Smoking Cessation Facilitated by Glucagon-like Peptide-1 (GLP-1) Analogues - a Randomized, Double-blind, Placebo-controlled Trial
Phase: PHASE2
Conditions: Glucagon-like Peptide-1, Smoking Cessation, Weight Change, Body, Craving
Sponsor: University Hospital, Basel, Switzerland

Smoking cessation by GLP-1 analogues - The SKIP-Study – Substudy “SKIP-fMRI” V1 13.10.2017 
 Page 1 of 7 
 
 
Appendix 5: Substudy fMRI   
1. Background  
Smokers compared to non-smokers exhibit increased functional brain activations in the prefrontal and 
limbic regions when exposed to craving-related smoking cue videos [1]. In this clinical trial (SKIP-study) the 
GLP-1 analogue Dulaglutide (Trulicity®) is evaluated as a treatment for smoking cessation. Supposing that 
GLP-1 and analogues modulates nicotine induced reward system [2, 3] we hypothesize that treatment with 
Dulaglutide (Trulicity®) attenuates craving and therefore functional brain activation. The aim of the present 
substudy is to evaluate effects of Dulaglutide treatment on functional neuronal changes in smokers who 
want to quit smoking.  
2. Recruitment and screening  
All SKIP-participants meeting the following in- and exclusion criteria are invited to participate in this 
substudy (until target sample size is reached).  
2.1. Inclusion criteria   
- 
Age 18-60 years 
- 
Written informed consent signed  
- 
Daily smokers who are willing to quit and exhibit one of the following criteria: 
 ≥10 cigarettes per day and 
 At least moderate nicotine dependence defined by a Fagerstroem Score of ≥5 points  
 Treatment with Varenicline (Champix®) 
 
2.2. Exclusion criteria  
- 
Pregnancy (incl. wish to become pregnant within next 3 months) or breast feeding 
- 
Pre-existing treatment with GLP-1 agonists  
- 
History of pancreatitis 
- 
Severe renal insufficiency (estimated glomerular filtration rate <30 ml/min/1,73 m2) 
- 
Instable psychiatric conditions including Anorexia nervosa    
- 
Medical conditions that affect brain function (e.g. stroke, epilepsy, space occupying lesions, multiple 
sclerosis, Parkinson’s disease, dementia, transient ischemic attack) 
- 
Current use of medications that alter brain function  
- 
Current illicit drug abuse including marijuana (alcohol ≤ 1 drink per day allowed) 
- 
Claustrophobia  
- 
Cardiac pacemaker, electronic device or ferromagnetic metal foreign bodies 
- 
Known or suspected allergy to trial product or related products  
 
 
 

Smoking cessation by GLP-1 analogues - The SKIP-Study – Substudy “SKIP-fMRI” V1 13.10.2017 
 Page 2 of 7 
 
 
3. Objective, outcome, assumptions 
3.1 Objective 
To investigate the influence of the GLP-1 analogue Dulaglutide (Trulicity®) versus placebo on functional 
neuronal changes in the prefrontal cortex and limbic region measured by different methods of fMRI in 
smokers who want to quit smoking.  
 
3.2 Outcome 
a) Behavioural outcomes include:  
 
Craving measured by a Visual Analogue Scale (VAS) [1].  
 
Working memory performance investigated by the N-back task scores. 
 
b) Functional neuronal changes are assessed through the surrogate of blood oxygenated level dependent 
(BOLD) signal, an indirect measure of neural activity. Three echo-planar imaging (EPI) sequences will be 
performed to investigate neural substrates of nicotine craving, working memory and resting state functional 
networks. 
 
c) Structural outcomes include structural plasticity of grey and white matter in regions parts of the reward 
pathway (i.e. anterior cingulate cortex, insula, striatum) and in subcortical regions. One T1 sequence and 
one DTI sequence will be performed to investigate changes in grey and white matter. 
Changes in the reward pathway are also assessed in the cerebro-spinal fluid (CBF) from the Arterial Spin 
Labelling (ASL) sequence.  
 
