Effects of Linagliptin on Endothelial Function and Global Arginine Bioavailability Ratio in Coronary Artery Disease Patients With Early Diabetes
Phase: PHASE4
Conditions: Type 2 Diabetes, Coronary Artery Disease
Sponsor: Medical University of Graz

 
Protocol V 2.4                                                                                                                                         Page 1 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
 
Title:  Effects of linagliptin on endothelial function and global arginine bioavailability ratio in 
           coronary artery disease patients with early diabetes  
 
Ethics number: to be added 
 
                     EudraCT number: 2013-000330-35 
Protocol code: HS-2012-1 
Date and Version number:   24/10/2014          Version 2.4     
Principal Investigator:  
Harald Sourij, MD, Associate Professor  
Co-Investigators:  
Norbert Tripolt, MSc, PhD 
Tatjana Stojakovic, MD, Assistant Professor 
Andreas Meinitzer, MSc. PhD         
Franz Hafner, MD 
Marianne Brodmann, MD 
Felix Aberer, MD                      
Biometrician:  
Regina Riedl, Dipl.-Ing. 
Trial site address and telephone number: 
Medical University of Graz, Department of Endocrinology and Metabolism, Cardiovascular Diabetology 
Research Group, Austria, 8036 Graz, Auenbruggerplatz 15; Telephone: +43 (0)316 385 13270 Fax: +43 
(0)316 385 14332 
Financial support: Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria  
Signatures: 
 
_________________________________________________ 
Confidentiality Statement 
This document contains confidential information that must not be disclosed to anyone other than the 
sponsor, the investigator team, regulatory authorities and members of the Research Ethics Committee. 
Trials Sponsor: 
Medical University of Graz 
Auenbruggerplatz 2-4 
8036 Graz  

 
Protocol V 2.4                                                                                                                                         Page 2 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
1. 
TABLE OF CONTENTS 
 
1. 
TABLE OF CONTENTS......................................................................................................................................... 2 
2. 
LIST OF ABBREVIATIONS ................................................................................................................................... 3 
3. 
AMENDMENT HISTORY ..................................................................................................................................... 4 
4. 
SYNOPSIS .......................................................................................................................................................... 4 
5. 
BACKGROUND AND RATIONALE ....................................................................................................................... 6 
6. 
AIMS OF THE STUDY ......................................................................................................................................... 7 
7. 
OBJECTIVES ....................................................................................................................................................... 7 
8. 
OUTCOMES ....................................................................................................................................................... 8 
9. 
STUDY DESIGN .................................................................................................................................................. 8 
10.    SELECTION AND WITHDRAWAL OF STUDY SUBJECTS ...................................................................................... 10 
11 
STUDY PROCEDURES ....................................................................................................................................... 13 
12 
METHODS ....................................................................................................................................................... 16 
13 
TREATMENT/INTERVENTION .......................................................................................................................... 18 
14 
INVESTIGATIONAL MEDICINAL PRODUCT (TAKEN FROM THE SMPC) .............................................................. 19 
15 
PHARMACOVIGILANCE ................................................................................................................................... 22 
16 
STUDY MONITORING ...................................................................................................................................... 25 
17 
ETHICS ............................................................................................................................................................ 25 
18. FINANCE ......................................................................................................................................................... 26 
19. INSURANCE ..................................................................................................................................................... 26 
20. REFERENCES.................................................................................................................................................... 27 
 

 
Protocol V 2.4                                                                                                                                         Page 3 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
2. 
LIST OF ABBREVIATIONS 
AUC 
Area Under the Curve 
sVCAM-1 
Soluble Vascular Cell Adhesion Molecule-1 
vWF 
von Willebrand Factor 
sICAM-1 
Soluble Intercellular Adhesion Molecule-1 
FMD 
Flow Mediated Dilation 
GABR 
Global Arginine Bioavailability Ratio 
AOR 
Arginine to Ornithine Ratio 
T2DM 
Diabetes Mellitus Type 2 
DPP4 
Dipeptidylpeptidase IV 
OD 
Once daily 
MTT 
Meal Tolerance Test 
CAD 
Coronary Artery Disease 
UKPDS 
United Kingdom Prospective Diabetes Study 
GLP-1 
Glucagon like-peptide-1 
HbA1c 
Glycated haemoglobin 
AST 
Aspartate-Aminotransferase 
ALT 
Alanine-Aminotransferase 
oGTT 
Oral glucose tolerance test 
GTN 
Glyceroltrinitrate 
 
 
 

 
Protocol V 2.4                                                                                                                                         Page 4 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
3. 
AMENDMENT HISTORY 
Amendment 
No. 
Protocol 
Version 
No. 
Date issued 
Author(s) of changes 
Details of Changes made 
1 
2.1 
05.Aug.2013 
Sourij, Tripolt 
1)MTT 
(Fortimel 
compact 
instead 
of 
Fortisip liquid) 
2)Combination 
of 
Screening and Baseline 
visits 
3) Blood storage 
2 
2.2 
22.Oct.2013 
Sourij, Tripolt 
1)Blood sampling 
2)Inclusion 
criteria: 
(Age 40 to 80 years) 
3 
2.3 
30.April 2014 
Sourij, Tripolt 
1)Exclusion 
criteria: 
HbA1c 
<6.0% 
(42mmol/mol) instead 
of 
HbA1c 
<6.5 
(48mmol/mol)  
4 
2.4 
24.October 2014 
Sourij, Tripolt 
1)Storage 
of 
blood 
samples in the Biobank 
 
