drug discovery and development for the treatment and ... · animal model of filariasis:...
TRANSCRIPT
IMMIP, Bonn Sabine Specht, Achim Hoerauf NPIMR, Northwick Park Simon Townson Muséum National d’Histoire Naturelle de Paris Coralie Martin
Drug discovery and development for the treatment and control of filariasis: repurposing emodepside
DNDi Robert Don Ivan Scandale
Animal Model of filariasis: Litomosoides sigmodontis
• Litomosoides sigmodontis is transmitted by a mite, Onithonyssus bacoti.
• The parasitized mite transmits third stage larvae (L3) during a blood-meal
• The larvae then migrate from the skin, through the lymphatics, to the thoracic (pleural) cavity where they mature and breed.
• The adult female worms release their microfilariae in the pleural cavity from where they make their way to the blood circulation, ready to be taken up by a mite feeding on the skin.
The only fully permissive model for filarial infections
Final host intermediate host
Adult 28 days Release of MF
55-60 days
L3 L2
L4
Ad
L1
In vitro efficacy: microfilariae
Minimum inhibitory concentration (MIC) = 0.1 µM (∼112 ng/ml) MIC is defined as the minimum concentration producing 100%
reduction of motility
Microfilariae L. sigmodontis Microfilariae A. viteae
MIC for L. sigmodontis adult worms is below 0.1 µM (∼112 ng/ml) (minimum concentration producing 100% reduction of motility)
MIC for O. gutturosa adult worms was measured at 0.048 µM (S. Townson et al. ASTMH 54th annual meeting 2005 abstract 280)
In vitro efficacy: adult worms
M T T A s s a y
1 0 µ M 1 µ M 0 .1 µ M 0.01 µ M 1 0% D M S O H e a t0 .0
0 .2
0 .4
0 .6
OD
550
nm
E m o d e p s i de
Adult worm L. sigmodontis
D0 3 months pi
9-12 weeks pt
Natural infection
Treatment‘s start
Worm recovery & analysis
Analysis: - parasite numbers - length of females/males - microfilariae counts
Patency
Randomization (weight, MF)
L4
Ad
L1
Jird model of filariasis: Litomosoides sigmodontis in jird
Exposure in jird
MIC
Dose mg/kg 12.5 25 70
formulation Suspension 2% Cremophor EL in saline
Cmax (ng/mL) 59 58.6 145
Tmax (h) 2 2.33 3.33
T1/2(h) 22 22 19.7
AUC0-last (ng·h/mL) 567 567 2097
(70 mg/kg)
unt re
a ted
0 0m
g /kg
3d
O 50m
g /k g
O 25m
g/kg
1 2 ,5mg/k
g
0
50
1 00
1 50
num
be
r o
f w
orm
sN
b of
reco
vere
d ad
ult w
orm
s
control
X = animals dead after treatment
3x100 5x50 5x25 5x12.5 mg/kg
Jirds infected with L. sigmodontis
100 mg/kg (3 days)
50 mg/kg (5 days)
25 mg/kg (5 days)
12.5 mg/kg (5 days)
Reduction of adult worms compare to control group 55 % 86 % 22 % 0 %
Formulation Suspension in 2% Cremophor EL Route of administration Oral gavage Readout 9 weeks post treatment
M ic rofila re m ia
Be fore
A fter
0 .1
1
1 0
1 0 0
10 0 0
1 00 0 0
MF
/10
µl
9 9 % r e d u c t io n
5 x 50 mg/kg dose : Cmax = 145 ng/mL AUC0-last = 2097 ng·h/mL
5 x 100 mg/kg dose was not tolerated
*
* = P< 0.05
Adult worms
Efficacy in Jird
Exposure in jird
1
10
100
1000
10000
100000
0 4 8 12 16 20 24
Con
cent
ratio
n (n
g/m
L)
Time (h)
