
STUDY visit: 
- 
Hold vitamin supplementation for 72 hours 
- 
Avoid NSAIDs and aspirin for 24 and 72 hours, respectively, if feasible 
- 
Refrain from smoking and avoid secondhand smoke exposure for 12 
hours 
- 
Consume no caffeine for 12 hours 

 
 
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Protocol Date: October 23, 2025 
- 
Abstain from exercise for 12 hours 
- 
Consume dinner between 1700 and 2200 on the evening prior to 
STUDY visit. Thereafter, the participant will begin fasting except for 
drinking sugar free liquids, except if hypoglycemia occurs.  
 
6.18.2 Dietary guidelines before study visits 
Participants should not restrict carbohydrates from the diet before the test. 
A general guideline is that pre-adolescents should consume at least 25 kcal 
(6.25 g/kg/day) in carbohydrates and adolescents and adults should 
consume at least 15 kcal (3.75 g)/kg/day in carbohydrates for 3 days before 
the MMTT. These are minimum amounts of carbohydrates; most diets will 
include more carbohydrates. Participants will not need to alter their diets 
unless they are consuming a carbohydrate-restricted diet.  
 
6.18.3 Insulin administration and glucose management  
Participants should maintain routine monitoring of blood glucose on the 
evening preceding and the morning of the MMTT. 
 
- 
Rapid-Acting Insulin: Participants may administer boluses of rapid-
acting insulin analogs (e.g., lispro, aspart) up until two hours before 
beginning the MMTT experiment. 
 
- 
Continuous Subcutaneous Insulin Infusion: Participants using insulin 
pumps may continue their basal insulin infusion up until the beginning 
of the basal sampling period of the MMTT. 
 
- 
Long-Acting Basal Insulin: Participants taking long-acting basal insulin 
(e.g., glargine, degludec) may continue taking their insulin per their 
current prescription. 
 
Hypoglycemia Management: 
- 
If participants have blood glucose levels between 54-70 mg/dL on the 
night prior to the test, they should break their fast to consume 4-16 
grams of glucose using glucose tablets, wait 15 minutes, and repeat a 
glucose measurement. If the glucose rises above 100 mg/dL, they 
should resume fasting. If the glucose remains below 100 mg/dL, they 
should consume another 4-16 grams of glucose and repeat the cycle 
until glucose rises above 100 mg/dL. 
 
- 
If glucose levels fall below 54 mg/dL on the night prior to the study, 
research staff will reschedule the MMTT study. 

 
 
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Protocol Date: October 23, 2025 
6.19 
Study protocol overview 
Figure 4 illustrates the experimental protocol for each study. 
 
6.20 
Arrival and preparation 
Upon arrival at the CRC, the PI or his MD, NP, or PA designate will 
conduct a brief history and physical exam. Then, clinical staff will 
establish intravenous catheter access to facilitate serial blood sampling 
throughout the study visit. Study personnel will use proper aseptic 
techniques to minimize the risk of infection. 
 
6.21 
Basal measurements 
A study team member will draw three baseline blood samples at -60, -
52.5, and -45 minutes before the MMTT begins (figure 4). These samples 
will serve as baseline measurements for glucose, insulin, C-peptide, and 
other metabolites as listed in Table 1. 
 
 

 
 
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6.22 
Study drug administration 
Forty-five minutes before receiving the mixed meal, participants will 
receive either Rybelsus® (oral semaglutide) or placebo, according to their 
randomized treatment sequence. The study drug will be administered with 
up to 120 mL of water in a fasting state, and participants will be instructed 
not to eat, drink, or take any other oral medications for at least 30 minutes 
after administration.  
 
The Vanderbilt Investigational Drug Service will store the study drugs and 
manage the blinding procedure. 
 
Rationale for drug dose and timing: We pragmatically selected a drug 
dose and timing based on existing literature and approved uses in T2DM. 
Semaglutide is a long-acting GLP-1Ra with a half-life that allows for once-
weekly dosing, when injected subcutaneously. However, in this study, we 
will use the oral form of semaglutide (Rybelsus®). This oral version 
requires daily administration and reaches peak plasma concentrations in 
approximately 1 hour23. Therefore, administration 45 minutes before the 
MMTT should maximize its postprandial effect.  
 
As our participants will be naïve to this drug class, we aim to minimize 
adverse drug effects, especially nausea. For this reason, we are using a 
single conservative 7 mg dose, rather than the full 14 mg dose.  
 
