A randomized, double blind, placebo-controlled, double dummy, three-way crossover study to investigate the effects of an intravenous ethanol clamp and a morphine infusion on resting state functional magnetic resonance imaging in healthy male volunteers

Although fMRI has been available for close to a decade, it has never gained
wide application in drug development. This is mainly due to technical
limitations in the way fMRI was elicited. In traditional setups, fMRI-signals
were brought about by repeated administration of a certain cognitive, sensory
or motor task, basically subtracting post- from pre-stimulatory scans.
Consequently, the alterations in brain activation highly depended on the
characteristics of the stimulus paradigm. Studies have been performed that show
how drugs change such stimulus-related fMRI-patterns. However, there are
practical limitations to the tasks that can be performed in a MRI-scanner, and
it has not been possible to design meaningful paradigms for all drugs. Ideally,
drug-induced fMRI-changes would be stimulus-independent, and merely related to
the concentrations and pharmacological effects of the drugs on different brain
areas. Until recently, this was not technically possible, but recent
innovations in signal analysis now allow the accurate detection of
resting-state, unactivated fMRI-signals. So far, no drug studies have been
performed with this innovative technique. The main objective of the current
study is to detect drug induced fMRI-effects. Alcohol as well as morphine have
been chosen for this study. Accurate infusion paradigms have been developed for
both ethanol and morphine. These paradigms allow the maintainance of stable
drug levels, with well-known CNS-effects. These fixed levels provide a stable
stimulus that should reduce the variability of the Resting State-pharmaco-MRI
(RS-phMRI) signal, which is considered an advantage at this early stage of
development. Ethanol was chosen because it induces a wide range of changes in
the central nervous system, which could be associated with different areas of
fMRI activation. Despite its mild to sometimes serious side effects, morphine
remains one of the most valuable analgesics in clinical practice. Because of
its common use in the clinical setting and because of the major experience with
this prototype µ-opioid receptor agonist within our research group (Dahan et
al.), morphine will also be investigated for its effects on brain activation
with fMRI.

Primary Objectives:
• To investigate the effects of a stable level of alcohol (0.6 g/L) on fMRI
activation patterns in healthy male volunteers,
• To investigate the effect of a stable level of morphine (80 nmol/L) on fMRI
activation patterns in healthy male volunteers.

Secondary Objectives:
• To assess the feasibility of PK/PD-analyses for alcohol-induced
fMRI-activation patterns,
• To assess the feasibility of PK/PD-analyses for morphine-induced
fMRI-activation patterns

This will be a randomized, double blind placebo-controlled, double dummy,
three-way crossover study. Washout periods will be at least seven days.

One study team member, who is not involved in any of the measurements, will
obtain the BrAC-measurements and adapt the infusion regimen accordingly. The
rest of the study team will remain blinded to the treatment randomisation.

Ethanol 10% w/v solution in 5% glucose will be delivered by intravenous
infusion to maintain blood ethanol concentration near 0.60 g/L for 150 minutes.
The target concentration of 0.60 g/L is expected to be well tolerated, since
this concentration has been safely employed in several previous CHDR studies
(CHDR0313 and CHDR0502 - data on file) for even longer periods (up to 5 hours).
In these previous studies the 0.6 g/L ethanol clamp showed statistically
significant pharmacodynamic CNS effects. Furthermore these levels are routinely
achieved during social drinking.

To avoid local pain in the beginning of the ethanol infusion, a parallel
infusion with glucose 5% will be given.

Prior to the administration of morphine, ondansetron 4 mg will be administered
intravenously to avoid nausea. A matching placebo will be administered prior to
the other occasions. During *morphine-occasions* an initial morphine dose of
100 µg/kg will be administered in one minute, followed by a continuous infusion
of 30 µg/kg/h for 2.5 hours in order to reach a stable morphine plasma
concentration of 80 nmol/L. Prior morphine studies using the same bolus, but a
30 µg/kg/h infusion for only 1 hour show that this infusion paradigm can
safely be used to create a stable serum level of 80 nmol/L with detectable
pharmacodynamic effects. The total amount of morphine administered during 1
occasion using this dosage scheme, will be about 14 mg for an average weighted
male subject, infused over a time period of 2.5 hours. This dose is considered
a safe and rational dose, since it is within the therapeutic range of morphine
(i.e. 2.5 mg-15 mg in 4-5 ml in 4-5 minutes intravenously, for acute pain)
according to the *Farmacotherapeutisch Kompas*.

Glucose 5% will be used as placebo.

Side effects of ethanol: 'drunkness', nausea, 'hangover'.
Side effects morphine: constipation, sedation, nausea (will be antagonized by
ondansetron), itching.
Rare side effects of morphine, not to be expected at the proposed dose:
psychomimetic effects, respiratory depression and release of histamine.
fMRI: claustrophobia.

Screening: 1 venapunction (22.5 ml in total).
Three intravenous cannulas will be inserted during every study day (there are 3
study days in total). One cannula will be used for the administration of
morphine/placebo, the second cannula will be used to administer ethanol/placebo
and the third cannula will be used for the pharmacokinetic bloodsampling of
morphine. 10 ml blood will be drawn 11 times, during each study day, to assess
morphine blood concentrations. 500 ml ethanol/placebo and 60 ml
morphine/placebo will be administered via the other two cannulas. To diminish
the vessel irritating, burning effect of ethanol during the beginning of the
ethanol infusion, 20 ml of glucose will also be administered during the first
10 minutes of infusion.
Follow-up visit: 1 venapunction (12.5 ml). The total amount of blood drawn
during the complete study period will be approximately 365 ml.

Serious or rare adverse events are not likely to appear during this project
using the doses described in the protocol, especially not since only healthy
subjects will be included in this study. The outcome of this study will
contribute to the development of fMRI as a biomarker in early drug development.