3.3 Assumptions: 
a) At the behavioural level: 
 
Decrease in nicotine craving perceived by the participants and improvement in working memory 
performance under treatment with Dulaglutide (Trulicity®) compared to placebo.  
 
Decrease in nicotine craving perceived by the participants and improvement in working memory 
performance in quitters compared to persistent smokers. 
 
Decrease in nicotine craving perceived by the participants and improvement in working memory 
performance under Varenicline (Champix®) treatment (visit week 12 versus baseline) assessed in 
placebo treated participants. 
 
Positive correlation between working memory performance and the severity of nicotine dependence, 
nicotine exposure and craving. 
 
b) At the functional neuronal level: 
 
Reduced BOLD signal in the reward and limbic pathway under treatment with Dulaglutide 
(Trulicity®) compared to placebo.  

Smoking cessation by GLP-1 analogues - The SKIP-Study – Substudy “SKIP-fMRI” V1 13.10.2017 
 Page 3 of 7 
 
 
 
Reduced BOLD signal in the reward and limbic pathway in quitters compared to persistent smokers.  
 
Reduced BOLD in the reward and limbic pathway under Varenicline (Champix®) treatment (visit 
week 12 versus baseline) assessed in placebo treated participants. 
 
Positive correlation between functional neuronal changes and the severity of nicotine dependence, 
nicotine exposure and craving. 
 
c) At the structural neuronal level: 
 
Less grey matter and white matter atrophy under treatment with Dulaglutide (Trulicity®) compared 
to placebo.  
 
Grey matter and white matter plasticity in quitters compared to persistent smokers.  
 
Less grey matter and white matter atrophy under Varenicline (Champix®) treatment (visit week 12 
versus baseline) assessed in placebo treated participants. 
 
Positive correlation between brain atrophy and the severity of nicotine dependence, nicotine 
exposure and and craving. 
 
4. Assessment and Procedures  
In addition to the regular study visits fMRI will be conducted at baseline (after inclusion and before injection 
of the first trial medication) and after 3 months of treatment (a time frame between visit 8 and 12 will be 
accepted).  
 
Before fMRI examination, smoking abstinence of at least 2 hours is required. Exposure to nicotine is 
assessed by end-expiratory exhaled carbon monoxide measurement, urinary cotinine (assessed at the 
regular visits 0 and 12), and former and actual nicotine consumption (pack years and average cigarettes 
per day during the last 3 days). Furthermore, severity of nicotine dependence is assessed at baseline by 
the Fagerstroem Score (at inclusion), craving by the German version of the “Questionnaire on Smoking 

Smoking cessation by GLP-1 analogues - The SKIP-Study – Substudy “SKIP-fMRI” V1 13.10.2017 
 Page 4 of 7 
 
 
urges” (QSU-G) (assessed at the regular visits 0 and 12) and a Visual Analogue Scale (VAS) of smoking 
urge.   
 
Study procedure 
 
Screeni
ng 
Week 
0 
Week 
1 
Week 
2 
Week 
3 
Week 
4 
Week 
5 
Week 
6 
Week 
7 
Week 
8 
Week 
9 
Week 
10 
Week 
11 
Week 
12 
Week 
24 
Week 
52 
End of 
Study 
Visit 
 
Study Visit 
 
V0  
V0 fMRI 
 
 
 
V4 
 
 
 
V8 
 
 
 
V12 
V12 fMRI 
V13 
V14 
EoSV 
fMRI 
Inclusion / 
exclusion criteria 
X 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Informed consent 
X 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Inclusion / 
randomization 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Medical history 
 
X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Smoking status 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
CO-measurement 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
VAS smoking urge 
(0-10) 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
QSU-G 
 
X 
 
 
 
X 
 
 
 
 
 
 
 
X 
 
 
 
