The Effect of Exenatide Compared to Lantus Insulin on Vascular Function in Type 2 Diabetes

The trial is a randomized, controlled, comparator study. Subjects and investigators will not
be blinded due to the nature of the treatment. After providing informed consent and meeting
the inclusion and exclusion criteria, subjects will undergo baseline studies then be
randomized to either treatment with Exenatide or Lantus insulin to achieve comparable
improvement in glycemic control, as measured by HbA1c. A computer program (randomization.com)
will be utilized to randomize 72 patients to receive either Exenatide or Lantus. The
treatment group will receive twice daily injections of Exenatide, initially of 5ug BID, and
increased to 10ug BID after 1 month. The control group will receive daily injections of
Lantus insulin each evening, which will be titrated to achieve blood glucose targets based on
self monitoring of blood glucose (SMBG), as outlined by the American Diabetes Association
(ADA) (goal: fasting 90-130, peak postprandial less than180 mg/dl). The subjects on Lantus
should achieve this goal by week 6 of the study, so that they have six weeks of maximal
therapy. The control group will receive Lantus with the goal of similar glycemic control
between the groups, with a goal of HbA1c reduction of 0.5-1.5% after 3 months. Based on
recent data, it should be feasible to accomplish similar improvements in glycemia between the
groups.

The trial will be preceded by a one-week screening and evaluation period, during which time
the patient will be informed about the trial, and qualification will be determined based on
the inclusion/exclusion criteria, as noted below. The patient will also be instructed in
injection technique and SMBG techniques at the screening visit. Subjects will be asked to
perform daily fasting blood glucose monitoring, and in addition on 2 days per week (1 weekday
and 1 weekend day) to obtain 6 blood glucose measurements (fasting, 1-2hours post-breakfast,
pre-lunch, 1-2 hours post-lunch, pre-dinner, and 1-2 hours post-dinner). Baseline studies
will then be performed at week 0, including fasting laboratory studies, FMD, PWA, and Meal
Challenge Test. The subject will then be randomized to receive treatment with either Lantus
or Exenatide for 12 weeks duration. Repeat studies will then be performed at 12 weeks,
including repeat of the baseline laboratory studies, FMD, PWA, and Meal Challenge test.

Schedule/Flow Chart

Visit 1 (week -1): Potential participants will be informed regarding the trial, records will
be reviewed, and inclusion/exclusion criteria will be evaluated. Informed consent will be
administered, and a history and physical will be performed. They will have baseline labs
drawn, including HbA1c, glucose, lipids, CBC, chemistry, renal function, liver function, and
urinalysis. If they are female and of reproductive age, they will also have a urine HCG
performed. Subjects will be fasting for this visit.

Visit 2 (week 0): Participants will come in fasting. Interval medical history and medications
will be reviewed. Vital signs will be obtained. PWA and FMD will be performed. The patient
will then have fasting labs drawn which will include glucose, insulin, c-peptide, lipids,
free fatty acids (FFA), CRP, TNFA, IL-6, ICAM, VCAM, endothelin 1, PAI-1 protein, PAI-1
activity, and FOX2. The patient will then have a mixed meal (time 0), and labs will again be
drawn at 15, 30 minutes, 45 minutes, 60 minutes, 120 minutes, 180 minutes, and 240 minutes
after the meal challenge measuring glucose, insulin, c-peptide, lipids, and FFA. At time 120
minutes, FWA and FMD will be performed again along with blood samples for CRP, TNFA, IL-6,
ICAM, VCAM, endothelin 1, PAI-1 protein, PAI-1 activity, and FOX2. At 240 minutes, PWA, FMD,
and TNG will be performed.

After completion of these tests, the patients will be randomized and start treatment with
either Exenatide 5ug BID or nightly Lantus beginning the following day. Lantus dose will be
based on clinical assessment, but starting doses will likely be between 10 and 20 units.
Patients will be instructed in SMBG techniques, as well as injection techniques for either
Byetta (Exenatide) or Lantus.

Week 1: Telephone contact. Review side effects and blood glucoses (BGs), adjust Lantus if
needed, and adjust oral hypoglycemic agents (OHA) in Exenatide treated group if clinically
indicated.

Week 2: Telephone contact. Review side effects and BGs, adjust Lantus if needed, and adjust
OHA in Exenatide treated group if clinically indicated.

Visit 3 (week 4): Patients will come in. Those in the Exenatide group will have the dose
increased to 10ug sq BID. The patients in the Lantus group will have their fasting BGs
reviewed and their dose adjusted. Side effects will be reviewed with all subjects. Subjects
in the Exenatide treated group will have their OHA adjusted if clinically indicated.

Week 6: Telephone contact. Review BGs and side effects, and adjust Lantus if needed. Lantus
dose should be at/close to maximal dose to achieve target fasting blood glucose goal.
Subjects in the Exenatide treated group will have their OHA adjusted if clinically indicated.

Week 8: Telephone contact. Review side effects and BGs, adjust Lantus if needed, and adjust
OHA in Exenatide treated group if clinically indicated.

Week 10: Telephone contact. Review side effects and BGs, adjust Lantus if needed, and adjust
OHA in Exenatide treated group if clinically indicated. At this time, we will discuss with
the subjects if they are interested in continuing their study medication upon completion of
the study. We will advise them to call their diabetes provider to then arrange for a
prescription that will start upon study completion. We will advise them at the beginning of
the study to set up a follow up appointment with their provider around the time of study
completion. We will speak with their diabetes provider if the subject wishes us to do so.