Mean Plasma Concentration of Emodepside after PO Administration at 10 mg/kg
Mean PO2
Mean PO5
MIC
Dose mg/kg 10 10
formulation clear solution 25% Capmul MCM in Corn oil
suspension 10% EtOH/40% Solutol/50% H2O
Cmax (ng/mL) 530 195
Tmax (h) 5 1.67
T1/2(h) 14 21.9
AUC0-last (ng·h/mL) 7390 2612
V e h ic le F B Z 2 m g /k g s c E M O 5 d S E M O 1 0 d S E M O 5 d C E M O 1 0 d C0
50
1 00
1 50
2 00
num
be
r o
f w
orm
s
control FBZ sc 5x2 5x10 10x10 5x10 mg/kg
Nb
of re
cove
red
adul
t wor
ms
10x10
M ic rofila rem ia
B efor e
2 4 h pt
4 wks p
t
8 wk s p
t0
5 00 0
1 0 00 0
1 5 00 0
V e h ic leF B Z 2 m g /kg s cE M O 5 d SE M O 1 0 d SE M O 5 d CE M O 1 0 d C
MF
/10
µl
Jirds infected with L. sigmodontis
5 mg/kg (5 days)
10 mg/kg (10 days)
5 mg/kg (5 days)
10 mg/kg (10 days)
Reduction of adult worms compare to control group 82.9 80.8 89.7 72.8
Route of administration Oral gavage Readout 9 weeks post treatment
40% Solutol suspension
25% Capmul solution
Adult worms
* * * *
The excipient Capmul MCM was not well tolerated in jirds
Treatment duration comparison
* = P< 0.05
Conclusions
Exposure of emodepside depends on the formulation
Reduction > 80% of adult worms is obtained when plasma
levels are close to the in vitro MIC (∼ 112 ng/ml); fulfills efficacy TPP requirements for a macrofilaricide
Longer treatment regimens don't seem to improve the pharmacological response
D0 30 days pi
Treatment start 75 days pt
Natural infection
Begin of treatment
Worm recovery & analysis
Analysis: parasite numbers
length of females/males microfilariae counts
Patency
Randomization (weight, MF)
L4
Ad
L1
Murine model of filariasis: Litomosoides sigmodontis in mouse
u n tre atedE M O 2 5m g /kgE MO 12 ,5 m g/kgE MO 1m g /kg0
2 0
4 0
6 0
8 0
control 5x25 5x12.5 5x1 mg/kg
Nb
of re
cove
red
adul
t wor
ms
Mice infected with L. sigmodontis
25 mg/kg (3 days)
12.5 mg/kg (5 days)
1 mg/kg (5 days)
Reduction of adult worms compare to control group 73 % 82 % 72 %
Formulation Solution 100% capmul MCM Route of administration Oral gavage Readout 75 days post treatment
5 x 50 mg/kg dose was not tolerated
5 x 25 mg/kg was partially tolerated: 2 animals died
Linearity of the pharmacokinetic profile allows extrapolating key PK parameters for 1 mg/kg dose: Cmax = 84 ng/ml
AUC0-last = 1399 ng·h/ml
Adult worms
* * *
* = P< 0.05
Efficacy in mice
Exposure in mouse
MIC
Dose mg/kg 6 12.5 25 50
formulation 100% Capmul MCM clear solution
Cmax (ng/mL) 508 1038 1553 3093
Tmax (h) 12 5.33 20 12
T1/2(h) ND 35.1 ND ND
AUC0-last (ng·h/mL) 8396 16354 25775 53594
Conclusion
Comparable efficacy was obtained at all tested doses (25, 12.5 and 1 mg/kg) Reduction of adult worms is about 80%
Exposure of emodepside depends on the formulation PK parameters of efficacious doses in both mouse and the jird
model are approximatively in the same ballpark: Mouse
1 mg/kg (capmul solution) Cmax = 84 ng/ml AUC0-last = 1399 ng·h/ml
Jird 10 mg/kg (solutol suspension) Cmax = 195 ng/ml AUC0-last = 2612 ng·h/ml