Cardiovascular Assessment (Telemetry)

Cardiovascular Assessment (Telemetry)
of the Göttingen Minipig
Andrea Greiter-Wilke
Head Safety Pharmacology, Roche
Outline
• Setup of minipig as research animal at Roche
• Cardiovascular specialties
• Minipig telemetry with reference compounds and
cross species comparison
• Roche compound:
Body temperature and QT
• Summary
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Minipigs at Roche
• Up to 2010: General tox and safety pharm studies in house used to be
performed in dogs as large animal species
• 2010: Decision to move from dogs to minipigs for ethical reasons
• Q3/ 2011: Göttingen Minipig established for toxicity, PK and telemetry
studies (first 6 female animals instrumented with transmitters).
Animals pair housed with enrichment provided by toys, straw, brushes and
daily “free” run out of kennel
3
Species Differences in Heart Rates
Minipig, Cynomolgus Monkey, Dog
dosing
bleeding, feeding
Minipigs more quiet after handling than dogs and monkeys, but more
influenced by food!
 feeding should occur before compound administration!
4
Other ECG Specialties
• QT interval ~320 ms, longer than in dogs or monkeys
• No background arrhythmia seen so far (no reports using telemetry in
literature), confirmed by other companies using the minipig
• Analysis of CV data takes longer due to more frequent changes in T wave
morphology requiring adaption of the ECG analysis algorithm (Ponemah)
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Moxifloxacin Validation Telemetry Study
Telemetry: Acquisition of cardiovascular data from instrumented animals via
radio waves - several hours of undisturbed ECG data acquisition possible.
Moxifloxacin: known to prolong the QT Interval, reference compound used in
clinical studies. QT interval prolongation as marker for potential arrhythmias
(torsades de pointes)
Study design: N=6
10, 30, 100 mg/kg moxifloxacin
QT interval
Data acquisition by telemetry for 20 h:
- Heart rate, aortic and left ventricular blood pressure, ECG parameters, body
temperature (BT), QT individually corrected (QTca)
Plasma samples for bioanalytical analysis: 0, 4, and 24 hours post dose
6
Effect on Heart Rate Corrected QT (QTca)
440
Minipig:+58 ms at 100 mg/kg
QTca
420
400
QTca (ms)
380
360
340
320
300
280
260
0 mg
10 mg
30 mg
100 mg
240
-2
0
2
4
6
8
10
Time (h)
12
14
16
18
20
22
QTca 30 m g/kg
280
Long duration with low peak in minipig,
steeper curve in dog
V eh
30 m pk
270
ms
260
250
240
Dog: +33 ms at 30 mg/kg
230
220
-2
0
2
4
6
8
10
Hours
12
14
16
18
20
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Moxifloxacin Kinetics
• Exposure rather flat with slow elimination, reflected in long PD effect.
• Minipigs can keep food in their stomach for several hours, may affect PK
parameters even after overnight fasting (gastric emptying times of >24 h
documented in the Yucatan minipigs)
• Housing on straw will also
increase amount of food in
the stomach
 More efforts ongoing to
evaluate ADME Properties
in the minipig
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Species Comparison of PK/PD Effects
Moxifloxacin
Dose
Minipig
Exposure
ng/ml
Peak QTc
increase
Monkey
Exposure
ng/ml
3 mg/kg
-
10 mg/kg
290
+11 ms
(n.s.)
860
30 mg/kg
860
+16 ms
100 mg/kg
3870
+58 ms
Peak QTc
increase
-
Dog
Human*
Exposure Peak QTc
ng/ml
increase
610
n.s.
+10 ms
(n.s.)