Visit 4 (week 12): Participants will come in fasting. If they are in the Exenatide group, we
will ask them not to take their morning dose at home, but to bring it in with them so that it
can be administered within 60 minutes of the meal tolerance test. Subjects will also be asked
to return any unused study drug at this final visit. Interval medical history and medications
will be reviewed. Vital signs will be obtained. PWA and FMD will be performed. The patient
will then have fasting labs drawn which will include CBC, Chem 20, HbA1C, urinalysis,
microalbumin, LFTs, glucose, insulin, c-peptide, lipids, FFA, CRP, TNFA, IL-6, ICAM, VCAM,
endothelin 1, PAI-1 protein, PAI-1 activity, and FOX2. The subjects randomized to Exenatide
will then take their morning dose, and all subjects will then have a mixed meal (time 0), and
labs will again be drawn at 15, 30 minutes, 45 minutes, 60 minutes, 120 minutes, 180 minutes,
and 240 minutes after the meal challenge measuring glucose, insulin, c-peptide, lipids, and
FFA. At time 120 minutes, PWA and FMD will be performed again along with labs for CRP, TNFA,
IL-6, ICAM, VCAM, endothelin 1, PAI-1 protein, PAI-1 activity, and FOX2. At 240 minutes, PWA,
FMD, and TNG will be performed.

Methods The Mixed Meal will consist of standard liquid meal, Boost, which is composed of
61.5g of carbohydrate, 15g of protein, and 6g of fat, in 360ml, with 360 calories. The
subjects will come in fasting. Starting at time 0, the Boost will be consumed over a five
minute time period. The studies will then be performed on visits 2 and 4.

Brachial artery flow mediated dilatation (FMD) evaluates endothelium-dependent reactivity in
the macrocirculation. This is carried out in temperature-controlled room (24-26 degrees C)
with a 30 minute acclimatization period. FMD of the brachial artery is measured at rest and
during reactive hyperemia using a high-resolution 10.0 MHz linear array transducer and an HDI
Ultramark 9 system. Reactive hyperemia is produced by inflating a pneumatic tourniquet
distally to the brachial artery to 50 mmHg above the systolic BP for 5 minutes, then
deflating it. Brachial artery diameter is measured before inflation of the cuff and 1-2
minutes after cuff deflation and expressed as the percentage change.

Trinitroglycerin-induced vasodilation evaluates endothelium independent vasodilation. The
brachial artery will be scanned before and 5 minutes after sublingual administration of 400
ug of trinitroglycerin. This will be performed only at 240 minutes, fifteen minutes after
completion of the FMD study to allow for the brachial artery to return to baseline.

Pulse wave analysis(PWA) is another method to evaluate the function of the vasculature. The
shape of the arterial pressure waveform provides a measure of systemic arterial stiffness.
All measurements will be made in the right arm using the Sphygmocore Px (Atcor Medical Blood
Pressure Analysis System, Australia) in a temperature-controlled room. With the wrist
slightly extended and supported on a pillow, the radial artery of the right arm is flattened
with a high fidelity micro manometer using gentle pressure. 20 sequential waveforms are
acquired and the system software generates an average peripheral and corresponding central
waveform, which is then subjected to further analysis of augmentation. Two pressure peaks
characterize the systolic part of the central waveform. The first peak results from LV
ejection, and the second results from the wave reflection. The difference between peaks
represents the degree to which central arterial pressure is augmented by wave reflection. AP
is the absolute increase in pressure from the reflected wave and AI is a measure of the
contribution that the wave reflection makes to the arterial pressure waveform, and is
expressed as a percentage of pulse pressure. The amplitude and timing of the reflected wave
ultimately depends on the stiffness of the small vessels and large arteries, and thus is a
measure of systemic arterial stiffness.

We will enroll 72 subjects to obtain 60 subjects who will complete the study. The subjects
will have Type 2 diabetes and will be randomized to one of two treatment arms.

Inclusion Criteria:

- age 18-75

- Type 2 Diabetes (diagnosed at least 3 months prior to study)

- HbA1c: above 7.0 and less than or equal to 10.0

- At least one HbA1c over preceding 3-6 months, and HbA1c at screening, with less than
1% difference between lowest and highest values

- Stable doses of antidiabetic medications (SU and/or Metformin) for 3 months

- reproductive age females must have negative urine HCG at screening, and be using
appropriate contraception during the study or be surgically sterile

- postmenopausal woman

- stable weight for 3 months prior to study (+/- 2kg)

- willingness to participate in the study

Exclusion Criteria:

- Type 1 diabetes

- Type 2 diabetes less than 3 months in duration

- HbA1c less than 7.0 or greater than 10

- age less than 18 or greater than 75

- pregnant or planning to become pregnant during study period

- current insulin therapy or insulin within 6 months prior to study

- current use of Thiazolidinedione or within 6 months prior to study

- current use of Nateglinide or Repaglinide

- current use of an Alpha-glucosidase Inhibitor

- current weight loss program

- active smoker, or quit smoking within preceding 6 months

- creatinine greater than 2.0 mg/dL

- total cholesterol greater than 300 mg/dL

- triglycerides greater than 600 mg/dL

- blood pressure greater than 160/105 mmHg

- ALT/AST greater than twice the upper limit of normal

- any other medical condition that may interfere with trial participation or trial
results

- if on Statin: Statin therapy for less than 3 months or dose change within preceding 3
months

- if on ACE Inhibitor: ACE Inhibitor therapy for less than 3 months or dose change
within preceding 3 months

- current use of any medication that is known to alter gastric motility