6.23 
Mixed meal tolerance test (MMTT) 
At time zero (figure 4) participants will consume a BOOST® High Protein 
shake (at 6 mL/kg up to 360 mL, consistent with other T1DM studies19, 24-
30). We will label this shake with 500 mg of liquid acetaminophen. The 
addition of acetaminophen serves as a marker for gastric emptying, 
allowing us to measure its levels later to assess the rate at which the 
stomach empties. We will collect plasma samples at -30, -15, 0, 10, 20, 
30, 60, 90, 120, 150, 180, and 240 min for measurement of compounds 
listed in table 1. 
 
6.24 
Flow mediated dilation (FMD) 
We will conduct FMD assessments during each MMTT visit to evaluate 
endothelial function, a key indicator of vascular health. 
 
Procedure: 
 
- 
Timing: FMD measurements will be performed at approximately 210 
minutes after the mixed meal ingestion. 
 
- 
Equipment: The Phillips EPIQ 7C ultrasound machine with an L12-3 
transducer will be used. 
 
- 
Personnel: An experienced ultrasonographer will conduct the FMD 
studies. 
 
Steps: 

 
 
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Protocol Date: October 23, 2025 
 
1. Baseline Measurements: 
 
- 
The participant rests in a supine position for at least 10 minutes. 
- 
Baseline brachial artery diameter and blood flow velocity are 
measured over at least 10 cardiac cycles. 
 
2. Vascular Occlusion: 
 
- 
A blood pressure cuff is placed on the forearm, 5 cm distal to the 
elbow. 
- 
The cuff is inflated to at least 50 mm Hg above systolic blood 
pressure for five minutes to induce ischemia. 
 
3. Post-Cuff Release Measurements: 
 
- 
The cuff is rapidly deflated. 
- 
Arterial diameter and flow velocity measurements are taken 
immediately and continued for three minutes to capture reactive 
hyperemia. 
 
4. Data Analysis:  
- 
FMD is calculated using the formula: 
 
%𝐹𝐹𝐹𝐹𝐹𝐹= 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑ℎ𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦𝑦−𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏
 
 
5. Endothelium-Independent Vasodilation: 
- 
After a 10-minute rest, 400 μg of sublingual nitroglycerin is 
administered. 
- 
Brachial artery diameter is measured continuously for three 
minutes. 
- 
This assesses the vascular smooth muscle response, independent 
of endothelial function. 
 
Safety Considerations: 
- 
Nitroglycerin administration 
o Participants with systolic blood pressure ≤100 mmHg will not 
receive nitroglycerin. 
o Participants will remain supine for at least 10 minutes after 
nitroglycerin administration to monitor for hypotension. 
 
 
6.25 
Study completion 

 
 
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Protocol Date: October 23, 2025 
Upon completion of the study, we will allow the study subject to eat, then 
the CRC staff will discharge the patient to home.  
 
6.26 
Rescheduling studies after a technical issue 
If a technical issue (e.g., loss of IV access) prevents the successful 
completion of a study visit, the PI may elect to reschedule the visit, 
provided there is no risk to the participant and they are willing to repeat 
the study. 
 
 
 
 
7.0 
Risks 
 
The safety and wellbeing of study participants is paramount. All potential risks will be 
communicated transparently during the consent/assent process and included in the 
relevant documentation.   
 
7.1 
Perceived low risks: 
- 
Venipuncture and Intravenous Angiocatheter Placement: Risks 
include potential hematoma, site infection, nausea, and vasovagal 
syncope. Mitigation: All procedures will be performed with 
participants seated. Sites will be cleaned with appropriate 
antiseptic before any skin incision. 
- 
Liquid Meal Consumption: Some participants may experience 
gastrointestinal symptoms like bloating or nausea post-
consumption. Mitigation: An anti-emetic may be provided under 
the discretion of the PI. 
7.2 
Other considered risks: 
- 
Nitroglycerin administration: Used in flow-mediated dilation 
studies, nitroglycerin might cause transient headaches, a dip in 
blood pressure, or symptoms of hypotension. Nitroglycerin will not 
be given to participants with a systolic blood pressure ≤100 
mmHg. After administration, participants will remain supine for 10 
minutes for the medication to clear. 
 