2030
+15 ms
2800
+20 ms
5870
+33 ms
7300
+35 ms
-
-
400 mg ~
5 mg/kg
200010-15 ms
3000
n.s. Not significant
All species suitable to detect human relevant QT effects
*Florian et al. 2011, Population pharmacokinetic and concentration-QTc models for moxifloxacin: Pooled analysis of 20
thorough QT studies
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Change in QTca relative to moxifloxacin
exposure – species comparison
Minipig suitable to detect QT
prolongation
10
Compound RO123 in Minipig Telemetry
5, 15, 30 mg/kg (CNS indication)
Design:
3 male, 3 female minipigs, ascending dose design
Data acquisition:
Heart rate, blood pressure, ECG and body temperature measured for 24 h
QT individually corrected (QTca, probabilistic method, Holzgrefe)
Blood samples for TK assessment at 4 h post dose
Free exposure: 5 mg/kg: 17 ng/ml
15 mg/kg: 41 ng/ml
30 mg/kg: 105 ng/ml
hERG IC20: 0.17 μM (= 81 ng/ml)
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Results: QTca and Body Temperature
QTca +50 ms
Temp -2°C
12
Individual Animal
QTca and Body Temperature
QTca
Temp
13
The Issues with Body Temperature and QT
A decrease in body temperature leads to QT prolongation (and vice versa),
demonstrated in several species (e.g. dog, man, minipig)
• Dog: QT correction for temperature: 14 ms per °C (Van der Linde, 2008)
• Anesthetized minipig: 19 ms per °C (Laursen, 2010)
• Internal study with TRPV1 in conscious minipigs
showed evidence for a 18 ms increase in QTca
per degree drop in body temperature
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RO123: Dog Telemetry Study
5, 10, 30 mg/kg
Design:
3 male, 3 female dogs, each animal its own control
Crossover dose design
Data acquisition:
Heart rate, blood pressure, ECG and body temperature measured for 20 h
ITS transmitters, QT individually corrected with probabilistic method (QTca)
5 min consecutive mean values reported, TK samples at 3 hours
Free exposure at 3 h:
5 mg/kg:
7 ng/ml
10 mg/kg:
9 ng/ml
30 mg/kg: 117 ng/ml
hERG IC20: 0.17 μM (= 81 ng/ml)
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Effect on QTca and Body Temperature
QTca
Shortening in QTca (-20 ms)
due to high heart rates
Body temp
no change in Body Temp
16
Attempt to Correct QTca for Temp Changes
RO123 in minipigs
QTcaBT= QTca -18 (38.5-BT)
1 degree temp decrease may increase the QT interval by ~18 ms
Is this a true QT-effect?
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Outlook: Jacketed ECG and Respiratory
Assessment
ECG equipment: Self adhesive electrodes attached to
skin; covered by undershirt and jacket with pockets
to carry transmitter
Parameters: ECG, heart rate
Respiratory equipment: RIP belts (Respiratory Inductive
Plethysmography), attached to abdomen and chest.
Parameters: respiration rate, tidal volume, minute
volume
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Jacketed ECG and Respiratory assessment
In house demonstration by vendor this summer
Proposed studies:
Compare JET (Jacketed external
telemetry) with instrumented
telemetry testing reference
compounds
- Non-invasive technique
- Enables incorporation of safety
pharmacology end-points into tox
studies
(ECG and respiration)
- pre-study training of animals
required
- No blood pressure measurement,
but could be added via minimally
invasive surgery
- Enables assessment of potential
tachyphylaxis after repeat dosing
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Summary and Conclusion
The Minipig in Cardiovascular Safety
Pharmacology
• The minipig needs more manpower and time for handling and ECG analysis
but is reacting less sensitive to disturbances (except food!)
• More sensitive to body temperature changes but less prone to CNS driven
heart rate changes than the dog
• PK/PD may be different to dog or monkey due to potentially longer gastric
emptying time and other ADME properties
• The minipig is suitable to detect QT prolongation at relevant concentrations
as shown with moxifloxacin and thioridazine
The minipig is a well recognized and valuable species in safety
pharmacology and raises less ethical concerns than the dog or monkey
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Acknowledgements
Roche Pharmaceutical
Sciences
Roland Jenni
David Waiz
Sonia Roberts
Eva Maria Amen
Alessandra Bergadano
Anne Eichinger
Silvan Aegerter
Georg Schmitt
Claudia Sünderhauf
Neil Parrot
Thierry Lavé
Thomas Weiser
Thomas Singer
Charles River
Laboratories
Henry Holzgrefe
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Doing now what patients need next
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Suitability as Species for Cardiovascular
Assessment
• High degree of anatomical, physiological, and pathophysiological
correspondence to man  use of swine in basic cardiovascular research
has a long history
• Göttingen minipig established between 1961-1964 by a combination of
Minnesota, Vietnamese pot bellied pig, and German Landrace
 best characterized breed
• Minipig increasingly utilized in
toxicology and safety pharmacology studies
(Lu, Remeysen, Somers, Saels, & De Clerck, 2001;
Lu, Vlaminckx, Cools, & Gallacher, 2012)
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Some Weird Things…no Drug on Board
Heart Rate and Body Temperature
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