Motivation 
 
X 
 
 
 
 
 
 
 
 
 
 
 
X 
 
X 
X 
Alcohol 
consumption/noxae 
 
X 
 
 
 
 
 
 
 
 
 
 
 
X 
 
X 
X 
Vital signs 
(AOBPM) 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
X 
X 
X 
Weight, height, 
BMI 
 
X 
 
 
 
X 
 
 
 
X 
 
 
 
X 
X 
X 
X 
Laboratory testing 
 
X 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
X 
X 
U-cotinine-
measurement 
 
X 
 
 
 
 
 
 
 
 
 
 
 
X 
X 
X 
X 
Study drug 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
 
 
 
 
Varenicline 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
 
 
 
 
New Medication 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Adverse events 
 
 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Substudy fMRI 
fMRI 
 
X 
 
 
 
 
 
 
 
 
 
 
 
X 
 
 
X 
 
4.1. fMRI procedure and acquisition 
Participants undergo a block-design fMRI study performing two structural sequences: T1-weighting (T1) to 
investigate changes in grey matter and diffusor tensor imaging (DTI) to investigate changes in white matter. 
Additionally, an Arterial Spin Labelling (ASL) sequence will be performed to assess changes in arterial 
perfusion.  
Finally three functional sequences (EPI) will be performed to investigate changes in the BOLD signal: 
Resting State Sequence, a Nicotine Craving Task[1] to investigate nicotine craving, and an N-Back Task to 
investigate working memory-related brain activations. 

Smoking cessation by GLP-1 analogues - The SKIP-Study – Substudy “SKIP-fMRI” V1 13.10.2017 
 Page 5 of 7 
 
 
4.1.1. Nicotine craving task 
The paradigm consists of an on-off block-design with two active conditions (smoking cue and control 
videos) and a neutral condition (cross displayed). The active condition uses video cues developed by Brody 
et al. [1, 4]. These cues are filmed from the first person point of view and are 45 seconds (s) in length. Each 
smoking video shows a potential craving situation, such as writing a letter and smoking a cigarette or 
standing outside of a nightclub smoking a cigarette. The control videos are matched for similar content 
except for the absence of smoking cues. After each video, a Visual Analogue Scale is presented for 2.5 s, 
and participants rate the degree of craving using an MR-compatible response box. The rating scale 
includes seven steps from no craving to high craving. After the rating, a rest period consists of the visual 
presentation of a fixation cross for 10 seconds. Each run includes five smoking and five control videos in a 
pseudo-randomized fashion and lasts 612 seconds. Each participant performs two runs. Before fMRI 
scanning, participants are instructed on the procedure and become familiar with the task by a training run 
outside of the MRI scanner. 
4.1.2. N-Back Task 
A rapid, mixed trial, event-related fMRI design is used with jittered interstimulus intervals incorporating 
random event presentation to optimize statistical efficiency [5]. During the N-back task [6], all subjects see 
series of letters with an interstimulus interval of 2 s. Each stimulus is presented for 1 s. During a baseline 
(0-back) condition, subjects are required to press the button with the right hand when the letter „X” appears. 
During 1-back and 2-back conditions, participants are instructed to press the button if the currently 
presented letter is the same as that presented 1 (1-back condition) or 2 trials beforehand (2-back 
condition). The three conditions will be presented in ten alternating 30 s blocks (2 × 1-back, 3 × 2-back and 
5 × 0-back) matched for the number of target letters per block (i.e., 2 or 3), in a pseudo-random order. 
4.1.3. Resting State Sequence 
 
 
 
 
       
For the resting-state scan (5 minutes), subjects are instructed to lie in dimmed light with their eyes open, to 
think of nothing in particular, and not to fall asleep. 
4.1.4. T1, DTI and ASL sequences 
During the structural scans, subjects are instructed to lie in scan without performing any particular tasks. 
5. Statistical Methods 
5.1 Sample Size 
In total 60 patients who are willing to participate in the main and the substudy and meet the additional 
eligibility criteria. The decision to include 60 patients is based on feasibility criteria such as costs, 
availability of staff, infrastructure, and readiness of patients to participate. We suppose that 60 patients are 
sufficient to generate meaningful results that allow generation of hypotheses. Measurement of functional 