Rybelsus® use: Rybelsus®, as with any medication, carries potential risks and 
side effects. Some of the most commonly reported side effects include nausea, 
vomiting, and diarrhea. Acute pancreatitis, though rare, is a serious side effect 
that has been reported with exenatide use (another medicine in the GLP-1Ra 
class).  
 
Gastrointestinal side effects are a relatively commonly adverse event associated 
with GLP-1Ra therapy. In the pivotal PIONEER 6 study, gastrointestinal adverse 
events occurred more commonly in participants receiving oral semaglutide 
(Rybelsus®). Gastrointestinal side effects occurred in 108 of 1591 patients 
(6.8%) in the oral semaglutide group vs. in 26 of 1592 (1.6%) in the placebo 
group. These gastrointestinal side effects were primarily nausea (in 46 of 1591 
patients [2.9%] vs. in 8 of 1592 [0.5%]), vomiting (in 24 of 1591 patients [1.5%] 

 
 
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Protocol Date: October 23, 2025 
vs. in 4 of 1592 [0.3%]), and diarrhea (in 22 of 1591 patients [1.4%] vs. in 6 of 
1592 [0.4%]), mostly nonserious. However, serious adverse events led to 
permanent discontinuation of oral semaglutide in 41 of 1591 patients (2.6%) and 
of placebo in 48 of 1592 patients (3.0%)32.  
 
Mitigation: To minimize these risks, we will carefully screen all 
participants prior to beginning the study. Our exclusion criteria exclude 
individuals with a history of pancreatitis and gastroparesis within the past 
3 years. We have chosen a conservative (7 mg) single dose of 
Rybelsus® for the study to minimize potential side effects. If appropriate 
in the judgement of the PI, the study team may provide an anti-emetic. 
 
7.3 
Discussion of Risks as Part of the Consent Process 
We will transparently discuss risks, benefits, and all procedures with 
potential study participants during the consent process. We will always use 
an IRB-approved consent and assent document. Understanding that 
consent is an ongoing process and not a one-time event, participants retain 
the right to withdraw their consent at any stage. Unforeseen adverse effects 
might emerge, and we will continuously monitor and, if necessary, adjust 
the protocol for patient safety. Any changes in study procedures, risks, or 
benefits will be communicated to participants after IRB approval. A revised 
written consent will be obtained when necessary. 
 
8.0 
Reporting of Adverse Events or Unanticipated Problems involving Risk to 
Participants or Others 
 
Adverse Events 
An AE will be considered to be any untoward medical occurrence in a subject, not 
necessarily having a causal relationship with the study.  The PI will continually monitor 
for any AEs.   
 
AEs will be graded according to following scale: 
 
0 = No adverse events 
1 = Mild: no limitation of usual activities, did not require treatment 
2 = Moderate: some limitation of usual activities, resolved with or without treatment,  
3 = Severe: inability to carry out usual activities, requiring medical intervention 
4 = Life-threatening or disabling 
5 = Death 
 
Serious Adverse Events 
Defining Serious Adverse Events 

 
 
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Consistent with FDA guidelines, serious adverse events (SAEs) will be 
defined as any untoward medical occurrence that:  
- 
requires inpatient hospitalization 
- 
results in persistent or significant disability 
- 
is suspected to cause a congenital anomaly or birth defect in a 
subject's unborn child 
- 
is life-threatening 
- 
results in death 
- 
is considered to be an important medical event based on 
appropriate medical judgement (e.g., bronchospasms requiring 
emergency department referral, seizures that might not result in 
hospitalization). 
Assessing relationship between a SAE and relationship to study procedures 
An SAE's relationship to the study procedures will be assessed and graded 
as either: not related, unlikely, possible, probable, or definite. 
Assessing whether an AE is an anticipated problem 
Any AE will be assessed for whether or not it was an anticipated problem. 
In accordance with Department of Health and Human Services guidance 
and consistent with 45 CFR part 46, an "unanticipated problem" will include 
any incident, experience, or outcome that meets all the following criteria: 
1. unexpected (in terms of nature, severity, or frequency) given  
a. the research procedures that are described in the protocol-related 
documents, including the IRB-approved research protocol and 
informed consent document; and  
b. the characteristics of the subject population being studied; related 
or possibly related to participation in the research; and 
2. suggests that the research places subjects or others at a greater risk of 
harm. 
3. related or possibly related to participation in the research; 
4. suggests that the research places subjects or others at a greater risk of 
harm than was previously known or recognized. 
Unanticipated, non-serious AEs 
All unanticipated, non-serious AEs and the study team’s response to the 
non-serious AE will be included in a report at the time of annual continuing 
review.  The PI will review the AEs and notify the Data Safety Monitor 
(DSM) and the IRB of any changes needed to the protocol. If needed, 
appropriate changes will be made to the consent form.   
Unanticipated SAEs 
In accordance with IRB policy, any unanticipated SAE that is considered 
possibly related to participation in the study will be reported within 7 

