The Toxicologist - Society of Toxicology

creased reticulocytes and lymphocytes, and increased neutrophils, at 7.50
mg/kg/day; increased reticulocytes, platelets, and neutrophils at 5.00 mg/kg/day;
increased glucose levels at 3.75, 5.00 and 7.50 mg/kg/day; decreased total protein,
globulin and albumin at 5.00 and/or 7.50 mg/kg/day; discolored glandular stomach
and/or thickened nonglandular stomach at 5.00 and 7.50 mg/kg/day; increased
stomach weight at 5.00 and 7.50 mg/kg/day; increased stomach:body weight ratios
at 2.50 and 3.75 mg/kg/day; and increased brain:body weight ratios at >2.50
mg/kg/day. Significant, dose-dependent increases were observed for Pig-a mutant
RBCs and RETs, and for mnRETs, but not for the other genotoxicity endpoints.
These results demonstrate Pig-a mutation and other genotoxicity endpoints can be
successfully integrated into subchronic toxicity studies, with potential reduction in
animal usage.
1919 COMPUTERIZED ARRHYTHMIA DETECTION IN
LARGE TELEMETERED ANIMALS: A NOVEL
STRATEGY TO ASSESS DRUG LIABILITIES.
R. Mikaelian 1 , S. Authier 1, 3 , F. Koeppel 2 , F. Rossi 2 , D. Labarre 2 , S. Fournier 1
and E. Troncy 3 . 1 Lab. Research Inc., Laval, QC, Canada, 2 Notocord, Paris, France
and 3 Faculty of Veterinary Medicine, University of Montreal, St. Hyacinthe, QC,
Canada. Sponsor: K. Draper.
A software application for arrhythmia detection was evaluated using control data
from untreated telemetered Beagle dogs (with and without left ventricular pressure
catheter) and cynomolgus monkeys. The technology was used to detect atrio-ventricular
type II block, sinusal pause, atrial, junctional and ventricular arrhythmias.
The computerized tool was used to evaluate at least 24-hour periods of continuous
ECG data and all detections were subjected to semi-automated review (ECG trace
evaluation from computer screen). All animals presented at least one incidence of
premature atrial contractions, junctional complexes, premature ventricular contractions
(PVCs) or atrio-ventricular (AV) blocks type II. Semi-automated review was
used to confirm and classify the arrhythmias. In monkeys, the use of a DII configuration
with a negative ECG lead inserted through the jugular vein and the positive
lead sutured to the diaphragm close to the apex of the heart increased the signal to
noise ratio and decreased artifacts. The incidence of ventricular arrhythmias was
comparable in dogs with and without left ventricular pressure (LVP) catheters (0-5
PVCs per 24 hour period) in the limited population that was evaluated (n=5 with
LVP and n=6 without LVP). As expected, the incidence of sinusal pause and AV
blocks in dogs was higher than monkeys. The software application could be useful
to increase efficacy of semi-automated ECG review obtained from telemetered animals
and help quantify the incidence of arrhythmias.
1920 HOW TO IMPROVE SENSITIVITY OF RESPIRATORY
SAFETY PHARMACOLOGY STUDIES IN
CYNOMOLGUS MONKEYS USING IMPEDANCE
MONITORED BY IMPLANTABLE TELEMETRY: THE
USE OF SUPER-INTERVALS.
F. Duguay 1 , S. Authier 1, 2 , S. Fournier 1 and B. Moon 3 . 1 Lab. Research Inc., Laval,
QC, Canada, 2 Faculty of Veterinary Medicine, University of Montreal, St. Hyacinthe,
QC, Canada and 3 Data Science International, St. Paul, MN. Sponsor: K. Draper.
Continuous respiratory monitoring with implantable telemetry identifies circadian
rhythm of respiratory parameters with lower variance during night time. This lower
variance is expected to be associated with higher sensitivity to detect drug effects.
The current study evaluated the effects of positive control drugs, medetomidine (0,
0.01, 0.02 and 0.04 mg/kg, IM) and buspirone (0, 0.03, 0.06, 0.12 mg/kg, IM) administered
in a Latin square design at approximately 4:15PM on each treatment
session to conscious cynomolgus monkeys (n=5). Analysis of variance (ANOVA)
and a posteriori pair-wise comparisons using Dunnet’s test was used with superblock
analysis at 0-1 hour, 1-4 hours and 4-20 hours. The number and interval of
post-dose timepoints were tailored to the pharmacokinetic profile of the drugs.
Medetomidine resulted in a decrease in respiratory rate at all doses administered.
Respiratory rate at peak effects was 37.6 breaths/minute (BPM) after saline treatment
compared with 29.8, 29.0, 27.8 BPM at low, mid and high dose, respectively.
At 15 min post-dose, minute volume was decreased by -9.5%, -17.0%, -21.8% at
low, mid and high doses, respectively and the effects were present until 60 min
post-dose. Buspirone induced an increase in respiratory parameters which were also
dose-dependent. Dose administration prior to periods with lower intrinsic variability
(late afternoon) may be a strategy to increase sensitivity. Tailored statistical
analysis with selected timepoints focused on peak exposure presents another strategy
to maximize sensitivity.