4. 
SYNOPSIS 
Study Title 
Effects of linagliptin on endothelial function and global arginine 
bioavailability ratio in coronary artery disease patients with early 
diabetes 
Study Design 
Randomised, double-blind, placebo-controlled, parallel group trial 
Study Participants 
Subjects at early stages of type 2 diabetes 
Number of Participants 
50 
Follow-up duration 
3 months 
Planned Duration 
16 months 

 
Protocol V 2.4                                                                                                                                         Page 5 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
Primary Objective 
The primary objective is to investigate the impact of a 12 week 
linagliptin treatment on endothelial function in patients with early 
T2DM.  
Secondary Objectives 
The secondary objective is to investigate the effect of a 12 week 
linagliptin treatment on  
- arginine bioavailability ratios (global arginine bioavailability ratio 
and arginine to ornithine ratio) 
- biochemical markers of endothelial function (sVCAM-1, sICAM-1, 
vWF) 
- the AUC of glucose, insulin and free fatty acids during the meal 
tolerance test 

 
Protocol V 2.4                                                                                                                                         Page 6 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
5. 
BACKGROUND AND RATIONALE 
 
Patients with type 2 diabetes (T2DM) are at increased risk of macrovascular events as well as 
microvascular complications (1). It is well known, that the pathophysiologic process of type 2 
diabetes starts many years before the diagnosis can be made on the basis of elevated fasting 
blood glucose.(2) In particular the data of the UKPDS study and the UKPDS post trial monitoring 
highlighted the importance of an early glucose lowering intervention in patients with T2DM with 
respect to micro- and macrovascular complications. (3, 4)  
We (5,6) and in particular the Euro Heart survey on Diabetes and the Heart (7) demonstrated, 
that in a cardiovascular high risk population, namely patients with coronary artery disease (CAD), 
about 35% suffer from manifest type 2 diabetes.  In addition, another 9 to 15% of CAD patients 
have postchallenge diabetes, diagnosed on the basis of an oral glucose tolerance test, which 
means that approximately a half of all patients with CAD have diabetes. 
Recently we could demonstrate that not only established type 2 diabetes diagnosed on the basis 
of fasting hyperglycaemia is associated with an increased cardiovascular risk, but also 
postchallenge hyperglycemia (i.e. impaired glucose tolerance or postchallenge diabetes).  
Dipeptidylpeptidase-4 (DPP-4) inhibitors increase endogenous glucagon like-peptide-1 (GLP-1) 
levels and GLP-1 in turn increases the insulin release from pancreatic beta-cells in a glucose 
dependent manner as well as suppresses glucagon secretion from pancreatic alpha cells. 
Investigations in type 2 diabetic patients showed that this drug class lowers both, fasting and 
postchallenge or postmeal glucose levels and hence, HbA1c and is well tolerated.  
However, the lowering of the surrogate measurement HbA1c has not necessarily turned out to 
translate into a reduced number of cardiovascular events in patients with T2DM. In contrary in 
particular for the thiazolidinedione Rosiglitazone concerns about an increased risk of 
cardiovascular events have been raised despite a robust HbA1c lowering effect. (8)  Therefore 
the FDA (9) and the EMA (10) issued in 2008 and 2010, respectively, guidance for new glucose 
lowering drugs, requiring proof of at least cardiovascular safety.  Cardiovascular outcome trials 
with Linagliptin are currently being performed (CAROLINA, CARMELINA), however, it will take a 
couple of years until the results are available.  

 
Protocol V 2.4                                                                                                                                         Page 7 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
A well known and validated cardiovascular surrogate parameter is endothelial dysfunction. We 
and others have shown previously, that endothelial dysfunction is present in patients with 
coronary artery disease and early diabetes and can be improved by pharmacological 
intervention. (11, 12) This surrogate measurement could be helpful in better understanding the 
cardiovascular effects of Linagliptin while awaiting the results of the definitive outcome trials. 
The aim of our current study is to investigate the effects of Linagliptin in coronary patients with 
early T2DM on various cardiovascular surrogate measurements including mechanical and 
biochemical endothelial function assessments. 
 
6. 
AIMS OF THE STUDY 
The overarching aim of our study is to investigate the effects of Linagliptin on endothelial 
function, arginine bioavailability ratios and postchallenge glycaemic control in patients with early 
diabetes and coronary atherosclerosis. 
 
7. 
OBJECTIVES 
7.1 
Primary objective 
The primary objective is to determine whether a 12 week Linagliptin treatment is associated with 
an improvement in endothelial function in patients with early diabetes.  
 