 
 
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Protocol Date: October 23, 2025 
calendar days of the PI's notification of the event to the IRB and DSM. The 
study team will continue to follow or obtain documentation of the resolution 
of any SAE.   
Adverse Event Reporting 
The annual summary of all unanticipated adverse events and any audit 
reports will be sent to the IRB at the time of continuing review. A copy of 
this report will also be sent to the NIH who will fund the PI on a K23 grant 
with the Research Performance Progress Report.   
Data and safety monitoring activities for this study will continue until all 
subjects have completed their participation and until a sufficient amount of 
time has passed beyond which any study-related AEs are unlikely.   
This protocol will be reviewed annually (at a minimum) by the Vanderbilt 
IRB.  The goal of this process is to determine the risks and benefits of the 
study in the actual experience of subjects and that measures taken to 
minimize risks are adequate. 
 
9.0 
Study Withdrawal/Discontinuation 
 
Subjects will be free to withdraw from the study at any time, which will be made clear at 
enrollment. Subjects will be withdrawn from the study if:  
- 
Pregnancy is detected 
- 
The PI’s (or designated MD, NP, or PA KSP) medical judgement is that participation 
places the subject at risk for harm  
 
10.0 
Statistical Considerations 
 
Aims 1-3  
 
A goal of this pilot study is to generate preliminary data to support a future, fully powered 
future study. This future study will determine how the insulinotropic and glucagonostatic 
components of GLP-1Ra therapy will improve metabolic outcomes in patients with stage 
2 T1DM treated with TZIELD®. We will employ a crossover study design to quantify the 
metabolic effect of the GLP-1Ra, Rybelsus®, versus placebo delivered 45 minutes 
before a mixed-meal tolerance test (MMTT). We will analyze this metabolic effect for 
each aims primary outcome: 1) postprandial glycemia, 2) disposition index, and 3) 
endothelial function.  
 
We plan to enroll twenty-four participants with stage 2 T1DM. Our plan allows for as 
much as a 20% drop-out rate and a final analysis of twenty participants. To address 
potential missing data due to dropouts, we will employ multiple imputation techniques. In 
determining each group’s sample size, we intend to obtain a statistical point estimate of 
the effect size of the two differing conditions (Rybelsus® versus placebo) on each aim’s 
primary outcome.  
 
We will also carry out bivariate linear regression analyses to estimate the individual 
contributions of the insulinotropic and glucagonostatic components of GLP-1Ra therapy 

 
 
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Protocol Date: October 23, 2025 
on metabolic outcomes. This will be treated as a secondary analysis and hence, it will 
not directly influence our primary power analysis. However, the results from this analysis 
will provide valuable insights for planning the fully powered future study. 
 
Primary outcome for Aim 1: Difference in postprandial hyperglycemia between GLP-1Ra 
and placebo studies, as measured by the incremental increase above basal in the 
plasma glucose concentration from 0 to 120 minutes, divided by the 120-minute time 
interval (i.e., iAUCglucose/120 min = AUCglucose0→120/120 min – AUCglucose -30→ -15/15 min).  
- 
Expected effect size (Δ): We expect a mean within-participant difference of 
approximately 12% or a that GLP-1Ra will effect a reduction in glucose AUC/120 
mg/dL from 165 to 145 mg/dL, based on other studies of postprandial glucose in 
early-stage T1DM5, 21, 33.  
- 
Expected variance (σ): DeFronzo et al. found the SD of the within-participant 
difference in the 2-hour postprandial glucose between exenatide (another GLP-1Ra), 
and placebo was 6 mg/dL34. Because our impression is that this variance for an 
OGTT seems small, we have set an expectation that our data will show a σ of twice 
this amount, or 12 mg/dL.  
- 
Minimum detectable difference (MDD): We have considered the minimum detectable 
difference for this pilot study as part of overall planning for larger, fully powdered 
future studies of GLP-1Ra in early stage T1DM. Based on n = 20, σ = 6 mg/d, α = 
0.05, and 1- β = 0.80, the minimum detectable difference is -8 to 8 mg/dL.  
- 
Minimum clinically important difference (MCID): Based on our clinical practice and 
studies of the renal glycosuric threshold,35, 36 we consider a 15 mg/dL difference the 
MCID because this reduction in glucose is sufficiently large to forestall the initiation 
of intensive insulin therapy in early-stage T1DM. Because the MDD and the MCID 
are similar in an absolute sense, we plan to use the observed Δ and σ from this 
study to inform planning the sample size of the fully powered follow up study testing 
the same outcome. 
 
