MATERIALS AND METHODS
Study design. This was a single-centre, double-blind,
randomized, placebo-controlled trial conducted between 23 November 2015
and 8 June 2016 at the CTC Clinical Trial Consultants Phase I unit in
Uppsala, Sweden. Study code IRL790C001, EudraCT No 2015-003586-29.
The study comprised two parts.
Part 1 was designed as a partial cross-over single-ascending-dose (SAD)
study with ascending dose levels of mesdopetam and one food interaction
cohort. Sixteen (16) subjects were included in one of two cohorts, eight
subjects in each cohort (six active treatment and two placebo), and the
cohorts were dosed in a zig-zag manner (5 mg-40 mg-160 mg and 15 mg-80
mg-food/80 mg) with a wash-out period of at least one week between
doses. Following a screening period of maximum 28 days, subjects were
confined to the research clinic from the evening before each dosing (Day
-1) until 24 hours post dose (Days 1-2) (food interaction group subjects
until at least eight hours after administration (Day 1)). A follow-up
visit was performed 5-10 days after last dose.
Part 2 examined multiple-ascending-dose (MAD) cohorts with study
treatment once daily for 10 consecutive days. Twenty-four (24) subjects
were included, twelve subjects in each dose cohort (nine on active
treatment, three on placebo), and the cohorts were dosed with 40 mg and
80 mg, respectively. Following a screening period of maximum 28 days,
subjects were confined to the research clinic from the evening before
first dosing (Day -1) and during the four first administration days (Day
1-4). Following a safety and tolerability review before leaving the
clinic on Day 4, the subjects visited the clinic daily for
administration of doses 5-9 under medical surveillance (Days 5-9). In
the evening of Day 9 the subjects were confined to the research clinic
again until 24 hours after administration of dose 10 (Days 10-11). A
follow-up visit was performed 5-10 days after the last dose.
This study was approved by the Ethics Review Board in Uppsala, Sweden
and conducted in compliance with the Declaration of Helsinki and the
International Conference on Harmonization (ICH) Guidelines for Good
Clinical Practice (GCP). All subjects provided written, informed written
consent before participating in any study procedures.
Treatments. Mesdopetam was provided as 5 mg, 20 mg and 40 mg
(free base) hard gelatine capsules. Placebo was provided formulated as
hard gelatine capsules identical in appearance to the mesdopetam
capsules.
Subjects. Healthy male subjects 18-50 years of age, weighing at
least 50 kg, with a body mass index between 18 and 30
kg/m2 were eligible for the study. Good health was
determined by medical history, physical examination, vital signs,
electrocardiogram (ECG), and laboratory tests at screening. Main
exclusion criteria included: history of any clinically significant
disease which, in the opinion of the Investigator, could either put the
subject at risk because of participation in the study, or influence the
results or the subject’s ability to participate in the study; use of any
prescribed or non-prescribed medication or herbal supplements within two
weeks prior to the first administration of study treatment;
administration of another new chemical entity or has participated in any
other clinical study that included drug treatment within three months of
the first administration of study treatment; regular use of tobacco
products, and/or history of drug or alcohol abuse.
Primary objectives and endpoints (safety and tolerability). In
both the SAD and MAD part of the study, safety assessments included:
frequency, seriousness and intensity of Adverse Events (AEs), physical
examination, 12-lead ECGs, Columbia Severity Suicidal Rating Scale
(C-SSRS), vital sign measurements, laboratory measurements (clinical
chemistry, hematology, and urinalysis). The SAD part also included
telemetry. AEs were collected from signing the informed consent form
(ICF) until the follow-up assessments. Serious Adverse Events (SAEs)
spontaneously reported by a subject to the Investigator after the
follow-up assessment, were to be handled in the same manner as SAEs that
occurred during the study.
Secondary objectives and endpoints (pharmacokinetic
parameters). In the SAD part, blood samples for measurement of plasma
concentrations of mesdopetam and its metabolites IRL902 and IRL872 were
collected at predetermined time points: pre‑dose, 20, 40 minutes, 1, 2,
3, 4, 6, 8, 10, 12 and 24 hours after intake of mesdopetam (up to 8
hours only in the food interaction cohort). In the MAD part, blood
samples were collected pre-dose, 20, 40 minutes, 1, 2, 3, 4, 6, 8, 10,
12 and 24 hours after the first and last dose of mesdopetam. A 48‑hour
sample was also taken after the first dose, and on Day 4 sampling was
done pre-dose, 1, 2 and 3 hours post dose.
Urine was collected for measurement of the concentrations of mesdopetam
and its metabolites in the single-dose cohorts (Part 1) at the
predetermined interval 0 to 24 hours post dose.
Bioanalytical methods. Plasma samples were analyzed for
mesdopetam and the metabolites IRL872 and IRL902 using ultra performance
liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) performed by
the National Veterinary Institute, Department of Chemistry, Environment
and Feed Hygiene Section of Chemical Analysis, Uppsala, Sweden. A
deuterated analogue of each molecule were used as internal standards.
The method was validated according to EMA guidelines (7) and the
bioanalytical experiments performed in accordance with the OECD
Principles of Good Laboratory Practice (GLP). The validated
concentration range was 6.00 to 6000 nmol/L for mesdopetam, and 3.00 to
1000 and 1.00 to 1000 nmol/L for IRL872 and IRL902 respectively.
Urine samples were analyzed for mesdopetam by ultra-performance liquid
chromatography-mass spectrometry (UPLC‑MS) at MetaSafe AB, Södertälje,
Sweden. One analytical run with the samples from dose cohort 80 mg
(without food) of the SAD part was done. The samples were diluted
10-fold with 0.1% formic acid and centrifuged before analysis.
Calibration samples and quality control samples were prepared in placebo
urine and treated as the unknown samples. Deuterated mesdopetam was used
as internal standard. The regression coefficient r2for the calibration curve, 2 to 12 µmol/L, was 0.9999. The accuracy of
two quality controls of 2.5 and 5 µmol/L mesdopetam was 98 and 102%.
Statistical analysis. No formal sample size calculation was
performed for this study and thereby no hypothesis testing. The sample
size was considered sufficient to provide adequate information for the
study objectives.
The Full Analysis Set (FAS), comprising all subjects who received
randomized study treatment and have available data, has been used for
the safety and tolerability assessments. Evaluations have been done
according to actual treatment regardless of randomization.
The Per Protocol (PP) analysis set comprises data from all randomized
subjects who have received study treatment and have evaluable PK
parameter data with no major protocol deviations with an impact on the
PK data. All protocol violations were presented and discussed at the
clean file meeting. The PP set has been used for presentation of PK
endpoints.
All statistical calculations were performed using the SAS® program
(Version 90.4, SAS Institute Inc., Cary, NC, USA). The statistical
analyses include descriptive statistics reflecting the explorative
nature of the study.
Pharmacokinetic calculations. The pharmacokinetic parameters
were calculated by non-compartmental analysis (NCA) using the software
Phoenix WinNonlin® version 6.3 or later (Pharsight Corporation, U.S.A.).
Plasma concentration values below the lower limit of quantitation and
missing values (e.g. no blood sample collected, or no value obtained at
analysis) were excluded from the NCA. Actual time-points for blood
sampling were used in the calculations of the individual parameters,
while nominal time points were denoted for summary statistics. Dose
proportionality of AUC and Cmax was estimated using a non-linear power
model. As an estimate of the accumulation ratio (AR) the quotient of the
AUC0-24h for the first and the last dose for each subject was
calculated.