7.2 
Secondary objective 
The secondary objective is to investigate the effect of a 12 week Linagliptin treatment on  
- arginine bioavailability ratios (global arginine bioavailability ratio and arginine to ornithine 
ratio) 
- biochemical markers of endothelial function (sVCAM-1, sICAM-1, vWF) 
- the AUC of glucose, insulin and free fatty acids during the meal tolerance test 

 
Protocol V 2.4                                                                                                                                         Page 8 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
8. 
OUTCOMES 
 
8.1 
Primary outcome 
Changes in endothelial function (assessed by flow mediated dilatation – FMD) by a 12 week 
Linagliptin treatment in patients with early T2DM. 
 
8.2 
Secondary outcome parameters 
- Changes in arginine bioavailability ratios (global arginine bioavailability ratio and arginine to 
ornithine ratio) 
- Changes in biochemical markers of endothelial function (sVCAM-1, sICAM-1, vWF) 
- Changes in the AUC of glucose, insulin and free fatty acids during the meal tolerance test 
 
9. 
STUDY DESIGN 
This is a single-centre, prospective, randomized, double-blind,  placebo-controlled, parallel group 
12 week clinical trial evaluating the effect of Linagliptin 5mg OD orally on cardiovascular 
surrogate measures in patients with early diabetes. 50 subjects will be randomised to receive 
either Linagliptin or placebo for 12 weeks. At baseline all subjects will undergo endothelial 
function assessment (FMD), blood sampling as well as a meal tolerance test. At the end of the 
12-week treatment period all subjects will undergo a repeat FMD, blood sampling as well as a 
meal tolerance test.   
 
 

 
Protocol V 2.4                                                                                                                                         Page 9 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
9.1 
Schematic overview on study design 
 
 
 
 
 
 
 
 
 
 
 
 
 
9.2 
Duration of Study 
It is anticipated that the study will run for 16 months (from first patient first visit until last 
patient last visit). 
 
9.3 
Source Data 
Source documents comprise the CRF and hospital records, laboratory records and 
correspondence. 
 
All documents will be stored safely in a confidential manner.  The subject will be referred to by a 
unique study subject number/code, their initials and date of birth on all study-specific 
documentations. The only exceptions will be the signed Consent Forms, Subject Identification 
log and subject clinical file, all of which will be stored securely by the clinical site.  
50 patients will be enrolled 
25 assigned to placebo 
25 assigned to Linagliptin 
12 weeks 
12 weeks 
Changes in endothelial function 
Changes in arginine bioavailability ratios 
Changes in biochemical markers of endothelial function 
Changes in glucose, insulin FFA levels 

 
Protocol V 2.4                                                                                                                                         Page 10 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
Source data will be made available for internal and external audits or inspections by regulatory 
authorities to authorised personnel only. 
 
9.4 
Randomisation and Blinding 
The randomisation plan will be designed by the Institute of Medical Informatics, Statistics and 
Documentation, Medical University Graz, Austria, which will pass the randomisation list to the 
Pharmacy of the University Hospital Graz for adequate labelling and blinding of the medication 
The labels of the study medication will display the name of the trial, the name of the 
investigational medicinal product and contact details of the principal investigator. 
Subject numbers will be assigned sequentially as each subject enters the study.  
 
 
9.5 
Unblinding 
In the rare case of a requirement to unblind study medication, the Prinicipal investigator will 
need give permission for unblinding. The unblinding list will be held by the Institute of Medical 
Informatics, Statistics and Documentation, Medical University of Graz, who is not involved in 
study investigations.  
 
10. 
SELECTION AND WITHDRAWAL OF STUDY SUBJECTS 
 
10.1 
Subject Selection 
The study population will consist of  
 
50 subjects with early diabetes (i.e. postchallenge diabetes (2h glucose >200 mg/dl or type 2 
diabetes treated with diet only or on a stable dose of metformin monotherapy)  
 
  
 
 
 
 

 
Protocol V 2.4                                                                                                                                         Page 11 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
10.2 
Subject Recruitment 
Patients will be identified from the outpatient clinic at the Department of Endocrinology and 
Metabolism, the Division of Cardiology, via Primary Care and adverts. 
 
10.3       Inclusion Criteria 
 
Age 40-80 
 
Early diabetes (postchallenge diabetes (2h glucose >200 mg/dl or type 2 diabetes treated with diet 
only or on a stable dose of metformin monotherapy) 
 
Coronary atherosclerosis (diagnosed via coronary angiography or coronary computer tomography)  
 
10.4 Exclusion Criteria 
 
Acute coronary syndrome or cerebrovascular event within the previous 4 weeks 
 
BMI > 35 kg/m2 
 
HbA1c <6.0% (42 mmol/mol) 
 
Serum creatinine > 2.5 mg/dl 
 
AST/ALT > 3x upper limit of normal 
 
HbA1c >9.0% (>75 mmol/mol) 
 
Heart failure > NYHA class II 
 
Uncontrolled hypertension (blood pressure > 165 / 100 mmHg) 
 
Treatment with orally administered steroids 
 
New onset statin or ACE-inhibitor within the previous 6 weeks 
 
Known Malignancy 
 
Pregnancy or breast feeding women. 
 