Primary outcome for Aim 2: Difference in disposition index (DI) between GLP-1Ra and 
placebo studies, as calculated by a set of differential equations encompassed by the oral 
glucose minimal model is that describe the glucose-insulin dynamics during an MMTT37.  
- 
Expected effect size (Δ): We expect GLP-1Ra will increase DI 21% based on studies 
of DI in stage 1 T1DM and the insulin-sensitizing and insulinotropic effect of GLP-
1Ra in healthy volunteers and individuals with T2DM38, 39. This amount would 
correspond to a 20.6 x 10–12 dL/kg/min2 per pmol/L increase in DI.  
- 
Expected variance (σ): Literature reporting the within-participant variance in DI 
across an intervention in early-stage T1DM is very limited, which is a factor 
prompting the present pilot study. We estimated the within-group variance in DI in a 
study of stage 1 T1DM as SD ≈ 38.7 × 10–12 dL/kg/min2 per pmol/L39. Assuming the 
standard deviation of DI would be similar for both exenatide and placebo and that the 
correlation coefficient, ρ, between the two treatments for DI was 0.5, we can 
estimate the expected standard deviation of the within-participant difference using 
the formula √ (SDGLP-1Ra2 + SDplacebo2 - 2ρ · SDGLP-1Ra · SDplacebo) ≈ 27.4 × 10–12 
dL/kg/min2 per pmol/L.  
- 
Minimum detectable difference (MDD): Based on n = 20, σ = 27.4 × 10–12 dL/kg/min2 
per pmol/L, α = 0.05, and 1- β = 0.80, the minimum detectable difference is -18 to 18 
dL/kg/min2 per pmol/L.  
- 
Minimum clinically important difference (MCID): Because DI highly influences 
glycemia in patients with stage 2 T1DM, we consider a 10% increase in DI this 

 
 
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Protocol Date: October 23, 2025 
study’s MCID. Based on Galderisi et al., this amount would correspond to 9.8 x 10–12 
dL/kg/min2 per pmol/L increase39. Although the MDD is less than the MCID, pre-
existing data informing our estimate of expected variance is scant, underscoring the 
importance of measuring this parameter in the pilot framework of this proposal.  
 
Primary outcome for Aim 3: Difference in brachial artery flow mediated dilation (%FMD) 
between GLP-1Ra and placebo studies, as measured by B-mode ultrasound calculated 
by the equation FMD (%) = [(Post-deflation diameter - Baseline diameter) / Baseline 
diameter] × 100. 
- 
Expected effect size (Δ): We expect GLP-1Ra will increase FMD by 2% based on a 
study of young adults with T1DM who received a GLP-1 infusion during 
hyperglycemia17.  
- 
Expected variance (σ): In our unpublished, crossover trial of two nutritional 
interventions in T1DM, the standard deviation of the difference in %FMD is 1.7%. We 
expect a similar variance in this study. 
- 
Minimum detectable difference (MDD): We have considered the minimum detectable 
difference for this pilot study as part of overall planning for larger, fully powdered 
future studies of GLP-1Ra in stage 2 T1DM. Based on n = 20, σ = 1.7%, α = 0.05, 
and 1- β = 0.8, the minimum detectable difference is -1.1 to 1.1%.  
- 
Minimum clinically important difference (MCID): A large meta-analysis of patients 
with cardiovascular risk factors suggests that a 1% increase in FMD corresponds to 
a 10% decrease in cardiovascular disease risk. Accordingly, we consider the MCID 
to be 1% in this study40. Because the MDD and the MCID are similar, we plan to use 
the observed Δ and σ from this study to inform planning the sample size of the fully 
powered follow up study testing the same outcome. 
 