Smoking cessation by GLP-1 analogues - The SKIP-Study – Substudy “SKIP-fMRI” V1 13.10.2017 
 Page 6 of 7 
 
 
brain activity by fMRI poses low risk to the patient. Therefore, the sample size is only limited by feasibility 
criteria. 
5.2 Planned Analysis 
The fMRI will be pre-processed using FSL (FSL Version 5.0.9; http://fsl.fmrib.ox.ac.uk) to make the data 
ready for statistical analyses. Details will be provided in a data management plan. There is an option to 
alter and add variables in an iterative process during statistical analysis. 
The analysis set includes all patients that signed the informed consent of this substudy and performed at 
least one fMRI. Missing data will not be imputed but frequency and reasons for missingness described. No 
hypotheses will be tested. Explorative analyses are performed for hypothesis generation. 
Summary statistics will be performed including reporting of frequencies of nominal and ordinal data and 
distribution parameters of numerical data. 
All outcomes will be analysed by two group comparison at 12 weeks relative to baseline. Groups at 12-
week visit are intervention or control arm, either quitters or persistent smokers. Analyses will be focussed 
on predefined assumptions described above. However, each possible combination of head-to-head 
comparisons will be made. Differences of outcomes between two groups will be analysed and frequentist p-
values provided for each outcome of each comparison.  
Further analyses include comparison of outcomes before and after Varenicline (Champix®) exposure in 
placebo treated participants and correlation of outcomes with the following variables: 
- 
severity of nicotine dependence (Fagerstroem Score) 
- 
nicotine exposure (pack years, actual number of cigarettes per day, urinary cotinine, end-expiratory 
exhaled carbon monoxide in ppm) 
- 
craving (QSU-G, VAS) 
- 
age 
- 
sex 
 
 
All alpha error levels will be reported. Despite alpha error inflation due to multiple testing, no alpha error 
correction will be performed. Interpretation of p-values will be of explorative nature and always reported as 
a whole. 
Detailed description of variables, statistical models, and presentation of results will be provided in a 
statistical analysis plan.  
Motivated by results, further explorative analyses that are not defined a priori in the statistical analysis plan 
might be carried out.  
 

Smoking cessation by GLP-1 analogues - The SKIP-Study – Substudy “SKIP-fMRI” V1 13.10.2017 
 Page 7 of 7 
 
 
REFERENCES 
1. 
Brody, A.L., et al., Neural substrates of resisting craving during cigarette cue exposure. Biol Psychiatry, 2007. 
62(6): p. 642-51. 
2. 
Engel, J.A. and E. Jerlhag, Role of appetite-regulating peptides in the pathophysiology of addiction: 
implications for pharmacotherapy. CNS Drugs, 2014. 28(10): p. 875-86. 
3. 
Zanchi, D., et al., The impact of gut hormones on the neural circuit of appetite and satiety: A systematic 
review. Neurosci Biobehav Rev, 2017. 80: p. 457-475. 
4. 
Zanchi, D., et al., Cigarette smoking leads to persistent and dose-dependent alterations of brain activity and 
connectivity in anterior insula and anterior cingulate. Addict Biol, 2015. 20(6): p. 1033-41. 
5. 
Ettinger, U., et al., Functional magnetic resonance imaging of a parametric working memory task in 
schizophrenia: relationship with performance and effects of antipsychotic treatment. Psychopharmacology 
(Berl), 2011. 216(1): p. 17-27. 
6. 
Broome, M.R., et al., Neural correlates of executive function and working memory in the 'at-risk mental state'. 
Br J Psychiatry, 2009. 194(1): p. 25-33.