 
 
 
 

 
Protocol V 2.4                                                                                                                                         Page 12 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
10.5 Withdrawal / Drop out of subjects 
Each subject has the right to withdraw from the study at any time without prejudice or 
compromise to future care.  
The investigator may discontinue or withdraw the subjects under the following circumstances: 
 
Significant protocol deviation 
 
Significant non-compliance with treatment regime or study procedures 
 
An adverse event that requires discontinuation of the study medication or results in inability to 
continue to comply with study procedures. If a subject is withdrawn due to an adverse event, the 
investigator will arrange for follow-up visits or telephone calls until the adverse event has resolved 
or stabilised. 
 
Consent withdrawn 
 
Lost to follow up 
 
The study will be stopped prematurely if any information relating to the IMP or any other aspect 
of the study arises that may cause harm to the participant. 
 
Any other situation that may, in the opinion of the investigator, make it unsafe or inappropriate 
for the subject to continue in the trial 
A drop-out rate of 10% was considered in the sample size estimate. In case of further drop-outs additional 
recruitment has to take place to avoid loss of statistical power. 
 
10.6 Payment to subjects 
   Reimbursement of reasonable travel expenses will be considered.   
 
10.7 End of study 
The study end is defined as the last visit of the last patient. In the case of new data suggesting a significant 
safety concern of the study drug, the trial will be prematurely stopped. 
 
 

 
Protocol V 2.4                                                                                                                                         Page 13 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
11 STUDY PROCEDURES  
11.1  Schedule of study procedures 
 
Screening (V1)* 
(up to 1 month prior 
to baseline) 
Baseline (V2) 
(week 0) 
Follow-up (V3) 
(Week 12 ± 1) 
Informed Consent 
X 
 
 
Inclusion/exclusion criteria 
X 
X 
 
Randomisation 
 
X 
 
Demography, medical history 
X 
 
 
Concomitant medication 
X 
X 
X 
Vital signs 
X 
X 
X 
Physical examination 
 
X 
 
Flow Mediated Dilatation (FMD) 
 
X 
X 
GABR, biochemical markers of 
endothelial function (sVCAM-1, sICAM-
1, vWF) 
 
X 
X 
Blood sampling  
X 
X 
X 
Meal tolerance test (MTT) 
 
X 
X 
Adverse Events 
 
 
X 
Dispense medication 
 
X 
 
Drug accountability 
 
 
X 
Pregnancy test (females with 
childbearing potential) 
X 
 
X 
*if blood samples to check inclusion/exclusion criteria are available within 4 weeks prior to 
randomisation, the screening visit and baseline visit can be performed on the same day 
 
 
 

 
Protocol V 2.4                                                                                                                                         Page 14 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
11.2   Visit Schedule 
Screening contact – Visit 1 (up to 1 month prior to potential randomisation) 
 
Sufficient time will be provided and subjects will be encouraged to discuss all queries with the 
research team 
 
Informed consent will be obtained by an investigator 
 
Check inclusion and exclusion criteria 
 
Demographics will be obtained: date of birth, gender, race, smoking status, alcohol consumption 
 
Weight 
 
Height 
 
Medical history 
 
Concomitant medication  
 
Vital signs: resting pulse and blood pressure  
 
Blood sample for HbA1c 
 
Baseline safety blood tests (fasting): Full blood cell count, renal function tests, liver function tests 
 
Pregnancy test in female woman of childbearing age. 
 
Baseline (week 0) 
 
Review inclusion and exclusion criteria 
 
Vital signs 
 
Weight 
 
Physical examination 
 
Concomitant medication review 
 
FMD measurement 
 
Blood sampling for cardiovascular surrogate measurements 
 
Meal tolerance test 
 
Randomisation: patients will be randomised to either Linagliptin 5 mg or placebo for the next 12 
weeks 
 
Dispense study medication.  
 

 
Protocol V 2.4                                                                                                                                         Page 15 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
Week 12 visit 
 
Weight 
 
Vital signs 
 
Concomitant medication review 
 
Adverse events assessment 
 
FMD measurement 
 
Blood sampling for cardiovascular surrogate measurements 
 
Meal tolerance test 
 
Drug accountability. 
 
Phone call 28 days after week 12 visit 
 
 
Assessment of adverse events  
 
 
 
11.3  Laboratory results 
All laboratory results will be reviewed and the reports signed by the study physician who will record 
whether it is normal, abnormal but not clinically significant, or abnormal and clinically significant. In 
the latter case, the eligibility of the subject will be reviewed. 
 
 

 
Protocol V 2.4                                                                                                                                         Page 16 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
12 METHODS 
12.1   Meal Tolerance Test (MTT)  
The MTT will be performed after an overnight fast (apart from water). A standard gauge cannula will be 
placed into a subcutaneous vein for blood sampling. In order to prevent blood clotting in the cannula and 
to keep the cannula working it will be occasionally flushed with sterile normal saline. Study medication 
will be given (time -15 mins) before the meal. A pre-meal blood sample will be taken (- 5mins) and then all 
subjects will be asked to drink  Fortimel compact (10 kcal/kg) over a period of 2-4 mins (time 0 mins).  
During the meal test further blood samples will be taken at 15, 30, 60, and 120 minutes.  All samples will 
be used for determination of glucose, insulin and free fatty acids.  The blood at each time point will be 
placed into a fluoride oxalate tube (1ml) for plasma glucose and into a serum tube for insulin and free 
fatty acids. 
 