1921 RESPIRATORY SAFETY PHARMACOLOGY
MONITORING IN CONSCIOUS GÖTTINGEN
MINIPIGS: QUALIFICATION OF A NEW MODEL.
C. Ponzi 1 , J. Gervais 1, 2 , E. Troncy 2 and S. Authier 1, 2 . 1 Lab. Research Inc., Laval,
QC, Canada and 2 Faculty of Veterinary Medicine, University of Montreal, St.
Hyacinthe, QC, Canada. Sponsor: K. Draper.
Respiratory safety pharmacology is core component of non-clinical safety assessments
as detailed in the ICH S7A guideline. The aimed of this study was to evaluate
the feasibility of respiratory monitoring in conscious Gottingen minipig using
pneumotachometer and data acquisition software for regulatory safety pharmacology.
Six (6) Gottingen minipigs, three (3) males and three (3) females were used on
this evaluation. Animals received a negative control drug (Saline 0.9%) and a positive
control drug (Methacholine, 0.0034 mg/kg, 0.0135 mg/kg, 0.068 mg/kg) by
intravenous injection using a Latin square design. Animals were acclimated to the
respiratory monitoring procedure before the evaluation. Respiratory function was
evaluated in conscious animals using a sealed mask and a pneumotachometer which
was connected to the respiratory monitoring acquisition system. On each dosing
occasion, respiratory function will be recorded continuously for a period of at least
five (5) minutes before dosing and reported as baseline monitoring. After dosing,
respiratory data was continuously recorded for at least 15 minutes. Parameters
which were monitored included tidal volume, respiratory rate and minute volume.
Baseline respiratory values in Göttingens minipigs were comparable to other laboratory
animal species after allometric conversion with values of 26.78 ± 3.27
breaths/min, 203.37 ± 20.19 mL/breath and 4.66 ± 0.51 L/min. Dose-dependent
respiratory changes were noted following methacholine administration in
Göttingen minipigs with significant increases in respiratory rate, tidal volume and
minute volume immediately after dosing. Based on our results, the Göttingen
minipigs appears to be an adequate model for respiratory safety pharmacology
when the use of this species is justified.
1922 SUBCUTANEOUS LOCAL TOLERANCE FOR BIOLOGIC
DRUG DEVELOPMENT: COMPARISON OF TWO
APPROACHES.
S. Fleming-Weis 1 ,L. M. Diehl 2 , D. Aleksandrowicz 1 , J. Morrow 1 ,K.J.
Zokowski 4 ,K. Ishida 1 ,L. E. Beebe 1 , J. M. Pletcher 3 , W.P.Davis 4 and J. B.
Clarke 1 . 1 Pharmacotoxicology, Biogen Idec, Cambridge, MA, 2 Toxicology, Charles
River Laboratories, Spencerville, OH, 3 Pathology Associates, Charles River Laboratories,
Frederick, MD and 4 Comparative Pathology, Biogen Idec, Cambridge, MA.
Little regulatory guidance is available about subcutaneous route qualification for biologics
drug development. Biologics are typically administered by the IV or subcutaneous
routes and often, early nonclinical testing programs evaluate the feasibility
of both routes. In some cases however formulation development cannot keep pace
with nonclinical testing which must precede clinical development. Thus testing is
either not conducted for technical reasons (insufficient concentration, stability,
etc.) or may be repeated at a later time with a more mature formulation. Whether
the objective of such testing should be largely to evaluate the effects at the local site
of administration, or to provide longer-term bridging toxicology by an alternate
route, is unclear from the available guidance. Unlike small molecules, for which administration
by an alternate route (e.g. from oral to IV or SC) may significantly affect
metabolic profile and thereby both pharmacological and toxicological profile,
route changes for biologics primarily affect bioavailability and immunogenicity.
Moreover, as immunogenicity in animals is considered of uncertain relevance to humans
(see ICH S6) it is unclear whether observed changes in immunogenicity profile,
would be interpretable from the perspective of assessing human risk. This
poster reviews the available guidance on local tolerance testing, presents a summary
of strategies taken by other companies using publicly available sources, and summarizes
the results of two different local tolerance designs employed by Biogen
Idec. Emphasis is placed on the overall objectives of local tolerance testing for the
purposes of biologics drug development, and a study design is proposed that incorporates
key areas of consideration for large molecules.
1923 CYNOMOLGUS MONKEYS: FACTORS AND ISSUES
FOR CONSIDERATION IN THE SELECTION OF
SEXUALLY MATURE MALES AND FEMALES FOR
PRECLINICAL SAFETY STUDIES.
D. Mitchell, H. Palmer, R. Davis and C. Chesher. Safety Assessment, Huntingdon
Life Sciences, Cambridgeshire, United Kingdom.
Sexually mature cynomolgus monkeys are increasingly used for preclinical safety
studies, particularly where medicines may affect reproductive organs. To ensure that
the study objectives are met one must confirm completion of sexual maturation before
dosing starts. It is generally accepted that using cynomolgus monkeys at least 4
SOT 2011 ANNUAL MEETING 411