 
Aim 4 
 
Our primary objective in this pilot study is to evaluate the independent effects of GLP-
1Ra (oral semaglutide) on metabolic outcomes in patients with early stage 3 Type 1 
Diabetes Mellitus (T1DM) using a randomized, double-blind, placebo-controlled 
crossover design. Each participant will undergo four Mixed Meal Tolerance Test (MMTT) 
visits: two at baseline and two after a six-month interval. During each pair of visits, 
participants will receive GLP-1Ra during one visit and placebo during the other, with the 
order randomized. 
 
We will analyze the metabolic effects of GLP-1Ra versus placebo for our primary 
outcome: the disposition index (DI). Secondary outcomes include postprandial glycemia 
and endothelial function as measured by flow-mediated dilation (FMD). 
 
We plan to enroll twelve participants with early stage 3 T1DM. Our plan allows for up to 
a 20% dropout rate, aiming for a final analysis of at least ten participants. Given the pilot 
nature of this study, our primary goal is to estimate effect sizes and variances to inform 
future, fully powered studies. 
 
We will employ statistical methods appropriate for a crossover design with repeated 
measures. Specifically, we will use linear mixed-effects models to analyze within-subject 
differences between GLP-1Ra and placebo conditions, accounting for potential period, 

 
 
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Protocol Date: October 23, 2025 
treatment, and carryover effects. The model will include fixed effects for treatment, 
period, and sequence, and a random effect for participants. 
 
- 
Expected effect size (Δ): Given the early-stage 3 T1DM participants and the effect 
seen in similar populations, we anticipate GLP-1Ra will increase DI by approximately 
15%. This would correspond to an increase of approximately 14.7 x 10–12 dL/kg/min2 
per pmol/L. 
 
- 
Expected variance (σ): Since this is a pilot study with limited data on DI in Stage 3 
T1DM, we have assumed a within-participant variance similar to previous studies, 
estimated at SD ≈ 38.7 × 10–12 dL/kg/min2 per pmol/L. Using this variance for the 
sample size of 12 participants, we will calculate confidence intervals for our 
estimates rather than aiming for a fully powered hypothesis test. 
 
- 
Minimum detectable difference (MDD): Based on n = 12, σ = 38.7 × 10–12 dL/kg/min2 
per pmol/L, α = 0.05, and 1- β = 0.80, the minimum detectable difference is 
estimated to be approximately -22 to 22 dL/kg/min2 per pmol/L. Due to the small 
sample size, results will primarily be used to determine the feasibility of DI 
measurements and estimate effect sizes for future studies. 
 
- 
Minimum clinically important difference (MCID): Because DI highly influences 
glycemia in patients with stage 2 T1DM, we consider a 10% increase in DI at the 12-
month MMTT as this study’s MCID. Based on Galderisi et al., this amount would 
correspond to 9.8 x 10–12 dL/kg/min2 per pmol/L increase39. Although the MDD is less 
than the MCID, pre-existing data informing our estimate of expected variance is 
scant, underscoring the importance of measuring this parameter in the pilot 
framework of this proposal.  
 
11.0 
Privacy/Confidentiality Issues 
 
A database will be designed for this study using REDCap (Research Electronic 
Data Capture) tools. REDCap is a secure, web-based application designed to 
support data capture for research studies, providing validated data entry, audit 
trails, seamless data downloads to common statistical packages, and mechanisms 
for importing data from external sources. It will reside on a secure server with 
access provided exclusively to the research personnel. Subjects will be identified 
with a study identification number. A key to the subject identification number will 
be kept in a separate locked file drawer to which only the Principal Investigator and 
research coordinators have access. Reports will thereby be generated without 
Protected Health Information (PHI) data, and access will be restricted so that 
statisticians, etc. do not have access to all data. 
Risk of leakage of PHI is minimized by keeping paper records in a locked cabinet 
and maintaining computerized records in the password protected REDCap data 
base. The principal investigator and the research staff are trained in HIPAA privacy 
regulations. The participant's identification is concealed, and a number is used as 
the identifier instead of the subject's name.  Only the principal investigator or 
members of the research team will have the list of study patient's names as the 
correlate with the study number. 

 
 
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28 
Protocol Date: October 23, 2025 
 
12.0 
Follow-up and Record Retention 
 
The study is anticipated to last for up to four years.  The study results will be maintained 
indefinitely for research purposes. 
 

 
 
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29 
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