12.2   Flow mediated dilation 
Endothelial dysfunction: Endothelium-dependent FMD following reactive hyperaemia and endothelium-
independent NMD following administration of GTN are examined in the brachial artery according to the 
guidelines described by Coretti et al (13). 
Using high resolution ultrasound measurements of the right brachial artery are taken after resting, after cuff 
deflation (250 mmHg for 5 minutes) of the forearm and after sublingual administration of 0.4 mg 
glyceroltrinitrate (GTN). Scans of the brachial artery are taken proximal to the antecubital fossa with 
simultaneous ECG recording. Diameter measurements are taken from one media-adventitia interface to the 
other for three to four times at baseline (the average is taken for calculating the baseline diameter), three 
times after 45 to 60 seconds after cuff deflation following reactive hyperaemia and four minutes after 
administration of GTN. GTN is applied 15 minutes after cuff deflation to allow arterial diameter to return to 
baseline, which will be controlled by measuring another baseline diameter.  
FMD-diameter is calculated as the average of the three diameter measurements following reactive 
hyperaemia. FMD and NMD are calculated as the percent change in diameter compared to baseline.  
 
 

 
Protocol V 2.4                                                                                                                                         Page 17 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
12.3  Blood sampling 
Over the 3 study visits in total approximately 51 ml of blood will be taken to determine the parameters 
outlined below. A potential remainder of serum and plasma will be stored anonymised (patient number 
and visit number only) at -80°C in the Biobank of the Medical University of Graz for potential future 
analyses.  
Twice, at baseline and after 3 months, blood (8ml LiHep) will be taken to analyse the impact of linagliptin 
on the number and function of endothelial progenitor cells. 
Laboratory measurements  
Insulin and c-peptide will be measured by chemiluminescence on an ADVIA Centaur system (Siemens 
Healthcare Diagnostics, Eschborn, Germany). FFA will be measured enzymatically (Wako Chemical, Neuss, 
Germany) on an Olympus AU640 (Olympus Diagnostica, Hamburg, Germany). Routine parameters will be 
determined using a cobas analyzer (Roche Diagnostics, Mannheim, Germany). 
GABR 
Arginine, ornithine and citrulline will be measured in serum samples with a conventional usual amino acid 
analysis technique, involving separation of amino acids by ion exchange chromatography followed by 
postcolumn continuous reaction with ninhydrin. Global arginine bioavailability ratio will be calculated by 
L-arginine divided by the sum of (L-ornithine plus L-citrulline). The arginine to ornithine ratio will be 
calculated by dividing L-arginine by L-ornithine levels. 
 
12.4 Data analysis and sample size estimation 
Data analysis 
Continuous variables will be presented as means, standard deviation, median, minimum and maximum, 
for categorical data frequencies and relative frequencies are used. To examine differences between 
groups at baseline, t-tests or Mann-Whitney U tests and chi-square tests will be used as appropriate. The 
primary outcome, FMD after 12 weeks, will be analysed using ANCOVA. Comparisons within groups will be 
performed using paired t-test or Wilcoxon rank-sum test. A p-value of <0.05 is considered to indicate 

 
Protocol V 2.4                                                                                                                                         Page 18 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
statistical significance. A statistical analysis plan will be prepared and finalized before database lock. 
 
Sample size  
Sample 
size 
was 
estimated 
using 
free 
available 
calculator 
http://www.quantitativeskills.com/sisa/calculations/samsize.htm. 
Assuming 
an 
improvement 
of 
endothelial dysfunction of 30% (relative) and a SD of 3% (% FMD) a total of 42 subjects will be needed to 
detect this difference with an alpha of 0.05 and a power of 0.90. To account for a dropout rate of about 
20% each group will consist of 25 patients. 
 
13 
TREATMENT/INTERVENTION 
Study Treatment/Intervention 
 
Placebo  
 
Linagliptin 
 
13.1  Description of Treatments/Interventions 
The subjects will receive either Linagliptin 5mg (licensed dose for treatment of type 2 diabetes) or 
matched placebo tables orally once daily for 12 weeks. The drug and placebo will be supplied by Böhringer 
Ingelheim as bulk ware study medication. Pharmacy at the Medical University of Graz, Austria will pack 
the medication as 12 weeks supplies for study participants and label study medication according to 
current regulatory requirements.  
 
Patients will be asked not to adjust their antidiabetic treatment during the study period. However, if 
glycaemic control appears to be inappropriately high during these 12 weeks, additional glucose lowering 
drugs may be used at the discretion of the principal investigator. Unless contraindicated, the first choice 
for rescue medication should be a sulfonylurea. 
 
 

 
Protocol V 2.4                                                                                                                                         Page 19 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
13.2 Subject Compliance 
The subjects will be instructed to return all unused or part-used medication and packaging from 
medication at the follow-up visit. Tablets will be counted out at the end of the twelve week treatment 
period to verify compliance.  
Significant non-compliance is defined as missing 20% or more doses of trial medication during the 12 
week treatment period. In the event of study medication non-compliance, participants would continue to 
be followed to their last visit. These data would not be part of the per protocol analysis but would form 
part of an intention to treat analyses. 
 
14 INVESTIGATIONAL MEDICINAL PRODUCT (TAKEN FROM THE SMPC) 
 
14.1 Mechanism of action 
Linagliptin is an inhibitor of the enzyme DPP-4 (Dipeptidyl peptidase 4, EC 3.4.14.5) an enzyme which is 
involved in the inactivation of the incretin hormones GLP-1 and GIP (glucagon-like peptide1, glucose-
dependent insulinotropic polypeptide). These hormones are rapidly degraded by the enzyme DPP-4. Both 
incretin hormones are involved in the physiological regulation of glucose homeostasis. Incretins are 
secreted at a low basal level throughout the day and levels rise immediately after meal intake. GLP-1 and 
GIP increase insulin biosynthesis and secretion from pancreatic beta cells in the presence of normal and 
elevated blood glucose levels. Furthermore GLP-1 also reduces glucagon secretion from pancreatic alpha 
cells, resulting in a reduction in hepatic glucose output. Linagliptin binds very effectively to DPP-4 in a 
reversible manner and thus leads to a sustained increase and a prolongation of active incretin levels. 
Linagliptin glucose-dependently increases insulin secretion and lowers glucagon secretion thus resulting in 
an overall improvement in the glucose homoeostasis. Linagliptin binds selectively to DPP-4 and exhibits a 
> 10,000 fold selectivity versus DPP-8 or DPP-9 activity in vitro. 
 
14.2 Therapeutical indications 
Linagliptin is indicated in the treatment of type 2 diabetes mellitus to improve glycaemic control in 
adults: 
as monotherapy 
-in patients inadequately controlled by diet and exercise alone and for whom metformin is 

 
Protocol V 2.4                                                                                                                                         Page 20 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
inappropriate due to intolerance, or contraindicated due to renal impairment. 
 
as combination therapy 
-in combination with metformin when diet and exercise plus metformin alone do not provide 
adequate glycaemic control. 
-in combination with a sulphonylurea and metformin when diet and exercise plus dual therapy 
with these medicinal products do not provide adequate glycaemic control. 
 
14.3 Undesireable effects 
In the pooled analysis of the placebo-controlled trials, the overall incidence of adverse events in patients 
treated with placebo was similar to linagliptin 5 mg (53.8% versus 55.0%). Discontinuation of therapy due 
to adverse events was higher in patients who received placebo as compared to linagliptin 5 mg (3.6% 
versus 2.3%). The most frequently reported adverse reaction was hypoglycaemia observed under the 
triple combination, linagliptin plus metformin plus sulphonylurea 14.7% versus 7.6% in placebo. 
In the placebo controlled studies 5.0% of patients experienced “hypoglycaemia” as an adverse reaction 
under linagliptin. 86.8% of these were mild and 13.2% were moderate. 
 
14.4 Absorption 
The absolute bioavailability of linagliptin is approximately 30%. Co-administration of a high-fat meal with 
linagliptin prolonged the time to reach Cmax by 2 hours and lowered Cmax by 15% but no influence on 
AUC 0-72h was observed. No clinically relevant effect of Cmax and Tmax changes is expected; therefore 
linagliptin may be administered with or without food. 
 
14.5 Distribution 
As a result of tissue binding, the mean apparent volume of distribution at steady state following a single 5 
mg intravenous dose of linagliptin to healthy subjects is approximately 1110 litres, indicating that 
linagliptin extensively distributes to the tissues. Plasma protein binding of linagliptin is concentration-
dependent, decreasing from about 99% at 1 nmol/l to 75-89% at ≥30 nmol/l, reflecting saturation of 
binding to DPP-4 with increasing concentration of linagliptin. At high concentrations, where DPP-4 is fully 
saturated, 70-80% of linagliptin was bound to other plasma proteins than DPP-4, hence 30-20% were 
unbound in plasma. 

 
Protocol V 2.4                                                                                                                                         Page 21 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
14.6 Excretion 
Following administration of an oral [14C] linagliptin dose to healthy subjects, approximately 85% of the 
administered radioactivity was eliminated in faeces (80%) or urine (5%) within 4 days of dosing. Renal 
clearance at steady state was approximately 70 ml/min. 
 
 
 

 
Protocol V 2.4                                                                                                                                         Page 22 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
15 PHARMACOVIGILANCE 
Safety endpoints: All adverse events reported by the patients will be assessed and reported as outlaid 
below. 
15.1 Definitions 
Adverse Events (AE) 
An adverse event is defined as  
any untoward medical occurrence, including an exacerbation of a pre-existing condition, in a patient or 
clinical investigation subject administered a pharmaceutical  product. The event does not necessarily have 
to have a causal relationship with this treatment (Linagliptin). 
 
Adverse Drug Reaction (ADR) 
An Adverse Drug Reaction (ADR) is any response to a drug which is noxious and unintended. 
This means that a causal relationship between study medication and an AE is at least a reasonable 
possibility i.e. the relationship cannot be ruled out. 
Serious Adverse Event  
A serious adverse event (SAE) is defined as any AE which: 
 
Results in death 
 
Is life-threatening 
 
Requires in-patient hospitalisation or prolongation of existing hospitalization 
 
Results in persistent or significant disability/incapacity 
 
Is a congenital anomaly/birth defect 
 
Is considered as serious, when base upon appropriate medical judgement that may jeopardise the 
patient/supject, and may require medical or surgical intervention to prevent one of the other 
seriousness criteria from occuring. 
 

 
Protocol V 2.4                                                                                                                                         Page 23 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
Patients may be hospitalised for administrative or social reasons during the study (e.g. days on which 
infusion takes place, long distance from home to site). These and other hospitalisations planned at the 
beginning of the study do not need to be reported as a SAE in case they have been reported at 
screening 
visit 
in 
the 
source 
data 
and 
have 
been 
performed 
as 
planned 
 
Suspected Unexpected Serious Adverse Reaction (SUSAR) 
A serious adverse reaction, the nature or severity of which is not consistent with the applicable product 
information as documented above. 
According to ICH E2A all SUSARs should be reported in an expedited manner to Competent Authorities, 
Ethics Committees and investigators concerned on an individual basis within timelines. 
Regulatory timelines which have to be met are as follows: 
- 
Fatal and life-threatening AEs: 7 calendar days after receipt 
- 
Remaining serious AEs: 15 calendar days after receipt 
 
Intensity/Severity of adverse Event 
The Intensity/Severity of the AE should be judged based on the following: 
Mild: 
 
Awareness of sign(s) or symptom(s) which is/are easily tolerated 
Moderate: 
Enough discomfort to cause interference with usual activity 
Severe:  
Incapacitating or causing inability to work or to perform usual activities 
 
Causal relationship of adverse event 
Medical judgement should be used to determine the relationship, considering all relevant factors, 
including pattern of reaction, temporal relationship, dechallenge or rechallenge, confounding factors such 
as  concomitant medication, concomitant diseases and relevant history. Assessment of causal relationship 
should be recorded in case report forms.  

 
Protocol V 2.4                                                                                                                                         Page 24 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
15.2 Reporting Procedure for all Adverse Events 
All Adverse events, serious and non-serious, will be collected, documented and reported on the 
appropriate CRFs/SAE reporting forms once informed consent has been signed and will end 28 days after  
completing the trial. 
The following information will be recorded:  
 
participant details 
 
adverse event description 
 
start date of event 
 
end date of event 
 
outcome of event 
 
severity of event 
 
treatment required 
 
relationship to study drug (i.e. causality/relatedness) 
 
assessment of relatedness to other suspect drug or device 
 
action taken with study drug 
 
whether subject withdrawn due to adverse event 
 
whether the event is serious 
 
Follow up information will be recorded as necessary 
AEs considered to be related to study medication as judged by a medically qualified investigator will be 
followed until resolution or the event is considered stable. All related AEs that result in a subject’s 
withdrawal from the study or are present at the end of the study will be followed up until a satisfactory 
resolution occurs. 
Pregnancy 
In rare cases, pregnancy might occur in clinical trials. Once a female subject has been enrolled into the 
clinical trial, after having taken study medication, the investigator must report any drug exposure during 
pregnancy.  
The outcome of the pregnancy associated with the drug exposure during pregnancy must be followed up.  

 
Protocol V 2.4                                                                                                                                         Page 25 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
15.3  Reporting Procedure for Serious Adverse Events 
The investigator shall report any Serious Adverse Events and non-serious Adverse Events which are 
relevant for a reported SAE and Adverse Events of Special Interest to Boehringer Ingelheim 
Pharmacovigilance Unique Entry Point, who will subsequently report the SAE to the ethics committee and 
local authorities.  
16 STUDY MONITORING 
A risk-based approach will be taken to determine the frequency of study monitoring for the study which 
will be agreed with the Principal Investigator. Monitoring will be undertaken according to ICH GCP and the 
study monitoring plan. The study monitor will be suitably trained, qualified and experienced to perform 
this task. Data will be evaluated for compliance with the protocol and accuracy in relation to source 
documents.  
 
17 ETHICS 
The Investigator will ensure that this study is conducted in accordance with the principles of the 
Declaration of Helsinki, GCP-ICH and according to the protocol and the requirements of the concerned 
regulatory authorities.  
The IMP is a licensed, well tolerated drug used within the indication and the measurements taken are 
either non-invasive are minimally invasive (blood sampling). Therefore we consider this trial as low risk for 
participants. 
17.1  Informed Consent 
1. Informed consent will be obtained for all participants in the study by the study physician. 
2. Written versions of the subject information and Informed consent will be presented to the 
subjects detailing:  
 
The exact nature of the study 
 
The implications and constraints of the protocol 
 
The known side effects and any risks involved in taking part.   
3. It will be clearly stated that the subject is free to discontinue their participation in the study at 
any time for any reason without prejudice to future care, and with no obligation to give the 
reason for withdrawal. 

 
Protocol V 2.4                                                                                                                                         Page 26 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
4. The subject will be allowed as much time as wished to consider the information, and the 
opportunity to question the Investigator, their usual care provider or other independent 
parties to decide whether they will participate in the study.  Written Informed Consent will 
then be obtained by means of subject dated signature and dated signature of the person who 
presented and obtained the informed consent.  
5. A copy of the signed Informed Consent will be given to the subjects. The original signed form 
will be retained at the study site. 
 
17.2 Ethical and Regulatory Approvals 
The protocol, informed consent form, participant information sheet and any proposed advertising 
material will be submitted to the Ethics Committee of the Medical University of Graz, Austria.  In addition, 
the study will be submitted for approval to the “Österreichische Agentur für Gesundheit und 
Ernährungssicherheit” (AGES). 
The Investigator will submit and, where necessary, obtain approval from the above parties for all 
substantial amendments to the original approved documents.  
 
18. 
FINANCE 
This study will be funded by Böhringer Ingelheim Pharma GmbH und KoKG, Biberach, Germany. 
 
19. 
INSURANCE 
Participant insurance according to legal requirements will be contracted. 
 

 
Protocol V 2.4                                                                                                                                         Page 27 of 27 
 
Division of Endocrinology and Metabolism
Cardiovascular Diabetology Research Group
Medical University of Graz
Auenbruggerplatz 15
Tel: ++43 (0) 316 385 13270
Fax: ++43 (0) 316 385 14332
20. 
REFERENCES 
 
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GLYCAEMIA WITH MACROVASCULAR AND MICROVASCULAR COMPLICATIONS OF TYPE 2 DIABETES 
(UKPDS 35): PROSPECTIVE OBSERVATIONAL STUDY. BMJ. 2000 AUG 12;321(7258):405-12. 
2. U.K. PROSPECTIVE DIABETES STUDY 16. OVERVIEW OF 6 YEARS' THERAPY OF TYPE II DIABETES: A 
PROGRESSIVE DISEASE. U.K. PROSPECTIVE DIABETES STUDY GROUP. DIABETES. 1995 NOV;44(11):1249-
58. 
3. EFFECT OF INTENSIVE BLOOD-GLUCOSE CONTROL WITH METFORMIN ON COMPLICATIONS IN 
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(UKPDS) GROUP. LANCET. 1998 SEP 12;352(9131):854-65. 
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GLUCOSE CONTROL IN TYPE 2 DIABETES. N ENGL J MED. 2008 OCT 9;359(15):1577-89. 
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HYPERGLYCEMIA FOR THE PRESENCE AND EXTENT OF CORONARY ATHEROSCLEROSIS: AN 
ANGIOGRAPHIC STUDY. ATHEROSCLEROSIS. 2008 JAN 8;8:8. 
6. WASCHER TC, SOURIJ H, ROTH M, DITTRICH P. PREVALENCE OF PATHOLOGICAL GLUCOSE 
METABOLISM IN PATIENTS UNDERGOING ELECTIVE CORONARY ANGIOGRAPHY. ATHEROSCLEROSIS. 
2004 OCT;176(2):419-21. 
7. BARTNIK M, RYDEN L, FERRARI R, MALMBERG K, PYORALA K, SIMOONS M, ET AL. THE PREVALENCE OF 
ABNORMAL GLUCOSE REGULATION IN PATIENTS WITH CORONARY ARTERY DISEASE ACROSS EUROPE. 
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DEATH FROM CARDIOVASCULAR CAUSES. N ENGL J MED. 2007 JUN 14;356(24):2457-71. 
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NEW HAMPSHIRE; 2008. P. 5. 
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11. AKCAKOYUN M, KARGIN R, TANALP AC, PALA S, OZVEREN O, AKCAY M, ET AL. PREDICTIVE VALUE OF 
NONINVASIVELY DETERMINED ENDOTHELIAL DYSFUNCTION FOR LONG-TERM CARDIOVASCULAR 
EVENTS AND RESTENOSIS IN PATIENTS UNDERGOING CORONARY STENT IMPLANTATION: A 
PROSPECTIVE STUDY. CORON ARTERY DIS. 2008 AUG;19(5):337-43. 
12. SOURIJ H, ZWEIKER R, WASCHER TC. EFFECTS OF PIOGLITAZONE ON ENDOTHELIAL FUNCTION, INSULIN 
SENSITIVITY, AND GLUCOSE CONTROL IN SUBJECTS WITH CORONARY ARTERY DISEASE AND NEW-
ONSET TYPE 2 DIABETES. DIABETES CARE. 2006 MAY;29(5):1039-45. 
13. CORRETTI MC, ANDERSON TJ, BENJAMIN EJ, CELERMAJER D, CHARBONNEAU F, CREAGER MA, ET AL. 
GUIDELINES FOR THE ULTRASOUND ASSESSMENT OF ENDOTHELIAL-DEPENDENT FLOW-MEDIATED 
VASODILATION OF THE BRACHIAL ARTERY: A REPORT OF THE INTERNATIONAL BRACHIAL ARTERY 
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